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PURPOSE Oxaliplatin-based adjuvant chemotherapy in patients with stage III colon cancer (CC) for 6 months remains a standard in high-risk stage III patients. Data are lacking as to whether early discontinuation of all treatment (ETD) or early discontinuation of oxaliplatin (EOD) could worsen the prognosis. MATERIALS AND METHODS We studied the prognostic impact of ETD and EOD in patients with stage III CC from the ACCENT/IDEA databases, where patients were planned to receive 6 months of infusional fluorouracil, leucovorin, and oxaliplatin or capecitabine plus oxaliplatin. ETD was defined as discontinuation of treatment and EOD as discontinuation of oxaliplatin only before patients had received a maximum of 75% of planned cycles. Association between ETD/EOD and overall survival and disease-free survival (DFS) were assessed by Cox models adjusted for established prognostic factors. RESULTS Analysis of ETD and EOD included 10,447 (20.9% with ETD) and 7,243 (18.8% with EOD) patients, respectively. Compared with patients without ETD or EOD, patients with ETD or EOD were statistically more likely to be women, with Eastern Cooperative Oncology Group performance status ≥ 1, and for ETD, older with a lower body mass index. In multivariable analyses, ETD was associated with a decrease in disease-free survival and overall survival (hazard ratio [HR], 1.61, P < .001 and HR, 1.73, P < .001), which was not the case for EOD (HR, 1.07, P = .3 and HR, 1.13, P = .1). However, patients who received < 50% of the planned cycles of oxaliplatin had poorer outcomes. CONCLUSION In patients treated with 6 months of oxaliplatin-based chemotherapy for stage III CC, ETD was associated with poorer oncologic outcomes. However, this was not the case for EOD. These data favor discontinuing oxaliplatin while continuing fluoropyrimidine in individuals with significant neurotoxicity having received > 50% of the planned 6-month chemotherapy.

e18520 Background: Homologous Recombination deficiency (HRD) represents a distinct entity in OC. Clinical data suggest that treatment selection can be based on both BRCA1/2 mutations and bearing Genomic Instability Status (GIS). Testing for GIS is critical in order to expand patients’ pool for targeted treatment. Myriad my Choice, is currently the only FDA approved test that can detect HRD by assessing BRCA1/BRCA2 mutation and GIS status in OC tumor specimens using 3 biomarkers: loss of heterozygosity, telomeric allelic imbalance and large-scale state transitions. To address this need, HeSMO has initiated a national program to provide access to myChoice to newly diagnosed patients with high grade stage III/IV OC. Methods: Patients with newly diagnosed stage III/IV high grade OC were eligible to participate in this program. The specific performance characteristics of myChoice CDx assay were determined on FFPE tumor samples by the evaluation of a range of representative tumor BRCA1 and BRCA2 sequence variants (e.g. single nucleotide variants, insertions or deletions and variants in homopolymers), Large Rearrangements (e.g. deletions and duplications affecting single and multiple exons) and a representative range of GIS. The overall results are composed of two major components: GIS Status (positive or negative) and tumor (t) BRCA1/2 Status (positive or negative). The combined results form the basis of the overall interpretation of the myChoice CDx Myriad HRD Status. Results: From December 2020 to January 2022, 454 patients from all over the country were tested within this program. 220 patients (48.46%) had a positive GIS report and 179 (39.43%) had a negative one. Among GIS positive cases, 122 patients were tBRCAwt (26.87%) 78 patients were tBRCA mutated (17.18%) and 10 patients had suspected deleterious BRCA1/2 mutations (2.20%). Inconclusive was the report in 38 specimens (8.37%) and myChoice Lab failed to complete the analysis in 15 cases (3.30%). Furthermore, mutations were also detected in a number of other genes, including but not limited to, ATM, BRIP1, PALB2, RAD51C, RAD51D, FANCL, CHEK2. Conclusions: In our series, 48.46% of the patients with high grade OC tested as BRCA1/2 and/or GIS positive, in accordance with published data, underlying the clinical need to implement GIS testing in OC patients’ molecular evaluation. Apart from the significant implications for treatment possibilities in an expanded patients’ population, these results are important for cancer prevention. We strongly believe that our results will strengthen our efforts for reimbursement of such testing in high grade OC patients, and will serve as a roadmap for the establishment of local HRD testing solutions.

e18677 Background: Venous ThromboEmbolism (VTE), might be a challenge with a lot of negative consequences for patients with active cancer. VTE affects ongoing anticancer treatment, worsening morbidity and mortality, increases economic burden and escalates psychological distress. Incidence of VTE in patients with cancer reported 20%. Current guidelines recommend pharmacologic prophylaxis in ambulatory cancer patients with Khorana score ≥2. Methods: ACT4CAT is a prospective observational phase IV study conducted by HeSMO Greece, aiming to record the clinical practice of VTE prophylaxis in active cancer patients. Ambulatory patients who received thromboprophylaxis enrolled after signing informed consent. Study was approved by bioethics committee. Results: 691 patients from 19 oncology departments received thromboprophylaxis in 1st line 57.6%, 2nd line 14.8%, adjuvant 9.0% and neoadjuvant 7.5%. Age ≥65 found 55%, BMI≥30 17.5% and males 63%. Tumor types: gastrointestinal 45.4%, lung 25.8%, urological 11.6%, gynecological 6.0%, breast 4.2% and others 7.0%. High-Risk for Thrombosis Agents (HRTAs) received 87.2%, specifically: platinum agents (56.3%), antimetabolites (54.2%) and immunotherapy (12.1%). 54,5% of the anticancer agents had potential drug-drug interaction (DDI) with anticoagulation treatment. Thromboprophylaxis duration lasted 5.3±3.5 months. Main agents were: tinzaparin 89.6%, fondaparinux 6.0%, bemiparin 2.2%, enoxaparin 1.6%, apixaban 0.3% and rivaroxaban 0.3%. Intermediate thromboprophylaxis dose received 68% of patients, lower in adjuvant setting (45.2%), with a preference in metastatic cases (OR: 1.5 95% CI: 1.02-2.3, p = 0.026). 14 thrombotic events reported (efficacy: 98.0%, 95%CI: 96.6-98.8%) and 12 grade 1 bleeding (1.7%, 95%CI: 1.0-3.0%). Conclusions: Prevention of VTE in ambulatory patients with active cancer found effective and safe. Apart from the Khorana score, specific patient characteristics, metastasis, HRTAs and DDIs seemed that affect clinical decision for thromboprophylaxis mainly with LMWHs and often on intermediate dose regardless the clinical setting. Oncologists appeared informed that CAT is not negligible risk. Clinical trial information: NCT03909399. [Table: see text]

e15601 Background: The duration of adjuvant oxaliplatin-combination treatment in stage III colorectal cancer (CRC) patients is still debatable. Circulating Tumor Cells (CTCs) have been proposed as a potential markers for detection of micrometastatic disease. The aim was to compare the elimination rate of CTCs in patients treated with three- and six-months treatment with FOLFOX or CAPOX, in stage III CRC patients. Methods: Peripheral blood samples were collected from 132 patients at baseline, after three (for all patients) and after six months (for those under six months treatment). Surgical specimens were collected from all patients for the evaluation of their genetic profiling using Sanger sequencing (Ras/Raf) and fragment analysis (microsatellite instability status). The detection and number of circulating tumor cells (CTCs) were evaluated using double immunofluorescence and a real time-polymerase chain reaction assay, at all three time points. Results: Median age of the patients was 62 years, 59.8% were males, 92.7% had a colon/sigmoid tumor location, 24.4% had tumor on the right colon and 99.2% had a good performance status (PS). Of all patients, 44.3% and 55.7% were treated with FOLFOX and CAPOX, respectively; patients received treatment for three and six months, were equally distributed. KRAS, NRAS and BRAFmutations were detected in 41.5%, 2.1% and 12.8%, respectively; whereas MSI-High status was detected in 9.8% of the patients. CTCs were detected in 43.2%, 42.4% and 54.2% of the patients, at baseline, after three and six months of treatment, respectively. Both positivity rate ( p< 0.001) and absolute number of CTCs ( p= 0.022) were decreased between baseline and three months of treatment. Moreover, a significant increase was observed both on the positivity rate ( p= 0.053) and absolute number of CTCs ( p< 0.001) between three and six months of treatment. Following Cox regression analysis, BRAF status and the detection of CTCs are significantly correlated with decreased time to progression. Conclusions: To conclude, the current study indicates that 3 months of adjuvant treatment is at least as efficacious as 6 months in eliminating CTCs. However, the increase of both the rate and number of positive CTCs after three months of treatment might highlight the emergence of resistant cancer cell clones.

196 Background: The ESMO clinical practice guidelines recommend consideration of Immunoscore (IS) for risk assessment of early colon cancer patients. IS clinical performance was assessed in the SCOT and IDEA-HORG trials evaluating 3 vs. 6 months (3m vs. 6m) of mFOLFOX6 adjuvant chemotherapy in stage III colorectal cancer (CRC). Methods: 1,002 formalin-fixed paraffin-embedded (FFPE) tumor samples (762 from SCOT;240 from HORG) were collected, of which 851 were eligible for biomarker analysis. Eligible samples were classified into 2 groups using pre-defined cut-offs (IS-Low, IS- High) and the performance of IS to predict 3 year disease-free survival (3y-DFS) was evaluated. Results: IS was successfully assessed in 846 cases (99%). 615 (72.7%) samples were classified as IS-High (311 and 304 in 3m and 6m arm, respectively). No significant association between IS and patients’ gender, age, PS, BMI or primary tumour location was observed. However, a significant difference between IS-High (43.7%) and IS Low (57.1%) was observed in the proportion of high risk (T4 and/or N2) tumours (p=0.001). Patients with IS-High tumors had significantly longer 3y-DFS (79.4%, 95%CI: 75.9%-82.4%) compared to those with IS-Low tumors (65.0%, 95%CI: 58.3%-70.9%); adjusted hazard ratio (HR) 1.9 (95%CI: 1.46-2.46; p

11 Background: Six months of oxaliplatin-based adjuvant chemotherapy in patients with stage III colon cancer (CC) remains a standard in high-risk stage III patients. Early treatment discontinuation (ETD) could worsen the prognosis. In addition, there is current lack of data on the prognostic impact of early oxaliplatin only discontinuation (EOD). Methods: We studied the prognostic impact of ETD and EOD in patients with stage III CC who participated in 11 relevant clinical trials of the ACCENT and IDEA databases, where patients were planned to receive 6 months of adjuvant fluoropyrimidine plus oxaliplatin (FOLFOX or CAPOX). ETD was defined as discontinuation of treatment before 75% of cycles of chemotherapy. EOD was defined as discontinuation of oxaliplatin only, while continuing the fluoropyrimidine, before 75% of cycles of oxaliplatin. Association between ETD/EOD and overall survival (OS) and disease-free survival (DFS) was assessed by Cox model adjusted for prognostic factors. Results: ETD analysis included 10,444 patients (FOLFOX n = 7,033; CAPOX n = 3,411), with 20.9% of patients with ETD (17.8% with FOLFOX and 27.2% with CAPOX, p < 0.001). Out of 7,243 patients, 18.8% experienced EOD (17.4% FOLFOX versus 21.4% with CAPOX, p < 0.001). Compared to patients without ETD or EOD, patients with ETD or EOD were statistically more likely to be women, older, with higher ECOG-PS ≥ 1, and in addition for ETD, a Body Mass Index (BMI) < 18.5 kg/m2. In multivariate analyses, ETD was associated with a decrease in DFS and OS in the overall population (HR: 1.40 95%CI 1.23-1.58, p < 0.001 and HR: 1.51 95%CI 1.31-1.74, p < 0.001, respectively). The same pattern was present with FOLFOX and CAPOX regimen, and also in low-risk and high-risk groups for each regimen with the exception of the CAPOX regimen in the low-risk group for DFS and OS. By contrast, EOD was not associated with reduced DFS or OS in the overall population (HR: 1.10 95%CI 0.77-1.58, p = 0.6 and HR: 0.97 95%CI 0.62-1.52, p = 0.9, respectively), in the low-risk group (HR: 0.97 95%CI 0.56-1.66, p = 0.9 and HR: 0.97 95%CI 0.51-1.82, p = 0.9, respectively) and high-risk group (HR: 1.22 95%CI 0.74-2.02, p = 0.4 and HR: 1.05 95%CI 0.53-2.08, p = 0.9, respectively) and for all subgroups of regimen. Conclusions: In patients treated with 6 months of oxaliplatin-based adjuvant chemotherapy for stage III CC, ETD was associated with a decrease in DFS and OS. By contrast, EOD was not significantly associated with poorer outcomes. In case of relevant neurotoxicity during a 6 months schedule, these data are not in favor of continuing oxaliplatin beyond 75% of planned cycles of adjuvant chemotherapy, and demonstrate that fluoropyrimidines remain the cornerstone of adjuvant chemotherapy in localized CC.

3517 Background: Incidence of early-onset colorectal cancer (eoCRC, age < 50) is steadily increasing. Decisions on adjuvant treatment (adjTx) regimen and duration should consider tx adherence, toxicity (tox) and expected outcomes in a population with life-expectancy longer than late onset CRC (loCRC, age ≥ 50). Methods: Individual patient data from stage II/III patients (pts) from 6 randomised trials in the IDEA database were used to compare characteristics, tx adherence, and adverse events of eoCRC to loCRC. To reduce the confounder of non-cancer-related deaths due to age/co-morbidities, time-to-recurrence (TTR) and cancer-specific survival (CSS) were compared by stratified Gay k-sample test. 5-year cancer-specific mortality (CSM) rate were estimated by adjusted cumulative incidence function. 3-year relapse-free survival (RFS) rate were compared by stratified and adjusted COX models. Results: Out of 16,349 pts included, 1564 (9.6%) were eoCRC. Compared to loCRC, eoCRC had lower percent of male pts (51% vs 57%, p < 0.01) better performance status (PS0 86% vs 80%, p < 0.01), similar T stage distribution (% T1-3/T4: 76/24 vs 77/23, p = 0.97), higher rate of N2 disease (24% vs 22%, p < 0.01), more likely to complete pre-planned duration of adjTx (83.2% vs 78.2%, p < 0.01) and received a higher tx intensity especially with 6 month tx (mean oxaliplatin dose intensity 75% vs 72%, p < 0.01; capecitabine 85% vs 78%, p < 0.01; 5FU 85% vs 82% p < 0.01). Gastrointestinal tox was more common in eoCRC (any grade nausea 58% vs 45%, p < 0.01; any grade vomiting 22% vs 16%, p < 0.01); haematological tox was more frequent in loCRC (62% vs, 69%, p = < 0.01); any grade neuropathy rate was similar (75%). Significant interaction was found between age and T stage for TTR (p = 0.04). Clinical outcome estimates and comparisons are shown in Table. Notably, high risk stage III (T4/N2) eoCRC had significantly lower 3-y RFS rate (54% vs 64%, HRadj 0.74, p < 0.01). Conclusions: eoCRC have better tx adherence than loCRC, as expected. While in high risk stage II and low risk stage III, cancer-specific outcomes are not different, in high risk stage III young age is negatively prognostic and associated with significantly higher relapse rate and risk of CRC death; this is despite a higher administered adjTx-intensity, suggesting a more aggressive disease biology. Clinical trial information: NCT00749450 (SCOT); NCT00646607 (TOSCA); NCT01150045 (CALGB/SWOG 80702); NCT00958737 (IDEA France) [Table: see text]

e18803 Background: Cancer Associated Thrombosis (CAT) is an increasing challenge for oncology patients since oncologists sometimes are reluctant to mitigate the risk with thromboprophylaxis. Active cancer patients while receiving chemotherapy have a 7fold risk of thrombosis compared with no cancer patients. Anticoagulation holds a prominent place in prevention of CAT usually with Low Molecular Weight Heparins (LMWHs). Methods: ACT4CAT is prospective observational study conducted by HeSMO across Greece, aiming to record the clinical practice of CAT prophylaxis in patients with solid tumors. Ambulatory, high thrombotic risk, active cancer patients who received thromboprophylaxis enrolled after signing informed consent. Results: Preliminary results collected from 18 oncology departments. From 431 enrolled patients 322 (65.4%) had completed the study. Tumor types included: lung 28.8%, gastrointestinal 39.8%, gynecological 7.0%, breast 4.4%, urological 7.0% and others 20%. Majority of patients (88.2%) received High-Risk for Thrombosis Chemotherapy Agents (HRTCAs) such as platinum agents (55.9%), antimetabolites (44.7%) and immunotherapy (12.6%). In 1st line were 62.1%, 2nd line 18.4%, adjuvant 8.9% and neoadjuvant 2.4%. The following table depicts: age, gender, metastatic disease, Khorana score ≥2 and HRTCAs. All patients received thromboprophylaxis for 5.3±3.6 months with: tinzaparin 90.8%, fondaparinux 5.5%, bemiparin 1.5%, enoxaparin 1.2%, apixaban 0.5% and rivaroxaban 0.5%. Intermediate doses received 70.9% of patients regardless clinical setting (1st, 2nd, adjuvant & neoadjuvant: 70.2%, 79.2%, 51.3% and 70.0% respectively, p = 0.0254), although intermediate doses were used more in metastatic stages (OR:2.4 95%CI: 1.4-4.2, p = 0.0028). Nine thrombotic events reported (2.1%, 95%CI: 1.1-3.9%), irrespective of clinical setting but with a trend towards prophylactic doses. Eleven grade 1 bleedings reported (2.6%, 95%CI: 1.4-4.5%), despite clinical setting or dose used. Conclusions: Thromboprophylaxis in ambulatory active cancer patients with high thrombotic risk is safe and effective. Oncologists are alerted about CAT negative influences in cancer patients’ prognosis. Apart from Khorana score, factors such as metastases, use of HRTCAs and drug-drug interactions influence the clinical decision of thromboprophylaxis in active cancer patients mainly with LMWHs and quite often with intermediate doses regardless clinical setting. Clinical trial information: NCT03909399. [Table: see text]

e14135 Background: CAT is the 2nd leading cause of death in oncology patients and there is need for thrombosis management across the natural history of cancer because of its dynamic nature. Anticoagulant therapy is the cornerstone of prevention and treatment, since thrombosis interferes with cancer treatment, increases health care resource utilization, imposes emotional and economic burden. Methods: A prospective observational study conducted by HeSMO across Greece, aiming to record the clinical practice of CAT prophylaxis in patients with solid tumors. Ambulatory, high risk for thrombosis, active cancer patients who received thromboprophylaxis are enrolled after signing informed consent. Results: Preliminary results are collected from 17 oncology departments. From the 272 enrolled patients, 176 (64.7%) have completed second visit (3-4 cycles of anticancer treatment). Primary cancers included: lung 31.3%, pancreas 26.1%, colorectal 13.6%, gynecological cancers 10.2%, stomach 7.8%, bladder 6.3%, and others.75.6% of the patients had metastatic disease. 1/3 of the patients were smokers or ex-smokers, and 33% underwent surgery. Most of patients (65.9%) were at 1st line treatment and 17.6% at 2nd line. The vast majority (90.3%) were treated with High-Risk for Thrombosis Chemotherapy Agents (HRTCAs) such as cisplatin etc. Regarding Khorana score, 65.1% had ≥2. In particular, 86.7% of patients with Khorana score ≤1 received HRTCAs while 95.4% of patients with score = 2.All patients received thromboprophylaxis, specifically: 93.0% tinzaparin, 5.2% fondaparinux and 1.8% other (enoxaparin, bemiparin) with average duration 5.3±3.1 months. 67.1% of the patients received higher than standard prophylactic doses. 3 patients (1.7%) experienced thrombotic events (2 DVT and 1 PE). These 3 patients had metastases and were treated with HRTCAs. Five grade 1 bleeding events were reported (2.8%). Conclusions: Thromboprophylaxis of CAT is both safe and effective. Oncologists are alerted about CAT negative influences in cancer patients’ prognosis. Apart from Khorana score, factors such as metastases, use of HRTCAs along with drug-drug interactions, increase the LMWHs usage often in higher than prophylactic doses in CAT management. Clinical trial information: NCT03909399.

4004 Background: In overall population, IDEA pooled analysis did not demonstrate non-inferiority (NI) regarding 3y DFS in pts with stage III CC receiving 3m vs. 6m of adj FOLFOX/CAPOX. However, in pts treated with CAPOX (especially in low-risk pts), 3m of therapy was as effective as 6m. Results of OS and 5y DFS are reported. Methods: OS was defined as time from enrollment to death due to all causes. OS NI margin was conservatively set to be Hazard Ratio (HR) = 1.11, which is equivalent to: the maximum acceptable loss of OS efficacy, by shortening treatment to 3m, was half of the OS efficacy gained in MOSAIC trial (i.e., 2.26% absolute reduction in 5y OS rate). Pre-planned sub-group analyses included by regimen and risk group for both OS and 5y DFS. NI was to be declared if the one-sided false discovery rate adjusted (FDRa) NI p-value < 0.025. Results: With an overall median survival follow-up of 72 m (range per study, 62 to 84 m), 2584 deaths and 3777 DFS events among 12,835 pts from six trials were observed. Across 6 studies, 39.5% of pts received CAPOX (rate by study, 0% to 75.1%). Overall, the 5y OS rate was 82.4% (3m) and 82.8% (6m), with estimated OS HR of 1.02 (95% confidence interval [CI], 0.95-1.11; FDRa NI p, 0.058) and absolute 5-y OS rate difference of -0.4% (95% CI, -2.1 to 1.3%). Overall, the 5y DFS rate was 69.1% (3m) and 70.8% (6m), with estimated DFS HR of 1.08 (95%CI, 1.01-1.15, FDRa NI p, 0.22). HRs (95% CI) within subgroups see table. Conclusions: 5y OS rate reported in IDEA trials was higher than historical rates, regardless of duration of therapy. While overall survival in IDEA did not meet prior statistical assumptions for NI in overall population, the 0.4% difference in 5y OS should be placed in clinical context. OS and 5y DFS results continue to support the use of 3m adjuvant CAPOX for the vast majority of stage III colon cancer pts. This conclusion is strengthened by the substantial reduction of toxicities, inconveniencies and cost associated with shorter treatment duration. Clinical trial information: NCT01150045; 2009-010384-16; NCT00749450; ISRCTN59757862; 2007-003957-10; UMIN000008543; 2007-000354 . [Table: see text]

9594 Background: IMpower110 (NCT02409342) evaluated atezo (anti–PD-L1) monotherapy as 1L treatment in PD-L1–selected patients (pts) with metastatic NSCLC and met its primary endpoint with statistically significant and clinically meaningful OS benefit in TC3 or IC3 wild-type (WT; EGFR/ALK-negative) pts. PROs were prespecified endpoints to assess pt perspectives on overall clinical benefit. Methods: Pts were randomized 1:1 to receive atezo 1200 mg IV q3w (Arm A) or platinum-based chemo (Arm B; 4 or 6 21-day cycles). Arm B non-squamous pts received cisplatin (cis) 75 mg/m2 or carboplatin (carbo) AUC 6 + pemetrexed 500 mg/m2 IV q3w; Arm B squamous pts received cis 75 mg/m2 + gemcitabine (gem) 1250 mg/m2 or carbo AUC 5 + gem 1000 mg/m2 IV q3w. PROs were assessed by the EORTC Quality of Life Questionnaire Core 30 (QLQ-C30) and lung cancer module QLQ-LC13. Time to confirmed deterioration (TTD) in QLQ-LC13 lung cancer symptoms (secondary endpoint) and change from baseline (BL) in global health status (GHS), functioning and lung cancer symptoms (exploratory endpoints) were analyzed in TC3 or IC3-WT pts. Clinically meaningful change was defined as a ≥10-point deterioration from BL. Results: Completion rates at BL (atezo, n = 107; chemo, n = 98) were high in both arms for the QLC-C30 (90% atezo, 86% chemo) and the QLC-LC13 (89% atezo, 85% chemo), and remained > 80% at most visits. Mean BL scores for GHS, physical functioning, and role functioning were moderate, symptom burden was low, and all were similar in both arms. No differences in TTD were seen between arms for cough (HR, 0.98; 95% CI: 0.48, 2.03), chest pain (HR, 1.02; 95% CI: 0.47, 2.22), dyspnea (HR, 0.96, 95% CI: 0.57, 1.60), and 3-symptom composite score (HR, 0.92; 95% CI: 0.59, 1.44). Mean change in physical function from BL to wk 42 was modestly improved with atezo and greater than or similar to chemo. No clinically meaningful worsening in dyspnea, cough or chest pain was seen with atezo vs chemo. Mean change in cough and chest pain from BL numerically improved immediately after start of treatment and was maintained to wk 48 with atezo. Fatigue and nausea/vomiting scores numerically improved immediately with atezo and were maintained to wk 48. Conclusions: QLQ-C30 and QLQ-LC13 completion rates were high at BL and most study visits. TTD of lung cancer-related symptoms was similar in both arms, indicating pts’ low BL symptom burden was maintained for a similar duration. Pts receiving atezo vs chemo sustained numerical improvements in physical function and no worsening in lung cancer-related symptoms. Clinical trial information: NCT02409342 .

171 Background: Dysbiosis has been associated with diseases and is of a major public health importance. Can lead to the passage of viable bacteria, their products or their fragments from the intestinal lumen through the mesenteric lymph nodes and other sites, known as bacterial translocation. The aim of the study was to determine whether microbial translocation occurs in stage II/III-IV colorectal cancer (CRC) patients and evaluate the usefulness of blood PCR for diagnosis of such translocation. Also to correlate the presence of Toll-Like Receptor and Vitamin D Receptor polymorphisms with the detection of microbial DNA fragments in the blood of CRC patients. Methods: Peripheral blood was obtained from 397 CRC patients (adjuvant n = 202 and metastatic n = 195) and 32 healthy individuals. DNA from all subjects was analyzed using PCR for amplification of genomic DNA encoding 16S rRNA, β-galactosidase gene of E. coli, Glutamine synthase gene of B. fragilis and 5.8S rRNA found in C. albicans. Results: Significantly higher rates of 16S rRNA, β-galactosidase, Glutamine synthase and 5.8S rRNA detection was observed in the pool of CRC patients than the controls ( p< 0.001). All microbial DNA fragments detected were also significantly associated with the metastatic disease ( p< 0.001) leading to shorter survival rates ( p< 0.001). Moreover, individuals with the homozygous mutant alleles of either TLR or VDR gene polymorphisms had significantly higher detection rates of microbial DNA fragments. Conclusions: The detection of microbial DNA fragments in patients with CRC highlights the role of these microbes in cancer development, progression and therefore in patients’ survival.

3500 Background: The IDEA aimed to investigate whether a 3-month (3M) of oxaliplatin/fluoropyrimidines-based adjuvant chemotherapy (CT) is non-inferior to the 6-month (6M) in 3-year disease free survival (DFS) in stage high risk stage II and in stage III colon cancer (CC). Methods: HORG-IDEA randomized patients between 3M and 6M of CT with FOLFOX4 or CAPOX with primary end point the 3 years DFS (3yDFS). Results: In total 1121 patients, 413 with high risk stage and 708 with stage IIICC, were randomized between May 2009 and October 2015. The median follow-up was 67 (38-126) months. There were 79 DFS events (43 in 3M and 38 in 6M arm) in high risk stage II patients leading to 3yDFS rate of 82.7 and 83.4% for 3M and 6M, respectively (HR: 1.05; 95%CI: 0.68-1.63, p = 0.829). Similarly, 214 DFS events (161 in 3M and 153 in 6M arm) has been recorded in stage III patients, leading to a 3yDFS rate of 72.9% in the 3M vs. 74.1% in the 6M (HR = 1.06; 95%CI: 0.81–1.42, p = 0.622). For high risk stage II patients receiving FOLFOX4, 3yDFS rate was 76.7% in the 3M vs.79.3% in the 6M (HR = 1.21; 95%CI: 0.54–2.70 p = 0.641). For high risk stage II patients receiving CAPOX 3-year DFS rate was 85.4% in the 3M vs. 83.8% in the 6M (HR = 0.99; 95%CI: 0.59–1.67 p = 0.968). For stage III CC patients receiving mFOLFOX6, 3-year DFS rate was 71.5% in the 3M vs.77.3% in the 6M (HR = 1.18; 95%CI: 0.74–1.86 p = 0.479). For stage III CC patients receiving CAPOX 3-year DFS rate was 74.5% in the 3M vs. 74.7% in the 6M (HR = 0.99; 95%CI: 0.70–1.44 p = 0.991). Conclusions: The results of the HORG-IDEA study are in line with those of the global IDEA project, indicating that 3yDFS is depended on the administered adjuvant regimen, and the choice of regimen and duration should be personalized. Clinical trial information: NCT01308086.

e23150 Background: Cancer is associated with thrombosis due to different pathophysiological processes. CAT is the 2nd cause of death in oncology patients and can occur anytime during the natural history of cancer. CAT is not rare complication, can delay anti-cancer therapy and increase health systems costs. Methods: A prospective observational study (Greek Management of Thrombosis-GMaT) conducted by HeSMO in Greek Oncology units for two years aiming to record clinical practice of CAT management. Patients with active cancer who received CAT treatment or thromboprophylaxis were enrolled after signing informed consent. Results: 546 patients were enrolled from 18 oncology units. Primary cancers were: lung 23.9%, pancreas 13.3%, breast 7.6%, colorectal 8.9%, stomach 8.3%, ovarian 7.6% and other 30.5%. 120 patients received LMWH for Venus Thombo-Embolism (VTE) treatment (Group A) and 426 for thromboprophylaxis (Group B). Group A: 89/120 (74.17%) patients continued in 2nd year and 58.6% received CAT treatment (6.9±4.4 months). Only 2 had VTE recurrence in 2nd year (versus 3 in 1st year). 4/120 (3.33%) had bleeding events (grade 1) in 1st year while no bleeding events occurred in 2nd year. Group B: 345/426 (80.98%) patients continued in 2nd year. 126 (30%) had Khorana score ≥3 and 300 (70%) had Khorana score ≤2. In 2nd year, 123 (35.65%) received thromboprophylaxis (7.3±3.7 months) while 79.4% of them were initially treated with High Thrombotic Treatment Agents (HTTA: e.g. platinum, 5-FU) and 83.1% had metastatic disease. In 2nd year, 52.5% received LMWHs at prophylactic dose and 47.5% at therapeutic dose. Overall, 12 (2.82%) had thrombotic events whereas 4 were recorded in 2nd year. Notably, patients treated with therapeutic doses had lower probability to have a thrombotic event (OR: 5.8, 95% CI: 1.7 to 20.5, p < .05). Six (1.41%) bleeding events (grade 1) occurred in 1st year and one (0.81%) in 2nd year. Conclusions: LMWHs can be used for long term CAT management. Therapeutic LMWHs doses as thromboprophylaxis are safe and effective. Khorana score is a useful model for CAT risk assessment but some other factors such as disease stage and HTTA might be taken into account. CAT can occur anytime during the natural history of cancer. Oncologists should be aware about CAT and its negative influences in patients’ prognosis and quality of life.

e13141 Background: Lynch Syndrome is associated with germline mutations in Mismatch Repair (MMR) genes ( MLH1, MSH2, MSH6, PMS2). CRC patients whose tumors exhibit high-level microsatellite instability (MSI-H) have an increased probability of LS. Although the diagnosis of LS has important implications for the patient and the family, germline genetic testing is not reimbursed by the Hellenic Public State Healthcare Services. To address this need HeSMO conducted a national program to screen and diagnose CRC patients with LS. Methods: All patients with CRC were eligible. Assessment for LS involved initially screening tumor tissue for the presence of MMR deficiency, either via molecular MSI testing or via immunohistochemistry (IHC) to detect the absence of one or more MMR proteins. Patients with an MMR-deficient tumor in the absence of a somatic cause (e.g. BRAF mutation or MLH1 promoter hypermethylation) underwent genetic counseling and germline testing to confirm a LS diagnosis. Results: From June 2017 to December 2018, 104 patients diagnosed with CRC were enrolled and tested. Median age of diagnosis was 58,5 years (range 32 - 89) and male-to-female ratio was 1.6:1. Fifty patients (48%) had tumors that exhibited the MSI-H phenotype. From the MSI-H tumors, 41 (82%) did not harbor the BRAF V600E mutation and 33 of them (80.5%) did not harbor an MLH1 promoter hypermethylation. Therefore, 33 patients were invited for genetic counseling and testing. Fifteen patients (45.45%) were diagnosed with LS: 6 ( 40 %) had a mutation in MLH1 (one of which had also a mutation in PMS2 gene), 4 (26.6%) in MSH6, 4 (26.6%) in MSH2 and 1 (6.6%) in PMS2. Conclusions: In our series, 30% of the CRC patients with MSI-H tumors were tested positive for LS. These results confirm the value of a universal screening program of CRC patients for LS. Hopefully, these results will convince the Hellenic Public State Healthcare Services to reimburse screening and germline genetic testing of CRC patients for LS.

3501 Background: 6m of oxaliplatin-based treatment is an option as adj chemotherapy for patients with high risk stage II CC (T4, inadequate nodal harvest, poorly differentiated, obstruction, perforation or vascular/perineural invasion). The IDEA collaboration showed shorter treatment duration to be appropriate for most pts with stage III colon cancer. The results of the 4 IDEA studies with stage II pts are presented here. Methods: A prospective, pre-planned pooled analysis of high-risk stage II patients from 4 concurrently conducted randomized phase III trials (SCOT, TOSCA, ACHIEVE-2, HORG) was performed to evaluate non-inferiority (NI) of 3m compared with 6m (ref) of adj FOLFOX/CAPOX (regimen preselected, not randomized). The primary endpoint was disease-free survival (DFS), NI was to be declared if the 2-sided 80% confidence interval (CI) for DFS hazard ratio (HR 3m v 6m) estimated by a stratified Cox model was below 1.2. 542 DFS events were required to provide 80% power to declare NI. NI was also examined within regimen, T4 (Yes v No) and inadequate nodal harvest (Yes v No) as pre-planned subgroups. Results: The primary analysis included 3273 randomised pts of which 1254 had FOLFOX and 2019 had CAPOX. There were 552 events and the median follow-up was 60.2 m. There was significantly less grade 3-5 toxicity with 3m treatment (p < .0001). The 5-year DFS rate was 80.7% and 84.0% for 3m and 6m treatment with an estimated DFS HR of 1.18 (80% CI:1.05-1.31, p for NI = 0.404). For CAPOX the estimated HR was 1.02 (80% CI: 0.88-1.17, p for NI = 0.087) and for FOLFOX the estimated HR was 1.42 (80% CI: 1.19-1.70, p for NI = 0.894). The test for interaction between duration and regimen was not statistically significant (p = .174 adjusted for multiple testing) but was stronger than that for the other subgroups examined. Conclusions: In the overall population non-inferiority for 3m adj treatment in pts with high-risk stage II CC was not shown. As with the stage III population the choice of adj regimen appears important (although this did not reach statistical significance) with a small difference in DFS between 3 and 6 m treatment if CAPOX is used. Clinical trial information: ISRCTN59757862.

e20608 Background: Osimertinib is an irreversible EGFR tyrosine kinase inhibitor (TKI), selective for EGFR TKI-sensitizing mutations and the T790M resistance mutation. We sought to determine the activity of osimertinib after progression on EGFR TKIs in pts with T790-negative ctDNA. Methods: A multicenter phase II study ( clinicaltrials.gov NCT02771314) of osimertinib (80 mg daily) was conducted in pts with metastatic EGFRmt NSCLC, who had progressed after previous treatment with EGFR TKIs. Serial serum and/or plasma samples were drawn for ctDNA analysis at enrollment, 1 month and every 3 months of treatment, until disease progression. Efficacy outcomes in pts without the T790M mutation in ctDNA at baseline are reported. Results: Thirty-seven NSCLC patients with undetectable baseline T790M in the plasma have been enrolled. Median age was 67 years, 21.6% were male, and histology was adenocarcinoma in 100%. More frequent adverse events (grade 1/2) included diarrhea (12.5%), fatigue (12.5%), anorexia (12.5%) and acneiform rash (10.4%). The overall response rate (ORR) was 40.5% (95% CI, 24.7-56.4%) and the disease stabilization rate 37.8%; the median progression-free survival (PFS) was 8.9 months (range, 1.6-30), and the estimated median overall survival (OS) 26 months (range, 2.2-30). At enrollment, EGFR mutations del19 and L858R were detected in ctDNA in 9 and 3 pts, respectively. After one month of treatment with osimertinib, EGFR mutations in ctDNA were not detectable in 4/9 and 2/3 of pts with del19 and L858R at baseline, respectively. Pts without detectable EGFRm ctDNA at baseline remained negative throughout the study. Efficacy according to baseline ctDNA status was as follows: Clinical trial information: NCT02771314. Conclusions: Osimertinib was effective in EGFR TKI pretreated pts without EGFR T790M mutation in plasma. Pts with detectable del19 or L858R mutations in ctDNA before treatment had worse clinical outcomes, despite the elimination of EGFRmt ctDNA.[Table: see text]

3599Background: The IDEA collaboration pooled data from nearly13,000 patients (pts), comparing 3 vs. 6 months (m) of adjuvant fluoropyrimidine plus oxaliplatin to test noninferiority for disease-fr...

e18868Background: Cancer has multiple processes that increase thrombogenicity. Thrombosis is the 2nd cause of death in cancer patients. CAT is common, could delay anti-cancer therapy and increase c...

e13525Background: Most international scientific organizations and guidelines recommend genetic counseling and testing for women with epithelial ovarian cancer. Identification of BRCA1/2 mutation ca...

e15521Background: Bevacizumab (BEV) is an active antiangiogenic agent for the treatment of all patients (pts) with advanced colorectal cancer (CRC). We investigated the toxicity, compliance and sur...

730 Background: The IDEA international collaboration aimed to combine data from 6 randomized trials to investigate whether a 3-month (3m) of oxaliplatin/fluoropyrimidines-based adjuvant chemotherapy (CT) is non-inferior to the 6-month(6m) for 3-year disease free survival (DFS)in stage III colon cancer (CC). Methods: HORG-IDEA randomized patients between 3Mand 6M of CT with mFOLFOX6 or CAPOX. DFS was estimated using the Kaplan–Meier method and described using 3 years DFS rate. Results: In total708 patients were randomized between May 2009 and October2015, 354in each arm. Among them the basic characteristics was: median age 63.9 years; mFOLFOX6: 41.8% and CAPOX 58.2%, N1: 74.9%, N2: 25.2%; T1-3: 86.4%, T4: 13.6%. DFS median follow-up was 54.2 months. There were 214 DFS events (109in 3M and 105 in 6M arm) leading to a 3-year DFS rate of 73.2% in the 3M vs. 74.9% in the 6M (HR = 1.03; 95%CI 0.80–1.43, p = 0.622).For patients receiving mFOLFOX6, 3-year DFS rate was 71.8% in the 3M vs.77.7% in the 6M (HR = 1.18; 95%CI 0.74–1.88 p = 0.478). For patients receiving CAPOX 3-year DFS rate was 74.7% in the 3M vs. 74.8% in the 6M (HR = 0.99; 95%CI 0.69–1.45 p = 0.994).94.2% and 78.0% of pts completed 3 and 6 months of CT, respectively. Overall, 96.9% and 89.5% of patients completed 3 months (arm A) and 6 months (arm B) of CT, respectively. Median oxaliplatin doses intensity were 97.3% in 3M and 73.2% in 6M (505.0 and 738.3 mg/m2).Overall maximum neuropathy during treatment grade 2/3-4 was 23.9/5.9%in 3M and38.7/13.7%in 6M; p < 0.0001. In addition, worst grade 2/3-4 diarrhea was 11.1/4/0 in 3M and in 12.3/7.36M; p = 0.03. Conclusions: Since the HORG-IDEA study was designed in order to contribute patients in the IDEA project, the result on the study should be interpreted together with those of the whole IDEA project. Nevertheless, the results of the HORG-IDEA study are in line with those of the whole IDEA project, indicating that the results are depended on the administered adjuvant regimen, and the choice of regimen and duration should be depended on tumor characteristics and patient preference. Clinical trial information: NCT01308086.

LBA1 Background: Since 2004, 6 months (m) of oxaliplatin (oxali)-based treatment has been the standard of care as adjuvant therapy for stage III CC. Since oxali is associated with cumulative neurotoxicity, shorter duration of adjuv therapy could spare pts toxicity and lead to substantial saving in health expenditures. Methods: A prospective, pre-planned pooled analysis of 6 concurrently conducted randomized phase III trials (SCOT, TOSCA, Alliance/SWOG 80702, IDEA France (GERCOR/PRODIGE), ACHIEVE, HORG) was performed to evaluate the non-inferiority (NI) of 3m compared with 6m (ref) of adjuv FOLFOX/XELOX. The primary endpoint was disease-free survival (DFS), defined as time from enrolment to relapse, 2nd CRC, and death (all causes). NI was to be declared if the 2-sided 95% confidence interval (CI) for DFS hazard ratio (HR 3m v 6m) estimated by a stratified Cox model was below 1.12. NI was examined within regimen and stage subgroups as pre-planned. Results: The analysis included 12,834 pts from 12 countries, accrued from 6/07 to 12/15. Stage distribution: 13% T1-2, 66% T3, 21% T4; 28% N2; 40% received XELOX. G3+ neurotoxicity was higher in the 6m v 3m arm (16 v 3% FOLFOX, 9 v 3% XELOX, p

e23193 Background: Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and a tumor with broad spectrum of targeted therapies already available or in clinical trials. Thus, molecular characterization of the tumor using the Next Generation Sequencing (NGS) technology, has become a key tool for NSCLC patients’ treatment decision and clinical management. Methods: The performance of a custom 23 gene multiplex amplification hot spot panel, based on Ion AmpliSeq Technology, was evaluated for the analysis of tumor DNA extracted from FFPE (Formalin Fixed Parraffin Embedded) tissue. Furthermore the Ion AmpliSeq™ RNA Fusion Lung Cancer Research Panel was used for fusion RNA transcript analysis. Tumors’ mutation spectrum was determined in a cohort of 502 patients with NSCLC using the aforementioned targeted gene panels. Results: The panel used for tumor DNA analysis in this study exhibit high rates (100%) of sensitivity, specificity and reproducibility at a mutation frequency of 3%. At least one DNA mutation was detected in 374 patients (74.5%) and an RNA fusion was identified in 16 patients, (3.2%). In total, alterations in a cancer driver gene were identified (including point mutations, gene rearrangements and MET amplifications) in 77.6% of the tumors tested. Among the NSCLC patients, 13.5% (68/502) presented a mutation in a gene with approved targeted therapy (EGFR, ALK ROS1) and 9.4% had an alteration in a gene related to emerging targeted therapies according the NCCN guidelines. These alterations include ERBB2, BRAF and MET mutations, MET amplification and RET rearrangements. The remaining 51.6% of the patients had a mutation in a gene that could be related to an off label therapy or give them access to a clinical trial. Conclusions: Thus the NGS panel validated is a reliable approach of clinical applicability for tumor molecular profile detection in NSCLC patients.

740 Background: The International Duration Evaluation of Adjuvant (IDEA) collaboration was established to prospectively analyze data from six randomized trials to assess whether a 3-month course of oxaliplatin/fluoropyrimidines (FU)-based adjuvant chemotherapy (CT) is non-inferior to the 6-month current standard treatment in stage III colon cancer (CC). The primary endpoint of IDEA was 3-year disease-free survival. The accrual goal for the Greek IDEA study was 1.000 patients. Methods: Greek IDEA randomized patients with stage III colon cancer between 3 months (arm A) and 6 months (arm B) of adjuvant CT with modified (m) FOLFOX6 or XELOX (depending on physician/patient choice). Toxicity was graded during treatment and follow-up using NCI-CTCAE v3.0. Results: From May 2009 to October 2015, 708 patients were randomized in Greek centers either to arm A (n = 354, 50%) or to arm B (n = 354, 50.%). 297 (41.9%) patients received mFOLFOX6 and 411 (58.%) XELOX. The median age was 67 years (20-75) and 579 (81.8%) of them had PS 0. The patients’ population was balanced for the major risk factor between the two arms: N1/N2 disease (68.1/31.9% vs. 68.9/31.1 for ARM A and B, respectively), obstruction (4.5% vs. 2.5 for ARM A and B, respectively) and perforation (5.1% vs. 6.2 for ARM A and B, respectively). Overall, 96.9% and 89.5% of patients completed 3 months (arm A) and 6 months (arm B) of CT, respectively. Median oxaliplatin dose was 505 mg/m2 in arm A and 738 mg/m2 in arm B. Toxicity profiles were comparable between the two arm and the two fluoropyrimidines backbones with a total incidence of Grade 3/4 adverse events 18.9/4.4% and 19.7/5.1% for mFOLFOX6 and XELOX, respectively. Grade 2/3-4 peripheral neuropathy during the study was similar between arm A (33.9/4%) and B (38.7/3.7%). Conclusions: Both mFOLFOX6 and XELOX were safe. More patients completed the scheduled treatment in the 3-arm schedule.

e18202Background: The importance of continuous medical education in oncology is obvious. The aim of this study was to shed light on the current status in Europe and to identify any obstacles in car...

623 Background: Adjuvant trastuzumab in combination with chemotherapy improves outcome of women with HER2 positive early breast cancer. However, the optimal duration of treatment remains unknown. I...

44 Background: To evaluate the efficacy and safety of FOLFIRI plus CRT with 5FU as adjuvant treatment for patients with OGC. Methods: Patients received treatment with FOLFIRI (irinotrecan 150 mg/m2, d1, LV 200 mg/m2, d1+2 and 5FU [400 mg/m2/d bolus and 600 mg/m2/d, 22 h infusion, d1+2]) for 2 15-day cycles followed by RT (45Gy) with 5FU continuous infusion (325 mg/m2/d in the 1st and 5th week) administration. Eight additional cycles of FOLFIRI were administered after the completion of CRT. BRCA1, ERCC1, XPD, TOPO-I, TOPO-IIA and B and TS mRNA expression was determined in the primary tumor where available. Results: The median age of the 171 enrolled patients was 62 years, 114 (66%) were males, 136 (79%) had R0 resections and 152 (89%) had at least a D1 resection. Treatment was completed as per protocol in 107 (63%) of the patients. CRT was completed in all but 5 (3%) patients. The median rate of drug exposure was 93% for irinotecan, 87% for 5FU and 91% for LV. The most common grade 3/4 adverse events were neutropenia (32%), febrile neutropenia (3.5%) and diarrhea (7%). After a median follow-up of 45.7 months 84 had relapsed and 70 were deceased. The median disease-free survival (DFS) was 30 months (95% CI: 18-41 months), while the projected median overall survival (mOS) was 53.7 months (95% CI: 30-77 months). The recurrence free probability at 5 years was 44% while the probability of survival at 5 years was 46%. From the studied pharmacogenetic markers only TS low expression was correlated with a trend towards improved DFS and OS in patients with R0 resections. Conclusions: These results show that the administration of FOLFIRI plus CRT with 5FU as adjuvant treatment in OGC is a feasible approach with acceptable toxicity and challenging efficacy which merits further evaluation in a randomized trial. No significant financial relationships to disclose.

1134 Background: Bevacizumab in combination with several cytotoxic chemotherapy option has recently emerged as a standard treatment of HER2-negative metastatic breast cancer. This study tries to id...

7519 Background: To compare the efficacy of MTA and ERL as second-line treatment of patients with advanced/metastatic NSCLC. Methods: Pts were randomized either to MTA (500 mg/m2 on d1, every 3 wee...

1116 Background: Docetaxel (D) plus epirubicin (E) is highly active first-line therapy for metastatic breast cancer (MBC), with acceptable toxicity profile. The addition of bevacizumab (B) was inve...

4536 Background: To compare the efficacy and tolerance of two oxaliplatin-based regimens as first-line treatment of advanced gastric cancer. Methods: Chemotherapy-naïve patients with measurable recurrent or metastatic gastric adenocarcinoma, PS (ECOG) 0–2 and adequate organ functions were randomly assigned to receive either irinotecan 200mg/m2 and oxaliplatin 80mg/m2 (IO), every 21 days or oxaliplatin 85mg/m2 on day 1, 5-FU 400 mg/m2 (over 1 hour infusion) + 600mg/m2 (over 22 hours infusion) on days 1 and 2, leucovorin (LV) 200mg/m2 on days 1 and 2 (FOLFOX4) every 2 weeks. Study endpoints: Overall Response Rate (ORR), Toxicity Time to Progression (TTP) and Survival (S). Results: 138 patients were enrolled and all were evaluable for response. Median number of cycles administered was 5.5 (range 1–10) for IO and 7 (range 1–18) for FOLFOX4. In an intent-to treat analysis the ORR (RR+CR) was 29.4% for IO arm and 34.3 % for FOLFOX4 arm (p= 0.587). The median response duration was 5.63 months (mo) for IO arm and 6,6mo for FOLFOX4 arm. Median TTP was 4.2mo and 6,1mo for IO and FOLFOX4 arm respectively (p= 0.012). Median OS was 9.4mo for IO and 11.97mo for FOLFOX4 (p= 0.456). Toxicity was acceptable, with one toxic death in each arm. Grade 3–4 vomiting (7.3%), diarrhea (11.8%), neutropenia (22%) and febrile neutropenia (5.9%) occurred more frequently in IO arm, while anaemia (4.3%) and grade II neurotoxicity (11.4%) was more frequent in FOLFOX4 arm. Conclusions: Both regimens are well tolerated and active in advanced gastric cancer. Based on the TTP and toxicity profile, the FOLFOX4 regimen merits to be further evaluated in prospective phase III trials. No significant financial relationships to disclose.

e19035 Background: The optimal treatment of patients with advanced NSCLC and PS 2 is not well established. Our group has shown that single agent is equally effective to doublets. Purpose of this study was to compare efficacy and toxicity of two single agents Paclitaxel and oral Vinorelbine. Methods: 75 stage IIIb wet and IV chemotherapy-naïve for metastatic disease patients with PS 2 were randomized to either Paclitaxel 90mg/m2 weekly (group A: 36pts) or Vinorelbine 60mg/m2 weekly (group B: 34pts). Both agents were given for three weeks on and one week off. Results: A total of 70 out of 75 patients were eligible for analysis. All patient and disease characteristics were well balanced. Partial response rate (PR) was 14% (95% CI, 4.7%-29.5%) and 6% (95% CI, 0.7%- 19.7%) for groups A and B respectively. Stable disease (SD) was 17% (95% CI, 6.4%-32.8%) and 12% (95% CI, 3.3%-27.5%) respectively. These rates did not differ significantly. Median survival (OS) was 5.3m (95% CI, 3.1–7.5 m) and 3.5m (95% CI, 1.6 - 5.4 m) respectively (P=0.6). Progression free survival (PFS) was 3.2m (95% CI, 1.9 - 4.6 m) and 2.1m (95% CI, 1.8 - 2.3 m) respectively (P=0.2). There was a non-statistically significant trend for more myelotoxicity in the vinorelbine group. Conclusions: A trend for higher efficacy and less toxicity of Paclitaxel in comparison to oral Vinorelbine was observed, without however reaching statistical significance. No significant financial relationships to disclose.

8112 Background: To investigate the prognostic and predictive value of tumoral BRCA1, RRM1 and RRM2 in clinical outcome of patients with NSCLC treated with the DG regimen. Methods: Tumor samples fr...

658 Background: Both Vinorelbine plus Gemcitabine (VG) regimen and Capecitabine (C) monotherapy are active salvage treatments in patients (pts) with advanced breast cancer (ABC). In this multicenter study we compared the efficacy and tolerability of the two regimens as salvage treatment in pts with ABC pretreated with taxane and anthracycline chemotherapy. Methods: Pts were randomized to receive either vinorelbine 25 mg/m2 plus gemcitabine 1000 mg/m2 (VG) both on day 1 in cycles every 2 weeks or capecitabine 1250 mg/m2 (C) twice a day on days 1–14 in cycles every 3 weeks. The primary end point of the study was to compare the time to disease progression (TTP). Results: A total of 114 pts were randomized to VG (n=60) and C (n=54). All pts were evaluable for toxicity and 58 VG and 54 C pts for response. Seven (VG) vs 9 (C) pts had stage IIIB disease and 6 vs 5 pts had PS 2. We observed one complete response on each arm and 14(24%) vs 12(22%) partial responses for an overall response rate of 25.8% vs 24.1% (p=0.8) in VG vs C pts, respectively. The median duration of response was 5 vs 12 months (p=0.02) and the median TTP 3.7 vs 5.8 months (p=0.4) for VG and C pts, respectively. A total of 339 VG and 270 C cycles were administered with no toxic deaths. Both regimens were overall well tolerated; grade 3–4 neutropenia 17% vs 4% (p=0.02), anemia 4% vs 2% (p=0.6), grade 3 thrombocytopenia 2% vs 2%, neurotoxicity 3% vs 2%, grade 2–4 hand-foot syndrome 2% vs 15% (p=0.009) for VG and C pts, respectively. Conclusions: In this preliminary analysis the VG and C regimens showed similar activity but different although rarely severe toxicity. Updated results will be presented at the meeting. No significant financial relationships to disclose.

14574 Background: The GC combination has become a standard of care for advanced TCC. D has demonstrated broad single agent activity in many solid tumors including bladder cancer. We evaluated the safety and the activity of their sequential administration in patients (pts) with locally advanced or metastatic TCC who have not received prior chemotherapy. Methods: Chemotherapy-naïve pts with histologically proven locally advanced or metastatic TCC were enrolled. G 1100 mg/m2 was administered over 30-minutes IV on days 1 and 15, C 80 mg/m2 on day 1 with the adequate hydration and D 80 mg/m2 over 1 h on day 15. Results: From 4/2004–12/2005, 26 pts (25 male, 1 female), median age 65.5 years (range, 48–75), (PS 0/1/2: 16/8/2) were enrolled onto the study. The majority (19pts, 73.1%) had metastatic disease. A median of 4 cycles (range 1–9) was given for a total of 113 cycles. There were 12 delayed cycles due to toxicity and 15 dose reductions. Three (16.7%) complete responses (CRs) and 6 (33.3%) partial responses (PRs) [2 of them were converted to CR with additional surgery] were observed in 18 evaluable pts [overall RR of 50%; 95% CI 26.9%-3.1%]. The median time to progression was 7.9, and the months while median survival has not yet reached. The 1-year survival is 68.86%. Gr III-IV hematologic toxicity included neutropenia (61.5%), febrile neutropenia (11.5%), anemia (7.7%) and thrombocytopenia (7.6%). Non hematologic toxicity was mild (grade III vomiting and diarrhea in 7.7% and 3.8% of the pts, respectively). There was no neutropenic sepsis or toxic death. Conclusions: The sequential administration of cisplatin, gemcitabine and docetaxel is an active treatment for pts with advanced TCC. Toxicity is not manageable and this regimen warrants further investigation. No significant financial relationships to disclose.

7058 Background: PS:2 is an independent negative prognostic factor for patients(pts) with NSCLC. Most of the information about prognosis, response, survival and treatment options was obtained from subset analysis of large trials. Single agent chemotherapy has been proven superior to best supportive care on survival or quality of life. Purpose was to evaluate prospectively if the combination chemotherapy GCb has superior efficacy compared to single agent G in pts with advanced NSCLC PS:2. Primary end-point was clinical benefit. Methods: Pts received either G: 1250 mg/m2 every 14 days (Arm A) or G: 1250 mg/m2 and Cb: 3AUC every 14 days (Arm B). Both treatments were given in cycles of 28 days. Four were the maximum number of cycles. 102 pts were enrolled. Ten pts were non -eligible. Baseline demographics were comparable for both groups. Median age was 73 and 70.5 for group A and B, male 83% and 72%, stage IV 64% and 72%, two disease sites 36% and 40.5% respectively. Relative dose intensity for G was 76% and ...