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Cisplatin is the standard of treatment for squamous cell carcinoma of the head and neck (SCCHN) that has demonstrated efficacy, either in locally advanced disease when combined with radiotherapy at high doses, or in metastatic/recurrent disease when combined with other agents. However, the usual toxicities related to cisplatin, such as neurotoxicity, nephrotoxicity, ototoxicity, and hematologic toxicities, especially when high doses have been administered, have important implications in the patients’ quality of life. The decision to administer cisplatin depends on several patient factors, such as age, performance status, weight loss, comorbidities, previous toxicities, chronic viral infection, or even the current SARS-CoV-2 pandemic. In order to establish recommendations for the management of patients with SCCHN, a group of experts in medical and radiation oncology from Spain and Latin-American discussed how to identify patients who are not candidates for cisplatin to offer them the most suitable therapeutic alternative.

Objectives The prognostic impact of circulating tumor cells (CTCs) or circulating tumor microemboli (CTM) in locally advanced head and neck squamous cell carcinoma (LA-HNSCC) is yet to be determined, with conflicting results in previous trials. The role of induction chemotherapy (ICT) in the management of LA-HNSCC is controversial with no predictive biomarkers to guide treatment strategy in this scenario. The aim of this trial is to determine the prognostic impact of CTCs and CTM, their biomarkers expression by immunocytochemistry (ICC), and its potential role as predictors of ICT benefit in LA-HNSCC. Materials and Methods Prospective study, with newly diagnosed stage III/IV non-metastatic LA-HNSCC patients treated with curative intent. Blood samples analyzed for CTCs and CTM before treatment using the ISET method. Results A total of 83 patients were included. CTCs counts were an independent prognostic factor for overall survival (OS; HR: 1.17; 95 %CI: 1.05–1.31; p = 0.005) and progression free survival (PFS; HR:1.14; 95 %CI: 1.03–1.26; p = 0.007). Using the Lausen and Schumacher technique, 2.8 CTCs/mL for OS and 3.8 CTCs/mL for PFS were defined as the best cut-offs. CTM were detected in 27.7% of patients, correlating with worse PFS (HR = 2.70; IC95%: 1.30–5.58; p = 0.007). MRP-7 expression in CTM correlated with worse OS (HR = 3.49; 95 %CI: 1.01–12.04; p = 0.047) and PFS (HR = 3.62; 95 %CI: 1.08–12.13; p = 0.037). CTCs counts were predictive of complete response to treatment (OR = 0.74; 95 %CI: 0.58–0.95; p = 0.022) and high counts (cut-off 3.8/mL) and CTM were potential predictors of ICT benefit. Conclusion CTCs/CTM had significant prognostic impact and potential role as predictors of ICT benefit in LA-HNSCC.

Squamous-cell carcinoma of the head and neck (SCCHN) is an important problem in Brazil, where epidemiological and socioeconomic features often create barriers to the implementation of combined modalities with curative potential. Cisplatin improves the efficacy of radiotherapy in the adjuvant treatment of localized SCCHN and in the definitive therapy of locally advanced disease. However, the addition of high-dose cisplatin to radiotherapy increases treatment toxicity and is not always warranted. A panel of experts convened in Sao Paulo, Brazil, for discussions and recommendations regarding the use of high-dose cisplatin in combination with radiotherapy in SCCHN. In addition to discussing their professional experience, panel members used the current literature to provide evidence-based, practical recommendations regarding sociodemographic or medical criteria that may preclude safe administration of cisplatin. It is hoped that the application of these recommendations in clinical practice may improve therapeutic results in Brazil and other countries with similar health-care environments.

Head and neck cancer is a heterogeneous disease, comprising multiple subsites with diverse etiologic factors, pathology and molecular features, response to treatment, and prognosis. Systemic treatment is usually incorporated in the management of locally advanced head and neck squamous cell carcinoma, and the use of induction chemotherapy has theoretical benefits on reducing the risk of distant metastasis, provide an in vivo testing of response and tumor biology and the potential to allow a more personalized and less toxic local treatment after downstaging. The aim of this review is to access the role of induction chemotherapy in patients with locally advanced oral cavity cancer. Clinical trials analyzing this treatment strategy in patients with resectable disease, followed by surgery, and in unresectable disease, followed by (chemo)radiotherapy or surgery are discussed, pointing out strengths and limitations of this data and highlighting the standard treatment in each clinical scenario. Future perspectives, including the incorporation of checkpoint inhibitors and biomarkers for patient selection are discussed. Surgery followed by (chemo)radiation is the standard of care for resectable oral cavity cancer patients, and chemoradiation is the standard for those considered as unresectable. Future trials with the incorporation of immunotherapy and better patient selection based on clinical and molecular biomarkers can bring new hopes for better therapeutic results in these patients.

The clinical and biological heterogeneity of head and neck cancer (HNC) is paralleled by a plethora of different symptoms that affect the patient's quality of life. These symptoms include, for instance, pain, fatigue, nutritional issues, airways obstruction, voice alterations and psychological distress. In addition, patients with HNC are prone to a high risk of infection, and may also suffer from acute complications, such as hypercalcemia, spine compression by bone metastasis or bleeding. Prolonging survival is also an inherent expectation for all patients. Addressing the above needs is crucial in all patients with HNC, and especially in those with recurrent and/or metastatic (RM) disease. However, research on how to address patients' needs in RM-HNC remains scarce. This paper defines patients' needs for RM HNC and presents an Expert Opinion on how to address them, proposing also some lines of research.

e21533 Background: Combination therapy with anti-PD1 and low-dose ipilimumab has shown reduced rate of immune-related adverse effects compared with standard dose used in the Checkmates studies 067 and 204. However, the discussion whether low-dose ipilimumab may hamper the response rate in advanced melanoma is still open. Methods: We conducted a retrospective analysis of response evaluation based on 18F-FDG PET/CT for patients with advanced melanoma treated with combination of nivolumab 3mg/kg plus ipilimumab 1mg/kg for 4 cycles (N3+I1) followed by anti-PD1 maintenance therapy and compared the results to RECIST 1.1 response criteria in the same population. Results: Between December 2017 and August 2020, 45 patients with advanced melanoma treated with N3+I1 in first-line setting were identified. Unresectable stage III/stage IV were 2/43 patients, respectively. Among stage IV patients, 60.5% were M1c, 23.3% had elevated LDH and 28% had brain metastasis (3 or more brain lesions: 58%). At a median follow-up of 16.7 months, 11 patients (24.4%) had G3/G4 toxicity. During induction phase, three patients (6.6%) discontinued all drugs and 2 other patients (4.4%) interrupted only ipilimumab. Review of response evaluation by RECIST was possible in 36 patients and showed an objective response of 50%. Complete response (CR): 11% and partial response (PR): 39%. Eight percent presented progressive disease (PD). In 37 patients, review of response evaluation using 18F-FDG PET/CT was possible. Twenty-four patients (65%) achieved metabolic CR, 5 (13.5%) PD and 8 (21.5%) were classified as non-CR non-PD. Median progression-free survival (PFS) and overall survival(OS) were not reached. 12-month PFS and OS were: 72.5 and 89%, respectively. During the study follow-up, only 1 patient with metabolic complete response relapsed and 3 out of 8 with non-CR non-PD progressed. Conclusions: Using low-dose ipilimumab combination does not hamper the response rates and, possibly due to fewer protocol interruptions, these patients may achieve more complete responses as showed by 18F-FDG PET/CT evaluation.

Background Circulating tumor microemboli (CTM) are clusters of circulating tumor cells (CTCs), involved in metastasis, as also transforming growth factor-β (TGF-β). The purpose of this study was to verify their role in progression-free survival (PFS). Methods Blood from patients with locally advanced head and neck squamous cell carcinoma (HNSCC; n = 53) was analyzed in 2 moments. TGF-β receptor I (TGF-βRI) expression was evaluated by immunocytochemistry. Results Comparing CTM1 (baseline) with CTM2 (first follow-up), patients with CTM1-positive disease who became CTM2-negative were classified as favorable (PFS 20 months). Patients with unfavorable evolution (CTM1-negative/CTM2-positive), had PFS of 17.5 months. Patients always CTM-negative showed PFS of 22.4 months, those always positive, 4.7 months (P

There is no established biomarker for cetuximab efficacy in recurrent head and neck squamous cell carcinoma (HNSCC). The aim of the present study was to evaluate the prognostic and predictive impact of PTEN, cMET, and p16 expression in recurrent HNSCC. In this retrospective study, 112 patients with recurrent HNSCC received chemotherapy (CT) alone (n = 37) or chemotherapy with cetuximab (n = 75). PTEN, cMET, and p16 protein expression were evaluated by immunohistochemistry. The median overall survival (mOS) for the patients treated with cetuximab + CT versus CT alone was 11.4 months and 7.0 months, (p = 0.949). The median progression-free survival (mPFS) was 6.2 months versus 3.0 months (p = 0.154). Patients with PTEN loss exhibited a mOS of 5.8 months versus 10.5 months (p = 0.002) and a mPFS of 3.2 months versus 4.7 months (p = 0.019). A multivariate analysis identified an independent association between PTEN loss and OS (HR 2.27; 95% confidence 95% CI 1.27-4.08; p = 0.006) and with PFS (HR 1.85; 95% CI 1.09-2.99; p = 0.022). A negative prognostic impact of PTEN loss was observed in the patients treated with cetuximab + CT, and not in the CT only group. Expression of cMET and p16 showed no impact on OS or PFS. The present findings confirm that PTEN is a prognostic factor for metastatic HNSCC and they support further studies of PTEN expression to evaluate its predictive value to cetuximab response.

Despite multiple modalities used to management of head and neck squamous cell carcinoma (HNSCC), disease control remains unsatisfactory. Immunotherapy is emerging as a novel therapeutic approach. This systematic review assesses clinical data regarding immunotherapy efficacy and safety.Data from 11 clinical trials testing immunotherapy in HNSCC were assessed. We performed the meta-analysis to correlate the overall survival (OS), response rate (RR), adverse effects, HPV status, and PD-L1 expression.Immunotherapy extended OS (hazard ratio = 0.77, p 0.0001) and RR significantly (risk ratio = 1.41, p = 0.02). Patients with HPV-positive HNSCC exhibited a better RR (risk ratio = 1.29, p = 0.24) and OS (11.5 vs. 6.3 months). PD-L1 positive tumors showed a higher OS (9.9 vs. 6.5 months). Moreover, immunotherapy caused less adverse effects than standard therapy.Our results indicate the benefit of immunotherapy for improving RR and OS of HNSCC patients. The benefit is higher in patients with HPV and PD-L1 positive tumors.

e22045 Background: Immune checkpoint blockade (ICB) has changed the natural history advanced melanoma (AM) with response rates about 40% and overall survival in 5 years of more than 30%. Interestingly, the site of metastasis may have impact on immune response due to the quantity and quality of immune infiltrate as we have seen in patients (pts) with liver metastasis treated with ICB. We have hypothesized that bone metastasis(BM) represents an immune less responsive site of disease Methods: We conducted a retrospective observational analysis of patients with AM treated with ICB at A.C. Camargo Cancer Center (AC) in São Paulo, Brazil. We analyze the impact of BM on progression-free (PFS) and overall survival (OS) using Kaplan Meier method, log-rank test and time-dependent COX regression model. Results: We analyzed 170 pts with AM treated with anti-PD1 (79%) or anti-PD1 + anti-CTLA4 (21%) between September 2013 and December 2019. Fifty-five percent in first-line, 22.4% second-line and the remaining in third or more lines of therapy. Ninety- four were male (55.3%), median age of 60.5 years (24.8 to 88.3) and 61 (35.9%) pts had BRAF mutation. Among stage IV patients (94%), 52 (32.4%) were M1c, 36 (22.4%) M1d and 46 (27%) had elevated LDH. Forty-two (26%) pts had BM. The overall response rate was 30.9% for pts with BM compared to 57.7% for pts without BM (p:0.004). In a median follow-up of 23.6 months (95% CI: 18.0-29.1), the median PFS and OS for pts with and without BM were 3.8 x 18.8 months (p 0.005) and 19.4months x not achieved (p 0.001), respectively. The 24-month analysis shows an overall survival rate of 38% for patients with BM compared to 62% for the rest of the cohort population. In a multivariate analysis for overall survival, acral melanoma, elevated LDH, ECOG performance status of 1 or 2 and BM were independent adverse prognostic factors (bone metastasis - HR: 2.3; 95%CI: 1.18-4.1; p:0.013). Conclusions: In this analysis, the presence of bone disease seems to be a worse independent prognostic factor for survival. A hypothesis would be the unfavorable bone microenvironment for the action of the immunotherapy.

10046 Background: Immune checkpoint blockade (ICB) has changed the natural history advanced melanoma (AM). Based on phase III trial, which used RECIST criteria, the complete response (CR) rate with anti-PD1 therapy is around 20%. In daily practice, PET/CT is a useful tool to evaluate response to treatment in melanoma patients. Little is known about the number of patients who achieve metabolic CR by PET/CT but with anatomic residual disease and their prognosis. Methods: We conducted a retrospective analysis of patients with AM treated with ICB who achieved metabolic CR by PET/CT but with residual disease on tomography and compared to patients with RECIST CR in a high-volume cancer center. Progression-free (PFS) and overall survival (OS) were obtained by Kaplan Meier method and log-rank test. Results: One hundred seventy pts with AM treated with anti-PD1 (79%) or anti-PD1 + anti- CTLA4 (21%) betweenSeptember 2013 and December 2019 were analyzed. At a median follow-up of 23.6 months, seventy-five (44%) pts achieved CR. RECIST criteria: 22 pts (29.3%) and metabolic CR: 53 pts (70.7%). All patients with metabolic CR had RECIST partial response. The median total time on treatment was 14.8m (95%CI:0.9-42.3). The median time to reach CR was 5.4m (95%CI: 3-39). The median time of treatment after CR was 6.8m (95%CI: 0-21.4). The rate of CR patients off treatment at the moment of this analysis was 69%. The median follow-up after discontinuing treatment was 5.2m. There was no difference in PFS (36 month-rate: 84.4% vs 74%, p:0.64) and OS (36 month-rate: 100% vs 86.3%, p:0.14) between pts with CR based on RECIST or PET-CT, respectively. Median time for PFS and OS have not been reached until the date cut-off. Nine pts have relapsed (12%). Seven of them had residual disease on tomography but with no metabolic active lesion(s) at the time of the end of treatment. Conclusions: Twice more patients achieve complete response considering only metabolic parameters on PET/CT compared to RECIST criteria and they seem to have comparable prognosis.

e17545 Background: Androgen receptor-targeted agents Abiraterone and Enzalutamide (Abi/Ez) prolonged overall survival in metastatic castration resistant prostate cancer (mCRPC). Patients with very-low serum testosterone levels seem to have less benefit from these therapies as well as more aggressive prostate cancer. Methods: A retrospective observational cohort study was conducted to evaluate whether a serum testosterone measured at time of start first-line therapy with Abi/Ez is related to overall survival (OS) and time-to-treatment failure (TTF) in mCRPC patients. Kaplan-Meier survival estimates and Cox-regression models were used for time-to-event analyses. The best cut-off for testosterone was defined using Log-rank statistics (Lausen and Schumacher). X² test and Mann-Whitney U-test were applied to compare categorical and continuous variables, respectively. Logistic regression was used to assess characteristics related to serum testosterone levels. Statistical significance was fixed at 0.05. Results: From May 2012 to February 2017, 100 patients were assessed. Median follow-up was 27.8 months (range 2.23 to 68.26). Pts with a high testosterone level ( > 28.2; n = 20) achieved a significantly higher OS (median 66.0 vs 31.9 mo, testosterone > 28.2 HR: 0.206, 95% CI 0.074 to 0.571, p = 0.002) and TTF (median 30.6 vs 11.8 mo, testosterone > 28.2 HR: 0.408, 95%CI 0.219 to 0.762, p = 0.005) than pts with a low serum testosterone level ( < 28.2; n = 80), regardless of receiving therapy with either Abi (n = 69) or Ez (n = 31). Pts with a higher testosterone level were younger (median 67.7 vs 73.6 years; p = 0.026), had a higher body mass index (BMI) (28.5 vs 25.9, p = 0.023) and a lower PSA at start Abi/Ez (12 vs 26, p = 0.031) than pts with lower values. Age (OR 0.93, 95%CI 0.8 to 0.9, p = 0.021), BMI (OR 1.21, 95%CI 1.1 to 1.4, p = 0.006) and baseline PSA (OR 1.2, 95%CI 1.03 to 1.4, p = 0.020) were significantly associated with testosterone > 28.2. After 4 months of Abi/Ez treatment, PSA decrease > 50% of baseline was seen more frequently in high testosterone levels group than in low testosterone levels pts (90% vs 57.5% of pts, respectively, p = 0.007). Conclusions: Pts with high levels of testosterone ( > 28.2) achieved a better OS and TTF when treated with Abi/Ez in first-line mCRPC than those with low levels. Testosterone can be considered a prognostic and predictive biomarker in this scenario, and could be used in treatment decision for this population.

e17538 Background: mCRPC phenotype involves androgen-receptor signalling mechanisms that support the use of abiraterone/enzalutamide (Abi/Ez). These therapies improve overall survival (OS) and quality-of-life, with a favourable safety profile. There is no validated data defining the best drug or sequence to be used. Methods: A retrospective study evaluated if a nomogram helps the decision-making of first-line for mCRPC. The nomogram evaluated time-to-treatment failure (TTF) from Abi/Ez and Docetaxel (Doc) treatment and had C-índex of 0.726. Time from start of androgen deprivation therapy to Abi/Ez or Doc, pain, Gleason score, testosterone and the lowest PSA in castration-sensitive scenario were analysed. All patients (pts) in Doc group used second-line Abi/Ez. The outcomes were: to evaluate whether the nomogram scores were associated with TTF/OS in Abi/Ez population; to compare OS between Abi/Ez and Doc poor prognostic (PP) groups based on the nomogram scores. Kaplan-Meier and Cox-regression models were used for time-to-event analyses. The cut-off was defined by Log-Rank. Statistical significance was fixed at 0.05. Results: From May/12 to Feb/20, 123 pts were assessed (79 received first-line Abi/Ez and 44 Doc). Median follow-up was 25.7 months (1.6 to 93.7). Nomogram scores based on Abi/Ez treatment (medium score of 65, 0-225) were statistically associated with OS (HR 1.02, 95% CI 1.01-1.02, p < 0.001) and TTF (HR 1.02, 95% CI 1.02-1.03, p < 0.001). 79 pts who received Abi/Enz were stratified as having good (GP) (score < 46), intermediate (IP) (score 46-112) and PP (score > 112), and it was associated with 75%, 25-75% and 25% probability to 1-year free from treatment failure, respectively. Pts with GP (n = 24) had a median TTF of 29.8m (15.4-44.2), IP (n = 44) 9.8m (4.1-15.4) and PP (n = 11), 4m (2.5-5.5), p = < 0.001. Pts with GP achieved higher TTF than IP (HR 2.3 95% CI 1.3-4.2 p = 0.005) and PP (HR 8.9 95% CI 3.8-20.6 p < 0.001). The results were similar for OS, once the median for GP was 54.0m (30.5-77.6); IP 34.8m (32.2-37.5); and PP 13.6m (9.3-17.9), p = 0.023 (GP versus IP: HR 2.1 95% CI 1.01-4.4 p = 0.046; GP vs PP: HR 3.6 95%CI 1.4-9.6 p = 0.011). Pts with a higher score and PP from Abi/Ez group were compared with Doc pts at first-line (n = 44), showing worse OS (HR 2.4 95%CI 1.03-5.6 p = 0.042) when treated with Abi/Ez. Conclusions: The nomograns scores showed good correlation with TTF/OS. In PP groups, treatment with Doc was associated with better OS than Abi/Ez, suggesting a possible tool on the first-line decision making.

202 Background: Survival outcomes for metastatic castration resistant prostate cancer (mCRPC) patients (pts) have greatly improved following the approval of Docetaxel and abiraterone(Abi)/enzalutamide(Ez). However, it is not clear who is likely to benefit more from these therapies in real life clinical practice. Methods: A retrospective cohort study was performed with mCRPC pts treated with Abi/Ez in pre-Docetaxel setting. Primary endpoint: to identify predictive biomarkers of long time to treatment failure (TTF), develop a nomogram and convert it into a web app. Secondary endpoint: to correlate biomarkers with overall survival (OS). Kaplan Meier survival estimates and Cox Regression models were used for time-to-event analyses. Statistical analysis was made with R software. All statistical tests were two-sided and statistical significance was fixed at 0.05. Results: From May2012 to October2017, 117 pts were assessed, 81 received Abi and 36 Ez. Median follow-up of 21 months (mo), estimated median TTF was 12.8mo (95%CI 9.98-15.7) for the total population. Predictive biomarkers for TTF included in the first nomogram model were time from start of androgen deprivation therapy (tADT) to start of Abi/Ez, pain at baseline, Gleason score, baseline testosterone and lower PSA nadir in castration sensitive prostate cancer (CSPC). The second nomogram model included pain and Gleason plus neutrophil counts, tADT to CRPC and baseline PSA at CRPC. C-index: 0.726 and 0.731 respectively, providing a reliable prediction of long-term benefit with Abi/Ez in this setting. All these characteristics were significantly associated with OS. Conclusions: The two nomogram achieved a good internal validation and can work as a tool to the decision-making process of the best strategy to first-line therapy in mCRPC pts.[Table: see text]

Central giant cell granulomas (CGCGs) are benign lesions of the jaws. Surgical management may cause significant morbidity, and noninvasive therapies such as intralesional corticoid, calcitonin, and, more recently, denosumab have been used as an option. The study aimed to describe histopathologic characteristics of CGCGs treated by denosumab. A 39-year-old man was referred to treat a CGCG. The imaginological examinations showed an extensive osteolytic lesion affecting the left maxilla. Tumor board evaluation proposed systemic therapy with denosumab. Four doses of denosumab (120 mg) were administered during the first month followed by 2 monthly doses (Thomas, 2010). After 3 months, there was facial edema, and the patient refused follow-up. Surgical treatment was performed, and the histopathologic examination showed a granulation tissue in a central region and a formation of mature bone trabeculae in the periphery. Typical areas of CGCG were not observed. This report shows that denosumab inhibits the giant cells of CGCG.

The multi-armed bandit (MAB) problem is concerned with an agent choosing which arm of a slot machine to play in order to optimize its reward. A family of reinforcement learning algorithms exists to tackle this problem, including a few variants that consider more than one agent (thus, characterizing a repeated game) and non-stationary variants. In this paper, we seek to evaluate the performance of some of these MAB algorithms and compare them with Q-learning when applied to a non-stationary repeated game, where commuter agents face thetask of learning how to choose a route that minimizes their travel times.

6061 Background: The prognostic impact of CTCs in LAHNSCC is yet to be determined, with conflicting results in previous trials, the majority utilizing cytokeratin dependent techniques for identification and counting of CTCs. The primary objective of this study is to determine the detection rates using the ISET method, and the prognostic role of CTCs in LAHNSCC patients (pts) treated with a curative intent. Methods: In this prospective study, peripheral blood samples of pts with non-metastatic LAHNSCC, stages III/IV, were analyzed for CTCs using the ISET method, in two scenarios: curative surgical resection and adjuvant radiotherapy (CTCs before RT) and candidates for a non-surgical strategy (unresectable or organ preservation) either with upfront RT concurrent with chemotherapy (CT) or cetuximab (CTCs before RT), or preceded by induction CT (CTCs before ICT). Results: Eighty-three pts were included, the majority males (83%), with oropharynx primary (50%) and submitted to ICT (40%). The detection rate of baseline CTCs was 94% (78/83), and CTCs counts were significantly correlated with survival. For each increase of 1 CTC at baseline there was a relative increase of 18% in the risk of death (HR = 1.18; 95%CI: 1.06-1.31; p < 0.001), 16% in the risk of progression (HR = 1.16; 95%CI: 1.04-1.28; p = 0.004) and a reduction of 26% in the odds of complete response to treatment (non-surgical group only - OR = 0.74; 95%CI: 0.58-0.95; p = 0.022). Using the maximum of the standardized log-rank statistic proposed by Lausen and Schumacher we establish cut off points for overall survival (OS) and progression-free survival (PFS). Pts with CTCs < 6.5/ml had an estimated 2y OS of 85.6% versus 22.9% for CTCs ≥ 6.5/ml (HR = 0.18; 95%CI: 0.06-0.49; P < 0.0001) and pts with CTCs ≤ 3.8/ml had an estimated 2y PFS of 71.8% versus 37% for CTCs > 3.8/ml (HR = 0.32; 95%CI:0.15-0.67; p = 0.001). Conclusions: The detection rate of baseline CTCs using the ISET method was very high in LAHNSCC and the counts of CTCs were strongly correlated with survival and response to treatment.

e16540 Background: Metastatic castration-resistant prostate cancer (mCRPC) phenotype involves androgen-receptor signalling mechanisms that support the use of enzalutamide (EZ) and abiraterone (Abi). These therapies improve overall survival (OS) and quality-of-life, with a favourable safety profile. There is no validated data defining the best drug or sequence to be used. Methods: A retrospective cohort of mCRPC patients (pts) was analysed at AC Camargo Cancer Center. The primary objective was to compare progression-free survival (PFS) and OS in patients treated with EZ or Abi as first line (docetaxel naïve pts). Kaplan-Meier, Log-Rank Test and Cox Regression were used for survival analysis. To address unbalanced characteristics between the two treatment groups treatment efficacy was compared in a propensity score matched cohort. Results: From May, 2002 to September, 2017, 120 pts were treated with Abi (84%) or EZ (36%). Median follow-up was 21.2 months. Median age at diagnosis was 66 (48-84), the majority were Gleason score 7 (34%) and median baseline PSA was 14. Median PFS was 17.4 months in EZ and 10.6 months in Abi group (HR = 0.65; 95%CI: 0.39-1.10; p = 0.11). Median OS was not reached and 31.6 months for EZ and Abi, respectively (HR = 0.60; 95%CI: 0.27-1.36; p = 0.22). EZ was associated with a better PSA response in the first 4 months of treatment (p < 0.001). Independent prognostic factors for worse OS and PFS were ECOG ≥ 1, treatment toxicity ≥ G1 and lower PSA doubling time before treatment and for better OS and PFS were PSA response in the first 4 months and alkaline phosphatase and lactate dehydrogenase response at any time. In the propensity score matched cohort including 72 patients PFS was better in EZ group (HR = 0.36; 95%CI: 0.20-0.64; p < 0.001) but there was no difference in OS (HR = 0.66; 95%CI: 0.27-1.63; p = 0.37). Conclusions: EZ was associated with prolonged PFS and better PSA response, with no OS improvement when compared with Abi for mCRPC before docetaxel, in a propensity score matched analysis.

Traffic noise is gaining importance in planning and operation of roads in developing countries, and particularly in Europe and Latin America. Many variables with different degrees of importance influence the perception of noise from roads. Thus, the problem of prioritizing road stretches for action against such noise is an important issue in environmental noise management. For example, it can be addressed using multicriteria methods. However, these methodologies require criteria or suitable variables to be ranked according to their relative importance. In the present study, for this ranking, a list of nine variables involved in the decision-making process (called “road stretch priority variables”) was presented in the form of questionnaires to high-level experts from Andalusia, southern Spain. These experts ranked the variables by relevance. Using the same data, seven social choice functions (Plurality, Raynaud, Kemeny-Young, Copeland, Simpson, Schulze, and Borda) were used in order to rank the variables. The results indicate that the most important variables were those that take into account the parameters of greatest exposure for the citizens, followed by variables related to the intensity of the problem analyzed. The results show that a combination of the use of social choice functions on aggregated information from expert panels can provide a consensus for ranking priority variables related to road stretches.

Objective The objective of this study was to assess the clinical value of 18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) after the first cycle of induction chemotherapy (IC) in locally advanced squamous cell carcinoma of the head and neck (LASCCHN). Methods and findings A prospective, single-arm, single center study was performed, with patients enrolled between February 2010 and July 2013.Patients (n = 49) with stage III/IVA-B LASCCHN who underwent IC with taxanes, cisplatin, and fluorouracil were recruited. Staging procedures included loco-regional and chest imaging, endoscopic examination, and PET/CT scan. On day 14 of the first cycle, a second PET/CT scan was performed. Patients with no early increase in regional lymph node maximum 18F-FDG standard uptake value (SUV), detected using 18F-FDG PET/CT after first IC had better progression-free survival (hazard ratio (HR) = 0.18, 95%, confidence interval (CI) 0.056-0.585; p = 0.004) and overall survival (HR = 0.14, 95% CI 0.040-0.498; p = 0.002), and were considered responders. In this subgroup, patients who achieved a reduction of ≥ 45% maximum primary tumor SUV experienced improved progression-free (HR = 0.23, 95% CI 0.062-0.854; p = 0.028) and overall (HR = 0.11, 95% CI 0.013-0.96; p = 0.046) survival. Conclusions These results suggest a potential role for early response evaluation with PET/CT examination in patients with LASCCHN undergoing IC. Increased regional lymph node maximum SUV and insufficient decrease in primary tumor uptake predict poorer outcomes.

335 Background: Despite therapeutic progress in the management of advanced prostate cancer during the past decade, metastatic castration-resistant prostate cancer (mCRPC) remains a disease that causes substantial morbidity and mortality worldwide. A greater understanding of biomarkers permits to guide personalized therapy and can inform clinical trials tailored to men most likely to derive benefit from a given therapy. We aimed to identify prognostic biomarker candidates of Abiraterone Acetate (AA) response in mCRPC patients. Methods: A retrospective clinical records analysis of mCRPC patients treated with AA at A. C. Camargo Cancer Center between January 2012 to December 2016 was realized. Baseline clinical parameters evaluated were: Age, ECOG performance status, metastatic disease at diagnosis, Gleason score, prostate-specific antigen (PSA), Neuroendocrine differentiation, duration of previous androgen-deprivation therapy (ADT), PSA doubling-time (PSAdt), Timing of AA (chemotherapy-naïve or not), PSA response and alkaline phosphatase (ALP) level. Data were analyzed in relation to progression free survival (PFS) stratified by each parameter. Results: We included 141 patients with mCRPC treated with AA to correlate prognostic biomarkers with PFS. Five risk factors individually were associated with poor prognosis and a high risk to progression during AA therapy and were included in the final model: ECOG ≥2 [Relative risk (RR) = 1.52]; PSAdt < 3 months (RR = 2.7); PSA response ( < 50% decline) (RR = 3.03); AA post docetaxel (RR = 1.63) and duration of previous ADT < 12 months (RR = 1.52). The probability to progression free survival in patients receiving AA calculated in 1, 2 and 3 years, was 39,2%, 15,2% and 6,2%, respectively. Conclusions: This analysis identified five factors used to model survival in mCRPC patients treat with AA in our institutional series. Whereas no biomarker has been validated as a predictor of response to a therapy in mCRPC, these those potential clinical biomarkers may help clinicians in distinguishing patients with mCRPC who would obtain the best survival benefit from AA treatment.

In this paper we propose a strategy to use messages posted in a blogging platform for real-time sensing of traffic-related information. Specifically, we use the data that appear in a blog, in Portuguese language, which is managed by a Brazilian daily newspaper on its online edition. We propose a framework based on two modules to infer the location and traffic condition from unstructured, non georeferenced short post in Portuguese. The first module relates to name-entity recognition (NER). It automatically recognizes three classes of named-entities (NEs) from the input post (LOCATION, STATUS and DATE). Here, a bootstrapping approach is used to expand the initially given list of locations, identifying new locations as well as locations corresponding to spelling variants and typographical errors of the known locations. The second module relates to relation extraction (RE). It extracts binary and ternary relations between such entities to obtain relevant traffic information. In our experiments, the NER module has yielded a F-measure of 96%, while the RE module resulted in 87%. Also, results show that our bootstrapping approach identifies 1;058 new locations when 10;000 short posts are analyzed.

525 Background: TKI have improved the prognosis of patients with mRCC, but rarely lead to durable response. Predictive clinical biomarkers have been studied in the last few years, but most are still controversial. Objective: Identify the role of the clinical and laboratorial biomarkers of prognosis and outcome in mRCC. Methods: A retrospective study with mRCC treated with VEGFR-TKi in first line at A C Camargo Cancer Center (Jan-07 to Apr-16). Studied biomarkers: induced hypertension (HTN), acquiried hypothyroidism, proteinuria, and neutrophil to lymphocyte ratio (NLR). Data were analized in relation to progression free survival (PFS), overall survival (OS), and objetive response rate (ORR) stratified by each marker. Results: We included 94 patients (76.6% sunitinib, 21.3% pazopanib, 2.1% sorafenib). Overall, ORR to VEGFR-TKI was 41.1%; clinical benefit rate was 82.1% (43% Stable disease). Median PFS was 11.4 months (mo)(CI 95% 8.7-14.1) and median OS was 32.1 mo(CI 95% 23.4-40.8). HTN was numerically associated with longer PFS (20.1 vs. 8.2 mo) and OS (37.2 vs. 28.2 mo), but not statistically significant. Only high level TSH (>10) was associated with significant longer PFS and OS, p=0.001 and paweek) predicted poor OS (9.6 vs 33.9 mo). A “NLR conversion” (before ≥3, turn to

e23067Background: Much is currently known about the role of circulating tumor cells (CTC) in diverse types of cancer. CTCs in metastatic (m) colorectal (CRC), breast and prostate cancers determine ...

Oncological liver surgery and interventions aim for removal of tumor tissue while preserving a sufficient amount of functional tissue to ensure organ regeneration. This requires detailed understanding of the patient-specific internal organ anatomy (blood vessel system, bile ducts, tumor location). The introduction of computer support in the surgical process enhances anatomical orientation through patient-specific 3D visualization and enables precise reproduction of planned surgical strategies though stereotactic navigation technology. This article provides clinical background information on indications and techniques for the treatment of liver tumors, reviews the technological contributions addressing the problem of organ motion during navigated surgery on a deforming organ, and finally presents an overview of the clinical experience in computer-assisted liver surgery and interventions. The review concludes that several clinically applicable solutions for computer aided liver surgery are available and small-scale clinical trials have been performed. Further developments will be required more accurate and faster handling of organ deformation and large clinical studies will be required for demonstrating the benefits of computer aided liver surgery.

There are few data that show pathologic complete response (pCR) to imatinib treatment in gastrointestinal stromal tumors (GISTs). We describe a case of a patient with pCR of a pelvic, locally advanced, high-risk GIST who was treated with neoadjuvant imatinib and ultimately underwent a conservative procedure. A 48-year-old male presented with a pelvic mass 10 cm in diameter. Biopsy revealed a gastrointestinal stromal tumor of rectal origin. Although it was considered initially resectable, an extensive procedure would have been necessary for complete resection. Treatment with imatinib was initiated, resulting in partial response. The patient remained on imatinib for over 15 months, maintaining stable disease. Radical prostatectomy with anal sphincter preservation was performed. Pathological report revealed no viable neoplastic cells. The use of imatinib was held for 6 months after the surgery. At a follow-up 15 months after surgery, the patient had no evidence of disease. Our report may help to guide future studies of neoadjuvant imatinib for large pelvic or rectum GISTs that are initially considered unresectable.

e17057 Background: The majority of head and neck cancer (HNC) cases will be locally advanced (LA) at presentation, and currently there are different options of treatment for these patients like upf...

6017 Background: Response to IC with triplet regimens adding taxanes to cisplatin and 5-fluorouracil (TPF), followed by chemoradiotherapy (CRT) for LASCCHN, is usually evaluated after 2 cycles of IC, based on bidimensional WHO or modified WHO criteria. Concerns regarding toxicity profile of TPF suggest a potential benefit of an early response evaluation approach that could select patients who would be spared from a toxic regimen and promptly started on an alternative treatment. The aim of this study is to assess the ability of evaluating early response after the first IC cycle based on a 40% decrease in standard-uptake value (SUV) measured by 18 FDG PET-CT on the 14th day. Methods: Patients with LASCCHN who underwent IC with TPF were prospectively evaluated. Staging procedure included locoregional and chest imaging, endoscopic examination and FDG PET-CT. At day 14 of first cycle, a second FDG PET-CT was performed and treating physicians were blinded for these findings. All cases were conducted according to the usual post-cycle 2 WHO or modified WHO criteria evaluation. Written informed consent was obtained from all recruited patients. Results: Between February 2010 and October 2012, 40 stage III/IV LASCCHN patients (34 oropharyngeal, 3 hypopharyngeal and 3 laryngeal) were recruited. With a median follow up of 11.4 months the actuarial 2 years overall (OS) and disease free survival (DFS) of all patients were 81.4% and 69.2%, respectively. Responders (any decrease of SUV) at day 14 PET CT had a better OS (90 vs. 27% - p

e16046 Background: Since the results of the RTOG 9111 trial, cisplatin based chemoradiation (CRT) has been the standard of care for LP in advanced laryngeal SCC. Recently, the role of taxanes in managing head and neck SCC has been studied. In 2002 we reported the interim results of a phase II clinical study designed to test the efficacy of P and C concurrent with RT for organ preservation in advanced L and HP SCC. Here we report the long term survival and LP rates. Methods: Eligible patients had untreated advanced L and HP SCC, stage T3N0 or higher and suitable for radical total laryngectomy. Treatment consisted of weekly P (30 mg/m2) and C (20 mg/m2) concurrent to RT up to 7040 cGy in 180 cGy/day fractions. Response evaluation was performed at 5040 cGy and at 4 weeks after completing RT. Salvage surgery was planned for patients not responding at 5040 cGy, residual tumor at the end of RT or at the time of local recurrence. Neck dissection was planned for clinically positive neck (cN1-3). Results: Between 06/1999 and 10/2001, 48 patients were enrolled in a single institution (35 L; 13 HP), 40 male and 8 female with a 58-year median age (39-74). The majority had T3 (64%) N1-3 (52%) disease and 38% needed tracheostomy prior to treatment. Grade (G) 3 and 4 mucositis was noted in 27% of patients, G 3-4 odynophagia in 50%, G 3-4 radiodermatitis in 35% and G 3-4 leucopenia in 13%, with no treatment related death. Two patients needed salvage surgery, one after 5040 cGy and one after 7040 cGy. The complete response rate to treatment was 95%. At a median follow up of 66 months the LP rate at 2 and 5 years were 88% and 54%, respectively. Recurrence free survival (RFS) was 51% at 2 and 47% at 5 years and overall survival (OS) was 81% and 52% at 2 and 5 years, respectively. Conclusions: The finding of similar LP rate and survival compared to the recent reports of high dose cisplatin CRT and neoadjuvant 3 drug CT followed by CRT in an advanced disease population suggests a role for platinum plus taxane as a radiosensitizer regimen in this scenario with acceptable toxicity, but further evaluation in a direct comparative trial with the standard regimen is needed.

e15133 Background: The role of palliative resection of the primary tumour in patients who present with metastatic colorectal cancer (mCRC) is unclear. Most recently bevacizumab has been used as first line treatment for mCRC showing improvement in survival with a slight increase in the risk of bleeding and rarely gastrointestinal (GI) perforation. These side effects would cause concern in patients with unresected colorectal cancers (CRC). Methods: Retrospective analysis of twelve patients treated straightaway by chemotherapy (CT) and bevacizumab without primary tumour resection, between January 2007 and August 2008. The aim of the study was to evaluate the rate of complications related to the unresected colorectal tumour and to determine the safety of bevacizumab use in this situation. All of these patients had none or minimal symptoms related to the primary tumour. Results: Mean age 54.6 years (range 28–75), 5 males and 7 females, all patients ECOG 0. The sites of the primary lesion were the rectum in 8 patients (66.6%), the left sigmoid colon in 3 (25%), and the transverse colon in 1 (8.3%). Eight patients (66.6%) presented with rectal bleeding at diagnosis (mild). The mean interval between diagnosis and start of CT was 40,8 days (range 6–125). The total number of bevacizumab cycles was 151 (mean 12,5 cycles, range 4–37). First line CT was FOLFOX-6 in 66% and FOLFIRI in 33% of patients. Only 3 patients (25%) developed low GI bleeding, all grade 1, without bevacizumab interruption. None of them developed intestinal perforation or obstruction. Two patients (16.6%) developed grade 1 epistaxis and 1 (8.3%) grade 2 hypertension. No other complications were observed in a mean follow up of 9.3 months. Conclusions: Our data show that upfront chemotherapy with bevacizumab in patients with unresected primary CRC and synchronous metastases is safe. No major complications related to the primary tumour were observed. Although our data comes from a limited number of patients there is a lack of prospective controlled trials in the literature on this topic. Therefore, in select cases, a non-operative management of asymptomatic or minimal symptomatic mCRC could be advised, even with the use of anti-angiogenic therapy. No significant financial relationships to disclose.