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188 Background: Our previous phase I/Ib study revealed modest clinical efficacy of rego/nivo in refractory MSS-CRC, implying benefits in selected populations. This has prompted us to investigate predictive biomarkers. Methods: Pre-treatment tumor samples from the previous phase Ib rego/nivo study were obtained and assessed for mRNA sequencing (RNAseq). Response-associated transcripts were identified using DESeq2 method and annotated using gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis. Results: A total of 19 pretreatment tumor samples were analyzed including 14 patients (pts) with disease control (DC) (2 partial response and 12 stable disease) and 5 pts with progression disease (PD). We observed significant upregulation of 89 genes including SFTPB ( P

427 Background: Gastric and esophageal cancers (GECs) together account for a significant global burden in terms of new diagnoses and deaths. Over the last several years, the utility of ctDNA has ranged from estimating tumor burden and characterizing the genomic landscape of tumor biology and response to therapy in the metastatic setting to detection of minimal residual disease (MRD) and cancer surveillance in the locally advanced setting. We have previously studied the role of a commercial ctDNA assay for MRD detection and surveillance in locally advanced GECs. Herein, we present our experience with the same ctDNA assay in advanced stage settings for GECs. Methods: In this retrospective analysis of real-world data obtained from commercial circulating tumor DNA (ctDNA) testing, 53 patients with recurrent/ metastatic esophageal cancer were analyzed. A total of 216 plasma samples were collected between 10/29/2008 and 08/23/2022. The patients were divided into 3 cohorts: Cohort A (N=30) included patients with stage II/III disease who had confirmed clinical recurrence (R). Cohort B (N=25) included recurrent and Stage IV patients who achieved a state of no evidence of disease (NED) on imaging. Cohort C (N=5) included recurrent and Stage IV patients who transiently achieved NED on imaging. A personalized, tumor-informed multiplex PCR-based next-generation sequencing assay (Signatera) was used to quantify ctDNA either postoperatively, on adjuvant or palliative therapy, or during active surveillance. Results: Of 53 patients, 30 patients with recurrent stage II/III esophageal cancer had ctDNA status available postoperatively within 150 days of confirmed clinical recurrence. Cohort A: Among these cases, 25 patients were ctDNA-positive ahead of clinical recurrence (sensitivity 83.3%) with a median of 31 days (range: 1-147 days). Cohort B: Next, we explored the correlation between ctDNA status and imaging, wherein, 96% (24/25) of patients showed a significant correlation between ctDNA status (positive or negative) and disease status by imaging (Fisher exact test p=0.0001). Of the 23 patients, 17 patients were ctDNA-negative and showed NED on imaging (negative predictive value of 100%; 17/17). Cohort C: 100% of patients (N=6) who demonstrated recurrent disease on imaging after NED were ctDNA-positive prior to imaging (positive predictive value of 100%). Conclusions: Our data demonstrate the utility of ctDNA in accurately predicting disease progression and support the potential use of ctDNA to inform treatment decisions or prompt early radiographic imaging. ctDNA may ultimately supersede traditional radiographic surveillance with the advantage of being minimally invasive and cost-effective in monitoring patients during/post-treatment.

429 Background: Gastroesophageal cancers (GECs) are the 2nd highest cause of cancer mortality globally. Biomarkers such as MMR, PD-L1, and HER2 are critical for treatment strategies. Emerging biomarkers in late-stage clinical development include FGFR2b. Approximately 30% of GECs express FGFR2b, which is associated with a poor prognosis. FGFR2 amplification ( FGFR2amp) is seen in a subset of patients and may be particularly responsive to FGFR2-targeted approaches. We sought to elucidate the genomic landscape of FGFR2ampGECs using a ctDNA platform. Methods: We retrospectively queried the Guardant Health database from 2017-2022 for patients with advanced GECs who had ctDNA NGS (Guardant360, Redwood City, CA) performed as part of clinical care. Co-alterations were evaluated for patients who harbor FGFR2amp vs those without FGFR2amp detected via ctDNA. Fisher’s exact test was used for group comparisons. Results: Approximately 7100 patients met the diagnosis criteria. FGFR2amp was detected in 263 patients (3.7%). The majority were males (66 and median age in the cohort of FGFR2amp patients was 66 years (range 22-81 yrs). Most amps were high (+++) in gastric and GEJ (plasma CN≥4) and more frequently observed in patients who are tested at diagnosis (44%) vs progression (19%) (p=0.0147). The mean VAF across samples with high-level FGFR2amp is 22.42%. Patients with FGFR2amp were enriched for EGFR co-occuring amplifications and cell cycle pathway alterations. CDH1 was frequently mutated in pts under 50 who harbor FGFR2amp (p=0.0028). Thirty nine percent of patients with FGFR2amp were also found to harbor a gene fusion and 14% of patients with FGFR2amps harbored an activating fusion in FGFR1/2/3. Conclusions: FGFR2 is a validated target in GECs, and the contexture of FGFR2amp will be important to defining patient subgroups with responses to FGFR2-directed therapy. Here we define the FGFR2amp landscape which may help inform future combination strategies for this emerging biomarker.[Table: see text]

228 Background: We previously conducted a phase I/Ib study with regorafenib and nivolumab in patients with refractory metastatic mismatch repair proficient (pMMR) colorectal cancer (CRC). This study aimed to investigate the biomarkers that predict the treatment response. Methods: Out of the 51 patients who received regorafenib and nivolumab, 22 archival pretreatment tumor samples were subjected to the Xerna TME Panel, a machine learning-based RNA-sequencing biomarker assay and were classified into one of four TME biomarker subtypes: Angiogenesis (A), Immune Active (IA), Immune Desert (ID), or Immune Suppressed (IS). Potential predictive biomarkers including the TME subtypes, KRAS (wild type vs mutant), PD-L1 (negative vs. positive, samples with > 1% tumor cells for PD-L1 were considered positive), CD8 expression (low vs. high), and Treg cells (low vs. high) in tumor microenvironment were evaluated for correlation with overall survival (OS), progression free survival (PFS) and disease control rate (DCR, defined as complete response + partial response + stable disease). Results: Among the 22 patients, 16 (72.7%) had liver metastasis and 15 (68.2%) had lung metastasis. KRAS mutation was found in 16 (68.2%) patients. 11/21 (52.4%) were positive for PD-L1. 12 (54.5%) had high CD8 expression, whereas 9/21 (42.9%) had high Treg cells in tumor microenvironment. Ten (45.5%) patients were classified as biomarker-positive (IA + IS subtypes) and 12 (54.5%) were biomarker-negative (A + ID) based on Xerna TME panel. Two (9.1%) patients achieved partial response, 12 (54.5%) had stable disease, and five (22.7%) developed progressive disease. The median PFS was 5.6 months and median OS was 13.1 months. No significant correlation was observed between RAS mutation (p = 0.664, p = 0.609), PD-L1 expression (p = 0.287, p = 0.173), CD8 (p = 0.152, p = 0.456) and PFS or OS. Low Treg was found to be associated with prolonged PFS (median: 9.8 vs. 1.9 months, p = 0.011) but not OS (p = 0.280). Similarly, only low Treg level was related with DCR (83.3% vs. 33.3%, p = 0.032). While not reaching statistical significance, Xerna TME biomarker-positive patients showed trends for higher median PFS (7.9 months vs. 4.1 months, p = 0.254), median OS (15.75 months vs. 11.9 months, p = 0.378), and higher DCR (70% vs. 58%, p = 0.675) compared to biomarker-negative patients. Additionally, the two patients with partial responses were Xerna TME biomarker-positive. Conclusions: Our study demonstrated that low Treg in tumor microenvironment is correlated with better prognosis in patients with refractory metastatic pMMR CRC who were treated with regorafenib plus nivolumab. Xerna TME panel analysis of these patients also showed trends for predictive clinical benefit. Prospective and larger cohort studies are needed to better define predictive biomarkers for this combination in the future.

347 Background: Zanidatamab (zani) is an anti-HER2 bispecific antibody against ECD4 and ECD2 with demonstrated activity and tolerability in a range of HER2-expressing cancers. This Phase (Ph) 2 study (NCT03929666) evaluates zani in combination with chemotherapy (chemo) as first-line treatment for patients (pts) with advanced HER2-expressing mGEA. Methods: Eligible pts for this ongoing, open-label study had not received any prior systemic therapy for mGEA. Pts received zani + physician’s choice of multi-agent chemo (mFOLFOX6, CAPOX, or FP). Antidiarrheal prophylaxis for cycle 1 was added after the first 25 pts were treated. Following demonstration of tolerability of the regimens in an initial safety cohort, the primary study objective was to evaluate antitumor activity. Results: Pts were enrolled between Aug 29, 2019 and Feb 18, 2022 with a data cutoff of July 28, 2022 (N=46 pts; zani + mFOLFOX6 [24], zani + CAPOX [20], or zani + FP [2]). Median age was 58 yrs; 85% male; 42 pts (91%) had HER2+ tumors (IHC 3+ or 2+ with ISH-positivity) based on central testing. Median duration of follow-up among all 46 pts was 21.5 months (mo) and 20 pts (43%) remain on treatment. In 38 response-evaluable pts with HER2+ tumors, confirmed objective response rate (cORR) was 79% (95% CI: 63-90%) and disease control rate was 92% (95% CI: 79-98%); 3 pts achieved complete response. Median duration of response (DOR) was 20.4 mo (95% CI: 6.8-not estimable [NE]), with 57% (17/30) pts having an ongoing response at data cut-off (1 pt has ongoing response >29 months). In all 42 pts with HER2+ tumors, median progression-free survival (PFS) was 12.5 mo (95% CI: 7.1-NE) and median overall survival (OS) was not yet reached. Survival rate at 18 mo was estimated to be 87.3%. The most common (≥25% pts) treatment-related (zani and/or chemo) adverse events (TRAE) in all pts were diarrhea, nausea, peripheral sensory neuropathy, decreased appetite, fatigue, vomiting, and hypokalemia. Diarrhea was the most common Gr3+ TRAE, lasting a median (interquartile range) of 3 (2-5) days, with the majority of events occurring in cycle 1; incidence of all Gr3+ events was 56% in 25 pts who did not receive prophylaxis and 14% in 21 pts who did. There were no treatment-related deaths. Conclusions: In pts with HER2+ mGEA, zani + chemo is a highly active treatment regimen with a manageable safety profile. This maturing data set demonstrates durable disease control with encouraging cORR, DOR, PFS and OS results. A global Ph 3 study (HERIZON-GEA-01; NCT05152147) evaluating zani in combination with physician’s choice of standard chemo with or without the PD-1 inhibitor, tislelizumab, for first-line treatment of advanced HER2+ mGEA is currently enrolling. Clinical trial information: NCT03929666 .

3028 Background: OBT076, an Antibody Drug Conjugate (ADC) consisting of a fully human IgG1 antibody conjugated via a cleavable linker to the derivative microtubule inhibitor DM4. It has specificity for the CD205/Ly75 target antigen which is an endocytic receptor overexpressed on the cell surface and immunosuppressive dendritic cells. This phase 1 study evaluates safety, tolerability, PK/PD and preliminary efficacy of OBT076 in solid tumor patients with high expression of target protein CD205 (CAP-CLIA validated centralized IHC test). Methods: Open label, two parts trial in patients with metastatic CD205+ve solid tumors who progressed on standard therapy. Part 1 of the study consisted in dose escalation from 1.6 mg/kg to 3.5 mg/kg. An mTPI design is used to guide to determine the maximum tolerated dose (MTD) Treatment was given on day 1 every 3 weeks followed by GCSF on day 8. Blood samples and flow cytometry were used to assess PK/PD. Tumor response was assessed every three cycles. Part 2 of trial is an expansion basket trial enriched in indications where preliminary efficacy has been shown. Results: The study completed Part 1 dose escalation. Part 2 expansion phase is ongoing. Between Dec 2019 and January 2022, 20 patients were enrolled (18 patients in the dose escalation and 2 in the ongoing expansion). The median age 61, 9 patients were males and 9 had ECOG PS 0. All patients had at least one metastatic site and 90% received at least 2 lines of chemotherapy in the metastatic setting. Recommended dose for the expansion phase is 3.0 mg/kg. No other significant side effects have been observed. PK data showed that Cmax of 40.000-90.000 ng/ml was achieved between 2.5 and 3.5mg/kg dose and is comparable to the therapeutic dose in mouse models. In part 1 of the study, 7 patients derived clinical benefit despite being in disease progression at trial entry. One patient with gastric cancer with linitis plastica experienced major improvement with complete disappearance of ascites and metastatic adenopathy after cycle 3. The six other patients had lasting stable disease and received between 5-14+ cycles with median of 5 cycles. Two patients with low PD-L-1 expression received checkpoint inhibitor treatment with pembrolizumab after 2 and 5 cycles of OBT076, both patients experienced near complete response after only one to two cycles. Conclusions: OBT076 at 3.0mg/kg has shown favorable safety profile with manageable neutropenia. The preliminary efficacy has shown preliminary antitumoral single agent activity in gastric, ovarian and lung cancer. The two patients who received a sequential administration of pembrolizumab after OBT076 showed major tumor activity. Sequential administration of OBT076 followed by a PD-1 inhibitor was also supported by PD markers and warrants further evaluation. Clinical trial information: NCT04064359. [Table: see text]

255 Background: With the advent of immunotherapy as an option for gastric, gastroesophageal junction (GEJ), or esophageal cancer, guidelines recommend testing for mismatch repair (MMR) or microsatellite instability (MSI) and programmed death-ligand 1 (PD-L1) at time of advanced cancer diagnosis. However, little real-world information is available on testing patterns and results for MMR/MSI and PD-L1. Methods: This study used the nationwide Flatiron Health electronic health record-derived de-identified database. Starting with a subset of 1594 patients (pts) from the Advanced Gastric/ Esophageal Cancer database who had initiated first-line (1L) treatment 01Jan2017-31Aug2020 and for whom additional abstraction for details on MMR/MSI and PD-L1 testing was conducted, adult pts with ≥3 months (mos) of follow-up were selected. 1L initiation was index date. For each biomarker, pts were classified as tested vs not. Pt and disease characteristics and test results were summarized. Testing relative to line of therapy and PD-1 inhibitor use were evaluated (data will be presented later). Results: Of 1142 eligible pts, 88% were initially diagnosed with advanced disease and 92% treated in community practice. 582 (51%) were tested for MMR/MSI and 571 (50%) for PD-L1; 451 pts were tested for both. MMR/MSI testing rates were 59% for gastric, 51% for GEJ, and 46% for esophageal. PD-L1 testing rates were similar across primary tumor sites (48-54%), but lower in those with squamous histology (38% for esophageal/GEJ). For both, testing increased over time with ̃40% in 2017 and 60% in 2020. For both, median number of tests per pt was 1 (range 1-6 for MMR/MSI, 1-4 for PD-L1). For both, mean time from initial diagnosis to first test was approximately 4 mos (> 5 mos in pts in 2017 and < 2 mos for those in 2020). Majority (> 68%) of all tests used tissue from primary tumor site. 46% of all MMR/MSI tests were performed with immunohistochemistry and 43% with next-generation sequencing; 5% were dMMR/MSI-H. 71% of all PD-L1 tests were performed using the commercial 22C3 assay. Reported composite positive score (CPS) results are summarized below. Conclusions: Rates of MMR/MSI and PD-L1 biomarker testing are increasing and time relative to initial diagnosis is shortening. A high proportion of pts tested positive for PD-L1 with CPS > 1. PD-L1 CPS varies by primary tumor site, histology, and tissue collection site. In the new era of 1L immunotherapy, increased rates of testing and reduced time to testing are likely to make more meaningful impact on treatment decisions.[Table: see text]

341 Background: Brain metastases from esophageal cancer are extremely rare with an estimated incidence of 1.7% but limited survival. Some reports highlight the rich microvascular density of such tumors and their distinctive degree of HER2, HIF1-a and EGFR expression, further emphasizing the potential role of angiogenesis in their neurotropic behavior. With this in mind, we aimed to illustrate the transcriptomic landscape of brain metastases from esophageal cancers and better understand the disease biology. Methods: Following IRB approval, we collected retrospective data on patients with a diagnosis of esophageal cancer with histology-proven brain metastases treated at our institution between 2008 and 2020. We identified 10 adequate, paired samples with available tissue for RNA extraction. Expression data was generated using NanoString TS 360 panels to characterize gene signatures of interest and analyzed using GSEA_4.1.0. Results: All 10 patients were Caucasian, 90% were male. Median age was 63 years. All had adenocarcinoma with G2-G3 histology. Median follow-up was 39.4 mos (95%CI, 27.4 to 51.4). At data cutoff, 6 patients had died. Median OS was 24.6 mos. Median time from curative surgery to CNS recurrence was 8.3 mos. Ninety percent of patients developed brain metastases within 24 mos of surgery. Median time from brain metastases to death was 4.7 mos. Almost a third of patients had HER2 positive disease. 48 gene signatures were analyzed; 5 being significantly enriched between metastatic and primary site accounting for cell cycle, DNA damage repair, MYC, mTOR signaling and immortality and stemness. Out of a pool of 760, significant overlap was seen between 12 genes across the 5 signatures of interest: POLE, LIG1, FEN1 (involved in DNA repair and replication); AURKA and PLK1 (cell proliferation and triggers for G2/M transition), BUB1 (establishment of the mitotic spindle checkpoint and chromosome congression), MCM2 and MCM4 (initiation of genome replication); BRIP1 and RAD51 (critical in homologous recombinational repair); CCNE1 (cell cycle G1/S transition) and WRAP53 (dual role as p53 regulator and protein involved in telomere elongation and DNA repair). ERBB2 was similarly enriched in primary and metastatic sites. Conclusions: These preliminary data demonstrate that the genomic basis of brain metastases in esophageal cancer goes beyond EGFR/ERBB2 signaling. A complex genomic interaction is present in brain metastases as compared to primary site that offers these cells the advantage for neurotropism. To our knowledge this is the first study attempting to illustrate genomic differences between primary and matched brain metastasis sites in esophageal cancer.

355 Background: Perioperative chemotherapy is the standard of care for locoregional gastric cancers in western populations. However, the impact of response to therapy as a biomarker of cancer survival has not been fully defined. This study focuses on the pathological response to neoadjuvant chemotherapy, as measured by tumor regression grade (TRG), for gastric cancer and its impact on patient outcomes, primarily overall survival. Methods: Patients undergoing gastrectomy for nonmetastatic invasive gastric adenocarcinoma following perioperative chemotherapy (clinical T2+/N+cM0) were identified from an institutional database (2000-2021). Demographics, clinical staging including histologic grade, surgical factors and survival outcomes were included. The association between TRG and overall survival from time of surgery was assessed. OS was estimated using the Kaplan Meier method with adjustment for covariates using Cox regression. Results: One hundred seventeen patients were identified. Median age was 65 years (IQR 57–73). The majority of the patients were male (n = 64, 55%). Seventy-six patients underwent total gastrectomy, 22 subtotal gastrectomy, and 19 distal gastrectomy. Six patients (5.1%) had a TRG of 0, 18 patients (15.4%) had a TRG of 1, 25 patients (21.4%) had a TRG of 2, and 68 patients (58.1%) had a TRG of 3. Median survival overall was 40.9 months (95% CI 28.7–66.4). TRG status was not significantly different between chemotherapy regimens (doublet vs triplet, p = 0.96). Median survival was longest in the TRG 0 group (86.9 months), followed sequentially by TRG 1 (74.5 months), TRG 2 (51.5 months), and lastly, TRG 3 group with 27.0 months. Increased tumor regression (lower TRG) was significantly associated with prolonged survival (p < 0.01 by log-rank for trend). After adjustment for clinical patient factors and tumor factors, TRG remained significantly associated with overall survival (Table; TRG hazard ratio 1.62, p = 0.007). In addition to TRG status, clinical T4 tumors and diffuse histology were associated with poor survival (cT4 hazard ratio 2.09, p = 0.039, diffuse histology hazard ratio 1.82 (p = 0.071). Conclusions: In patients receiving perioperative chemotherapy for treatment of gastric cancer, response to therapy as defined by TRG is independently prognostic of survival.[Table: see text]

302 Background: The RAINBOW trial established the standard of care for treatment of metastatic GEAs with ramucirumab and paclitaxel after failure of fluoropyrimidine and platinum-based chemotherapy. While the combination achieved an objective response rate (ORR) of 28%, the incidence of any grade neuropathy was 46%. Therefore, there is an unmet need for novel treatment combinations that minimize the long-term toxicity of neuropathy. In a recently published Asian study, the combination of RAM+TAS-102 showed good disease control and acceptable toxicity profile. Methods: This was a single arm, single institution phase II trial using the combination of TAS-102 plus RAM in refractory GEAs. Patients (pts) received RAM 8mg/kg intravenously on day 1 and 15, and TAS-102 35mg/m2 orally twice daily on days 1-5 and days 8-12 every 28-day cycle. The primary endpoint was 6-months overall survival (OS) rate and secondary endpoints were progression free survival (PFS), ORR and safety profile. The trial was registered at www.clinicaltrials.gov (NCT03686488). Results: At data cut-off of August 15, 2021, 23 pts were enrolled. Baseline demographics are as follows: median age of 62 years (range: 23-74), median lines of prior therapy of 1 (1: 14 pts vs ≥2: 9 pts) and location of primary tumor (GEJ:19 vs GC: 4). 6-month OS rate was 56.2%. Median OS was 6.2 month (95% CI: 5.4-7.0) and median PFS was 4.9 months with median observation of 2.3 months. Of 17 evaluable pts defined as more than one baseline imaging, 1 (6%) had partial response (PR) and 15 (88%) had stable disease (RECIST v1.1). Eleven pts came off the study due to progression of disease, 8 for toxicities and 4 for consent withdrawal. Most common treatment-emergent adverse events (TEAEs) were diarrhea (39%), fatigue (39%) and hypertension (39%). Total 11 pts (48%) experienced grade 3 and 4 TEAEs, and most common Gr3 and 4 TEAEs were neutropenia (17%) and anemia (13%). Conclusions: The combination of RAM and TAS-102 showed very similar disease control rate as the study in Asia. The combination has now shown modest activity in advanced GEAs and should be investigated further now in the context of patients receiving immunotherapy-based treatment as first-line treatment. A randomized phase II study is currently enrolling patients with ramucirumab and TAS-102 or paclitaxel. Clinical trial information: NCT03686488.

284 Background: Ramucirumab, a humanized monoclonal antibody targeting VEGFR2, is used for treatment of metastatic gastroesophageal adenocarcinoma after disease progression on first-line chemotherapy. Superior survival outcome is expected when combined with paclitaxel. However, many patients suffer from chemotherapy-induced peripheral neuropathy after oxaliplatin-containing first-line treatment and are unable to tolerate paclitaxel. Irinotecan has shown survival benefit as a single agent or in combination with other agents for treating gastroesophageal cancer, but has not been evaluated with ramucirumab. We hypothesized that the combination regimen of irinotecan and ramucirumab administered as second-line treatment for advanced gastroesophageal adenocarcinoma will be better tolerated than ramucirumab and paclitaxel with similar clinical efficacy. Methods: The primary objective of this multi-institutional, single-arm phase 2 clinical trial is to determine the progression-free survival (PFS) after disease progression on up to one line of cytotoxic chemotherapy. Secondary objectives include objective response rate, overall survival, time to progression, and clinical benefit; and to evaluate toxicity and tolerability. Patient-derived xenograft and organoid models generated in a subgroup of patients. Investigation of blood-based angiome profiling and cell-free DNA are planned. Patients received 8 mg/kg ramucirumab with 180 mg/m2 irinotecan IV every 14 days. A sample of 40 achieves 85.7% power at a one-sided significance level of 5% to detect a median PFS of 4 months compared to historic control of 2.5 months assuming the accrual time of 12 months and additional follow-up of 12 months and using a one-sample log rank test. NCT03141034. Results: Forty patients were enrolled from four institutions from December 2017 through May 2021. All patients received platinum-based chemotherapy prior to enrollment, 8 patients had HER2 positive disease, and 6 patients had received an immune checkpoint inhibitor. As of September 2021, median follow up time was 7.7 months. Median PFS was 4.6 months (95% CI 2.7 – 5.4). Of 31 patients evaluable for response, 9 patients (29%) had objective responses (1 complete response, 8 partial responses) and 5 patients (16%) had stable disease greater than 6 months. Diarrhea, nausea, vomiting, and neutropenia were common adverse events; no G3/4 neuropathy was reported. Patient-derived organoid and xenograft models were generated from 9 patient samples, treated in vitro to correlate with each patient’s disease response. Conclusions: Ramucirumab and irinotecan appears to be effective and well-tolerated in patients with previously treated gastroesophageal adenocarcinoma. This regimen is now part of standard guidelines and could be a preferred option for patients after disease progression on first-line chemotherapy. Clinical trial information: NCT03141034.

TPS4157 Background: GEA remains incurable and novel therapies are needed. Studies have shown that cytotoxic chemotherapy can enhance antigenicity of tumors, leading to the recent practice changing studies that demonstrate checkpoint inhibition therapy combined with chemotherapy in PD-L1 overexpressing patients significantly improves patient survival (Keynote-590 and Checkmate-649). But long-term use can also subsequently dampen the immune response. Moreover, the stop-and-go strategy with chemotherapy can maintain patient survival while minimizing chemotherapy related side effects when compared to the traditional strategy of continuous chemotherapy. These observations prompted the inception of this trial with the hypothesis that a short course of FOFLOX therapy combined with immunotherapy will likely have similar activity to that of continuing FOFLOX until disease progression when combined with immunotherapy. We also will examine the hypothesis that low dose radiotherapy can further augment immunotherapy efficacy. Methods: This is a multicenter, randomized phase II study examining Nivo alone vs radiation therapy (RT) with Nivo in subjects who did not have disease progression with 3 months of FOLFOX + Nivo. Subjects with advanced unresectable or metastatic GEA cancer are eligible. All subjects will receive FOLFOX + Nivo therapy. Subjects who demonstrate at least stable disease, on their first imaging assessment at 2 months will receive 1 additional month of FOLFOX + Nivo, and then will be randomly assigned at a 1:1 ratio to receive either Nivo alone or Nivo + RT. After 4 mos of therapy, patients who remain on study will receive Nivo Q4WKly. The primary endpoint is to demonstrate that the addition of fractionated radiation to immunotherapy is associated with an improvement in the 12-month progression-free survival (PFS) proportion from 25% (i.e., historical control estimate; Nivo alone; Arm A) to approximately 50% (i.e., with the fractional radiation and Nivo; Arm B). A key secondary aim is to demonstrate that short course FOLFOX of 3 months + Nivo is similar in efficacy to continuing FOLFOX until disease progression. Another secondary aim of this study is to demonstrate safety of the combination of fractionated RT + Nivo. Target sample size is 74 patients. The study is now open at six sites across the United States. Clinical trial information: NCT04021108.

238 Background: Gastric (GC) and gastroesophageal adenocarcinomas (GEA) are molecularly diverse. Molecular biomarkers of clinical significance have been identified that impact treatment decision making. TP53 is the most frequently altered gene with approximately 50% of patients harboring mutations. However, TP53 mutations have not yet been confirmed as a target of therapeutic benefit. This study aimed to identify distinct genomic alterations that are dominant in TP53 mutated (MUT) versus wild-type (WT) GC and GEA in order to elucidate alternative therapeutic targets within these subsets. Methods: De-identified data for 3741 patients with GC and GEA was obtained from Foundation Medicine. The data obtained were age, gender, tumor mutational burden (TMB), and the distinct genomic alterations noted on DNA sequencing. The dataset was sorted by TP53 mutation status. Differences in mutation frequency were detected using the Fisher’s exact test of independence with a p-value of < 0.01 designated as the cutoff value for statistical significance. Results: The dataset consisted of 2946 GCs and 795 GEAs. TP53 mutations were present in 65.8% of specimens. 61.6% of GCs and 81.4% of GEAs were TP53 MUT positive (p = < .001). Median TMB score and the frequency of tumors with a TMB score > 10 was similar in both TP53 MUT and WT groups. 49 genes had statistically different mutation frequencies in TP53 MUT vs. WT patients. Top co-occurring genetic alterations in TP53 MUT patients included amplification and point mutations in MYC, CCNE1, MET, ERBB2, and EGFR. Amplification and point mutations in MDM2, CDK4, ARID1A, PIK3CA, and ERBB3 were the top co-occurring genetic alterations in TP53 WT patients. Conclusions: There was a high frequency of TP53 mutations in this group of GC and GEA patients, with a higher incidence of TP53 mutations identified in GEA samples. The mutational profiles of these tumors differed according to TP53 mutation status. These differences may be able to serve as the foundation for future clinical investigations.

170 Background: Few epidemiological studies address differences in outcomes by gender in locoregional esophageal cancer (LEC) for which the current standard of care is chemoradiation followed by surgical resection. Although male gender is associated with the majority of LEC cases, we sought to determine if gender could impact clinical presentation as well as surgical and oncologic outcomes in our single institution 20 year experience. Methods: A retrospective query of our institution’s IRB-approved database of patients that had surgical therapy between 2008 and 2019 for esophageal cancer (EC) was performed. Patients were stratified by gender and analyzed based on characteristics such as tumor histology, tumor location, clinical stage at presentation, age at diagnosis, receipt of neoadjuvant therapy, surgical intent, surgical complications, length of post-operative hospital stay, response to neoadjuvant therapy, final pathology, and recurrence. Chi-square, ANOVA and Kaplan Meier survival analysis were performed on the previously defined groups. Results: The cohort studied included 1180 patients with resection for EC. Of those, 1005 (85.2%) had adenocarcinoma, 145 (12.3%) had squamous cell cancer (SCC), 10 (0.8%) had adenosquamous carcinoma, and 20 (1.7%) had other histological variants. There were 985 (83.5%) male patients and 195 (16.5%) female patients. SCC was more common in females (29.2% in females vs. 8.9% in males, p = 0.000) and females tended to have tumor location in the upper thoracic esophagus more often (4.7% in females vs. 0.9% of males, p = 0.000). Additionally, females developed surgical complications more often than males (72.2% vs. 64.7%, p = 0.045). Staging at diagnosis (p = 0.508), receipt of neoadjuvant treatment (p = 0.676), and age at diagnosis (65.3 years in males vs. 66.3 years in females, p = 0.934) had no association with gender. Response to neoadjuvant therapy (p = 0.157) and cancer recurrence (p = 0.434) did not have significant associations with gender. The median overall survival was not statistically significantly different but trended to be longer for females (73.4 months in females [95% CI: 51.5-95.4] vs. 47.0 months in males [95% CI: 39.6-54.5], p = 0.160). Conclusions: Based on our high-volume cancer center study, female patients were more likely to have SCC, upper thoracic esophageal lesions, and surgical complications following resection. While univariate analysis did not demonstrate significant differences in overall survival between genders, there are plans to report additional data after controlling for other variables. Further studies are warranted to validate these findings, given the potential for higher prioritization of an organ preservation approach for this patient population.

TPS472 Background: Adenocarcinoma of esophagus (EAC) and GEJ is the fastest rising cancer in the US. The outcomes are extremely poor with median overall survival (OS) being 12 mo in patients (pts) with metastatic disease. The standard first line treatment for metastatic EAC is platinum-based regimen with median progression free survival (PFS) of 6 mo. Second line options are associated with limited efficacy. An analysis of TCGA has shown 40% of EAC harboring abnormalities in HR genes, most likely resulting from chronic acid reflux induced DNA damage. HR dysregulation is commonly associated with high LOH. Sensitivity to PARP inhibition has been shown to be a surrogate for HR defects or BRCAness phenotype. Clinically PARP inhibitors have shown activity in HR defective prostate and ovarian cancers. These findings provide the basis for this study. Methods: Pts with metastatic esophageal/GEJ/proximal gastric adenocarcinoma, previously treated with 1 line of platinum containing chemotherapy, and harboring high LOH and/or deleterious alteration(s) in HR genes ( BRCA1/2, PALB2, ATM, BARD1, BRIP1, CDK12, CHEK2, FANCA, RAD51, RAD51B, RAD51C, RAD51D, RAD54L, NBN, ARID1A, GEN1) are eligible for this study. Pts can be prescreened at the time of diagnosis of locally advanced or metastatic disease by genomic analysis of the most recent available tumor tissue. Pts will receive oral niraparib until disease progression or unacceptable toxicity. Primary objective is response rate (RR). Secondary objectives are safety and tolerability, progression free survival (PFS), and disease control rate (DCR). Exploratory objectives include correlation between high LOH and response to niraparib, mechanisms of resistance to PARP inhibition, EZH2 expression and its correlation with response and resistance to PARP inhibition, and analysis of germline HR gene mutations and correlation with response to niraparib. Estimated sample size is 43. The study has recently opened to accrual at Indiana University with intended collaboration with 2 additional sites. Clinical trial information: NCT03840967.

556 Background: First line therapy for advanced cholangiocarcinoma (CCA) is currently gemcitabine and cisplatin. However, survival rarely exceeds one year with this regimen. PI3K/AKT activation has been shown to increase resistance to chemotherapy in CCA; therefore, inhibiting this pathway may improve chemotherapy’s efficacy. This phase II study evaluated the safety and efficacy of copanlisib, a potent and reversible pan-class I PI3K inhibitor, with gemcitabine and cisplatin in advanced CCA. Methods: Between July 2016 and April 2019, pts with histologically confirmed advanced/unresectable CCA received cisplatin (25 mg/m2), gemcitabine (1000mg/m2), and copanlisib 60mg on day 1 and 8, every 21 days as first line treatment. The primary endpoint was PFS at 6 months. Secondary endpoints were RR, median OS and PFS, and safety profile. A single-arm Simon’s two-stage minimax design with one-sided 10% type I error and 80% power was used. Based on ABC-01 and ABC-02 studies, PFS6 for gemcitabine and cisplatin were 57.1% and 59.3%, respectively. Therefore, PFS6 of 57% was considered not to warrant further study and ≥72% to warrant further investigation. Results: Twenty-four pts received at least one dose of the study drug (62.5% female, median age 64 years), with 70.8% intrahepatic, 16.7% extrahepatic, and 12.5% gallbladder cancer. For all pts, median OS was 13.9 months (95% CI: 6.8-17.9) and median PFS was 6.2 months (95% CI: 1.3-11.1). PFS at 6 and 12 months was 57.0% and 42.2%, and 6 and 12-month OS was 73.9% and 53.2%, respectively. Only 19 pts were considered evaluable for RR. Five pts were either lost to follow up, withdrew consent, or died before a second scan was done. Six pts achieved PR (31.5%) and 11 (57.9%) had SD. Grade 3 or higher adverse events (AE) occurred in 75% of pts. The most common grade 3/4 AEs were decreased neutrophil count (40%) and increased lipase (20%). Treated related AEs led to drug discontinuation for 3 pts (12.5%) and dose modification for 7 pts (29.2%). Conclusions: Gemcitabine, cisplatin, and copanlisib in combination did not meet the primary endpoint of 6-month PFS. However, additional correlative work is ongoing to identify a possible biomarker for copanlisib. Clinical trial information: NCT02631590.

125 Background: Neoadjuvant chemo-radiation is a standard of care for locally advanced rectal cancer. Patients with pathologic complete response (pCR) have improved outcomes with less local and systemic failure. Dual targeting with platelet derived growth factor (PDGF) and vascular endothelial growth factor receptor (VEGFR) in combination with radiation can escalate tumor response with radiation. Lenvatinib is an oral multi-kinase inhibitor and had shown potent anti-tumor activity in xenograft models cultured with human colorectal cancer (CRC) lines. Methods: Patients with stage II or III rectal cancer, confirmed by endoscopic ultrasound or MRI, were recruited in 3 cohorts of 3 patients per dose level, with an expansion cohort at the MTD. Lenvatinib oral daily dose started at 14 mg (cohort 1) and was escalated to 20 mg (cohort 2) followed by 24 mg (cohort 3). In this 3+3 design, patients received dose escalation of lenvatinib with standard doses of capecitabine (850 mg/m2 PO BID) concurrent with external beam radiation on days 1-5 weekly for 28 treatments. Following completion patients underwent surgery in 6-10 weeks. Results: Twenty patients with median age of 55 were enrolled in 3 cohorts (1 patient was ineligible). There were no dose limiting toxicity at the maximum tested dose of lenvatinib (24 mg). Two patients are still awaiting surgery. 12 patients have undergone low anterior resection and 5 patients have had abdominoperineal resection. Therefore, out of 17 patients, 29.4% (5/17) showed pCR, and downstaging was observed in 71% of the patients (12/17). The mean neoadjuvant rectal cancer score (NAR) was 11.4 and median NAR was 8.43. Six patients had grade 3 adverse events (AEs) (1 rectal pain,1 transaminitis, 2 lymphopenia, 1 HTN, 1 with both leukocytosis and hyponatremia). No grade 4 AEs were noted. Most common AEs were hypertension, rectal pain, nausea, diarrhea, fatigue and dermatitis. No peri operative complications were observed. Conclusions: The study shows that the combination of lenvatinib and capecitabine with radiation is well tolerated in locally advanced rectal cancer with promising mean NAR score. The encouraging results will need to be validated in a randomized study. Clinical trial information: NCT02935309.

TPS4149 Background: Patients with advanced gastric cancer experience a 5 year survival rate 2 twice daily. Each cycle length will be 28 days. The primary endpoint is 6 month OS and secondary endpoints are safety, objective response rate and PFS. Fifteen patients will be enrolled in the first stage. If ≥ 7 of the 15 are alive at 6 months, an additional 10 patients will be enrolled in the second phase. Enrollment is currently ongoing. Clinical trial information: NCT03686488.

694 Background: Despite routine use of neoadjuvant chemoradiation, patients with advanced rectal tumors experience significant rates of treatment failure and recurrence. Radiation resistance is a particular problem. Dual targeting of PDGF and VEGFR (Vascular endothelial cell growth factor receptor) in combination with radiation can enhance tumor response. Lenvatinib inhibits the kinase activities of VEGFR1-3, FGFR1-4, PDGFRα, KIT, and RET and in vivo results show that it effectively delays the growth of human colorectal xenografts. Methods: This is a phase I clinical trial of lenvatinib in combination with capecitabine administered with radiation. Patients with stage II or III rectal cancer confirmed by endoscopic ultrasound or MRI were eligible for the study. In this 3+3 phase I study with 3 cohorts, patients were treated with escalating doses of lenvatinib administered in combination with standard doses of capecitabine (850 mg/m2 PO BID D1-5 weekly for 5 ½ to 6 weeks) and external beam radiation therapy (180 cGY on D1-5 weekly for 5 ½ to 6 weeks). Patients underwent surgery 6-10 weeks after neoadjuvant therapy. Results: Nine patients have been enrolled in the 3 cohorts with the median age of 51 years. Lenvatinib dosing started at 14 mg PO daily (cohort 1) and was safely escalated to 20 mg PO daily (cohort 2) followed by 24 mg PO daily (cohort 3). There were no DLTs at the maximum tested dose of lenvantinib (24 mg). 5 patients have undergone low anterior resection and 4 have had abdominoperineal resection. The pathological complete response (pCR) rate was 33.33%, and downstaging was observed in 100% of patients. Median neoadjuvant rectal cancer score (NAR) was 8.7. Three pts had grade 3 events (2 hypertension (HTN), 1 lymphopenia) without any grade 4 events. Most common AEs were HTN and fatigue. No perioperative complications were observed. Tissues for all pts have been collected for planned correlative studies. Conclusions: This study shows that the combination of lenvatinib with capecitabine, and EBRT is well tolerated. NAR score and downstaging rates are encouraging. Currently we are enrolling 10 additional pts at the maximum tested dose of lenvatinib to further evaluate efficacy and safety. Clinical trial information: NCT02935309.

TPS525 Background: The current standard of treatment for cholangiocarcinoma (CCA) is gemcitabine and cisplatin that favored both overall survival (OS) and progression free survival (PFS) when compared to gemcitabine alone. The survival however remains less than than 1 year. Predominant activation of PI3K/AKT signaling pathway is seen in cell line and human tumors of CCA promoting tumorigenesis and increased resistance to radiation and chemotherapy. Inhibition of this pathway sensitizes CCA cells to therapies. Copanlisib is a selective and reversible pan-class I PI3K inhibitor. In preclinical studies, copanlisib demonstrated anti-tumor activity in PIK3CA mutated cells particularly in BC. In a Phase I study, 4 treatment naïve patients with CCA showed response, including 1 complete response. The maximum tolerated dose of copanlisib was determined to be 0.8 mg/kg in this study. We hypothesize that the addition of copanlisib to gemcitabine + cisplatin will enhance the efficacy of the current standard regimen in advanced CCA. Tumor tissue will be collected on every patient for PTEN immunohistochemical staining and NGS analysis using a 26-genes panel. Methods: This is a single institution phase II single arm two-stage design trial using copanlisib in combination with gemcitabine and cisplatin in patients with advanced CCA. Eligible patients include those diagnosed with advanced, unresectable CCA that are treatment naïve or should have received adjuvant treatment more than 6 months prior to initiating the trial. Patients will be treated with Cisplatin (25 mg/m2) plus Gemcitabine (1000 mg/m2) and Copanlisib (60 mg) on days 1 and 8 on a 21 days cycle. Primary objective of the study is PFS at 6 months with secondary objectives being response rate, median PFS, OS, safety and tolerability. Accrual began on June 28, 2016, with planned enrollment for 25 patients. 14 eligible patients will be enrolled in the first stage. If 8 or more patients (≥57%) are alive and progression free at 6 months, an additional 11 patients will be enrolled in the second stage. 11 patients have been enrolled until now. After 3 cycles, response and progression will be evaluated using RECIST v1.1. Clinical trial information: NCT02631590.

e16544 Background: Poor outcomes in castrate resistant prostate cancer (CRPC) patients is a growing concern urging the need for innovative treatments. Cancer testis antigens (CTAs) like NY-ESO-1 are aberrantly expressed in several cancers including prostate cancer (PC). Given its tumor-restricted expression and ability to elicit spontaneous cytotoxic & antibody-mediated immune responses, NY-ESO-1 shows promise as an immunotherapy target. With the expertise of RPCI in NY-ESO-1 targeted therapeutics and limited information on NY-ESO-1 expression in CRPC, we sought this study. Methods: Immunohistochemical expression of NY-ESO-1 was analyzed in a series of PC samples from 2 different institutions. Two TMAs consisted of triplicate cores from 37 patients with localized PC (with cores from cancerous areas & the normal tissue adjacent to it), and 36 mCRPC patients. We also included 17 mCRPC whole sections for analyses. Intensity and percentage of NY-ESO-1 staining were recorded. The intensity was characterized as low (0-1+) and high (2-3+). Results: The median age in this cohort was 62 years. NY-ESO-1 IHC was positive for cytoplasmic staining in 33 of 111 (26.4%) evaluable cases including 41% in localized PC, 22.6% in benign areas adjacent to tumor, and 35.5% in CRPC. 23 (18.4%) had 1+, 7 (5.6%) had 2+ and 3 (2.4%) had 3+ cytoplasmic staining intensity. No statistical difference was noted in cytoplasmic staining with tumor grade. Gleason grade 8 -10 tumors (33 of 103 [35.4%]) correlated with lower intensity staining (0-1+) pattern (p = 0.028). NY-ESO-1 expression did not correlate with age, race, disease free or overall survival in this cohort. Conclusions: Heterogeneous NY-ESO-1 expression in PC and other tumors is linked to DNA methylation status of its promoter and tumor cells. We noted NY-ESO-1 expression in a third of the patients with CRPC, making it a credible immunotherapeutic target. NY-ESO-1 expression has been shown to be induced and upregulated in cancer by treatment with demethylating agent. Thus targeting NY-ESO-1 in concert with epigenetic modulation maybe therapeutically meaningful in patients with CRPC. Additional efforts at validating NY-ESO-1 expression in CRPC with CLIA approved IHC and qPCR assays (Omniseq) are ongoing and will be reported.

e13081 Background: Synchronous breast cancers are uncommon and account for around 2% of all breast cancer diagnosis. Lobular histology is considered a risk factor for synchronous breast cancers. We sought to study the trends in synchronous breast cancer of ductal histology and influence of age by interrogating the SEER database. Methods: The SEER Research data 1973-2013 was interrogated for synchronous infiltrating ductal carcinoma diagnosis (2 diagnosis within 6 months of each other). Overall survival (OS), the primary endpoint, was defined as the time (in months) from diagnosis to death from any cause. Univariate proportional hazards modeling results were used to assess the effect of age, race and stage on overall survival. All associations were considered statistically significant at an alpha error < 0.01. All analyses were performed using SAS version 9.4. Results: 1469 cases were identified. Data was categorized by age group: ≤ 65 years or > 65 years. 60% were 65 years or younger. 85% were Caucasians, 9.6% African Americans and 5.2% others. Younger women (≤ 65 years) had a statistically higher proportion of Stage III/IV breast cancer diagnosis as compared to older women (33.4% vs 25.2%; p = 0.002). The incidence rate of synchronous breast cancers has been rising since 1973, more pronounced in the older age group. Incidence rates overall have risen from 0.09/100,000 persons in 1973-1980 to 0.29/100,000 persons in 2001-2013 (p < 0.001). Incidence rates for synchronous breast cancer in women > 65 years has increased from 0.30/100,000 persons in 1973-1980 to 1.03/100,000 persons in 2001-2013. The adjusted OS among older women is significantly worse than that of younger women (HR 1.05; 95% CI 1.04-1.05; p < 0.001). Conclusions: Better imaging techniques and breast cancer screening guidelines have likely improved breast cancer detection rates thus leading to a rise in the incidence of synchronous breast cancers. It can be speculated that underlying medical problems and advanced age result in more morbidity and subsequent mortality in older women with standard treatment. The finding of more advanced disease among younger women deserves scrutiny as to cause.

9566 Background: Ipilimumab-related colitis has been well described, but the clinical presentation of colitis related to MONO or COMBO therapy has not. We aimed to characterize clinical features that define this serious adverse event. Methods: This retrospective study included melanoma pts with colitis screened from 6 academic centers treated with either MONO or COMBO therapy. Clinically relevant colitis was defined as diarrhea/colitis symptoms requiring systemic steroids. The onset, management, and outcomes related to colitis were summarized. Results: We screened 866 pts and identified 72 with clinically relevant colitis. For the MONO cohort, the incidence was 3.5% (23/657) and 23.4% (49/209) in the COMBO cohort. MONO-colitis occurred at a median 33 weeks (wks) into therapy, while median onset was 8 wks with COMBO therapy. One pt had grade 5 colitis from COMBO therapy. Despite the use of systemic steroids, COMBO-colitis needed more infliximab therapy (38.8% vs 26.1%). The median prednisone equivalent dose was higher for COMBO therapy (1.5 vs 1 mg/kg), and the median taper was shorter for MONO-colitis (4 vs 6 wks). Steroid dose-escalation for worsening symptoms during taper was more common with COMBO-colitis (42.9% vs 17.3%). Relapse was similar between cohorts (MONO: 26.1%, COMBO: 20.4%). Relapses occurred more frequently in COMBO therapy with tapers shorter than the median (38.1% vs 25.0%), and more frequently in MONO therapy with steroid doses lower than the median (60% vs 21.7%). MONO-colitis pts (17.4%) were less likely than COMBO-colitis pts (46.9%) to be restarted on PD-1 therapy. When restarted, only 13% with COMBO therapy relapsed as compared to 50% with MONO therapy. Objective response rates for MONO and COMBO cohorts were 72.7% and 56.1%, respectively. Conclusions: Colitis occurred with a much higher incidence in COMBO therapy. MONO-colitis was associated with a milder course with later onset, shorter duration and lower dose of steroids, fewer dose-escalations, and need for infliximab as compared to COMBO therapy. Relapse of colitis was generally associated with shorter steroid tapers for COMBO therapy and lower steroid doses for MONO therapy.

e20567 Background: Long-term cancer survivors require comprehensive care. The purpose of this study was to describe how survivorship care fits into oncologists’ clinical time, and characterize long-term cancer survivors’ problems and oncology follow-up care. Methods: We abstracted 18,882 medical records of unique cancer patient visits during 2010 at a major NCI-designated cancer center and then evaluated survivor care for one week in April, 2010 to characterize how oncologists spend their clinical time. Finally, we selected three subgroups from the survivor population (n≈100 each) of survivors at 1-5 years, 6-10 years, and >10 years after diagnosis. We collected demographic data, purpose of visit, cancer-specific information, late and long-term effects, and type of care delivered, including surveillance for recurrence, intervention, prevention, and coordination of care. Results: In the larger group of 18,882, only 14% of survivors were more than 10 years post-diagnosis. Approximately two-thirds of the survivors were women. Breast cancer survivors comprised 38%, and survivors of hematologic malignancies accounted for 21% of the population. During the one week studied, the majority of oncologists' patients (74%) were actively receiving treatment; only 5% of their patients were 5 or more years post-diagnosis. Second or secondary malignancies were noted in 8% of patients. Late and long-term effects were uncommon. Approximately 25% of survivors beyond five years were observed to have late effects due to cancer treatment, most common being fatigue, neurological endocrine, and cardiac. Of the 300 selected survivors, sixty-two percent received only surveillance care during their visit. Only 3% of these patients received an entire array of survivorship care that included surveillance, intervention, co-ordination and prevention. Conclusions: A small proportion of oncologists’ visits were with long-term cancer survivors (5-14%) of whom only 25% had late or long-term effects of cancer treatment so overall very few of office visits were with long-term survivors who had late and long-term complications. All visits involved surveillance for cancer recurrence but there was little focus on prevention, intervention, and coordination of care for cancer survivors.

10599 Background: Prediction of behavior of thymomas is difficult since complete surgical excision can be curative. In order to better understand the biology of the disease processes, we performed ...