Effect of a MUC5AC Antibody (NPC-1C) Administered With Second-Line Gemcitabine and Nab-Paclitaxel on the Survival of Patients With Advanced Pancreatic Ductal Adenocarcinoma: A Randomized Clinical Trial.

Importance: Treatment options are limited for patients with advanced pancreatic ductal adenocarcinoma (PDAC) beyond first-line 5-fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX), with such individuals commonly being treated with gemcitabine and nab-paclitaxel. Objective: To determine whether NPC-1C, an antibody directed against MUC5AC, might increase the efficacy of second-line gemcitabine and nab-paclitaxel in patients with advanced PDAC. Design, Setting, and Participants: This multicenter, randomized phase II clinical trial enrolled patients with advanced PDAC between April 2014 and March 2017 whose disease had progressed on first-line FOLFIRINOX. Eligible patients had tumors with at least 20 MUC5AC staining by centralized immunohistochemistry review. Statistical analysis was performed from April to May 2022. Interventions: Patients were randomly assigned to receive gemcitabine (1000 mg/m2) and nab-paclitaxel (125 mg/m2) administered intravenously on days 1, 8, and 15 of every 4-week cycle, with or without intravenous NPC-1C 1.5 mg/kg every 2 weeks. Main Outcomes and Measures: The primary end point was overall survival (OS). Secondary end points were progression-free survival (PFS), objective response rate (ORR), and safety. Pretreatment clinical variables were explored with Cox proportional hazards analysis. Results: A total of 78 patients (median [range] age, 62 [36-78] years; 32 [41%] women; 9 [12%] Black; 66 [85%] White) received second-line treatment with gemcitabine plus nab-paclitaxel (n = 40) or gemcitabine plus nab-paclitaxel and NPC-1C (n = 38). Median OS was 6.6 months (95% CI, 4.7-8.4 months) with gemcitabine plus nab-paclitaxel vs 5.0 months (95% CI, 3.3-6.5 months; P = .22) with gemcitabine plus nab-paclitaxel and NPC-1C. Median PFS was 2.7 months (95% CI, 1.9-4.1 months) with gemcitabine plus nab-paclitaxel vs 3.4 months (95% CI, 1.9-5.3 months; P = .80) with gemcitabine plus nab-paclitaxel and NPC-1C. The ORR was 3.1% (95% CI, 0.4%-19.7%) in the gemcitabine plus nab-paclitaxel and NPC-1C group and 2.9% (95% CI, 0.4%-18.7%) in the gemcitabine plus nab-paclitaxel group. No differences in toxicity were observed between groups, except that grade 3 or greater anemia occurred more frequently in patients treated with gemcitabine plus nab-paclitaxel and NPC-1C than gemcitabine plus nab-paclitaxel (39% [15 of 38] vs 10% [4 of 40]; P = .003). The frequency of chemotherapy dose reductions was similar in both groups (65% vs 74%; P = .47). Lower performance status, hypoalbuminemia, PDAC diagnosis less than or equal to 18 months before trial enrollment, lymphocyte-to-monocyte ratio less than 2.8, and CA19-9 greater than 2000 IU/mL were independently associated with poorer survival. Conclusions and Relevance: In this randomized clinical trial of advanced PDAC, NPC-1C did not enhance the efficacy of gemcitabine/nab-paclitaxel. These data provide a benchmark for future trials investigating second-line treatment of PDAC. Trial Registration: ClinicalTrials.gov Identifier: NCT01834235.

Prospective Phase II Trials Validate the Effect of Neoadjuvant Chemotherapy on Pattern of Recurrence in Pancreatic Adenocarcinoma.

OBJECTIVE: The objective of this study was to characterize the patterns of first recurrence after curative-intent resection for pancreatic adenocarcinoma (PDAC). SUMMARY OF BACKGROUND DATA: We evaluated the first site of recurrence after neoadjuvant treatment as locoregional (LR) or distant metastasis (DM). To validate our findings, we evaluated the pattern from 2 phase II clinical trials evaluating neoadjuvant chemotherapy (NAC) in PDAC. METHODS: We identified site of first recurrence from a retrospective cohort of patients from 2011 to 2017 treated with NAC followed by chemoradiation and then an operation or an operation first followed by adjuvant therapy, and 2 separate prospective cohorts of patients derived from 2 phase II clinical trials evaluating patients treated with NAC in borderline-resectable and locally advanced PDAC. RESULTS: In the retrospective cohorts, 160 out of 285 patients (56.1%) recurred after a median disease-free survival (mDFS) of 17.2 months. The pattern of recurrence was DM in 81.9% of patients, versus LR in 11.1%. This pattern was consistent in patients treated with upfront resection and adjuvant chemotherapy (DM 83.0%, LR 16.9%) regardless of margin-involvement (DM 80.1%, LR 19.4%). The use of NAC did not alter pattern of recurrence; 81.7% had DM and 18.3% had LR. This pattern also remained consistent regardless of margin-involvement (DM 94.1%, LR 5.9%). In the Phase II borderline-resectable trial (NCI# 01591733) cohort of 32 patients, the mDFS was 34.2 months. Pattern of recurrence remained predominantly DM (88.9%) versus LR (11.1%). In the Phase II locally-advanced trial (NCI# 01821729) cohort of 34 patients, the mDFS was 30.7 months. Although there was a higher rate of local recurrence in this cohort, pattern of first recurrence remained predominantly DM (66.6%) versus LR (33.3%) and remained consistent independent of margin-status. CONCLUSIONS: The pattern of recurrence in PDAC is predominantly DM rather than LR, and is consistent regardless of the use of NAC and margin involvement.

Care Patterns and Overall Survival in Patients With Early-Onset Metastatic Colorectal Cancer.

PURPOSE: Colorectal cancer (CRC) incidence in patients younger than 50 years of age, commonly defined as early-onset (EO-CRC), is rising. EO-CRC often presents with distinct clinicopathologic features. However, data on prognosis are conflicting and outcomes with modern treatment approaches for metastatic disease are still limited. MATERIALS AND METHODS: We prospectively enrolled patients with metastatic CRC (mCRC) to a biobanking and clinical data collection protocol from 2014 to 2018. We grouped the cohort based on age at initial diagnosis: < 40 years, 40-49 years, and ≥ 50 years. We used regression models to examine associations among age at initial diagnosis, treatments, clinicopathologic features, and survival. RESULTS: We identified 466 patients with mCRC (45 [10%] age < 40 years, 109 [23%] age 40-49 years, and 312 [67%] age ≥ 50 years). Patients < 40 years of age were more likely to have received multiple metastatic resections (odds ratio [OR], 3.533; P = .0066) than their older counterparts. Patients with EO-CRC were more likely to receive triplet therapy than patients > 50 years of age (age < 40 years: OR, 6.738; P = .0002; age 40-49 years: OR, 2.949; P = .0166). Patients 40-49 years of age were more likely to have received anti-EGFR therapy (OR, 2.633; P = .0016). Despite differences in care patterns, age did not predict overall survival. CONCLUSION: Despite patients with EO-CRC receiving more intensive treatments, survival was similar to the older counterpart. However, EO-CRC had clinical and molecular features associated with worse prognoses. Improved biologic understanding is needed to optimize clinical management of EO-CRC. The cost-benefit ratio of exposing patients with EO-CRC to more intensive treatments has to be carefully evaluated.

Revisiting MET: Clinical Characteristics and Treatment Outcomes of Patients with Locally Advanced or Metastatic, MET-Amplified Esophagogastric Cancers.

BACKGROUND: Metastatic esophagogastric cancers (EGCs) have a poor prognosis with an approximately 5% 5-year survival. Additional treatment approaches are needed. c-MET gene-amplified tumors are an uncommon but potentially targetable subset of EGC. Clinical characteristics and outcomes were evaluated in patients with MET-amplified EGC and compared with those without MET amplification to facilitate identification of these patients and possible treatment approaches. PATIENTS AND METHODS: Patients with locally advanced or metastatic MET-amplified EGC at Massachusetts General Hospital (MGH) were identified using fluorescent in situ hybridization analysis, with a gene-to-control ratio of ≥2.2 defined as positive. Non-MET-amplified patients identified during the same time period who had undergone tumor genotyping and treatment at MGH were evaluated as a comparison group. RESULTS: We identified 233 patients evaluated for MET amplification from 2002 to 2019. MET amplification was seen in 28 (12%) patients versus 205 (88%) patients without amplification. Most MET-amplified tumors occurred in either the distal esophagus (n = 9; 32%) or gastroesophageal junction (n = 10; 36%). Of MET-amplified patients, 16 (57%) had a TP53 mutation, 5(18%) had HER2 co-amplification, 2 (7.0%) had EGFR co-amplification, and 1 (3.5%) had FGFR2 co-amplification. MET-amplified tumors more frequently had poorly differentiated histology (19/28, 68.0% vs. 66/205, 32%; p = .02). Progression-free survival to initial treatment was substantially shorter for all MET-amplified patients (5.6 vs. 8.8 months, p = .026) and for those with metastatic disease at presentation (4.0 vs. 7.6 months, p = .01). Overall, patients with MET amplification had shorter overall survival (19.3 vs. 24.6 months, p = .049). No difference in survival was seen between low MET-amplified tumors (≥2.2 and <25 MET copy number) compared with highly amplified tumors (≥25 MET copy number). CONCLUSION: MET-amplified EGC represents a distinct clinical entity characterized by rapid progression and short survival. Ideally, the identification of these patients will provide opportunities to participate in clinical trials in an attempt to improve outcomes. IMPLICATIONS FOR PRACTICE: This article describes 233 patients who received MET amplification testing and reports (a) a positivity rate of 12%, similar to the rate of HER2 positivity in this data set; (b) the clinical characteristics of poorly differentiated tumors and nodal metastases; and (c) markedly shorter progression-free survival and overall survival in MET-amplified tumors. Favorable outcomes are reported for patients treated with MET inhibitors. Given the lack of published data in MET-amplified esophagogastric cancers and the urgent clinical importance of identifying patients with MET amplification for MET-directed therapy, this large series is a valuable addition to the literature and will have an impact on future practice.

Hypofractionated Radiation Therapy for Unresectable/Locally Recurrent Intrahepatic Cholangiocarcinoma.

OBJECTIVE: The aim of this study was to evaluate outcomes for patients with unresectable intrahepatic cholangiocarcinoma (ICC) treated with hypofractionated proton or photon radiation therapy (HF-RT). METHODS: We retrospectively identified 66 patients with ICC who were treated with HF-RT from 2008 to 2018. Median age at RT was 76 years (range 30-92), including 27 patients (41%) aged ≥ 80 years. Median RT dose was 58.05 Gy (range 37.5-67.5), all delivered in 15 daily fractions. Thirty-two patients received proton RT and 34 patients received photon RT. RESULTS: Median follow-up times from diagnosis and RT start were 21 months and 14 months, respectively. In total, five patients (7.6%) developed local failure. The 2-year outcomes were 84% local control (LC) and 58% OS. Among the 51 patients treated with definitive intent, the 2-year LC rate was 93% and the OS rate was 62%. On multivariate analysis for LC, older age was associated with a lower risk of local failure [hazard ratio (HR) 0.91; p = 0.02], while prior surgery (HR 16.5; p = 0.04) and macrovascular invasion (HR 123.93; p = 0.02) were independently associated with an increased risk of local failure. On multivariate analysis for OS, female sex (HR 0.33; p = 0.001) and prior chemotherapy (HR 0.38; p = 0.003) remained significantly associated with OS. On multivariate analysis for OS, compared with photon RT, there was a trend towards improved survival with proton RT (HR 0.50; p = 0.05). The rate of overall grade 3 + toxicity was 11%. One patient developed radiation-induced liver disease and was treated with corticosteroids. CONCLUSIONS: HF-RT yields high rates of local control and is an effective modality to optimize biliary control for unresectable/locally recurrent ICC.

Author Correction: Liquid versus tissue biopsy for detecting acquired resistance and tumor heterogeneity in gastrointestinal cancers.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Liquid versus tissue biopsy for detecting acquired resistance and tumor heterogeneity in gastrointestinal cancers.

During cancer therapy, tumor heterogeneity can drive the evolution of multiple tumor subclones harboring unique resistance mechanisms in an individual patient1-3. Previous case reports and small case series have suggested that liquid biopsy (specifically, cell-free DNA (cfDNA)) may better capture the heterogeneity of acquired resistance4-8. However, the effectiveness of cfDNA versus standard single-lesion tumor biopsies has not been directly compared in larger-scale prospective cohorts of patients following progression on targeted therapy. Here, in a prospective cohort of 42 patients with molecularly defined gastrointestinal cancers and acquired resistance to targeted therapy, direct comparison of postprogression cfDNA versus tumor biopsy revealed that cfDNA more frequently identified clinically relevant resistance alterations and multiple resistance mechanisms, detecting resistance alterations not found in the matched tumor biopsy in 78% of cases. Whole-exome sequencing of serial cfDNA, tumor biopsies and rapid autopsy specimens elucidated substantial geographic and evolutionary differences across lesions. Our data suggest that acquired resistance is frequently characterized by profound tumor heterogeneity, and that the emergence of multiple resistance alterations in an individual patient may represent the 'rule' rather than the 'exception'. These findings have profound therapeutic implications and highlight the potential advantages of cfDNA over tissue biopsy in the setting of acquired resistance.

TAS-120 Overcomes Resistance to ATP-Competitive FGFR Inhibitors in Patients with FGFR2 Fusion-Positive Intrahepatic Cholangiocarcinoma.

ATP-competitive fibroblast growth factor receptor (FGFR) kinase inhibitors, including BGJ398 and Debio 1347, show antitumor activity in patients with intrahepatic cholangiocarcinoma (ICC) harboring activating FGFR2 gene fusions. Unfortunately, acquired resistance develops and is often associated with the emergence of secondary FGFR2 kinase domain mutations. Here, we report that the irreversible pan-FGFR inhibitor TAS-120 demonstrated efficacy in 4 patients with FGFR2 fusion-positive ICC who developed resistance to BGJ398 or Debio 1347. Examination of serial biopsies, circulating tumor DNA (ctDNA), and patient-derived ICC cells revealed that TAS-120 was active against multiple FGFR2 mutations conferring resistance to BGJ398 or Debio 1347. Functional assessment and modeling the clonal outgrowth of individual resistance mutations from polyclonal cell pools mirrored the resistance profiles observed clinically for each inhibitor. Our findings suggest that strategic sequencing of FGFR inhibitors, guided by serial biopsy and ctDNA analysis, may prolong the duration of benefit from FGFR inhibition in patients with FGFR2 fusion-positive ICC. SIGNIFICANCE: ATP-competitive FGFR inhibitors (BGJ398, Debio 1347) show efficacy in FGFR2-altered ICC; however, acquired FGFR2 kinase domain mutations cause drug resistance and tumor progression. We demonstrate that the irreversible FGFR inhibitor TAS-120 provides clinical benefit in patients with resistance to BGJ398 or Debio 1347 and overcomes several FGFR2 mutations in ICC models.This article is highlighted in the In This Issue feature, p. 983.

Pencil Beam Scanning Proton Beam Chemoradiation Therapy With 5-Fluorouracil and Mitomycin-C for Definitive Treatment of Carcinoma of the Anal Canal: A Multi-institutional Pilot Feasibility Study.

PURPOSE: Definitive chemoradiation with concurrent 5-fluorouracil (5-FU)/mitomycin C (MMC) is an effective treatment for localized anal cancer, but it is associated with significant acute long-term treatment-related toxicity. Pencil beam scanning proton beam (PBS-PT) radiation therapy may potentially reduce this toxicity. This is a multi-institutional pilot study evaluating the feasibility of definitive concurrent chemoradiation with PBS-PT in combination with 5-FU and MMC for carcinoma of the anal canal. METHODS AND MATERIALS: Patients were enrolled on a National Cancer Institute-sponsored, prospective, multi-institutional, single-arm pilot study (NCT01858025). Key eligibility criteria included Eastern Cooperative Oncology Group 0 to 2, age ≥18 years, histologically confirmed invasive squamous cell carcinoma of the anal canal, and clinically staged T1-4, N0-3 disease. Patients were treated with PBS-PT per Radiation Therapy Oncology Group 0529 dose schema and concurrent 5-FU/MMC on day 1 and 29. The primary objective of this study was to determine feasibility of PBS-PT with concurrent 5-FU/MMC, defined as grade 3+ dermatologic toxicity less than 48% (reported grade 3+ dermatologic toxicity from Radiation Therapy Oncology Group 98-11). Secondary objectives were to determine the rates of overall grade 3+ toxicities, clinical complete response rate, and disease outcomes. RESULTS: Between February 2014 and April 2017, we enrolled 25 patients into our study, all of whom were analyzed. Twenty-three patients (92%) completed treatment per protocol, and 2 patients died on treatment. Median time to completion of treatment was 42 days (range, 38-49). The grade 3+ radiation dermatitis rate was 24%. Median follow-up is 27 months (range, 21-50) among the 21 patients still alive. The overall rate of clinical complete response was 88%. The 2-year local failure, colostomy-free survival, progression-free survival, and overall survival are 12%, 72%, 80%, and 84%, respectively. CONCLUSIONS: In our prospective, multi-institutional pilot study of PBS-PT with concurrent 5-FU/MMC, PBS-PT was found to be feasible. A phase 2 study of proton beam radiation therapy is currently underway.

Total Neoadjuvant Therapy With FOLFIRINOX in Combination With Losartan Followed by Chemoradiotherapy for Locally Advanced Pancreatic Cancer: A Phase 2 Clinical Trial.

IMPORTANCE: Patients with locally advanced pancreatic cancer have historically poor outcomes. Evaluation of a total neoadjuvant approach is warranted. OBJECTIVE: To evaluate the margin-negative (R0) resection rate of neoadjuvant FOLFIRINOX (fluorouracil, leucovorin, oxaliplatin, and irinotecan) and losartan followed by chemoradiotherapy for locally advanced pancreatic cancer. DESIGN, SETTING, AND PARTICIPANTS: A single-arm phase 2 clinical trial was conducted at a large academic hospital from August 22, 2013, to May 22, 2018, among 49 patients with previously untreated locally advanced unresectable pancreatic cancer as determined by multidisciplinary review. Patients had Eastern Cooperative Oncology Group performance status 0 or 1 and adequate hematologic, renal, and hepatic function. Median follow-up for the analysis was 17.1 months (range, 5.0-53.7) among 27 patients still alive at study completion. INTERVENTIONS: Patients received FOLFIRINOX and losartan for 8 cycles. Patients with radiographically resectable tumor after chemotherapy received short-course chemoradiotherapy (5 GyE × 5 with protons) with capecitabine. Patients with persistent vascular involvement received long-course chemoradiotherapy (50.4 Gy with a vascular boost to 58.8 Gy) with fluorouracil or capecitabine. MAIN OUTCOMES AND MEASURES: R0 resection rate. RESULTS: Of the 49 patients (26 women and 23 men; median age 63 years [range, 42-78 years]), 39 completed 8 cycles of FOLFIRINOX and losartan; 10 patients had fewer than 8 cycles due to progression (5 patients), losartan intolerance (3 patients), and toxicity (2 patients). Seven patients (16%) had short-course chemoradiotherapy while 38 (84%) had long-course chemoradiotherapy. Forty-two (86%) patients underwent attempted surgery, with R0 resection achieved in 34 of 49 patients (69%; 95% CI, 55%-82%). Overall median progression-free survival was 17.5 months (95% CI: 13.9-22.7) and median overall survival was 31.4 months (95% CI, 18.1-38.5). Among patients who underwent resection, median progression-free survival was 21.3 months (95% CI, 16.6-28.2), and median overall survival was 33.0 months (95% CI, 31.4 to not reached). CONCLUSIONS AND RELEVANCE: Total neoadjuvant therapy with FOLFIRINOX, losartan, and chemoradiotherapy provides downstaging of locally advanced pancreatic ductal adenocarcinoma and is associated with an R0 resection rate of 61%. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01821729.

Predictors of Resectability and Survival in Patients With Borderline and Locally Advanced Pancreatic Cancer who Underwent Neoadjuvant Treatment With FOLFIRINOX.

OBJECTIVE: The aim of this study was to determine (1) whether preoperative factors can predict resectability of borderline resectable (BR) and locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC) after neoadjuvant FOLFIRINOX, (2) which patients might benefit from adjuvant therapy, and (3) survival differences between resected BR/LA patients who received neoadjuvant FOLFIRINOX and upfront resected patients. BACKGROUND: Patients with BR/LA PDAC are often treated with FOLFIRINOX to obtain a margin-negative resection, yet selection of patients for resection remains challenging. METHODS: Clinicopathologic data of PDAC patients surgically explored between 04/2011-11/2016 in a single institution were retrospectively collected. RESULTS: Following neoadjuvant FOLFIRINOX, 141 patients were surgically explored (BR: 49%, LA: 51%) and 110 (78%) were resected. Resected patients had lower preoperative CA 19-9 levels (21 vs 40 U/mL, P = 0.03) and smaller tumors on preoperative computed tomography (CT) scan (2.3 vs 3.0 cm, P = 0.03), but no predictors of resectability were identified. Median overall survival (OS) was 34.2 months from diagnosis for all FOLFIRINOX patients and 37.7 months for resected patients. Among resected patients, preoperative CA 19-9 >100 U/mL and >8 months between diagnosis and surgery predicted a shorter postoperative disease-free survival (DFS); Charlson comorbidity index >1, preoperative CA 19-9 >100 U/mL and tumor size (>3.0 cm on CT or >2.5 cm on pathology) predicted decreased OS. DFS and OS were significantly better for BR/LA PDAC patients treated with neoadjuvant FOLFIRINOX compared with upfront resected patients (DFS: 29.1 vs 13.7, P < 0.001; OS: 37.7 vs 25.1 months from diagnosis, P = 0.01). CONCLUSION: BR/LA PDAC patients with no progression on neoadjuvant FOLFIRINOX should be offered surgical exploration. Except size, traditional pathological parameters fail to predict survival among resected FOLFIRINOX patients. Resected FOLFIRINOX patients have survival that appears to be superior than that of resectable patients who go directly to surgery.

Real-time Genomic Characterization of Advanced Pancreatic Cancer to Enable Precision Medicine.

Clinically relevant subtypes exist for pancreatic ductal adenocarcinoma (PDAC), but molecular characterization is not yet standard in clinical care. We implemented a biopsy protocol to perform time-sensitive whole-exome sequencing and RNA sequencing for patients with advanced PDAC. Therapeutically relevant genomic alterations were identified in 48% (34/71) and pathogenic/likely pathogenic germline alterations in 18% (13/71) of patients. Overall, 30% (21/71) of enrolled patients experienced a change in clinical management as a result of genomic data. Twenty-six patients had germline and/or somatic alterations in DNA-damage repair genes, and 5 additional patients had mutational signatures of homologous recombination deficiency but no identified causal genomic alteration. Two patients had oncogenic in-frame BRAF deletions, and we report the first clinical evidence that this alteration confers sensitivity to MAPK pathway inhibition. Moreover, we identified tumor/stroma gene expression signatures with clinical relevance. Collectively, these data demonstrate the feasibility and value of real-time genomic characterization of advanced PDAC.Significance: Molecular analyses of metastatic PDAC tumors are challenging due to the heterogeneous cellular composition of biopsy specimens and rapid progression of the disease. Using an integrated multidisciplinary biopsy program, we demonstrate that real-time genomic characterization of advanced PDAC can identify clinically relevant alterations that inform management of this difficult disease. Cancer Discov; 8(9); 1096-111. ©2018 AACR.See related commentary by Collisson, p. 1062This article is highlighted in the In This Issue feature, p. 1047.

Total Neoadjuvant Therapy With FOLFIRINOX Followed by Individualized Chemoradiotherapy for Borderline Resectable Pancreatic Adenocarcinoma: A Phase 2 Clinical Trial.

Importance: Patients with borderline-resectable pancreatic ductal adenocarcinoma have historically poor outcomes with surgery followed by adjuvant chemotherapy. Evaluation of a total neoadjuvant approach with highly active therapy is warranted. Objective: To evaluate the margin-negative (R0) resection rate in borderline-resectable pancreatic ductal adenocarcinoma after neoadjuvant FOLFIRINOX (fluorouracil, irinotecan, and oxaliplatin) therapy and individualized chemoradiotherapy. Design, Setting, and Participants: A single-arm, phase 2 clinical trial was conducted at a large academic hospital with expertise in pancreatic surgery from August 3, 2012, through August 31, 2016, among 48 patients with newly diagnosed, previously untreated, localized pancreatic cancer determined to be borderline resectable by multidisciplinary review, who had Eastern Cooperative Oncology Group performance status 0 or 1 and adequate hematologic, renal, and hepatic function. Median follow-up for the analysis was 18.0 months among the 30 patients still alive at study completion. Interventions: Patients received FOLFIRINOX for 8 cycles. Upon restaging, patients with resolution of vascular involvement received short-course chemoradiotherapy (5 Gy × 5 with protons) with capecitabine. Patients with persistent vascular involvement received long-course chemoradiotherapy with fluorouracil or capecitabine. Main Outcomes and Measures: The primary outcome was R0 resection rate; secondary outcomes were median progression-free survival (PFS) and median overall survival (OS). Results: Of the 48 eligible patients, 27 were men and 21 were women, with a median age of 62 years (range, 46-74 years). Of the 43 patients who planned to receive 8 preoperative cycles of chemotherapy, 34 (79%) were able to complete all cycles. Twenty-seven patients (56%) had short-course chemoradiotherapy, while 17 patients (35%) had long-course chemoradiotherapy. R0 resection was achieved in 31 of the 48 eligible patients (65%; 95% CI, 49%-78%). Among the 32 patients who underwent resection, the R0 resection rate was 97% (n = 31). Median PFS among all eligible patients was 14.7 months (95% CI, 10.5 to not reached), with 2-year PFS of 43%; median OS was 37.7 months (95% CI, 19.4 to not reached), with 2-year OS of 56%. Among patients who underwent resection, median PFS was 48.6 months (95% CI, 14.4 to not reached) and median OS has not been reached, with a 2-year PFS of 55% and a 2-year OS of 72%. Conclusions and Relevance: Preoperative FOLFIRINOX followed by individualized chemoradiotherapy in borderline resectable pancreatic cancer results in high rates of R0 resection and prolonged median PFS and median OS, supporting ongoing phase 3 trials. Trial Registration: ClinicalTrials.gov Identifier: NCT01591733.

Primary tumor sidedness is an independent prognostic marker for survival in metastatic colorectal cancer: Results from a large retrospective cohort with mutational analysis.

Recent reports demonstrate inferior outcomes associated with primary right-sided vs left-sided colorectal tumors in patients with metastatic colorectal cancer (mCRC). We sought to describe our experience with mCRC patients on whom we have molecular data to determine whether primary tumor sidedness was an independent prognostic marker for overall survival (OS). mCRC patients with documented primary tumor sidedness who received mutational profiling between 2009 and 2014 were identified (n = 367, median follow-up 30.4 months). Mutational profiling for >150 mutations across commonly mutated cancer genes including RAS, PIK3CA, BRAF, and PTEN as well as treatment data, including receipt of a biologic agent, were collected. Univariable/multivariable models were used to analyze relationships between collected data and OS. Among 367 patients, sidedness breakdown was as follows: 234 left (64%), 133 right (36%). 56% were male, with a median age at diagnosis of 57 (range 24-89). A total of 143 patients had RAS mutations. Five-year OS was 41%, median OS was 54 months (range 1-149). Five-year OS for left- vs right-sided tumors was 46% vs 24% (P < .0001). On univariable analysis, among both RAS wildtype and mutant tumors, left-sided tumors continued to have improved OS vs right-sided tumors (HR: 0.49, 95% CI: 0.34-0.69 RAS wildtype; HR: 0.61, 95% CI: 0.40-0.95 RAS mutant). Left-sidedness was an important prognostic factor for OS among RAS wildtype patients despite treatment with or without a biologic agent (P < .05). Left-sidedness remained significant for improved OS on multivariable analysis (P < .0001). Left-sided primary tumor remained most important prognostic factor for OS, even when adjusting for mutational status and receipt of biologic agent.

Convergent Therapeutic Strategies to Overcome the Heterogeneity of Acquired Resistance in BRAFV600E Colorectal Cancer.

Clonal heterogeneity associated with acquired resistance presents a critical therapeutic challenge. Whole-exome sequencing of paired tumor biopsies and targeted sequencing of cell-free DNA (cfDNA) from patients with BRAFV600E colorectal cancer receiving BRAF inhibitor combinations identified 14 distinct alterations in MAPK pathway components driving acquired resistance, with as many as eight alterations in a single patient. We developed a pooled clone system to study clonal outgrowth during acquired resistance, in vitro and in vivoIn vitro, the dynamics of individual resistant clones could be monitored in real time in cfDNA isolated from culture media during therapy. Outgrowth of multiple resistant clones was observed during therapy with BRAF, EGFR, and MEK inhibitor combinations. However, ERK inhibition, particularly in combination with BRAF and EGFR inhibition, markedly abrogated clonal outgrowth in vitro and in vivo Thus, convergent, up-front therapy may suppress outgrowth of heterogeneous clones harboring clinically observed resistance alterations, which may improve clinical outcome.Significance: We observed heterogeneous, recurrent alterations in the MAPK pathway as key drivers of acquired resistance in BRAFV600E colorectal cancer, with multiple concurrent resistance alterations detectable in individual patients. Using a novel pooled clone system, we identify convergent up-front therapeutic strategies capable of intercepting multiple resistance mechanisms as potential approaches to suppress emergence of acquired resistance. Cancer Discov; 8(4); 417-27. ©2018 AACR.See related commentary by Janku, p. 389See related article by Corcoran et al., p. 428This article is highlighted in the In This Issue feature, p. 371.

Tolerability and Long-term Outcomes of Dose-Painted Neoadjuvant Chemoradiation to Regions of Vessel Involvement in Borderline or Locally Advanced Pancreatic Cancer.

PURPOSE: We reviewed our experience involving patients with borderline resectable or locally advanced pancreatic cancer, treated with the dose-painted (DP) boost technique to regions of vessel involvement which preclude upfront surgical resection. We evaluated patient outcomes with respect to tolerability and treatment outcomes. MATERIALS AND METHODS: We retrospectively reviewed 99 patients with borderline resectable (n=25) or locally advanced pancreatic cancer (n=74) treated with DP-neoadjuvant chemoradiation from 2010 to 2015. Tumor and regional lymph nodes were prescribed 50.4 Gy and the region around the involved blood vessel was boosted to 58.8 Gy in 28 fractions. The primary outcome was acute toxicity and late duodenal toxicity. Secondary outcomes included conversion to surgical resectability, local failure, disease-free survival, and overall survival (OS). Cox proportional hazards models were performed to evaluate for predictors of survival. RESULTS: All but 1 patient completed chemoradiation. The rates of grade 2+ and 3+ nausea were 40% and 12%, respectively. With regards to late toxicity, 5 patients developed potential RT-related grade 3+ duodenal complications including duodenal ulceration/bleeding (n=3) and duodenal stricture (n=2). With a median follow-up of 15 months, the median OS was 18.1 months. Among 99 patients in our study, 37 patients underwent surgical resection. For patients who underwent surgical resection (n=37), the median OS was 30.9 months. On multivariate analysis, only normalization of CA 19-9 post-RT was associated with improved OS. CONCLUSIONS: We found that DP-neoadjuvant chemoradiation to regions of vessel involvement is both feasible and well tolerated. In addition, we demonstrated that over one third of patients with initially deemed unresectable disease were able to undergo surgical resection after receiving neoadjuvant therapy including DP-chemoradiation.

Phase II Study of Proton-Based Stereotactic Body Radiation Therapy for Liver Metastases: Importance of Tumor Genotype.

Background: We evaluated the efficacy and safety of risk-adapted, proton-based stereotactic body radiation therapy (SBRT) for liver metastases from solid tumors. Methods: This single-arm phase II single institutional study (NCT01239381) included patients with limited extrahepatic disease, 800 mL or greater of uninvolved liver, and no cirrhosis or Child-Pugh A, who had received proton-based SBRT to one to four liver metastases from solid tumors. Treatment comprised 30 to 50 Gray equivalent (GyE) in five fractions based on the effective volume of liver irradiated. Sample size was calculated to determine if local control (LC) at one year was greater than 70%. The cumulative incidence of local failure was used to estimate LC. The association of tumor characteristics, including genetic alterations in common cancer genes such as BRAF, EGFR, HER2, KRAS, NRAS, PIK3CA, and TP53 with local tumor control, was assessed. All statistical tests were two-sided. Results: Eighty-nine patients were evaluable (colorectal, n = 34; pancreatic, n = 13; esophagogastric, n = 12; other, n = 30). Median tumor size was 2.5 cm (range = 0.5-11.9 cm). Median dose was 40 GyE (range = 30-50 GyE), and median follow-up was 30.1 months (range = 14.7-53.8 months). There was no grade 3 to 5 toxicity. Median survival time was 18.1 months. The one- and three-year LC rates were 71.9% (95% confidence limit [CL] = 62.3% to 80.9%) and 61.2% (95% CL = 50.8% to 71.8%), respectively. For large tumors (≥6 cm), one-year LC remained high at 73.9% (95% CL = 54.6% to 89.8%). Mutation in the KRAS oncogene was the strongest predictor of poor LC (P = .02). Tumor with both mutant KRAS and TP53 were particularly radioresistant, with a one-year LC rate of only 20.0%, compared with 69.2% for all others (P = .001). Conclusions: We report the largest prospective evaluation to date of liver SBRT for hepatic metastases, and the first with protons. Protons were remarkably well tolerated and effective even for metastases that were 6 cm or larger. KRAS mutation is a strong predictor of poor LC, stressing the need for tumor genotyping prior to SBRT and treatment intensification in this patient subset.

Prognostic Significance of Surgical Margin Size After Neoadjuvant FOLFOX and/or FOLFIRI for Colorectal Liver Metastases.

PURPOSE: Optimal margin size when resecting colorectal liver metastases (CRLM) remains unclear, particularly in the setting of perioperative chemotherapy. We evaluated the prognostic significance of margin size in patients who received neoadjuvant FOLFOX and/or FOLFIRI prior to resection of CRLM. METHODS: Clinicopathologic factors were collected for patients who underwent curative liver resections for CRLM between 4/2004-1/2016 and received neoadjuvant oxaliplatin and/or irinotecan and 5-FU (FOLFOX, FOLFIRI). Margins were categorized as < 1, ≥ 1-< 5, ≥ 5-< 10, or ≥ 10 mm and evaluated for association with overall survival (OS) and disease-free survival (DFS) by Cox multiple regression analysis. Margin status was classified as positive (< 1 mm) or negative (≥ 1 mm) and similarly evaluated. RESULTS: Of 227 patients, the median age was 58 years and most had synchronous (80%) lesions. The majority had colon cancers (75%). Margin sizes were 13% < 1 mm, 27% ≥ 1-< 5 mm, 23% ≥ 5-< 10 mm, 36% ≥ 10 mm. Most (63%) received chemotherapy post-liver resection. Five-year OS and DFS were 54% (95% CI 46-62%) and 22% (95% CI 16-28%), respectively. Positive margins significantly increased the risk of death without post-liver resection chemotherapy (HR = 3.32, p = 0.0077), but not with post-liver resection chemotherapy (HR = 1.00, p = 0.99). Negative margin sizes of ≥ 1-< 5, ≥ 5-< 10, and ≥ 10 mm were not significant predictors of OS (p > 0.05). CONCLUSION: Patients undergoing liver resection for CRLM should receive post-resection chemotherapy if negative margins (≥ 1 mm) cannot be achieved. For patients receiving FOLFOX and/or FOLFIRI chemotherapy, wider margins did not improve OS.

Long-term outcomes and toxicities of a large cohort of anal cancer patients treated with dose-painted IMRT per RTOG 0529.

PURPOSE: To describe the outcomes and toxicities of the largest cohort to date of patients with anal squamous cell carcinoma uniformly treated with concurrent chemoradiation using dose-painted intensity modulated radiation therapy (DP-IMRT) according to RTOG 0529. METHODS AND MATERIALS: We identified 99 eligible patients with anal cancer who were treated at our institution with definitive chemoradiation using DP-IMRT between 2005 and 2015 per RTOG 0529 dosing guidelines. Primary study endpoints included event-free survival (defined as recurrence, colostomy, or death) and overall survival. Secondary endpoints were treatment duration and acute and late toxicity. RESULTS: At a median follow-up of 49 months (range, 2-114 months), 92% of patients had a clinical complete response. Fifteen percent underwent colostomy, including 4 pretreatment colostomies, 6 planned abdominoperineal resections (APRs), 4 salvage APRs, and 1 APR for treatment-related complications. Thirteen patients developed local recurrence, of whom 6 developed synchronous metastatic disease. The 4-year overall survival was 85.8%, and 4-year event-free survival was 75.5%. Median treatment duration was 43 days (range, 10-68 days). The overall rate of non-hematologic grade 3+ acute and grade 2+ late toxicities was 20% and 15%, respectively. CONCLUSIONS: Long-term outcomes and tolerability were excellent In the largest cohort to date of patients with anal cancer who received DP-IMRT prescribed per RTOG 0529.