The Revised R Status is an Independent Predictor of Postresection Survival in Pancreatic Cancer After Neoadjuvant Treatment

OBJECTIVE

To investigate the oncological outcomes of patients with pancreatic ductal adenocarcinoma (PDAC) who had an R 0 or R 1 resection based on the revised R status (1 mm) after neoadjuvant therapy (NAT).

BACKGROUND

The revised R status is an independent prognostic factor in upfront-resected PDAC; however, the significance of 1 mm margin clearance after NAT remains controversial.

METHODS

Patients undergoing pancreatectomy after NAT for PDAC were identified from 2 prospectively maintained databases. Clinicopathological and survival data were analyzed. The primary outcomes were overall survival (OS), recurrence-free survival (RFS), and pattern of recurrence in association with R 0 >1 mm and R 1 ≤1 mm resections.

RESULTS

Three hundred fifty-seven patients with PDAC were included after NAT and subsequent pancreatic resection. Two hundred eight patients (58.3%) received FOLFIRINOX, 41 patients (11.5%) received gemcitabine-based regimens, and 299 individuals (83.8%) received additional radiotherapy. R 0 resections were achieved in 272 patients (76.2%) and 85 patients (23.8%) had R 1 resections. Median OS after R 0 was 41.0 months, compared with 20.6 months after R 1 resection ( P = 0.002), and even longer after additional adjuvant chemotherapy ( R 0 44.8 vs R1 20.1 months; P = 0.0032). Median RFS in the R 0 subgroup was 17.5 months versus 9.4 months in the R 1 subgroup ( P < 0.0001). R status was confirmed as an independent predictor for OS ( R 1 hazard ratio: 1.56, 95% CI: 1.07-2.26) and RFS ( R 1 hazard ratio: 1.52; 95% CI: 1.14-2.0). In addition, R 1 resections were significantly associated with local but not distant recurrence ( P < 0.0005).

CONCLUSIONS

The revised R status is an independent predictor of postresection survival and local recurrence in PDAC after NAT. Achieving R 0 resection with a margin of at least 1 mm should be a primary goal in the surgical treatment of PDAC after NAT.

Pancreatic Serous Cystadenoma: A Continuing Diagnostic Challenge

Objective:

Summary Background data:

Serous cystadenoma (SCA) is a benign cystic pancreatic neoplasm of the pancreas, accounting for approximately 15% of resected pancreatic cysts. Current recommendations are to proceed with surgical resection in symptomatic patients or when there is uncertainty regarding diagnosis. The latter continues to be a challenge since intentional resection of a serous cystadenoma account for only a minority of resected of cases.

Methods:

Retrospective single-institution review of patients who on final pathology had a diagnosis of pancreatic serous cystadenoma and of patients who had this diagnosis and were managed non-operatively. Demographic data, cyst characteristics, and growth rate were collected for analysis.

Results:

A total of 250 patients were analyzed. Median age was 62 (range 22 – 89), 65% were female, and 34% had symptoms. Tumor size ranged from 0.6 to 20, with a median of 3.4 cm. The morphological appearance was microcystic in 58%, macrocystic in 16%, mixed-type in 23%, and solid in 3%. Pancreatic duct dilation and pancreatic atrophy were found in 22% and 14%, respectively. The average growth rate was 1.8 mm/year regardless of tumor size. Of the 172 patients who underwent surgery, serous cystadenoma was the preoperative diagnosis in only 33%. A correct diagnosis was independently associated with large tumors and cyst fluid CEA analysis. Pancreatic duct dilation was independently associated with an in-growing cyst and presence of calcification.

Conclusion:

SCA is a slow-growing pancreatic cystic neoplasm that is mostly asymptomatic but can lead to pancreatic duct dilation and atrophy in some patients. A surprisingly small number of correct preoperative diagnoses confirms that this entity continues to be a diagnostic challenge. A more thorough preoperative workup that includes EUS should improve the rate of mis-diagnosis.

Caregiver-reported quality of communication in pancreatic and periampullary cancer

BACKGROUND

Communication between caregivers and clinical team members is critical for transitional care, but its quality and potential impact on outcomes are not well understood. This study reports on caregiver-reported quality of communication with clinical team members in the postpancreatectomy period and examines associations of these reports with patient and caregiver outcomes.

METHODS

Caregivers of patients with pancreatic and periampullary malignancies who had undergone pancreatectomy were surveyed. Instrument measures assessed care experiences using the Caregiver Perceptions About Communication with Clinical Team Members (CAPACITY) instrument. The instrument has two main subscales: communication, assessing the extent to which providers helped caregivers comprehend details of clinical visits, and capacity, defined as the extent to which providers assessed whether caregivers were able to care for patients.

RESULTS

Of 265 caregivers who were approached, 240 (90.6%) enrolled in the study. The mean communication and capacity subscale scores were 2.7 ± 0.6 and 1.5 ± 0.6, respectively (range, 0-4 [higher = better]). Communication subscale scores were lower among caregivers of patients who experienced (vs. those who did not experience) a 30-day readmission (2.6 ± 0.5 vs. 2.8 ± 0.6, respectively; p = .047). Capacity subscale scores were inversely associated with restriction in patient daily activities (a 0.04 decrement in the capacity score for every 1 point in daily activity restriction; p = .008).

CONCLUSIONS

After pancreatectomy, patients with pancreatic and periampullary cancer whose caregivers reported worse communication with care providers were more likely to experience readmission. Caregivers of patients with greater daily activity restrictions were less likely to report being asked about the caregiver's skill and capacity by clinicians.

PLAIN LANGUAGE SUMMARY

This prospective study used a validated survey instrument and reports on the quality of communication between health care providers and caregivers as reported by caregivers of patients with pancreatic and periampullary cancer after pancreatectomy. In an analysis of 240 caregivers enrolled in the study, lower communication scores (the extent to which providers helped caregivers understand clinical details) were associated with higher odds of 30-day patient readmission to the hospital. In addition, lower capacity scores (the extent to which providers assessed caregivers' ability to care for patients) were associated with greater impairment in caregivers. The strikingly low communication quality and capacity assessment scores suggest substantial room for improvement, with the potential to improve both caregiver and patient outcomes.

Portal Vein or Superior Mesenteric Vein Thrombosis with Dose-Escalated Radiation for Borderline or Locally Advanced Pancreatic Cancer

PURPOSE

Portal vein and superior mesenteric vein thrombosis (PVT/SMVT) are potentially morbid complications of radiation dose-escalated local therapy for pancreatic cancer. We retrospectively reviewed records for patients treated with and without intraoperative radiation (IORT) to identify risk factors for PVT/SMVT.

METHODS

Ninety-six patients with locally advanced or borderline resectable pancreatic adenocarcinoma received neoadjuvant therapy followed by surgical exploration from 2009 to 2014. Patients at risk for close or positive surgical margins received IORT boost to a biologically effective dose (BED10) > 100. Prognostic factors for PVT/SMVT were evaluated using competing risks regression.

RESULTS

Median follow-up was 79 months for surviving patients. Fifty-six patients (58%) received IORT. Twenty-nine patients (30%) developed PVT/SMVT at a median time of 18 months. On univariate competing risks regression, operative blood loss and venous repair with a vascular interposition graft, but not IORT dose escalation or diabetes history, were significantly associated with PVT/SMVT. The development of thrombosis in the absence of recurrence was significantly associated with a longstanding diabetes history, post-neoadjuvant treatment CA19-9, and operative blood loss. All 4 patients who underwent both IORT and vascular repair with a graft developed PVT/SMVT. PVT/SMVT in the absence of recurrence is not associated with significantly worsened overall survival but led to frequent medical interventions.

CONCLUSIONS

Approximately 30% of patients who underwent neoadjuvant chemoradiation for PDAC developed PVT/SMVT a median of 18 months following surgery. This was significantly associated with venous reconstruction with vascular grafts, but not with escalating radiation dose. PVT/SMVT in the absence of recurrence was associated with significant morbidity.

Smoking impairs the effect of neoadjuvant FOLFIRINOX on postresection survival in pancreatic cancer

INTRODUCTION

Smoking plays an important role in carcinogenesis, including pancreatic ductal adenocarcinoma (PDAC). However, little is known about the association between smoking status and prognosis in resected PDAC.

METHODS

All patients who underwent resection for PDAC were identified from two prospective institutional databases. Clinicopathologic data as well as demographics including smoking status were extracted. Survival analysis and multivariable Cox regression modelling was performed. Restricted cubic splines were used for linear data to define cut-off points.

RESULTS

Out of 848 patients, 357 (42.1%) received neoadjuvant treatment (NAT), 491 upfront resection (57.9%), and 475 (56%) adjuvant therapy. The median overall survival (OS) was 27.8 months, 36.1 months, and 23.0 months for the entire cohort, after NAT and upfront resection. 464 patients were never smokers (54.7%), 250 former smokers (29.5%), and 134 active smokers (15.8%). In the multivariable model, the interaction of neoadjuvant FOLFIRINOX and active smoking was associated with the highest risk for decreased OS (harzard ratio (HR) 2.35; 95% confidence interval 1.13-4.90) and strongly mitigated the benefit of FOLFIRNOX (HR 0.40; 95% CI 0.25-0.63). Adjusted median OS in NAT patients with FOLFIRINOX was not reached for never and former smokers, compared to 26.2 months in active smokers. Based on the model, a nomogram was generated to illustrate the probability of 5-year survival after PDAC resection.

CONCLUSION

The present study confirms that neoadjuvant FOLFIRINOX is associated with excellent survival and demonstrates that active smoking reduces its benefit. The nomogram can assist in daily clinical practice and emphasises the importance of smoking cessation in patients with PDAC, especially prior to NAT with FOLFIRINOX.

Profile of the Postoperative Care Provided for Patients With Pancreatic and Periampullary Cancers by Family and Unpaid Caregivers

PURPOSE

Patients with pancreatic and periampullary cancers may experience significant reduction in their quality of life and often rely on family and unpaid caregivers for assistance after surgery. However, as caregivers are not systematically identified, little is known about the nature, difficulty, and personal demands of assistance they provide. We aim to assess the frequency and difficulty of specific assistance caregivers provide and identify potential interventions that could alleviate the caregiving demands.

METHODS

This was a prospective, multi-institutional study of caregivers accompanying patients with periampullary and pancreatic cancer at their 1-month postpancreatectomy office visit. An instrument that drew heavily on the National Study of Caregiving was administered to caregivers.

RESULTS

Of 240 caregivers, more than half (58.3%) of caregivers were the patients' spouse, a quarter (25.8%) were daughters or sons, 12.9% other relatives, and 2.9% nonrelatives. Caregivers least frequently provided assistance with transportation (14.6% every day) and most frequently provided assistance with housework (65.0% every day, P = .003) and diet (56.5% every day, P = .004). Caregivers reported the least difficulty helping patients with exercise (1.5% somewhat difficult). Caregivers reported significantly more difficulty with assisting with housework (14.5% somewhat difficult, P < .001) and diet (14.9% somewhat difficult, P < .001). Caregivers identified the immediate postpancreatectomy and early discharge periods as the most stressful phases. They also reported having received very little information about available services that could have supported their efforts.

CONCLUSION

Caregivers of patients with periampullary or pancreatic cancer provide considerable assistance in the postoperative period and many reported difficulty in assisting with housework and diet. Work is needed to better prepare and support caregivers to better enable them to adequately care for patients with pancreas and periampullary cancer.

IPMN-LEARN: A linear support vector machine learning model for predicting low-grade intraductal papillary mucinous neoplasms

Backgrounds/Aims

We aimed to build a machine learning tool to help predict low-grade intraductal papillary mucinous neoplasms (IPMNs) in order to avoid unnecessary surgical resection. IPMNs are precursors to pancreatic cancer. Surgical resection remains the only recognized treatment for IPMNs yet carries some risks of morbidity and potential mortality. Existing clinical guidelines are imperfect in distinguishing low-risk cysts from high-risk cysts that warrant resection.

Methods

We built a linear support vector machine (SVM) learning model using a prospectively maintained surgical database of patients with resected IPMNs. Input variables included 18 demographic, clinical, and imaging characteristics. The outcome variable was the presence of low-grade or high-grade IPMN based on post-operative pathology results. Data were divided into a training/validation set and a testing set at a ratio of 4:1. Receiver operating characteristics analysis was used to assess classification performance.

Results

A total of 575 patients with resected IPMNs were identified. Of them, 53.4% had low-grade disease on final pathology. After classifier training and testing, a linear SVM-based model (IPMN-LEARN) was applied on the validation set. It achieved an accuracy of 77.4%, with a positive predictive value of 83%, a specificity of 72%, and a sensitivity of 83% in predicting low-grade disease in patients with IPMN. The model predicted low-grade lesions with an area under the curve of 0.82.

Conclusions

A linear SVM learning model can identify low-grade IPMNs with good sensitivity and specificity. It may be used as a complement to existing guidelines to identify patients who could avoid unnecessary surgical resection.

EGFR is a potential therapeutic target for highly glycosylated and aggressive pancreatic neuroendocrine neoplasms

pNENs are relative indolent tumors with heterogeneous clinical presentation at diagnosis. It is important to establish aggressive subgroups of pNENs and identify potential therapeutic targets. Patients with pNEN (322 cases) were included to examine the association between glycosylation biomarkers and clinical/pathological traits. The molecular and metabolic features stratified by glycosylation status were assessed by RNA-seq/whole exome sequencing and immunohistochemistry. A considerable proportion of patients had elevated glycosylation biomarkers (carbohydrate antigen [CA] 19-9, 11.9%; CA125, 7.5%; carcinoembryonic antigen [CEA], 12.8%). CA19-9 (hazard ratio [HR] = 2.26, P = .019), CA125 (HR = 3.79, P = .004) and CEA (HR = 3.16, P = .002) were each independent prognostic variables for overall survival. High glycosylation group, defined as pNENs with elevated level of circulating CA19-9, CA125 or CEA, accounted for 23.4% of all pNENs. High glycosylation (HR = 3.14, P = .001) was an independent prognostic variable for overall survival and correlated with G3 grade (P < .001), poor differentiation (P = .001), perineural invasion (P = .004) and distant metastasis (P < .001). Epidermal growth factor receptor (EGFR) was enriched in high glycosylation pNENs using RNA-seq. EGFR was expressed in 21.2% of pNENs using immunohistochemistry and associated with poor overall survival (P = .020). A clinical trial focusing on EGFR expressed pNENs was initiated (NCT05316480). Thus, pNEN with aberrant glycosylation correlates with a dismal outcome and suggests potential therapeutic target of EGFR.

Identification of high-risk features in mucinous cystic neoplasms of the pancreas

BACKGROUND

Mucinous cystic neoplasms of the pancreas are uncommon tumors that have the potential of becoming cancer. There is no consensus regarding the high-risk features of these tumors. Our study aimed to identify the preoperative demographic, clinical, or radiologic factors that can predict the presence of high-grade dysplasia or invasive carcinoma in mucinous cystic neoplasms of the pancreas.

METHODS

We identified 157 patients who underwent resection and fulfilled the pathologic criteria for mucinous cystic neoplasms of the pancreas in a prospectively maintained database spanning 3 decades (1990-2020). Multivariable logistic regression was used to identify predictors of high-grade dysplasia or invasive carcinoma in mucinous cystic neoplasms of the pancreas.

RESULTS

The rate of high-grade dysplasia or invasive carcinoma was 11%. Tumor size ≥4 cm (P < .001), mural nodularity (P = .04), and a serum CA 19-9 level >37 U/mL (P < .001) were associated with high-grade dysplasia or invasive carcinoma. In the multivariable analysis, tumor size ≥4 cm (odds ratio 16.9, 95% confidence interval 2.04-140, P = .009) and a CA 19-9 level >37 U/mL (odds ratio 5.68, 95% confidence interval 1.52-21.3, P = .010) were predictors of high-grade dysplasia or invasive carcinoma. There were no tumors with high-grade dysplasia or invasive carcinoma in patients with tumor size <4 cm in the absence of an elevated CA 19-9 or mural nodularity.

CONCLUSION

Tumors with a size ≥4 cm and/or a high CA 19-9 level should be considered for prompt surgical resection. Conversely, tumors <4 cm with no other high-risk features have a negligible risk for high-grade dysplasia or invasive carcinoma and may benefit from nonoperative surveillance. Mural nodularity is an additional suspicious feature. These findings may contribute to future guidelines.

Assessment of Caregivers' Burden When Caring for Patients With Pancreatic and Periampullary Cancer

BACKGROUND

Family and other unpaid caregivers play an active role in the recovery of individuals with pancreatic and periampullary cancer after pancreatectomy. However, little is known about caregivers' experiences and how to better support them.

METHODS

Caregivers accompanying patients to 1-month postpancreatectomy visits at 3 hospitals completed an electronic survey between November 2018 and February 2020. We examine measures of absenteeism and work productivity loss among the subset of caregivers who reported working for pay and comparatively assess caregiver experiences by employment status. All analyses were performed as 2-sided tests.

RESULTS

Of 265 caregivers approached for study participation, 240 (90.6%) enrolled. Caregivers were primarily female (70.8% female, 29.2% male) and spouses (58.3%) or adult children (25.8%) of patients, with a median age of 60 years. Of the 240 caregivers included in the study, 107 (44.6%) worked for pay. Nearly half (44.4%) of working caregivers reported being absent from work because of caregiving amounting to a 14% loss in work hours. While at work, 58.9% of working caregivers reported increased work difficulty as a result of caregiving. Taken together, an estimated 59.7% loss in work productivity was experienced because of caregiving in the month following pancreatectomy. After adjustment for sociodemographic factors, working (vs nonworking) caregivers reported increased financial (odds ratio [OR] = 2.32; P = .04) and emotional (OR = 1.93; P = .04) difficulties and daily activity restrictions (OR = 1.85; P = .048).

CONCLUSIONS

Working caregivers of patients with pancreatic and periampullary cancer experience negative impacts on work and productivity, and caregiving-related financial and emotional difficulties may be amplified. This study highlights the need for workplace policies to support unpaid cancer caregiving.

Number of Worrisome Features and Risk of Malignancy in Intraductal Papillary Mucinous Neoplasm

BACKGROUND

The 2017 revised International Association of Pancreatology guidelines for management of intraductal papillary mucinous neoplasm (IPMN) describe worrisome features (WF) and high-risk stigmata (HRS), recommending resection in the latter and further work-up and close surveillance for patients with WF. The effect of multiple WF on the likelihood of malignancy has not been evaluated.

STUDY DESIGN

Eight hundred ten patients who underwent pancreatic resection for IPMN in 2 tertiary referral centers were identified from prospective institutional databases. Patients were retrospectively categorized into subgroups according to the number of WF or HRS and presence of malignancy, defined as high-grade dysplasia (HGD) or invasive cancer on final pathology.

RESULTS

Three hundred seventy-nine (47%) patients had HRS, 370 (46%) had 1 or more WF, and 61 patients (7%) had neither. Malignancy was present in 70% (n = 267) of patients with HRS and in 30% (n = 127) of those with WF. Only 3 of 61 patients without WF/HRS had malignancy, and all only in the form of HGD. The risk of malignancy increased in a stepwise fashion with the number of WF, to 22%, 34%, and 59% with 1, 2, and 3 WF, respectively (p = 0.001), and reached 100% in patients with 4 or more WF. Although the relative risks differed for particular WF, the areas under the curve were not statistically different.

CONCLUSION

We confirm that presence of HRS in IPMN is associated with a very high likelihood of malignancy. The presence of a single WF has a malignancy risk of 22%, and additional WF increase this risk significantly. When 3 or more WF are present, the risk is similar to that of HRS.

ABO blood group distribution and risk of malignancy in patients undergoing resection for intraductal papillary mucinous neoplasm (IPMN)

BACKGROUND

The ABO blood type has been associated with risk of development of several malignancies, including pancreatic cancer. Data regarding IPMN is equivocal. To investigate this further, we analyzed the association between the ABO blood group and the presence of malignancy in a large cohort of resected IPMN and its influence in survival.

METHODS

819 patients who underwent pancreatic resection for IPMN in the Massachusetts General Hospital (MGH) and Cambridge University Hospitals NHS Foundation Trust (CUH) from January 1993 to December 2020 were identified from prospective institutional databases. Pathological characteristics and blood type were correlated.

RESULTS

The distribution of blood types A, B, AB and O was 384 (47%), 92 (11%), 44 (5%) and 299 (37%), respectively. This blood type distribution was different than the reference population of the MGH and the CUH, which is 55% non-O blood group, and 45% type O. There was a significant predominance of non-O blood types when compared with O-blood type in patients with malignant IPMN (i.e. patients with high-grade dysplasia and invasive cancer) (67% vs 33%, OR 1.31 95%CI: 0.98-1.75, p = 0.069). The association was stronger for IPMN with invasive cancer (OR 1.43 95%CI: 1.01-2.02, p = 0.039). Blood group did not influence survival.

CONCLUSION

Non-O blood type is associated with need for resection in IPMN and with presence of invasive carcinoma.

A Combination of Biochemical and Pathological Parameters Improves Prediction of Postresection Survival After Preoperative Chemotherapy in Pancreatic Cancer: The PANAMA-score

OBJECTIVE

To build a prognostic score for patients with primary chemotherapy undergoing surgery for pancreatic cancer based on pathological parameters and preoperative Carbohydrate antigen 19-9 (CA19-9) levels.

BACKGROUND

Prognostic stratification after primary chemotherapy for pancreatic cancer is challenging and prediction models, such as the AJCC staging system, lack validation in the setting of preoperative chemotherapy.

METHODS

Patients with primary chemotherapy resected at the Massachusetts General Hospital between 2007 and 2017 were analyzed. Tumor characteristics independently associated with overall survival were identified and weighted by Cox-proportional regression. The pancreatic neoadjuvant Massachusetts-score (PANAMA-score) was computed from these variables and its performance assessed by Harrel concordance index and area under the receiving characteristics curves analysis. Comparisons were made with the AJCC staging system and external validation was performed in an independent cohort with primary chemotherapy from Heidelberg, Germany.

RESULTS

A total of 216 patients constituted the training cohort. The multivariate analysis demonstrated tumor size, number of positive lymph-nodes, R-status, and high CA19-9 to be independently associated with overall survival. Kaplan-Meier analysis according to low, intermediate, and high PANAMA-score showed good discriminatory power of the new metrics (P < 0.001). The median overall survival for the three risk-groups was 45, 27, and 12 months, respectively. External validation in 258 patients confirmed the prognostic ability of the score and demonstrated better accuracy compared with the AJCC staging system.

CONCLUSION

The proposed PANAMA-score, based on independent predictors of postresection survival, including pathologic variables and CA19-9, not only provides better discrimination compared to the AJCC staging system, but also identifies patients at high-risk for early death.

Passing the Scalpel: Lessons on retirement planning from retired academic surgeons

BACKGROUND

Almost half of practicing surgeons in the United States are currently older than 55, but guidelines on how to prepare for retirement are limited. We sought to identify possible facilitators for, and obstacles to, surgeons' preparations for retirement.

METHODS

A qualitative study was conducted using semi-structured interviews with clinically inactive academic surgeons. Emergent themes were identified via a grounded theory approach.

RESULTS

We interviewed 12 surgeons (83% male; median age 75 years). Major barriers to retirement from surgery included uncertainty about when to retire, limited identity outside of surgery, and perception of retirement as strictly individual/private. Facilitators of a successful retirement identified by the participants included early career financial planning, awareness of career trajectory, development of post-surgery goals, and utilization of collective knowledge.

CONCLUSION

There are numerous barriers encountered by surgeons seeking to transition from clinical practice to retirement that could be overcome by dedicated departmental and institutional efforts.

Conditional Survival in Resected Pancreatic Ductal Adenocarcinoma Patients Treated with Total Neoadjuvant Therapy

BACKGROUND

Dynamic survival data based on time already survived are lacking for resected borderline resectable/locally advanced (BR/LA) pancreatic ductal adenocarcinoma (PDAC) patients who received total neoadjuvant therapy (TNT) with FOLFIRINOX followed by chemoradiation. Conditional survival, i.e., the probability of surviving an additional length of time after having already survived an amount of time, offers such information. We aimed to determine actuarial and conditional overall (OS, COS) and disease-free survival (DFS, CDFS) among this cohort.

METHODS

Clinicopathologic data were retrospectively collected for resected BR/LA PDAC patients who received TNT (2011-2019). COS and CDFS rates were calculated for patients being event (death/recurrence)-free at multiple intervals and by recurrence status.

RESULTS

After a median follow-up of 32.1 months, the 183 patients had a median OS and DFS of 39.1 months and 16.8 months, respectively. COS and CDFS increased as a function of time already survived. The probability of surviving an additional 24 months if a patient survived 2 years post-operatively was 70%, whereas the 4-year actuarial OS was 47%. Similarly, the probability of surviving disease-free an additional 24 months after 2 years was 66%, while actuarial 48-month DFS was 27%. COS for disease-free patients increased further over time. For patients remaining disease-free 12 months post-operatively, BR vs. LA status at diagnosis, tumor ≤ 4 cm at diagnosis, and R0 resection were independent predictors of favorable additional OS and DFS.

CONCLUSIONS

For resected TNT-treated BR/LA PDAC patients, the probability of surviving an additional length of time increases as a function of survival already accrued. Dynamic survival estimates may allow personalized follow-up and counseling.

Revision of Pancreatic Neck Margins Based on Intraoperative Frozen Section Analysis Is Associated With Improved Survival in Patients Undergoing Pancreatectomy for Ductal Adenocarcinoma

OBJECTIVE

To test the hypothesis that complete, tumor-free resection at the pancreatic neck, achieved either en-bloc or non-en-bloc (ie, revision based on intraoperative frozen section [FS] analysis), is associated with improved survival as compared with incomplete resection (IR) in pancreatic ductal adenocarcinoma.

SUMMARY BACKGROUND DATA

Given the likely systemic nature of pancreatic ductal adenocarcinoma, the oncologic benefit of achieving a histologically complete local resection, particularly through revision of a positive intraoperative FS at the pancreatic neck, remains controversial.

METHODS

Clinicopathologic and treatment data were reviewed for 986 consecutive patients with ductal adenocarcinoma at the head, neck, or uncinate process of the pancreas who underwent open pancreatectomy as well as intraoperative FS analysis between 1998 and 2012 at Massachusetts General Hospital and between 1998 and 2013 at the University of Verona. Overall survival (OS) and perioperative morbidity and mortality were compared across 3 groups: complete resection achieved en-bloc (CR-EB), complete resection achieved non-en-bloc (CR-NEB), and IR.

RESULTS

The CR-EB cohort comprised 749 (76%) patients, CR-NEB 159 patients (16%), and IR 78 patients (8%). Other than a higher incidence of vascular resection among CR-NEB and IR patients, no demographic, pathologic (eg, tumor grade, lymph node positivity, superior mesenteric artery involvement), or treatment factors (eg, neoadjuvant and adjuvant therapy use) differed between the groups. Median OS was significantly higher in patients with CR-EB (28 mo, P = 0.01) and CR-NEB resections (24 mo, P = 0.02) as compared with patients with IR resections (19 mo). After adjusting for clinicopathologic and treatment characteristics, CR-EB and CR-NEB margin status were found to be independent predictors of improved OS (relative to IR, CR-EB hazard ratio [HR] 0.65, 95% confidence interval [CI] 0.49-0.86; CR-NEB HR 0.69, 95% CI 0.50-0.96). There were no intergroup differences in perioperative morbidity and mortality, including rates of pancreatic fistula.

CONCLUSIONS

For patients with ductal adenocarcinoma at the head, neck, or uncinate process of the pancreas undergoing pancreatectomy, complete tumor extirpation via either en-bloc or non-en-bloc complete resection based on FS analysis is associated with improved OS, without an associated increased perioperative morbidity or mortality.

Simulated Volume-Based Regionalization of Complex Procedures: Impact on Spatial Access to Care

OBJECTIVE

This study simulates the regionalization of pancreatectomies to assess its impact on spatial access in terms of patient driving times.

BACKGROUND

Although policies to regionalize complex procedures to high-volume centers may improve outcomes, the impact on patient access is unknown.

METHODS

Patients who underwent pancreatectomies from 2005 to 2014 were identified from California's statewide database. Round-trip driving times between patients' home ZIP code and hospital addresses were calculated via Google Maps. Regionalization was simulated by eliminating hospitals performing <20 pancreatectomies/yr, and reassigning patients to the next closest hospital that satisfied the volume threshold. Sensitivity analyses were performed for New York and Medicare patients to assess for influence of geography and insurance coverage, respectively.

RESULTS

Of 13,317 pancreatectomies, 6335 (47.6%) were performed by hospitals with <20 cases/yr. Patients traveled a median of 49.8 minutes [interquartile range (IQR) 30.8-96.2] per round-trip. A volume-restriction policy would increase median round-trip driving time by 24.1 minutes (IQR 4.5-53.5). Population in-hospital mortality rates were estimated to decrease from 6.7% to 2.8% (P < 0.001). Affected patients were more likely to be racial minorities (44.6% vs 36.5% of unaffected group, P < 0.001) and covered by Medicaid or uninsured (16.3% vs 9.8% of unaffected group, P < 0.001). Sensitivity analyses revealed a 17.8 minutes increment for patients in NY (IQR 0.8-47.4), and 27.0 minutes increment for Medicare patients (IQR 6.2-57.1).

CONCLUSIONS

A policy that limits access to low-volume pancreatectomy hospitals will increase round-trip driving time by 24 minutes, but up to 54 minutes for 25% of patients. Population mortality rates may improve by 1.5%.

Influence of Klebsiella pneumoniae and quinolone treatment on prognosis in patients with pancreatic cancer

BACKGROUND

An increasing body of evidence suggests that microbiota may promote progression of pancreatic ductal adenocarcinoma (PDAC). It was hypothesized that gammaproteobacteria (such as Klebsiella pneumoniae) influence survival in PDAC, and that quinolone treatment may attenuate this effect.

METHODS

This was a retrospective study of patients from the Massachusetts General Hospital (USA) and Ludwig-Maximilians-University (Germany) who underwent preoperative treatment and pancreatoduodenectomy for locally advanced or borderline resectable PDAC between January 2007 and December 2017, and for whom a bile culture was available. Associations between tumour characteristics, survival data, antibiotic use and results of intraoperative bile cultures were investigated. Survival was analysed using Kaplan-Meier curves and Cox regression analysis.

RESULTS

Analysis of a total of 211 patients revealed that an increasing number of pathogen species found in intraoperative bile cultures was associated with a decrease in progression-free survival (PFS) (-1·9 (95 per cent c.i. -3·3 to -0·5) months per species; P = 0·009). Adjuvant treatment with gemcitabine improved PFS in patients who were negative for K. pneumoniae (26·2 versus 15·3 months; P = 0·039), but not in those who tested positive (19·5 versus 13·2 months; P = 0·137). Quinolone treatment was associated with improved median overall survival (OS) independent of K. pneumoniae status (48·8 versus 26·2 months; P = 0·006) and among those who tested positive for K. pneumoniae (median not reached versus 18·8 months; P = 0·028). Patients with quinolone-resistant K. pneumoniae had shorter PFS than those with quinolone-sensitive K. pneumoniae (9·1 versus 18·8 months; P = 0·001).

CONCLUSION

K. pneumoniae may promote chemoresistance to adjuvant gemcitabine, and quinolone treatment is associated with improved survival.

Tumor Microenvironment Immune Response in Pancreatic Ductal Adenocarcinoma Patients Treated With Neoadjuvant Therapy

BACKGROUND

Neoadjuvant folinic acid, fluorouracil, irinotecan, and oxaliplatin (FOLFIRINOX) and chemoradiation have been used to downstage borderline and locally advanced pancreatic ductal adenocarcinoma (PDAC). Whether neoadjuvant therapy-induced tumor immune response contributes to the improved survival is unknown. Therefore, we evaluated whether neoadjuvant therapy induces an immune response towards PDAC.

METHODS

Clinicopathological variables were collected for surgically resected PDACs at the Massachusetts General Hospital (1998-2016). Neoadjuvant regimens included FOLFIRINOX with or without chemoradiation, proton chemoradiation (25 Gy), photon chemoradiation (50.4 Gy), or no neoadjuvant therapy. Human leukocyte antigen (HLA) class I and II expression and immune cell infiltration (CD4+, FoxP3+, CD8+, granzyme B+ cells, and M2 macrophages) were analyzed immunohistochemically and correlated with clinicopathologic variables. The antitumor immune response was compared among neoadjuvant therapy regimens. All statistical tests were 2-sided.

RESULTS

Two hundred forty-eight PDAC patients were included. The median age was 64 years and 50.0% were female. HLA-A defects were less frequent in the FOLFIRINOX cohort (P = .006). HLA class II expression was lowest in photon and highest in proton patients (P = .02). The FOLFIRINOX cohort exhibited the densest CD8+ cell infiltration (P < .001). FOLFIRINOX and proton patients had the highest CD4+ and lowest T regulatory (FoxP3+) cell density, respectively. M2 macrophage density was statistically significantly higher in the treatment-naïve group (P < .001) in which dense M2 macrophage infiltration was an independent predictor of poor overall survival.

CONCLUSIONS

Neoadjuvant FOLFIRINOX with or without chemoradiation may induce immunologically relevant changes in the tumor microenvironment. It may reduce HLA-A defects, increase CD8+ cell density, and decrease T regulatory cell and M2 macrophage density. Therefore, neoadjuvant FOLFIRINOX therapy may benefit from combinations with checkpoint inhibitors, which can enhance patients' antitumor immune response.

Pancreatic acinar cell carcinoma: A multi-center series on clinical characteristics and treatment outcomes

BACKGROUND

Acinar cell carcinoma (ACC) is a very rare tumor of the exocrine pancreas, representing less than 1% of all pancreatic malignancies. The majority of data regarding ACC are limited to small case series.

METHODS

This is a retrospective study conducted at a large healthcare system from 1996 to 2019. Patients with pathologically confirmed ACC were included, and demographic data, tumor characteristics, and treatment outcomes were abstracted by chart review. Survival curves were obtained by using the Kaplan-Meier method and compared using the log-rank test.

RESULTS

Sixty-six patients with ACC were identified. The median patient age at diagnosis was 64, and 42% presented with metastatic disease. The majority presented with abdominal pain or pancreatitis (69%), and laboratory parameters did not correlate with tumor size, metastatic disease, or survival. Several somatic abnormalities were noted in tumors (BRCA2, TP53, and mismatch-repair genes). In patients with localized disease that underwent resection, the median time to develop metastatic lesions was 13 months. The median overall survival (OS) was 24.7 months from diagnosis, with a survival difference based on metastatic disease at diagnosis (median 15 vs 38 mos). Surgery was associated with improved survival in non-metastatic cases (p = 0.006) but not metastatic cases (p = 0.22), and chemotherapy showed OS benefit in metastatic disease (p < 0.01). Patients with metastatic ACC treated after 2010 utilized more platinum-based agents, and there was a OS benefit to FOLFOX or FOLFIRINOX chemotherapy compared to gemcitabine or capecitabine-based regimens (p = 0.006).

CONCLUSION

Pancreatic ACC patients often present with advanced disease. Surgery was associated with survival benefit among patients presenting with localized disease. The use of FOLFOX or FOLFIRINOX chemotherapy regimens was associated with improved OS in metastatic patients. These data add to our knowledge in this rare malignancy, and improves understanding about the genomic underpinnings, prognosis and treatment for acinar cancers.

Assessment of the Long-Term Impact of Pancreatoduodenectomy on Health-Related Quality of Life Using the EORTC QLQ-PAN26 Module

BACKGROUND

Long-term pancreatoduodenectomy (PD) survivors have previously reported favorable quality of life (QoL). However, there has been a paucity of studies utilizing pancreas-specific modules for QoL assessment, which may uncover disability that general modules cannot detect.

METHODS

The European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30 and QLQ-PAN26 questionnaires were administered to PD survivors who were at least 5 years out of their operations for neoplasms (1998-2011, study cohort) and compared their scores with published preoperative scores of patients with pancreatic cancer (control cohort). The clinical relevance (CR) of differences was scored as small (5-10), moderate (10-20), or large (> 20) based on validated interpretation of clinically important differences.

RESULTS

Of 1266 patients who underwent PD, there were 305 survivors with valid contact information, of whom 248 responded to the questionnaire (response rate 81.3%) and made up the study cohort. The median follow-up was 9.1 years (range 5.1-21.2 years). When compared with the control cohort, patients in the study cohort reported higher pancreatic pain (41.7 ± 17.6 vs. 18.1 ± 20.5, p < 0.001, CR large), sexuality dissatisfaction (63.0 ± 37.5 vs. 35.1 ± 34.3, p < 0.001, CR large), altered bowel habits (37.6 ± 30.6 vs. 20.0 ± 24.5, p < 0.001, CR moderate), and digestive symptoms (26.3 ± 29.5 vs. 18.7 ± 27.8, p = 0.002, CR small) scores. There was a higher prevalence of bloating, indigestion, and flatulence, but lower prevalence of future health worry (71.7% vs. 89.6%, p < 0.001) and limitation in planning activities (30.1% vs. 48.3%, p < 0.001) at 5 years.

CONCLUSION

While post-PD patients had better long-term global QoL than healthy controls, a more granular, pancreas-specific questionnaire uncovered digestive abnormalities and sexuality dissatisfaction. These data can better inform clinical decision making and provide potential areas for improvement and patient support.

Transcriptomic Analysis of Laser Capture Microdissected Tumors Reveals Cancer- and Stromal-Specific Molecular Subtypes of Pancreatic Ductal Adenocarcinoma

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) lethality is multifactorial; although studies have identified transcriptional and genetic subsets of tumors with different prognostic significance, there is limited understanding of features associated with the minority of patients who have durable remission after surgical resection. In this study, we performed laser capture microdissection (LCM) of PDAC samples to define their cancer- and stroma-specific molecular subtypes and identify a prognostic gene expression signature for short-term and long-term survival.

EXPERIMENTAL DESIGN

LCM and RNA sequencing (RNA-seq) analysis of cancer and adjacent stroma of 19 treatment-naïve PDAC tumors was performed. Gene expression signatures were tested for their robustness in a large independent validation set. An RNA-ISH assay with pooled probes for genes associated with disease-free survival (DFS) was developed to probe 111 PDAC tumor samples.

RESULTS

Gene expression profiling identified four subtypes of cancer cells (C1-C4) and three subtypes of cancer-adjacent stroma (S1-S3). These stroma-specific subtypes were associated with DFS (P = 5.55E-07), with S1 associated with better prognoses when paired with C1 and C2. Thirteen genes were found to be predominantly expressed in cancer cells and corresponded with DFS in a validation using existing RNA-seq datasets. A second validation on an independent cohort of patients using RNA-ISH probes to six of these prognostic genes demonstrated significant association with overall survival (median 17 vs. 25 months; P < 0.02).

CONCLUSIONS

Our results identified specific signatures from the epithelial and the stroma components of PDAC, which add clarity to the nature of PDAC molecular subtypes and may help predict survival.

Patient and Caregiver Considerations and Priorities When Selecting Hospitals for Complex Cancer Care

BACKGROUND

Healthcare policies have focused on centralizing care to high-volume centers in an effort to optimize patient outcomes; however, little is known about patients' and caregivers' considerations and selection process when selecting hospitals for care. We aim to explore how patients and caregivers select hospitals for complex cancer care and to develop a taxonomy for their selection considerations.

METHODS

This was a qualitative study in which data were gathered from in-depth interviews conducted from March to November 2019 among patients with hepatopancreatobiliary cancers who were scheduled to undergo a pancreatectomy (n = 20) at a metropolitan, urban regional, or suburban medical center and their caregivers (n = 10).

RESULTS

The interviews revealed six broad domains that characterized hospital selection considerations: hospital factors, team characteristics, travel distance to hospital, referral or recommendation, continuity of care, and insurance considerations. The identified domains were similar between participants seen at the metropolitan center and urban/suburban medical centers, with the following exceptions: participants receiving care specifically at the metropolitan center noted operative volume and access to specific services such as clinical trials in their hospital selection; participants receiving care at urban/suburban centers noted health insurance considerations and having access to existing medical records in their hospital selection.

CONCLUSIONS

This study delineates the many considerations of patients and caregivers when selecting hospitals for complex cancer care. These identified domains should be incorporated into the development and implementation of centralization policies to help increase patient access to high-quality cancer care that is consistent with their priorities and needs.

Risk of malignancy in small pancreatic cysts decreases over time

BACKGROUND

Pancreatic cysts <15 mm without worrisome features have practically no risk of malignancy at the time of diagnosis but this can change over time. Optimal duration of follow-up is a matter of debate. We evaluated predictors of malignancy and attempted to identify a time to safely discontinue surveillance.

METHODS

Bi-centric study utilizing prospectively collected databases of patients with pancreatic cysts measuring <15 mm and without worrisome features who underwent surveillance at the Massachusetts General Hospital (1988-2017) and at the University of Verona Hospital Trust (2000-2016). The risk of malignant transformation was assessed using the Kaplan-Meier method and parametric survival models, and predictors of malignancy were evaluated using Cox regression.

RESULTS

806 patients were identified. Median follow-up was 58 months (6-347). Over time, 58 (7.2%) cysts were resected and of those, 11 had high grade dysplasia (HGD) or invasive cancer. Three additional patients had unresectable cancer for a total rate of malignancy of 1.7%. Predictors of development of malignancy included an increase in size ≥2.5 mm/year (HR = 29.54, 95% CI: 9.39-92.91, P < 0.001) and the development of worrisome features (HR = 9.17, 95% CI: 2.99-28.10, P = 0.001). Comparison of parametric survival models suggested that the risk of malignancy decreased after three years of surveillance and was lower than 0.2% after five years.

CONCLUSIONS

Pancreatic cysts <15  mm at the time of diagnosis have a very low risk of malignant transformation. Our findings indicate the risk decreases over time. Size increase of ≥2.5 mm/year is the strongest predictor of malignancy.

Neoplastic-Stromal Cell Cross-talk Regulates Matrisome Expression in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a highly desmoplastic reaction, warranting intense cancer-stroma communication. In this study, we interrogated the contribution of the BET family of chromatin adaptors to the cross-talk between PDAC cells and the tumor stroma. Short-term treatment of orthotopic xenograft tumors with CPI203, a small-molecule inhibitor of BET proteins, resulted in broad changes in the expression of genes encoding components of the extracellular matrix (matrisome) in both cancer and stromal cells. Remarkably, more than half of matrisome genes were expressed by cancer cells. In vitro cocultures of PDAC cells and cancer-associated fibroblasts (CAF) demonstrated that matrisome expression was regulated by BET-dependent cancer-CAF cross-talk. Disrupting this cross-talk in vivo resulted in diminished growth of orthotopic patient-derived xenograft tumors, reduced proliferation of cancer cells, and changes in collagen structure consistent with that of patients who experienced better survival. Examination of matrisome gene expression in publicly available data sets of 573 PDAC tumors identified a 65-gene signature that was able to distinguish long- and short-term PDAC survivors. Importantly, the expression of genes predictive of short-term survival was diminished in the cancer cells of orthotopic xenograft tumors of mice treated with CPI203. Taken together, these results demonstrate that inhibiting the activity BET proteins results in transcriptional and structural differences in the matrisome are associated with better patient survival. IMPLICATIONS: These studies highlight the biological relevance of the matrisome program in PDAC and suggest targeting of epigenetically driven tumor-stroma cross-talk as a potential therapeutic avenue.

Timing But Not Patterns of Recurrence Is Different Between Node-negative and Node-positive Resected Pancreatic Cancer

OBJECTIVE

Our aim was to evaluate recurrence patterns of surgically resected PDAC patients with negative (pN0) or positive (pN1) lymph nodes.

SUMMARY BACKGROUND DATA

Pancreatic ductal adenocarcinoma (PDAC) is predicted to become the second leading cause of cancer death by 2030. This is mostly due to early local and distant metastasis, even after surgical resection. Knowledge about patterns of recurrence in different patient populations could offer new therapeutic avenues.

METHODS

Clinicopathologic data were collected for 546 patients who underwent resection of their PDAC between 2005 and 2016 from 2 tertiary university centers. Patients were divided into an upfront resection group (n = 394) and a neoadjuvant group (n = 152).

RESULTS

Tumor recurrence was significantly less common in pN0 patients as compared with pN1 patients, (upfront surgery: 55% vs. 77%, P < 0.001 and 64% vs. 78%, P = 0.040 in the neoadjuvant group). In addition, time to recurrence was significantly longer in pN0 versus pN1 patients in the upfront resected patients (median 16 mo pN0 vs. 10 mo pN1 P < 0.001), and the neoadjuvant group (pN0 21 mo vs. 11 mo pN1, P < 0.001). Of the patients who recurred, 62% presented with distant metastases (63% of pN0 and 62% of pN1, P = 0.553), 24% with local disease (27% of pN0 and 23% of pN1, P = 0.672) and 14% with synchronous local and distant disease (10% of pN0 and 15% of pN1, P = 0.292). Similarly, there was no difference in recurrence patterns between pN0 and pN1 in the neoadjuvant group, in which 68% recurred with distant metastases (76% of pN0 and 64% of pN1, P = 0.326) and 18% recurred with local disease (pN0: 22% and pN1: 15%, P = 0.435).

CONCLUSION

Time to recurrence was significantly longer for pN0 patients. However, patterns of recurrence for pN0 vs. pN1 patients were identical. Lymph node status was predictive of time to recurrence, but not location of recurrence.

Does preoperative pharmacologic prophylaxis reduce the rate of venous thromboembolism in pancreatectomy patients?

BACKGROUND

Whether the risk of venous thromboembolism (VTE) may be reduced by preoperative administration of prophylactic heparin is unknown. We hypothesized that timing of heparin administration does not significantly alter the incidence of VTE in pancreatic surgery.

METHODS

An analysis was conducted using data from Massachusetts General Hospital's National Surgical Quality Improvement Program from 2012 to 2017. All patients admitted for elective pancreatic resection were included. The primary outcome was development of VTE. Multivariable regression was performed, adjusting for patient demographics and various clinical factors.

RESULTS

In total, 1448 patients were analyzed, of whom 1062 received preoperative heparin (73.3%). Overall, 36 (2.5%) patients developed VTE. On unadjusted analysis, there was no statistically significant difference between patients who received preoperative heparin compared with those who did not (2.6% vs. 1.3%, respectively; p = 0.079). On adjusted analysis, there was an association with increased VTE rates among patients who received preoperative heparin (OR 2.93, 95% CI 1.10-7.81; p = 0.031).

CONCLUSION

There was an association between preoperative heparin administration and increased incidence of VTE on adjusted analysis, possibly reflecting appropriate surgical judgment in patient selection for prophylaxis. These data question the inclusion of preoperative VTE pharmacologic prophylaxis as a reliable quality indicator.

FOLFIRINOX Versus Gemcitabine-based Therapy for Pancreatic Ductal Adenocarcinoma: Lessons from Patient-derived Cell Lines

BACKGROUND/AIM

FOLFIRINOX [fluorouracil (5-FU), irinotecan, oxaliplatin] and gemcitabine plus nab-paclitaxel are standard treatments for patients with pancreatic ductal adenocarcinoma (PDAC). Despite efficacy rates of less than 32%, evidence is lacking to guide the use of one drug over the other. Herein, we compared the sensitivity of patient-derived PDAC cell lines to each of these regimens.

MATERIALS AND METHODS

Changes in the growth of 19 low-passage patient-derived PDAC cell lines were evaluated in response to treatment with FOLFIRINOX and gemcitabine plus paclitaxel (Gem-Pac).

RESULTS

Six cell lines exhibited optimal sensitivity (high EMax and low GI50) to FOLFIRINOX and three cell lines exhibited optimal sensitivity to Gem-Pac. Several cell lines that were optimally sensitive to one drug regimen exhibited very poor response to the other.

CONCLUSION

Further characterization of cancer cells exhibiting preferential sensitivity to each of these regimens may allow the identification of biomarkers to guide the selection of appropriate chemotherapy for a given patient.

Impact of adjuvant therapy in patients with invasive intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND

There is limited data on the efficacy of adjuvant therapy (AT) in patients with invasive intraductal papillary mucinous neoplasms of the pancreas (IPMN). This single center retrospective cohort study aims to assess the impact of AT on survival in these patients.

METHODS

Patients undergoing surgery for invasive IPMN between 1993 and 2018 were included in the study. We compared the clinicopathologic features and evaluated overall survival (OS) using multivariate Cox regression adjusting for adjuvant therapy, age, T and N stage, perineural and lymphovascular invasion. We also assessed survival differences between surgery alone and AT in node negative (N0) and node positive (N+) subgroups.

RESULTS

103 patients were included in the study; 69 underwent surgery alone while 34 also received AT. Patients in the AT group were significantly younger, presented at higher T and N stages and had more perineural and lymphovascular invasion. Median OS in the surgery alone group was 134 months and 65 months in the AT group, p = 0.052. On multivariate analysis, AT was not associated with improved OS; hazard ratio (HR) = 1.03 (0.52-2.05). In N0 patients, compared to surgery alone, AT was associated with a worse median OS (65 vs 167 months, p = 0.03), whereas in N+ patients there was a non-significant improvement (50.5 vs 20.4 months, p = 0.315).

CONCLUSION

AT did not improve survival in the overall cohort even after multivariate analysis. N0 patients have excellent survival, and AT should probably be avoided in them, whereas it may be considered in patients with N+ disease.

An elevated CA 19-9 is associated with invasive cancer and worse survival in IPMN

BACKGROUND

Current guidelines for IPMN include an elevated serum carbohydrate antigen (CA) 19-9 among the worrisome features. However, the correlation of CA 19-9 with histological malignant features and survival is unclear. Serum CEA is also currently used for preoperative management of IPMN, although its measurement is not evidence-based. Accordingly, we aimed to assess the role of these tumor markers as predictors of malignancy in IPMN.

METHODS

IPMN resected between 1998 and 2018 at Massachusetts General Hospital were analyzed. Clinical, pathological and survival data were collected and compared to preoperative levels of CA 19-9 and CEA. Receiver operating characteristic (ROC) and Cox regression analyses were performed considering cut-offs of 37 U/ml (CA 19-9) and 5 μg/l (CEA).

RESULTS

Analysis of 594 patients showed that preoperative CA 19-9 levels > 37 U/ml (n = 128) were associated with an increased likelihood of invasive carcinoma when compared to normal levels (45.3% vs. 18.0%, P < 0.001), while there was no difference with respect to high-grade dysplasia (32.9% vs 31.9%, P = 0.88). The proportion of concurrent pancreatic cancer was higher in patients with CA 19-9 > 37 U/ml (17.2% vs 4.9%, P < 0.001). An elevated CA 19-9 was also associated with worse overall and disease-free survival (HR = 1.943, P = 0.007 and HR = 2.484, P < 0.001 respectively). CEA levels did not correlate with malignancy.

CONCLUSION

In patients with IPMN, serum CA19-9 > 37 U/ml is associated with invasive IPMN and concurrent pancreatic cancer as well as worse survival, but not with high-grade dysplasia. Serum CEA appears to have minimal utility in the management of these patients.

Hedgehog signaling promotes angiogenesis directly and indirectly in pancreatic cancer

INTRODUCTION

The inhibition of Hedgehog (Hh) signaling in pancreatic ductal adenocarcinoma (PDAC) reduces desmoplasia and promotes increased vascularity. In contrast to these findings, the Hh ligand Sonic Hedgehog (SHH) is a potent proangiogenic factor in non-tumor models. The aim of this study was to determine the molecular mechanisms by which SHH affects the tumor stroma and angiogenesis.

METHODS

Mice bearing three different xenografted human PDAC (n = 5/group) were treated with neutralizing antibodies to SHH. After treatment for 7 days, tumors were evaluated and the expression of 38 pro- and antiangiogenic factors was assessed in the tumor cells and their stroma. The effect of SHH on the regulation of pro- and antiangiogenic factors in fibroblasts and its impact on endothelial cells was then further assessed in in vitro model systems.

RESULTS

Inhibition of SHH affected tumor growth, stromal content, and vascularity. Its effect on the Hh signaling pathway was restricted to the stromal compartment of the three cancers. SHH-stimulated angiogenesis indirectly through the reduction of antiangiogenic THBS2 and TIMP2 in stromal cells. An additional direct effect of SHH on endothelial cells depended on the presence of VEGF.

CONCLUSION

Inhibition of Hh signaling reduces tumor vascularity, suggesting that Hh plays a role in the maintenance or formation of the tumor vasculature. Whether the reduction in tumor growth and viability seen in the epithelium is a direct consequence of Hh pathway inhibition, or indirectly caused by its effect on the stroma and vasculature, remains to be evaluated.

Variation in long-term oncologic outcomes by type of cancer center accreditation: An analysis of a SEER-Medicare population with pancreatic cancer

BACKGROUND

Cancer center accreditation is designed to identify centers that provide high-quality cancer care. This also guides patients and referring physicians towards centers of excellence for specialized care. We sought to examine if cancer center accreditation was associated with improved long-term oncologic outcomes in patients with pancreatic adenocarcinoma.

METHODS

Using the SEER-Medicare database, we identified patients who underwent pancreatectomy for pancreatic adenocarcinoma from 1996 to 2013. Hospitals were categorized into three groups: National Cancer Institute-designated (NCI-designated) centers, Commission on Cancer (CoC)-accredited centers, and "non-accredited" (NA) centers. Multilevel mixed-effects models were used to calculate adjusted examined lymph nodes, disease-specific survival (DSS), and overall survival (OS).

RESULTS

We identified 5,118 patients who underwent pancreatectomy at 632 hospitals (41.0% NA, 49.6% CoC, 9.4% NCI). NCI-designated centers had a greater median number of lymph nodes examined compared with CoC-accredited or NA centers (14 vs. 10 vs. 11.0 nodes, respectively; p < 0.001). Patients treated at NCI centers had a higher 5-year DSS compared to those treated at CoC or NA centers (31.2% vs. 23.6% vs. 23.0%, respectively; p < 0.001). Finally, patients treated at NCI centers had a higher 5-year OS compared to those treated at CoC or NA centers (23.5% vs. 18.9% vs. 17.9%, respectively; p < 0.001). The associations held true when adjusted analyses were performed.

CONCLUSION

Patients with resected pancreatic cancer treated at NCI-designated centers were associated with improved long-term oncologic outcomes. There was no difference between CoC-accredited centers compared with NA centers. Meticulous validation of accreditation is warranted globally prior to implementation.

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.

Diabetes mellitus is associated with unfavorable pathologic features, increased postoperative mortality, and worse long-term survival in resected pancreatic cancer

BACKGROUND

The risk of pancreatic ductal adenocarcinoma (PDAC) is increased in patients with diabetes mellitus (DM), particularly in those with new-onset DM. However, the impact of DM on outcomes following pancreatic surgery is not fully understood. We sought to explore the effects of DM on post-resection outcomes in patients undergoing either upfront resection or following neoadjuvant treatment (NAT).

METHODS

Resections for PDAC between 2007 and 2016 were identified from a prospectively-maintained database. Data on demographics, pathology, and perioperative outcomes were compared between patients with or without DM. Survival analysis was performed using Kaplan-Meier curves and adjusted for confounders by a Cox-proportional hazards model.

RESULTS

662 patients were identified, of whom 277 (41.8%) had DM. Diabetics were more likely to be male, had higher BMI, and higher ASA-scores. At pathology, DM was associated with larger tumors (30 vs. 26 mm; p = 0.041), higher rates of lymph-node involvement (69% vs. 59%; p = 0.031) and perineural invasion (88% vs. 82%; p = 0.026). Despite having similar rates of complications, diabetics experienced higher 30-day mortality (3.2% vs. 0.8%; p = 0.019). Median overall survival was worse in diabetic patients (18 vs. 34 months; p < 0.001); this effect was more pronounced in patients with NAT (18 vs. 54 months; p < 0.001). At multivariate analysis, DM was confirmed as an independent predictor of post-resection survival.

CONCLUSION

DM is a common comorbidity in PDAC and is associated with unfavorable pathology, as well as worse postoperative and oncologic outcomes. The blunted effect on survival is more pronounced in patients who undergo resection following NAT.

Main Pancreatic Duct to Parenchymal Thickness Ratio at Preoperative Imaging is Associated with Overall Survival in Upfront Resected Pancreatic Cancer

BACKGROUND

Pancreatic cancer induces parenchymal atrophy and duct dilation. The aim of this study was to evaluate whether these radiologic modifications are associated with outcomes.

METHODS

Upfront pancreaticoduodenectomy patients with available preoperative contrast enhanced CT scan imaging were retrospectively analyzed. Thickness of the pancreas, size of the main pancreatic duct (MPD), and distance of the tumor from the ampulla were assessed. A training cohort was selected, including short- (3-12 months following surgery) and long-term (≥ 36 months) survivors. Identified survival determinants were validated in the overall cohort.

RESULTS

Two-hundred-sixteen patients were analyzed. In the training cohort (N = 118), 68 patients (57.6%) were in the short-term and 50 (42.4%) in the long-term survival group. The short-term survival group had significantly higher CA 19-9 levels (p = 0.027), larger tumors (32.6 ± 12.1 mm vs. 26.5 ± 11.6 mm, p = 0.007), poorer differentiation (p = 0.003), higher rate of R < 1 mm resections (54% vs. 32%, p = 0.008), and reduced receipt of adjuvant chemotherapy (p = 0.020). The MPD-to-pancreatic thickness ratio was significantly lower in the short-term survivors (3.6 ± 6.2 vs. 8.2 ± 12.0, p = 0.016). In the entire cohort, an MPD-to-pancreatic thickness ratio ≥ 3.5 was associated with improved OS [median 33.0 months IQR (19.7-48.1) versus 17 months IQR (14.8-19.2), p = 0.004], and confirmed by a Cox-proportional hazards model independently associated with OS (HR = 0.58; p = 0.009), together with tumor size (HR = 1.02; p =0.012), R1/R2 status (HR = 1.53; p = 0.029), and receipt of adjuvant treatment (HR = 0.61; p = 0.021).

CONCLUSIONS

High MPD-to-pancreatic thickness ratio was associated with improved long-term survival in pancreaticoduodenectomy for cancer. Whether these features are related to tumor chronicity, indolent biology, or local growth over metastasis remains to be determined.

Association Between Pancreatic Fistula and Long-term Survival in the Era of Neoadjuvant Chemotherapy

Importance

In the past decade, the use of neoadjuvant therapy (NAT) has increased for patients with borderline and locally advanced pancreatic ductal adenocarcinoma (PDAC). Data on pancreatic fistula and related overall survival (OS) in this setting are limited.

Objective

To compare postoperative complications in patients undergoing either upfront resection or pancreatectomy following NAT, focusing on clinically relevant postoperative pancreatic fistula (CR-POPF) and potential associations with OS.

Design, Setting, and Participants

This retrospective cohort study was conducted on data from patients who underwent pancreatic resection for PDAC at the Massachusetts General Hospital from January 1, 2007, to December 31, 2017.

Exposures

Pancreatic cancer surgery with or without NAT.

Main Outcomes and Measures

Overall morbidity and CR-POPF rates were compared between NAT and upfront resection. Factors associated with CR-POPF were assessed with univariate and multivariate analysis. Survival data were analyzed by Kaplan-Meier curves and a Cox proportional hazards regression model.

Results

Of 753 patients, 364 were men (48.3%); median (interquartile range) age was 68 (61-75) years. A total of 346 patients (45.9%) received NAT and 407 patients (54.1%) underwent upfront resection. At pathologic examination, NAT was associated with smaller tumor size (mean [SD], 26.0 [15.3] mm vs 32.7 [14.4] mm; P < .001), reduced nodal involvement (102 [25.1%] vs 191 [55.2%]; P < .001), and higher R0 rates (257 [74.3%] vs 239 [58.7%]; P < .001). There were no significant differences in severe complication rate or 90-day mortality. The rate of CR-POPF was 3.6-fold lower in patients receiving NAT vs upfront resection (13 [3.8%] vs 56 [13.8%]; P < .001). In addition, factors associated with CR-POPF changed after NAT, and only soft pancreatic texture was associated with a higher risk of CR-POPF (38.5% vs 6.3%; P < .001). Survival analysis showed no differences between patients with or without CR-POPF after upfront resection (26 vs 25 months; P = .66), but after NAT, a worse overall survival rate was observed in patients with CR-POPF (17 vs 34 months; P = .002). This association was independent of other established predictors of overall survival by multivariate analysis (hazard ratio, 2.80; 95% CI, 1.44-5.45; P < .002).

Conclusions and Relevance

Neoadjuvant therapy may be associated with a significant reduction in the rate of CR-POPF. In addition, standard factors associated with CR-POPF appear to be no longer applicable following NAT. However, once CR-POPF occurs, it is associated with a significant reduction in long-term survival. Patients with CR-POPF may require closer follow-up and could benefit from additional therapy.

Major Complications Independently Increase Long-Term Mortality After Pancreatoduodenectomy for Cancer

BACKGROUND

Postoperative major morbidity has been associated with worse survival gastrointestinal tumors. This association remains controversial in pancreatic cancer (PC). We analyzed whether major complications after surgical resection affect long-term survival.

METHODS

Records of all PC patients resected from 2007 to 2015 were reviewed. Major morbidity was defined as any grade-3 or higher 30-day complications, per the Clavien-Dindo Classification. Patients who died within 90 days after surgery were excluded from survival analysis.

RESULTS

Of 616 patients, 81.7% underwent pancreatoduodenectomy (PD) and 18.3% distal pancreatectomy (DP). Major complications occurred in 19.1% after PD and 15.9% after DP. In patients who survived > 90 days, the likelihood of receiving adjuvant treatment was 43.9% if major complications had occurred, vs. 68.5% if not (p < 0.001), and those who received it started the treatment median 10 days later compared with uncomplicated patients (median 60 days (50-72) vs. 50 days (41-61), p = 0.001). By univariate analysis, in addition to the conventional pathology-related prognostic determinants and the receipt of adjuvant treatment, major complications worsened long-term survival after PD (median OS 26 months vs. 15, p = 0.008). A difference was also seen after DP, but it did not reach statistical significance, likely related to the small sample size (median OS 33 months vs. 18, p = 0.189). At multivariate analysis for PD, major postoperative complications remained independently associated with worse survival [HR 1.37, 95%CI (1.01-1.86)].

CONCLUSIONS

Major surgical complications after pancreaticoduodenectomy are associated with worse long-term survival in pancreatic cancer. This effect is independent of the receipt of adjuvant treatment.

Modified FOLFIRINOX for resected pancreatic cancer: Opportunities and challenges

Pancreatic cancer is one of the leading causes of cancer death worldwide. Adjuvant chemotherapy has been developed based on the experiences made with palliative chemotherapy, and advocated to improve long-term survival of patients with this disease. However, the optimal chemotherapeutic regimen remains controversial. Recently, Conroy et al demonstrated the impressive benefits of modified FOLFIRINOX over gemcitabine alone in the multicenter Partenariat de Recherche en Oncologie Digestive 24 (PRODIGE-24) trial. The remarkable results mark a new milestone in treating resectable pancreatic cancer and have now changed the standard of care for this patient population. In this commentary, we discuss an issue of difference of tumor grade between the PRODIGE-24 trial and previous phase III trials. We also discuss potential biomarkers predicting therapeutic response to modified FOLFIRINOX. Finally, we summarize several ongoing clinical trials of replacing part of the FOLFIRINOX regimen with Xeloda/S-1/nanoliposomal irinotecan for pancreatic cancer.

Role of Tumor-Associated Macrophages in the Clinical Course of Pancreatic Neuroendocrine Tumors (PanNETs)

PURPOSE

This study evaluated the potential role of immune cells and molecules in the pathogenesis and clinical course of pancreatic neuroendocrine tumors (PanNET).

EXPERIMENTAL DESIGN

Surgically resected PanNETs (N = 104) were immunohistochemically analyzed for Ki67 index, mitotic rate, macrophage, CD4⁺ cells, and CD8⁺ T-cell infiltration, as well as HLA class I, PD-L1, and B7-H3 expression. Results were correlated with clinicopathologic characteristics as well as with disease-free (DFS) and disease-specific (DSS) survival.

RESULTS

The median age of the 57 WHO grade 1 and 47 WHO grade 2 patients was 55 years. High intratumoral CD8⁺ T-cell infiltration correlated with prolonged DFS (P = 0.05), especially when the number of tumor-associated macrophages (TAM) was low. In contrast, high peritumoral CD4⁺ cell and TAM infiltration was associated with a worse DFS and DSS. PD-L1 and B7-H3 were expressed in 53% and 78% PanNETs, respectively. HLA class I expression was defective in about 70% PanNETs. HLA-A expression correlated with favorable DSS in PD-L1-negative tumors (P = 0.02). TAM infiltration (P = 0.02), WHO grade (P = 0.04), T stage (P = 0.01), and lymph node positivity (P = 0.04) were independent predictors of DFS. TAM infiltration (P = 0.026) and T stage (P = 0.012) continued to be predictors of DFS in WHO grade 1 PanNET patients. TAM infiltration was the sole independent predictor of DSS for WHO grade 1 and 2 patients (P = 0.02). Therefore, this biomarker may contribute to identifying WHO grade 1 patients with poor prognosis.

CONCLUSIONS

TAM infiltration appears to be the most informative prognostic biomarker in PanNET. It may represent a useful immunotherapeutic target in patients with PanNET.

Total pancreatectomy for pancreatic malignancy with preservation of the spleen

BACKGROUND

Total pancreatectomy may be necessary to achieve margin-negative resection for pancreatic cancer. However, despite the desirability of saving the spleen, the feasibility, safety, and oncological outcomes of spleen-preserving total pancreatectomy have not been studied in patients with malignancy involving the pancreatic neck or proximal body. The aim of this study was to report the efficacy of spleen-preserving total pancreatectomy using the Warshaw technique for patients with pancreatic malignancies.

METHODS

A retrospective analysis of patients who underwent total pancreatectomy for malignant pancreatic diseases between December 2006 and January 2018 focused on comparing the clinical outcomes between conventional operations with splenectomy and spleen-preserving total pancreatectomy using the Warshaw technique.

RESULTS

Thirty-eight patients among a total of 59 total pancreatectomies had the spleen preservation by the Warshaw operation. In this series, the pancreatic ductal adenocarcinomas resected with the Warshaw technique were of smaller tumor size but had greater rates of vascular invasion, resulting in the more frequent vascular resection. No patients had splenic complications requiring splenectomy, but two patients intended to have the Warshaw operation were converted to splenectomy because of splenic malperfusion. Asymptomatic perigastric varices were noted in 4 patients. Postoperative morbidity and mortality were comparable between the Warshaw and conventional operation groups. Recurrence-free and overall survival was similar in both groups.

CONCLUSION

In patients with pancreatic malignancy, total pancreatectomy with preservation of the spleen using the Warshaw technique achieves outcomes comparable with conventional total pancreatectomy with splenectomy in selected patients.

New observations on the utility of CA19-9 as a biomarker in Lewis negative patients with pancreatic cancer

BACKGROUND

Carbohydrate antigen 19-9 (CA19-9) is the best-validated biomarker for pancreatic cancer. The National Comprehensive Cancer Network (NCCN) guideline asserts that "CA19-9 will be undetectable in Lewis antigen-negative individuals". However, reports of CA19-9 secretion and its significance in Lewis (-) patients with pancreatic cancer have been inconsistent. This study was to examine serum CA19-9 levels in patients with pancreatic cancer according to Lewis status.

METHODS

Patients with pancreatic cancer (1482 cases) were retrieved from a prospectively maintained database. Patients with benign pancreatic disease (210 cases) and normal subjects (315 cases) were used as controls. Lewis genotypes were examined by fucosyltransferase 3 (FUT3) sequencing.

RESULTS

In patients with pancreatic cancer, 8.4% of subjects were Lewis (-), but only 41.9% of Lewis (-) subjects had CA19-9 values ≤ 2 U/mL. CA19-9 was even elevated (>37 U/mL) in 27.4% of Lewis (-) patients. The area under the receiver operating characteristic (ROC) curve for CA19-9 as a diagnostic biomarker was 0.842 in Lewis (-) patients with pancreatic cancer, which is closing to that of CA19-9 applied in all of patients with pancreatic cancer (0.898). Lewis (-) status was an independent prognostic factor for shorter survival in a multivariable analysis (hazard ratio (HR), 1.30, 95% confidence interval (CI), 1.03-1.64; P = 0.028).

CONCLUSIONS

Not all Lewis (-) patients with pancreatic cancer are non-secretors of CA19-9. Contrary to general understanding, CA19-9 can retain its utility as a biomarker in these patients in spite of Lewis (-) genotype.

Abstract 210: Uncovering a novel layer of complexity in the architecture of pancreatic cancer

Single cell technologies have described heterogeneity across tissues, but the spatial distribution and forces that drive single cell phenotypes has not been well defined. We integrated single cell RNA-seq (scRNA-Seq) and phospho mass cytometry (CyTOF) with high-content digital imaging to investigate tumor heterogeneity of human pancreatic cancer (PDAC) using a novel tumor-architecture approach.

Patient-derived PDAC cells co-cultured at different ratios with cancer associated fibroblasts (CAFs) were found to heterogeneously acquire proliferative (PRO) and invasive (EMT) phenotypes. scRNA-Seq enabled the identification of a novel cell phenotype with upregulation of both PRO and EMT programs, which we named the double positive (DP) phenotype. Functional studies confirmed the heterogeneous activation of PRO and EMT programs with different patterns of tumor growth and metastasis in mice orthotopically xenografted with distinct PDAC:CAF ratios.

In a time-course experiment of PDAC cells with CAF conditioned media (CM), mass spectrometry-based phosphoproteomics demonstrated selective enrichment of MAPK and STAT3 pathways. This was validated with mass cytometry (CyTOF) at the single cell level in our cell line model as well as from primary PDAC tumors, which identified the dual enrichment of MAPK and STAT3 signaling in the DP cell population. Functional validation of MAPK and STAT3 signaling was performed with small molecule inhibitors of MAPK (Trametinib) and STAT3 (pyrimethamine) in our cell line models.

To evaluate the generalizability of these cell subpopulations, we performed RNA-ISH for EMT (FN1) and PRO (MKI67) across 195 human PDAC primary tumors and scored 319,626 cancer cells revealing significant heterogeneity of PRO, EMT, and DP cells among patients. Single-cell analysis within the context of tissue architecture

revealed these cells were grouped together in discrete tumor glands. Using each of the 3 cell types (PRO, EMT, and DP), we classified 8 distinct types of tumor glands in these primary tumors. This provided the ability to define inter and intra-tumor heterogeneity at the tumor gland level, which provides an extra layer of tumor cell organization not appreciable with single cell analysis alone. We showed that tumor glands are independent functional units in human PDACs carrying distinct prognostic information. In fact, by comparing their prognostic power we noticed that some tumor glands are positively linked with worsened survival (Type I p=0.003, Type II p=0.04, Type II p=0.001 and Type VII p=0.02), while Type III glands are associated with a favorable patient prognosis (p=0.01, log-rank test).

In conclusion, our study showed for the first time at this scale level that integrating single-cell technologies with tissue architectural information provides a more comprehensive landscape of intra-tumoral cancer cell heterogeneity that has implications on PDAC cell behavior and patient outcomes.

Citation Format: Matteo Ligorio, Srinjoy Sil, Jose Malagon-Lopez, Sandra Misale, Murat Karabacak, Linda Nieman, Shyamala Maheswaran, Daniel A. Haber, Andrew L. Warshaw, Carlos Fernandez-Del Castillo, Cristina R. Ferrone, Wilhelm Haas, Martin Aryee, David T. Ting. Uncovering a novel layer of complexity in the architecture of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 210.