Role of Diagnostic Laparoscopy During Pancreatic Cancer Surgery in the Modern Era

INTRODUCTION

Despite improvements in preoperative image resolution, approximately 10% of curative-intent resection attempts for pancreatic ductal adenocarcinoma are aborted at the time of operation. To avoid nontherapeutic laparotomy, many surgeons perform intraoperative diagnostic laparoscopy (DL) to identify radiographically occult metastatic disease. There are no consensus guidelines regarding DL in pancreatic cancer. The goal of this study is to investigate the efficacy of same-procedure DL at avoiding nontherapeutic laparotomy.

METHODS

A single-institution retrospective review was performed from 2016 to 2022, identifying 196 patients with pancreatic ductal adenocarcinoma who were taken to the operating room for open curative-intent resection. Patient demographic, tumor characteristic, treatment, and outcome data were abstracted. Univariate and multivariate Cox hazard ratio analysis was performed to investigate risk factors for overall survival and recurrence-free survival. Number needed to treat (NNT) was calculated to identify number of DLs necessary to avoid one nontherapeutic laparotomy.

RESULTS

Curative-intent resection was achieved in 161 (82.1%) patients. One hundred twenty six (64.0%) patients received DL prior to resection and DL identified metastatic disease in three (2.4%) patients with an NNT of 42. NNT of DL in a subgroup analysis performed on clinically high-risk patients (defined by preoperative or preneoadjuvant therapy carbohydrate antigen 19-9 > 500 U/mL) is 11. Receipt of DL did not prolong operative times in patients receiving pancreaticoduodenectomy when accounting for completed versus aborted resection.

CONCLUSIONS

Although intraoperative DL is a short procedure with minimal morbidity, these data demonstrate that same-procedure DL has potential efficacy in avoiding nontherapeutic laparotomy only in a subgroup of clinically high-risk patients. Focus should remain on optimizing preoperative patient selection and further investigating novel diagnostic markers predictive of occult metastatic disease.

Epidemiology and survival outcomes of colorectal mixed neuroendocrine-non-neuroendocrine neoplasms and neuroendocrine carcinoma

BACKGROUND

Mixed neuroendocrine-non-neuroendocrine neoplasms are a rare subtype of neuroendocrine neoplasm consisting of ≥30% each of neuroendocrine and non-neuroendocrine differentiation. Neuroendocrine carcinomas are poorly differentiated neuroendocrine tumors. The epidemiology and prognosis of colorectal mixed neuroendocrine-non-neuroendocrine neoplasms and neuroendocrine carcinomas are not clearly defined in the literature. We sought to examine the presentation, patterns of care, and outcomes of patients with mixed neuroendocrine-non-neuroendocrine neoplasms and neuroendocrine carcinomas.

METHODS

We identified patients diagnosed with stage I-III colorectal (excluding appendix) mixed neuroendocrine-non-neuroendocrine neoplasms or neuroendocrine carcinomas with only one-lifetime cancer diagnosis who underwent surgical resection between 2010 and 2018 from the National Cancer Database. We performed bidirectional selection to identify variables to include in a multivariable Cox proportional hazards model.

RESULTS

We identified 189 patients with a diagnosis of stage I to III colorectal mixed neuroendocrine-non-neuroendocrine neoplasms, 66% of whom had poorly differentiated tumors and 482 with neuroendocrine carcinomas. Among patients with stage III disease, 68% of patients with mixed neuroendocrine-non-neuroendocrine neoplasms and 54% of patients with neuroendocrine carcinomas received adjuvant chemotherapy. The median survival for the overall patients with mixed neuroendocrine-non-neuroendocrine neoplasms and neuroendocrine carcinomas cohorts were 38 and 42 months, respectively (P = .22), and the median survival for patients with mixed neuroendocrine-non-neuroendocrine neoplasms and neuroendocrine carcinomas with stage III disease were 30 and 25 months, respectively (P = .27). In multivariable analysis, fewer number of positive nodes and receipt of adjuvant chemotherapy were independently associated with decreased risk of mortality for patients with mixed neuroendocrine-non-neuroendocrine neoplasms and neuroendocrine carcinomas.

CONCLUSION

Adjuvant chemotherapy is associated with improved survival in stage III mixed neuroendocrine-non-neuroendocrine neoplasms and neuroendocrine carcinomas. Future studies are warranted to identify subsets of patients benefiting most from adjuvant therapy.

Peritoneal Metastases After Intraductal Papillary Mucinous Neoplasm Resection: How Common are They?

INTRODUCTION

Peritoneal metastases (PMs) following resection of pancreatic intraductal papillary mucinous neoplasms (IPMNs) are rare. Consequently, prevalence, risk factors, and prognosis are not well known. We reviewed our institution's experience and published literature to further characterize the scope of this phenomenon.

METHODS

All pancreatectomy cases (556 patients) performed at a tertiary care center between 2010 and 2020 were reviewed to identify IPMN diagnoses. Patients with adenocarcinoma not arising from IPMN, or a history of other malignancies were excluded.

RESULTS

Seventy-eight patients underwent pancreatectomy with IPMN on final pathology at our institution; 51 met inclusion criteria. Of these, there were five cases of PMs (4:1 females:males). Four had invasive carcinoma arising from IPMN and one had high-grade dysplasia at the index operation. Female sex and invasive histology were significantly associated with PM (P < 0.05). PM rates by sex were 3% (95% confidence interval [CI]: 0.5-15) in males and 22% (95% CI: 9-45) in females. Rates by histology were 2.9% (95% CI: 0.5-15) for noninvasive IPMN, and 23.5% (95% CI: 9.5-47) for invasive carcinoma arising from IPMN. Median interval from surgery to PMs was 7 mo (range: 3-13).

CONCLUSIONS

PMs following IPMN resection are rare but may be more common in patients with invasive histology. Although rare, PMs can arise in patients with noninvasive IPMNs. Further studies on pathophysiology and risk factors of PM following IPMN resection are needed and may reinforce adherence to guidelines recommending long-term surveillance.

Surgical Management of G3 Gastroenteropancreatic Neuroendocrine Neoplasms: A Systematic Review and Meta-analysis

BACKGROUND

Grade 3 (G3) gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs) are rare, aggressive tumors with poor prognosis. The World Health Organization 2017 and 2019 classifications further subdivided G3 NENs into G3 neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs). Current guidelines favor medical management in most of these patients, and the role of surgical management is not well defined. We performed a systematic literature review and meta-analysis of surgical management versus nonsurgical management for G3 GEP NENs.

MATERIALS AND METHODS

A PRISMA-compliant systematic review of the MEDLINE, Embase, Scopus, and Cochrane Library databases (end-of-search date: 16 July 2021) was conducted. Individual patient survival data were reconstructed, and random-effects meta-analyses were performed.

RESULTS

Fourteen studies comprising 1810 surgical and 910 nonsurgical patients were systematically reviewed. Publication bias adjusted meta-analysis of 12 studies (1788 surgical and 857 nonsurgical patients) showed increased overall survival (OS) after surgical compared with nonsurgical management for G3 GEP NENs [hazard ratio (HR) 0.40, 95% confidence interval (CI) 0.31-0.53]. Subgroup meta-analyses showed increased OS after surgical management for both pancreatic and gastrointestinal primary sites separately. In another subgroup meta-analysis of G3 GEP NETs (not NECs), surgical management was associated with increased OS compared with nonsurgical management (HR 0.26, 95% CI 0.11-0.61).

CONCLUSIONS

Surgical management of G3 GEP NENs may provide a potential survival benefit in well-selected cases. Further research is needed to define which patients will benefit most from surgical versus nonsurgical management. The current literature is limited by inconsistent reporting of survival outcomes in surgical versus nonsurgical groups, tumor grade, differentiation, primary tumor site, and selection criteria for surgical and nonsurgical management.

Is There a Role for Surgical Resection of Grade 3 Neuroendocrine Neoplasms?

BACKGROUND

Grade 3 (G3) gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs) are aggressive tumors with poor survival outcomes for which medical management is generally recommended. This study sought to evaluate outcomes of surgically treated G3 GEP-NEN patients.

METHODS

A single-institutional prospective NEN database was reviewed. Patients with G3 GEP-NENs based on World Health Organization (WHO) 2019 definitions included well-differentiated neuroendocrine tumors (G3NET) and poorly differentiated neuroendocrine carcinomas (G3NEC). Clinicopathologic factors were compared between groups. Overall survival from G3 diagnosis was assessed by the Kaplan-Meier method.

RESULTS

Surgical resection was performed for 463 patients (211 G1, 208 G2, 44 G3). Most had metastatic disease at presentation (54% G1, 69% G2, 91% G3; p < 0.001). The G3 cohort included 39 G3NETs and 5 G3NECs, 22 of pancreatic and 22 of midgut origin. Median overall survival (mOS; in months) was 268.1 for G1NETs, 129.9 for G2NETs, 50.5 for G3NETs, and 28.5 for G3NECs (p < 0.001). Over the same period, 31 G3 patients (12 G3NETs, 19 G3NECs) were treated non-surgically, with mOS of 19.0 for G3NETs and 12.4 for G3NECs.

CONCLUSIONS

Surgical resection of G3 GEP-NENs remains controversial due to poor prognosis, and surgical series are rare. This large, single-institutional study found significantly lower mOS in patients with resected G3NENs than those with G1/G2 tumors, reflecting more aggressive tumor biology and a higher proportion with metastatic disease. The mOS for resected G3NETs and G3NECs exceeded historical non-surgical G3NEN series (mOS 11-19 months), suggesting surgery should be considered in carefully selected patients with G3NENs, especially those with well-differentiated tumors.

Management of Duodenal Neuroendocrine Tumors: Surgical versus Endoscopic Mucosal Resection

BACKGROUND

Management of duodenal neuroendocrine tumors (DNETs) is not standardized, with smaller lesions (< 1-2 cm) generally treated by endoscopic mucosal resection (EMR) and larger DNETs by surgical resection (SR). This study reviewed how patients were selected for treatment and compared outcomes.

PATIENTS AND METHODS

Patients with DNETs undergoing resection were identified through institutional databases, and clinicopathologic data recorded. χ² and Wilcoxon tests compared variables. Survival was determined by Kaplan-Meier, and Cox regression tested association with survival.

RESULTS

Among 104 patients, 64 underwent EMR and 40 had SR. Patients selected for SR had larger tumor size, younger age, and higher T, N, and M stage. There was no difference in progression-free (PFS) or overall survival (OS) between SR and EMR. In 1-2 cm DNETs, there was no difference in PFS between SR and EMR [median not reached (NR), P = 0.1]; however, longer OS was seen in SR (median NR versus 112 months, P = 0.03). In 1-2 cm DNETs, SR patients were more likely to be node-positive and younger. After adjustment for age, resection method did not correlate with survival. Comparison of surgically resected DNETs versus jejunoileal NETs revealed longer PFS (median NR versus 73 months, P < 0.001) and OS (median NR versus 119 months, P = 0.004) DISCUSSION: In 1-2 cm DNETs, there was no difference in survival between EMR and SR after adjustment for age. Recurrences could be salvaged, suggesting that EMR is a reasonable strategy. Compared with jejunoileal NETs, DNETs treated by SR had improved PFS and OS.

Progress in the Management of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNETs) are a heterogeneous and orphan group of neoplasms that vary in their histology, clinical features, prognosis, and management. The treatment of PNETs is highly dependent on the stage at presentation, tumor grade and differentiation, presence of symptoms from hormonal overproduction or from local growth, tumor burden, and rate of progression. The US Food and Drug Administration has recently approved many novel treatments, which have altered decision making and positively impacted the care and prognosis of these patients. In this review, we focus on the significant progress made in the management of PNETs over the past decade, as well as the active areas of research. Expected final online publication date for the Annual Review of Medicine, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

ASO Author Reflections: Endoscopic Management is Reasonable for <2 cm Duodenal Neuroendocrine Tumors

Optimal management of duodenal neuroendocrine tumors (DNETs) has not been well-defined, especially for DNETs 1-2 cm in size. Recent studies comparing endoscopic mucosal resection (EMR) and surgical resection demonstrate EMR is safe and effective for these intermediate-sized DNETs. Expert and consensus guidelines could consider updating recommendations to reflect the outcomes of EMR in DNETs and the importance of endoscopic surveillance in these patients to evaluate for local recurrence.

Mismatch Repair Status Correlates with Survival in Young Adults with Metastatic Colorectal Cancer

BACKGROUND

Young adults with metastatic colorectal cancer (mCRC) may have higher rates of deficient mismatch repair (dMMR) than older patients. This study sought to assess patterns of MMR-testing and survival among young adult mCRC patients in the National Cancer Database (NCDB), hypothesizing that dMMR correlates with worse survival than in MMR-proficient (pMMR) patients.

METHODS

Stage-IV colorectal cancers were identified in NCDB (2010-2016). Demographic and clinical features were compared between younger (age ≤ 30) and older mCRC patients and tested for association with overall survival. Stage-IV disease without other recorded metastatic sites defined peritoneal metastasis (PM). Fisher-exact tests compared proportions and Cox models tested association with overall survival.

RESULTS

Of 124,587 stage-IV colorectal cancers, 1,123 (0.9%) were in young patients. Young patients were more likely to have mucinous histology, high-grade, rectal primaries, and isolated peritoneal metastases (P < 0.001). Younger patients more often had MMR-testing (29.1 versus 16.6%), with dMMR found at similar rates in young and older patients (21.7 versus 17.1% of those tested, P= 0.4). Despite higher rates of adverse prognostic features, younger patients had better survival (median 20.7 versus 14.8 months, P < 0.001). In MMR-tested patients, dMMR correlated with higher mortality risk compared to pMMR (median 16.6 months versus 25.5 months, P = 0.01). On multivariable analysis, grade and MMR-status remained independently associated with survival.

CONCLUSIONS

Median survival was worse with dMMR by 8.9 months compared to pMMR in young adults with mCRC. Despite higher rates of familial syndromes in young patients and recommendations for universal MMR-testing, over 70% of young mCRC patients had no MMR-status recorded.

Tissue Diagnosis Is Associated With Worse Survival in Hepatocellular Carcinoma: A National Cancer Database Analysis

BACKGROUND

Biopsy to achieve tissue diagnosis (TD) of hepatocellular carcinoma (HCC) risks needle tract seeding. With chest wall and peritoneal recurrences reported, TD could worsen cancer outcomes. We investigated HCC outcomes after TD compared to clinical diagnosis (CD), hypothesizing that TD adversely affects overall survival (OS).

METHODS

The National Cancer Database (NCDB) Participant User File for liver cancer was reviewed, including patients with nonmetastatic HCC treated with major hepatectomy or transplantation. Clinical diagnosis patients were matched 1:1 to TD patients per propensity score. Survival was examined in the unmatched and matched cohorts.

RESULTS

Of 172 283 cases, 16 366 met inclusion criteria. Mean age was 60.8 years, 12 100 (73.9%) were male, and 48.4% of patients received hepatectomies. Clinical diagnosis occurred in 70.4% of cases, and 29.6% underwent TD. Cox regression confirmed the diagnostic method as an independent predictor of OS in addition to age, Charlson-Deyo score, grade, delay of surgery, lymphovascular invasion, nodal stage, and procedure type, favoring transplantation over hepatectomy. After propensity matching on these factors, 4251 patients were matched from each group. In the matched cohort, patients with TD had a significantly lower OS than patients with CD (median: 65.5 vs. 85.6 ± 2.7 months, P < .001). The corresponding 5-year survival was lower in the TD group (47.6% vs. 60.9% P < .001).

CONCLUSION

Hepatocellular carcinoma patients with preoperative TD had decreased OS compared to CD, which persisted after propensity matching. This study supports avoiding biopsy for HCC whenever possible.

ASO Author Reflections: Indolent Growth and Small Bowel Neuroendocrine Tumor Management

Surgical treatment is central to management of small bowel neuroendocrine tumors (SBNETs). Current controversies include whether to resect asymptomatic primary tumors in the setting of unresectable metastases, the role of minimally invasive surgery, and how best to incorporate/sequence medical treatments. Low SBNET incidence, long event-times, and variability in disease burden, surgical technique, and institutional treatment preferences remain obstacles to conducting randomized surgical trials for SBNETs. With increasing referral of these patients to high-volume centers, cooperation between experienced SBNET clinicians should allow design of high-quality randomized trials to test new treatments and answer key questions.

The Landmark Series: Management of Small Bowel Neuroendocrine Tumors

Surgical resection is the foundation for treatment of small bowel neuroendocrine tumors (SBNETs). Guidelines for surgical management of SBNETs rely on retrospective data, which suggest that primary tumor resection and cytoreduction improve symptoms, prevent future complications, and lengthen survival. In advanced NETs, improvement in progression-free survival has been reported in large, randomized, controlled trials of various medical treatments, including somatostatin analogues, targeted therapy, and peptide receptor radionuclide therapy. This review discusses important studies influencing the management of SBNETs and the limitations of current evidence regarding surgical interventions for SBNETs.

Surgical Management of Neuroendocrine Tumor Liver Metastases

Patients with neuroendocrine tumor liver metastases (NETLMs) may develop carcinoid syndrome, carcinoid heart disease, or other symptoms from overproduction of hormones. Hepatic resection and cytoreduction is the most direct treatment of NETLMs in eligible patients, and cytoreduction improves symptoms, may reduce the sequelae of carcinoid syndrome, and extends survival. Parenchymal-sparing procedures, such as ablation and enucleation, should be considered during cytoreduction to maximize treatment of multifocal tumors while preserving healthy liver tissue. For patients with large hepatic tumor burdens, high-grade disease, or comorbidities precluding surgery, liver-directed and systemic therapies can be used to palliate symptoms and improve progression-free survival.

Metastatic Colorectal Cancers with Mismatch Repair Deficiency Result in Worse Survival Regardless of Peritoneal Metastases

BACKGROUND

Mismatch-repair deficiency (dMMR) predicts worse chemoresponsiveness but better survival in early-stage colorectal adenocarcinoma. This study examined metastatic colorectal and appendix cancers with and without peritoneal metastasis (PM) in the National Cancer Database (NCDB), hypothesizing that dMMR tumors show better survival.

METHODS

Stage 4 colon, rectum, and appendix cancers (2010-2016) were identified in the NCDB (including goblet cell carcinoids, excluding neuroendocrine tumors). Stage 4 disease without liver, bone, brain, lung, or distant nodal metastases defined PM. Fisher's exact tests were used to compare proportions, and Kaplan-Meier analysis was used to evaluate survival.

RESULTS

Of 130,125 stage 4 colon, rectum, and appendix cancers, 27,848 (21.4%) had PM. Appendix primary tumors had PM more commonly than colon or rectum cancer (83.6% vs. 20.6% and 12.1% of stage 4 cases; p < 0.0001). More PM patients had MMR testing than patients with other metastasis (OM) (21.4% vs. 16.1%), and testing increased from 9.6% in 2010 to 26.3% in 2016 (both p < 0.0001). Among the PM patients, MMR testing was least common for appendix cancers (9.0%). When tested, PM patients more often had dMMR (22.9% [1122/4900] vs. 15.4% [2532/16,495] of OM patients; p < 0.0001). Colon primary tumor had dMMR most frequently (25.0% vs. 14.6% and 14.5% for rectal and appendix tumor; p < 0.0001). Most PM patients received chemotherapy (66.2%). Immunotherapy use increased over time (1.1% of PM diagnoses in 2010 vs. 20.8% in 2016). For MMR-tested stage 4 patients, dMMR correlated with worse survival (median OM, 19.7 vs. 23.9 months, p < 0.0001; median PM, 19.9 vs. 24.6 months, p = 0.035).

CONCLUSIONS

The NCDB showed dMMR predicting worse survival for stage 4 colorectal cancers with and without PM and dMMR existing in 14.5-25% of tested patients, suggesting that increased attention to MMR testing in stage 4 colorectal and appendix cancers can identify many patients who could potentially benefit from immunotherapy.

It Is Time to Rethink Biomarkers for Surveillance of Small Bowel Neuroendocrine Tumors

BACKGROUND

Tumor biomarkers (TBMs) reflect disease burden and correlate with survival for small bowel neuroendocrine tumors (SBNETs). This study sought to determine the performance of chromogranin A (CgA), pancreastatin (PST), neurokinin A (NKA), and serotonin (5HT) during follow-up assessment of resected SBNETs.

METHODS

An institutional database identified patients undergoing surgery for SBNETs. Tumor biomarker levels were assessed as categorical (normal vs elevated) and continuous variables for association with progression-free survival (PFS) and overall survival (OS) via the Kaplan-Meier method with Cox multivariable models adjusted for confounders. Sensitivity, specificity, and predictive values of TBM levels in identifying imaging-confirmed progression were calculated.

RESULTS

In 218 patients (44% female, 92% node + , 73% metastatic, 97% G1 or G2), higher levels of CgA, PST, NKA, and 5HT correlated with higher-grade and metastatic disease at presentation (p < 0.05). Elevated pre- and postoperative CgA, PST, and NKA correlated with lower PFS and OS (p < 0.05; median follow-up period, 49.6 months). Normal CgA, PST, and NKA were present in respectively 20.3%, 16.9%, and 72.6% of the patients with progression, whereas elevated levels were present in respectively 69.5%, 24.8%, and 1.3% of the patients without progression. Using TBMs to determine progression showed superiority of PST (78.9% accuracy) over CgA (63.3% accuracy) or CgA and PST together (60.3% accuracy).

CONCLUSION

Although specific for progression, NKA was rarely elevated, limiting its usefulness. Pre- and postoperative PST and CgA correlated with disease burden and survival, with PST providing better discrimination of outcomes. During the follow-up period, use of PST most accurately detected progression. These results suggest that PST should replace CgA for SBNET surveillance.

Metastatic pancreatic neuroendocrine tumors have decreased somatostatin expression and increased Akt signaling

BACKGROUND

Patients with pancreatic neuroendocrine tumors often present with metastases, which reduce survival. Molecular features associated with pancreatic neuroendocrine tumor tumorigenesis have been reported, but mechanisms of metastasis remain incompletely understood.

METHODS

RNA sequencing was performed on primary and metastatic pancreatic neuroendocrine tumors from 43 patients. Differentially expressed genes were identified, and quantitative polymerase chain reaction used to confirm expression differences. BON cells were transfected with short interfering RNAs and short hairpin RNAs to create knockdowns. Expression changes were confirmed by quantitative polymerase chain reaction, cell viability assessed, and protein levels evaluated by Western blot and immunofluorescence.

RESULTS

Nodal and hepatic metastases had decreased expression of somatostatin compared with primary tumors (P = .003). Quantitative polymerase chain reaction in a validation cohort confirmed 5.3-fold lower somatostatin expression in hepatic metastases (P = .043) with no difference in somatostatin receptor, synaptophysin, or chromogranin A expression. Somatostatin knockdown in BON cells increased cell metabolic activity, viability, and growth. Somatostatin-knockdown cells had significantly higher levels of phosphorylated Akt protein and higher mTOR compared with controls.

CONCLUSION

Pancreatic neuroendocrine tumor metastases have lower expression of somatostatin than primary tumors, and somatostatin knockdown increased growth in pancreatic neuroendocrine tumor cell lines. This was associated with increased activation of Akt, identifying this pathway as a potential mechanism by which loss of somatostatin expression promotes the metastatic phenotype.

Implementation of an EMR integrated pathway for the management of malignant bowel obstruction

813

Background: Despite published evidence based interventions for malignant bowel obstruction (MBO), implementation of a standard pathway is challenging. We hypothesized that using industrial engineering techniques and a modified dynamic sustainability framework for implementation, we can implement an electronic medical record (EMR) based pathway in the management of MBO. Methods: A workflow in the management of MBO was developed using iterative meetings from 8/2018 to 4/2019 including gateway stakeholders (surgical oncology, gynecological oncology and medical oncology), interventional stakeholders (gastroenterology, interventional radiology) and supportive stakeholders (hospital medicine, palliative care, nutrition, nursing). Industrial engineers were utilized to study human factors, and perform a method study. EMR integration was performed using EPIC systems Agile MD pathway and educational materials were created. Interventions such as early placement of gastrostomy tubes, total parenteral nutrition and medications were protocolized. Results: Since implementation, over 6 months the pathway and order set has been activated 56 times. Orders have been employed 21 times through the AgileMD pathway demonstrating a pathway drift of 62.5%. Educational materials have been accessed routinely during this time. Conclusions: Feasibility of implementing an EMR integrated MBO pathway is demonstrated with early suggestion of pathway drift. Utilizing tools of implementation science are necessary to facilitate widespread adoption of evidence based interventions in the management of patients with MBO.

Cost-effectiveness of Maintenance Capecitabine and Bevacizumab for Metastatic Colorectal Cancer

Importance

Unregulated drug prices increase cancer therapy costs. After induction chemotherapy, patients with metastatic colon cancer can receive maintenance capecitabine and bevacizumab therapy based on improved progression-free survival, but whether this treatment's cost justifies its benefits has not been evaluated in the United States.

Objective

This study sought to determine the influence of capecitabine and bevacizumab drug prices on cost-effectiveness from a Medicare payer's perspective.

Design, Setting, and Participants

The incremental cost-effectiveness of capecitabine and bevacizumab maintenance therapy was determined with a Markov model using a quality-of-life penalty based on outcomes data from the CAIRO phase 3 randomized clinical trial (RCT), which included 558 adults in the Netherlands with unresectable metastatic colorectal cancer who had stable disease or better following induction chemotherapy. The outcomes were modeled using Markov chains to account for patients who had treatment complications or cancer progression. Transition probabilities between patient states were determined, and each state's costs were determined using US Medicare data on payments for capecitabine and bevacizumab treatment. Deterministic and probabilistic sensitivity analyses identified factors affecting cost-effectiveness.

Main Outcomes and Measures

Life-years gained were adjusted using CAIRO3 RCT quality-of-life data to determine quality-adjusted life-years (QALYs). The primary end point was the incremental cost-effectiveness ratio, representing incremental costs per QALY gained using a capecitabine and bevacizumab maintenance regimen compared with observation alone.

Results

Markov model estimated survival and complication outcomes closely matched those reported in the CAIRO3 RCT, which included 558 adults (n = 197 women, n = 361 men; median age, 64 and 63 years for patients in the observation and maintenance therapy groups, respectively) in the Netherlands with unresectable metastatic colorectal cancer who had stable disease or better following induction chemotherapy. Incremental costs for a 3-week maintenance chemotherapy cycle were $6601 per patient. After 29 model iterations corresponding to 60 months of follow-up, mean per-patient costs were $105 239 for maintenance therapy and $21.10 for observation. Mean QALYs accrued were 1.34 for maintenance therapy and 1.20 for observation. The incremental cost-effectiveness ratio favored maintenance treatment, at an incremental cost of $725 601 per QALY. The unadjusted ratio was $438 394 per life-year. Sensitivity analyses revealed that cost-effectiveness varied with changes in drug costs. To achieve an incremental cost-effectiveness ratio of less than $59 039 (median US household income) per unadjusted life-year would require capecitabine and bevacizumab drug costs to be reduced from $6173 (current cost) to $452 per 3-week chemotherapy cycle.

Conclusions and Relevance

Antineoplastic therapy is expensive for payers and society. The price of capecitabine and bevacizumab maintenance therapy would need to be reduced by 93% to make it cost-effective, a finding useful for policy decision making and payment negotiations.

The Pancreas as a Site of Metastasis or Second Primary in Patients with Small Bowel Neuroendocrine Tumors

BACKGROUND

The small bowel and pancreas are the most common primary sites of neuroendocrine tumors (NETs) giving rise to metastatic disease. Some patients with small bowel NETs (SBNETs) present with synchronous or metachronous pancreatic NETs (PNETs), and it is unclear whether these are separate primaries or metastases from one site to the other.

METHODS

A surgical NET database including patients undergoing operations for SBNETs or PNETs was reviewed. Patients with synchronous or metachronous tumors in both the small bowel and pancreas were identified, and available tissues from primary tumors and metastases were examined using a 4-gene quantitative polymerase chain reaction (qPCR) and immunohistochemistry (IHC) panel developed for evaluating NETs of unknown primary.

RESULTS

Of 338 patients undergoing exploration, 11 had NETs in both the small bowel and pancreas. Tissues from 11 small bowel tumors, 9 pancreatic tumors, and 10 metastases were analyzed. qPCR and IHC data revealed that three patients had separate SBNET and PNET primaries, and five patients had SBNETs that metastasized to the pancreas. Pancreatic tissue was unavailable in two patients, and qPCR and IHC gave discrepant results in one patient.

CONCLUSIONS

NETs in both the small bowel and pancreas were found in 3% of our patients. In nearly two-thirds of evaluable patients, the pancreatic tumor was a metastasis from the SBNET primary, while in the remaining one-third of patients it represented a separate primary. Determining the origin of these tumors can help guide the choice of systemic therapy and surgical management.

Correction to: Peritoneal Metastases in Colorectal Cancer

In the original article Fadi Dahdaleh's last name was spelled incorrectly. It is correct as reflected here.

Prospective Validation of the Iowa Rectal Surgery Risk Calculator

BACKGROUND

The Iowa Rectal Surgery Risk Calculator estimates risk for proctectomy procedures. The Iowa Calculator performed well on NSQIP 2010-2011 training and 2005-2009 validation datasets, but was not prospectively validated and did not include low anterior resections. This study sought to demonstrate validity on new independent data, to update the calculator to include low anterior resection, and to compare performance to other risk assessment tools.

METHODS

Non-emergent ACS-NSQIP proctectomy and low anterior resection data from 2010 to 2015 (n = 65,683) were included. The Iowa Calculator generated risk estimates for 30-day morbidity using 2012-2015 data. An Updated Calculator used 2010-2011 training data to include low anterior resection, with validation on 2012-2015 data. NSQIP data provided NSQIP Morbidity Model predictions and a custom web-script collected ACS-NSQIP Online Surgical Risk Calculator predictions for all patients.

RESULTS

Proctectomy morbidity (not including low anterior resection) decreased from 40.4% in 2010-2011 to 37.0% in 2012-2015. Low anterior resection had lower morbidity (22.4% in 2012-15). The Iowa Calculator demonstrated good discrimination and calibration using 2012-2015 data (C-statistic 0.676, deviance + 9.2%). After including low anterior resection, the Updated Iowa Calculator performed well during training (c-statistic 0.696, deviance 0%) and validation (C-statistic 0.706, deviance + 7.9%). The Updated Iowa Calculator had significantly better discrimination and calibration than morbidity predictions from the ACS Online Calculator (C-statistic 0.693, P < 0.001, deviance - 28.1%) and NSQIP General/Vascular Surgery Model (C-statistic 0.703, P < 0.05, deviance - 40.8%).

CONCLUSION

When applied to new independent data, the Iowa Calculator supplies accurate risk estimates. The Updated Iowa Calculator includes low anterior resection, and both are prospectively validated. Risk estimation by the Iowa Calculators was superior to ACS-provided risk tools.

Translational Diagnostics and Therapeutics in Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNET) are rare tumors, but have been increasing in incidence. Although typically thought of as indolent, more than half of patients present with metastatic disease. For many years, the only mutations commonly known in these tumors were those in the MEN1 gene. Recently, the genetics underlying PNETs have been further defined through exome sequencing. The most frequent alterations found in sporadic PNETs are in MEN1, DAXX/ATRX, and a variety of genes in the mTOR pathway. Confirmation of these mutations has prompted trials with a number of drugs active in these pathways, and two drugs were eventually approved in 2011-sunitinib and everolimus. New data additionally identify the MET and CD47 receptors as potential novel drug targets. Yet despite improvements in progression-free survival with sunitinib and everolimus, further studies defining when to use these agents and factors associated with limitations in their utility are needed. As more discoveries are made in the laboratory that elucidate additional molecular mechanisms important in the initiation and metastasis of PNETs, continued efforts to translate these discoveries into distinct new therapies will be needed to improve patient survival. Clin Cancer Res; 22(20); 5022-9. ©2016 AACR SEE ALL ARTICLES IN THIS CCR FOCUS SECTION, "ENDOCRINE CANCERS REVISING PARADIGMS".

Abstract 1368: RABL6A, a novel critical regulator of Akt-mTOR signaling in pancreatic neuroendocrine tumor cells

Introduction: A better molecular understanding of pancreatic neuroendocrine tumors (PNETs) is needed to improve patient diagnosis and treatment. Everolimus (mTOR inhibitor) is a standard-of-care therapy for PNET patients based on aberrant activation of the PI3K/Akt/mTOR kinase pathway in tumors. However, sustained mTOR inhibition paradoxically promotes Akt kinase hyperactivation due to loss of negative feedback regulation and tumors become drug resistant. Our data reveal that RABL6A, a novel oncoprotein amplified in PNETs, is a key regulator of this clinically relevant pathway.

Methods: RABL6A and Akt protein levels were manipulated using viral shRNAs in BON1 PNET cells. Transcript levels were assayed by microarray and qRT-PCR, proteins assessed by western blotting, and cell proliferation and survival measured by cell counts, trypan blue exclusion and EdU incorporation. Effect of RABL6A expression on sensitivity to clinically relevant drugs, MK2206 (Akt inhibitor) and everolimus, were tested.

Results: Silencing of RABL6A in PNET cells causes G1 and G2/M cell cycle arrest, and pathway analysis of microarray data suggested inactivation of Akt signaling in the arrested cells. Immunoblotting confirmed dramatic loss of Akt phosphorylation at Ser-473 along with impaired phosphorylation and activation of its targets, PRAS40 and FOXO-1/3. Phosphorylation of S6K, a downstream target of Akt-mTOR signaling, was also reduced by RABL6A deficiency. The mechanism by which RABL6A controls Akt-S473 phosphorylation is currently not known although we demonstrated that mTORC2 (the kinase that phosphorylates Akt at Ser473) remains active in RABL6A deficient cells since the phosphorylation of other mTORC2 substrates (SGK1 and PKCα) is unaffected. Given the central role of Akt1 in tumorigenesis, we hypothesized that reinstating its activity may rescue the arrest phenotype caused by RABL6A loss. Restoration of Akt1 in RABL6A-depleted cells partially rescued the G1 phase arrest and induced S phase entry but was insufficient to allow mitosis, suggesting RABL6A regulates other factors required for cell division. Finally, drug response assays showed that RABL6A loss desensitizes PNET cells to Akt and mTOR inhibitors.

Conclusion: Our previous work showed RABL6A promotes G1 progression in PNET cells by inactivating Rb1, an established suppressor of PNET pathogenesis. We now show that RABL6A also controls Akt phosphorylation and is essential for Akt-mTOR activation. Thus, RABL6A controls multiple cancer pathways necessary for PNET cell cycle progression and survival. We are testing if RABL6A status in PNETs predicts responsiveness to combination therapies targeting Akt and mTOR. Overall, this work identifies RABL6A as a new essential activator of Akt1-mTOR signaling, suggesting it is a new potential biomarker and target for anticancer therapy in PNET patients.

Citation Format: Shaik Amjad Ume Salma, Jussara Hagen, Jacki Reilly, Ryan Sheehy, Nitija Tiwari, Jackson Nteeba, Scott K. Sherman, Thomas M. O'Dorisio, James R. Howe, Andrew M. Bellizzi, Benjamin W. Darbro, Dawn E. Quelle. RABL6A, a novel critical regulator of Akt-mTOR signaling in pancreatic neuroendocrine tumor cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1368. doi:10.1158/1538-7445.AM2017-1368

Liver-directed surgery of neuroendocrine metastases: What is the optimal strategy?

INTRODUCTION

Neuroendocrine tumors (NETs) frequently metastasize to the liver. Operative debulking offers symptomatic relief and improved survival; however, the frequent presence of multifocal, bilobar disease and high recurrence rates introduces doubt regarding their optimal management. Parenchyma-sparing debulking (PSD) procedures (ablation, enucleation, wedge resections) may offer similar survival improvements as resection while minimizing morbidity and preserving functional liver tissue.

METHODS

Clinicopathologic variables from 228 patients with small bowel or pancreatic NETs managed operatively at one institution were collected. Liver-directed surgery was carried out when substantial debulking was deemed feasible. Survival was assessed by use of the Kaplan-Meier method.

RESULTS

A total of 108 patients with pancreatic NET or small bowel NET underwent liver-directed surgery with primarily PSD procedures. Nearly two-thirds of patients achieved 70% cytoreduction and 84% had concurrent resection of their primary. The median number of lesions treated was 6 (range, 1-36). There were no 30-day operative mortalities. The 30-day major complication rate was 13.0%. Patients who achieved 70% cytoreduction enjoyed improved progression free (median 3.2 years) and overall survival (median not reached).

CONCLUSION

PSD procedures are safe and can achieve significant cytoreduction, which is associated with improved survival. Lowering the debulking target threshold to 70% may benefit NET patients by increasing eligibility for cytoreduction.

Somatic alterations of CDKN1B are associated with small bowel neuroendocrine tumors

CDKN1B, a cyclin-dependent kinase inhibitor associated with G1 arrest, was recently proposed as an important tumor suppressor gene in small bowel neuroendocrine tumors (SBNETs). The rate of frameshift mutations in SBNET primaries are reportedly 7.4%, and hemizygous deletions are 6.7%. We set out to confirm the role of CDKN1B mutations and copy number variants (CNVs) in primary SBNETs, and whether these are also found in pancreatic neuroendocrine tumors (PNETs). Genomic DNA was isolated from 90 primary SBNETs and 67 PNETs. Coding exons of CDKN1B were amplified by PCR and sequenced. CNV analysis was performed by quantitative PCR, p27 expression was evaluated using immunohistochemistry. In SBNETS, three frameshifts, one missense mutation, and three CNVs were observed. The total rate of CDKN1B alterations was 7.0% (6 of 86; 95% confidence interval (CI) 3.2-4.4%). The frameshift rate was 3.5% (95% CI 1.1-9.8%). One SBNET patient had a hemizygous deletion of CDKN1B, and two patients had duplications (3.4%; 95% CI -0.41-7.2%). One PNET patient had a duplication, and two patients had hemizygous deletions (4.8%; 95% CI -0.44-10%). Alterations of cell-cycle control due to alterations in CDKN1B may be one mechanism by which SBNETs develop, which could have implications for new treatment modalities.

Esophageal cancer in a family with hamartomatous tumors and germline PTEN frameshift and SMAD7 missense mutations

Germline mutations in the PTEN tumor-suppressor gene cause autosomal-dominant conditions such as Cowden and Bannayan-Riley-Ruvalcaba syndromes with variable presentations, including hamartomatous gastrointestinal tumors, dermatologic abnormalities, neurologic symptoms, and elevated cancer risk. We describe a father and son with extensive hamartomatous gastrointestinal polyposis who both developed early-onset esophageal cancer. Exome sequencing identified a novel germline PTEN frameshift mutation (c.568_569insC, p.V191Sfs*11). In addition, a missense mutation of SMAD7 (c.115G>A, p.G39R) with an allele frequency of 0.3% in the Exome Variant Server was detected in both affected individuals. Fluorescence in situ hybridization for PTEN in the resected esophageal cancer specimen demonstrated no PTEN copy loss in malignant cells; however, results of an immunohistochemical analysis demonstrated a loss of PTEN protein expression. While the risks of many cancers are elevated in the PTEN hamartoma tumor syndromes, association between esophageal adenocarcinoma and these syndromes has not been previously reported. Esophageal adenocarcinoma and extensive polyposis/ganglioneuromatosis could represent less common features of these syndromes, potentially correlating with this novel PTEN frameshift and early protein termination genotype. Alternatively, because simultaneous disruption of both the PTEN and TGF-β/SMAD4 pathways is associated with development of esophageal cancer in a mouse model and because SMAD4 mutations cause gastrointestinal hamartomas in juvenile polyposis syndrome, the SMAD7 mutation may represent an additional modifier of these individuals' PTEN-mutant phenotype.

A practical method to determine the site of unknown primary in metastatic neuroendocrine tumors

INTRODUCTION

The site of a primary neuroendocrine tumor (NET) tumor is unknown before treatment in approximately 20% of small bowel (SBNET) and pancreatic (PNET) cases despite extensive workup. It can be difficult to discern a PNET from an SBNET on hematoxylin and eosin stains, and thus, more focused diagnostic tests are required. Immunohistochemistry (IHC) and gene expression profiling are two methods used to identify the tissue of origin from biopsied metastases.

METHODS

Tissue microarrays were created from operative specimens and stained with up to seven antibodies used in the NET-specific IHC algorithm. Expression of four genes for differentiating between PNETs and SBNETs was determined by quantitative polymerase chain reaction and then used in a previously validated gene expression classifier (GEC) algorithm designed to determine the primary site from gastrointestinal NET metastases.

RESULTS

The accuracy of the IHC algorithm in identifying the primary tumor site from a set of 37 metastases was 89%, with only one incorrect call. Three other samples were indeterminate as the result of pan-negative staining. The GEC's accuracy in a set of 136 metastases was 94%. The algorithm identified the primary tumor site in all cases in which IHC failed.

CONCLUSION

Performing IHC, followed by GEC for indeterminate cases, identifies accurately the primary site in SBNET and PNET metastases in virtually all patients.

RABL6A promotes G1-S phase progression and pancreatic neuroendocrine tumor cell proliferation in an Rb1-dependent manner

Mechanisms of neuroendocrine tumor (NET) proliferation are poorly understood, and therapies that effectively control NET progression and metastatic disease are limited. We found amplification of a putative oncogene, RABL6A, in primary human pancreatic NETs (PNET) that correlated with high-level RABL6A protein expression. Consistent with those results, stable silencing of RABL6A in cultured BON-1 PNET cells revealed that it is essential for their proliferation and survival. Cells lacking RABL6A predominantly arrested in G1 phase with a moderate mitotic block. Pathway analysis of microarray data suggested activation of the p53 and retinoblastoma (Rb1) tumor-suppressor pathways in the arrested cells. Loss of p53 had no effect on the RABL6A knockdown phenotype, indicating that RABL6A functions independent of p53 in this setting. By comparison, Rb1 inactivation partially restored G1 to S phase progression in RABL6A-knockdown cells, although it was insufficient to override the mitotic arrest and cell death caused by RABL6A loss. Thus, RABL6A promotes G1 progression in PNET cells by inactivating Rb1, an established suppressor of PNET proliferation and development. This work identifies RABL6A as a novel negative regulator of Rb1 that is essential for PNET proliferation and survival. We suggest RABL6A is a new potential biomarker and target for anticancer therapy in PNET patients.

Medical management of metastatic medullary thyroid cancer

Medullary thyroid cancer (MTC) is an aggressive form of thyroid cancer that occurs in both heritable and sporadic forms. Discovery that mutations in the rearranged during transfection (RET) proto-oncogene predispose to familial cases of this disease has allowed for presymptomatic identification of gene carriers and prophylactic surgery to improve the prognosis of these patients. A significant number of patients with the sporadic type of MTC and even those with familial disease still present with lymph node or distant metastases, making surgical cure difficult. Over the past several decades, many different types of therapy for metastatic disease have been attempted with limited success. Improved understanding of the molecular defects and pathways involved in both familial and sporadic MTC has resulted in new hope for these patients with the development of drugs targeting the specific alterations responsible. This new era of targeted therapy with kinase inhibitors represents a significant step forward from previous trials of chemotherapy, radiotherapy, and hormone therapy. Although much progress has been made, additional agents and strategies are needed to achieve durable, long-term responses in patients with metastatic MTC. This article reviews the history and results of medical management for metastatic MTC from the early 1970s up until the present day.

Limitations of somatostatin scintigraphy in primary small bowel neuroendocrine tumors

BACKGROUND

Somatostatin receptor scintigraphy (SRS; octreoscan) is used in neuroendocrine tumors to locate the primary tumor site and delineate the extent of disease. SRS has decreased sensitivity for small bowel neuroendocrine tumors (SBNETs). The reasons for SRS nonlocalization are not clear. We sought to determine factors that correlate with successful primary tumor localization by SRS in patients with resected SBNETs, and also identify factors that confound interpretation of SRS reports.

METHODS

Records of patients with resected SBNETs were reviewed for SRS results, tumor size, multifocality, N, and M status. Somatostatin receptor 2 (SSTR2) expression was analyzed in resected tumors by quantitative polymerase chain reaction. SRS reports were reviewed and categorized as localizing the primary tumor or not. A nuclear medicine physician independently reviewed available images.

RESULTS

Of 37 patients with preoperative SRS, the primary tumor was localized in 37%. Of all the factors tested, only small tumor size correlated significantly with SRS nonlocalization. Overexpression of SSTR2 was not significantly different between tumors that were or were not localized by SRS, regardless of tumor size. There were three instances where the SRS report did not agree with the nuclear medicine physician's interpretation as to whether SRS localized the primary tumor. In each case, uptake in mesenteric nodes was a confounding factor.

CONCLUSIONS

SBNETs <2 cm are most likely to be missed by SRS. SSTR2 expression did not correlate with SRS nonlocalization of the primary tumor. Uptake in mesenteric nodes may help indicate an SBNET primary but can also interfere with its visualization within the small bowel.

Resident involvement in postoperative conversations: an underused opportunity

BACKGROUND

Because of established attending-patient and family relationships and time constraints, residents are often excluded from the immediate postoperative conversation with family. Interpersonal and communication skills are a core competency, and the postoperative conversation is an opportunity to develop these skills. Our objective is to assess attitudes, experience, and comfort regarding resident participation during postoperative conversations with families.

MATERIALS AND METHODS

Residents and attending surgeons in an academic surgery center were surveyed regarding resident involvement in the postoperative conversation with families. Paper surveys were administered anonymously. Nonparametric statistics compared responses.

RESULTS

There were 45 survey respondents (23 residents, 22 attendings). All residents rated postoperative conversations with families, as "important" or "very important". Residents reported being "comfortable" or "very comfortable" with postoperative conversations. However, on average, residents reported fewer than 10 postoperative conversation experiences per year. Feedback was received by <30% on postoperative communication skills, but 88% wanted feedback. Most attendings reported it is "important" or "very important" for residents to communicate well with families during postoperative conversations, but rated residents' performance as significantly lower than the residents' self-assessments (P < 0.001). Attendings on average were only "somewhat comfortable" or "moderately comfortable" with residents conducting postoperative conversations with families, and only 68% reported allowing residents to do so. When bad news was involved, only 27% allowed resident participation. Most attendings (86%) believed residents need more opportunities with postoperative conversations.

CONCLUSIONS

Although most residents reported being comfortable with postoperative conversations, these survey results indicate that they have few opportunities. Developing a workshop on communication skills focused on the postoperative conversations with families may be beneficial.

Development of an improved risk calculator for complications in proctectomy

BACKGROUND

Rectal surgery is associated with high complication rates, but tools to prospectively define surgical risk are lacking. Improved preoperative risk assessment could better inform patients and refine decision making by surgeons. Our objective was to develop a validated model for proctectomy risk prediction.

METHODS

We reviewed non-emergent ACS-NSQIP proctectomy data from 2005 to 2011 (n = 13,385). Logistic regression identified variables available prior to surgery showing independent association with 30-day morbidity in 2010-2011 (n = 5,570). The resulting risk model's discrimination and calibration were tested against the NSQIP-supplied morbidity model, and performance was validated against independent 2005-2009 data.

RESULTS

Overall morbidity for proctectomy in 2010-2011 was 40.2%; significantly higher than the 23.0 % rate predicted by the NSQIP-provided general and vascular surgery risk model. Frequent complications included bleeding (16.3%), superficial infection (9.2%), and sepsis (7.4%). Our novel model incorporating 17 preoperative variables provided better discrimination and calibration (p < 0.05) than the NSQIP model and was validated against the 2005-2009 data. A web-based calculator makes this new model available for prospective risk assessment.

CONCLUSIONS

We conclude that the NSQIP-supplied risk model underestimates proctectomy morbidity and that this new, validated risk model and risk prediction tool ( http://myweb.uiowa.edu/sksherman ) may allow clinicians to counsel patients with accurate risk estimates using data available in the preoperative setting.

Pancreastatin predicts survival in neuroendocrine tumors

BACKGROUND

Serum neurokinin A, chromogranin A, serotonin, and pancreastatin reflect tumor burden in neuroendocrine tumors. We sought to determine whether their levels correlate with survival in surgically managed small bowel (SBNETs) and pancreatic neuroendocrine tumors (PNETs).

METHODS

Clinical data were collected with Institutional Review Board approval for patients undergoing surgery at one center. Progression-free (PFS) and overall (OS) survival were from the time of surgery. Event times were estimated by the Kaplan-Meier method. Preoperative and postoperative laboratory values were tested for correlation with outcomes. A multivariate Cox model adjusted for confounders.

RESULTS

Included were 98 SBNETs and 78 PNETs. Median follow-up was 3.8 years; 62 % had metastatic disease. SBNETs had lower median PFS than PNETs (2.0 vs. 5.6 years; p < 0.01). Median OS was 10.5 years for PNETs and was not reached for SBNETs. Preoperative neurokinin A did not correlate with PFS or OS. Preoperative serotonin correlated with PFS but not OS. Higher levels of preoperative chromogranin A and pancreastatin showed significant correlation with worse PFS and OS (p < 0.05). After multivariate adjustment for confounders, preoperative and postoperative pancreastatin remained independently predictive of worse PFS and OS (p < 0.05). Whether pancreastatin normalized postoperatively further discriminated outcomes. Median PFS was 1.7 years in patients with elevated preoperative pancreastatin versus 6.5 years in patients with normal levels (p < 0.001).

CONCLUSIONS

Higher pancreastatin levels are significantly associated with worse PFS and OS in SBNETs and PNETs. This effect is independent of age, primary tumor site, and presence of nodal or metastatic disease. Pancreastatin provides valuable prognostic information and identifies surgical patients at high risk of recurrence who could benefit most from novel therapies.

GIPR expression in gastric and duodenal neuroendocrine tumors

BACKGROUND

Compounds targeting somatostatin-receptor-type-2 (SSTR2) are useful for small bowel neuroendocrine tumor (SBNET) and pancreatic neuroendocrine tumor (PNET) imaging and treatment. We recently characterized expression of 13 cell surface receptor genes in SBNETs and PNETs, identifying three drug targets (GIPR, OXTR, and OPRK1). This study set out to characterize expression of this gene panel in the less common neuroendocrine tumors of the stomach and duodenum (gastric and duodenal neuroendocrine tumors [GDNETs]).

METHODS

Primary tumors and adjacent normal tissue were collected at surgery, RNA was extracted, and expression of 13 target genes was determined by quantitative polymerase chain reaction. Expression was normalized to GAPDH and POLR2A internal control genes. Expression relative to normal tissue (ddCT) and absolute expression (dCT) were calculated. Wilcoxon tests compared median expression with false discovery rate correction for multiple comparisons.

RESULTS

Gene expression was similar in two gastric and seven duodenal tumors, and these were analyzed together. Like SBNETs (n = 63) and PNETs (n = 51), GDNETs showed significant overexpression compared with normal tissue of BRS3, GIPR, GRM1, GPR113, OPRK1, and SSTR2 (P < 0.05 for all). Of these, SSTR2 had the highest absolute expression in GDNETs (median dCT 4.0). Absolute expression of BRS3, GRM1, GPR113, and OPRK1 was significantly lower than SSTR2 in GDNETs (P < 0.05 for all), whereas expression of GIPR was similar to SSTR2 (median 4.3, P = 0.4).

CONCLUSIONS

As in SBNETs and PNETs, GIPR shows absolute expression close to SSTR2 but has greater overexpression relative to normal tissue (21.1 versus 3.5-fold overexpression). We conclude that GIPR could provide an improved signal-to-noise ratio for imaging versus SSTR2 and represents a promising novel therapeutic target in GDNETs.