Faculty Bibliography

No common malignancy is as rapidly and inevitably fatal as pancreatic ductal adenocarcinoma (PDA). This grim fact has driven substantial research efforts into this disease in recent decades. Unfortunately, the investment has yet to result in a meaningful increase in 5-year survival. This has prompted many pancreatic cancer researchers and advocates to redouble their efforts, but also requires one to step back and ask why the previous efforts were lacking and to consider why pancreatic cancer is so difficult to treat. The difficulties are legion. PDA is characterized by an insidious clinical syndrome, but is rarely diagnosed at a time when surgical resection is feasible. We lack markers of early detection and screening programs remain unproven even in high risk populations. The location of the tumor in the retroperitoneum, the advanced age of patients, and the systemic effects of disease limit the options for local therapy. Chemotherapy may provide a small benefit, but most efforts to improve on the current regimens consistently and stubbornly fail in advanced clinical trials. The molecular and cellular features of ductal pancreatic tumors are aggressive and underlay multiple levels of therapeutic resistance. Non-cell-autonomous features including stromal proliferation, reduced vascular density and immune suppression also contribute to therapeutic resistance. Growing awareness of these the fundamental features of PDA has begun to guide ongoing research efforts. Clinical trials are now specifically targeting these tumor properties and actively focusing on the therapeutic implications of tumor stroma. As reviewed here, reflecting on the fundamental question of why pancreatic cancer is so difficult to treat is a necessary and informative exercise that will aid our efforts to improve patient outcomes. These efforts will lead to improvements in clinical trial design, expand our focus to include the molecular and histologic implications of novel treatment paradigms, and ultimately change the lives of our patients.

Gemcitabine was approved for advanced pancreatic cancer in 1996. We investigated uptake and predictors of its use. We identified 3,231 individuals > 65 years in the SEER-Medicare database with stage IV pancreatic adenocarcinoma, diagnosed between 1998-2005, who survived > 30 days. Of these, 54% received chemotherapy, 93% with gemcitabine. Gemcitabine nonreceipt was associated with advanced age and unmarried (OR: 0.65, 95% CI: 0.55-0.76). Diagnosis in 2004-2005 versus 1998-2000 was more likely to receive gemcitabine (OR: 1.51, 95% CI: 1.23-1.84) as were higher SES patients (highest versus lowest quintile, OR: 2.14, 95% CI: 1.60-2.85). Gemcitabine was rapidly adopted among elderly advanced pancreatic cancer patients; several factors are associated with use.

 Neuroendocrine tumors (NETs) describe a heterogeneous group of tumors with a wide range of morphologic, functional, and behavioral characteristics. Pancreatic neuroendocrine tumors (pNET) are a subset of NETs which are increasing in incidence and prevalence. These tumors are generally slow growing and behave in an indolent fashion. However, when these tumors spread they can be life threatening and difficult to treat with current modalities. In 2011, the landscape of treatment for pNET was changed with the approval of two targeted agents, sunitinib and everolimus, the first new therapies for this disease in over 20 years. Data from these clinical trials and extensive preclinical work into the underlying molecular pathways in neuroendocrine tumors has generated intense interest in the quest to identify additional effective agents in this challenging disease. At the 2012 American Society of Clinical Oncology (ASCO) Annual Meeting, several researchers presented updated data regarding the use of targeted agents, alternative chemotherapeutic agents and combinations of these in the treatment of pNET. Corrie et al. (Abstract #4121) reported data from a chemotherapy clinical trial replacing 5-FU with capecitabine and evaluating the addition of cisplatin in NETs. Several authors reviewed the addition of the anti VEGF monoclonal antibody bevacizumab into combination therapy. Ducreux et al (Abstract #4036) presented results from a trial of chemotherapy plus bevacizumab while Firdaus et al. (Abstract #4127) reported the results of combination therapy with octreotide, bevacizumab, and pertuzumab. Hobday et al. (Abstract #4048) reported positive results of an interim analysis of combination therapy with an mTOR inhibitor and bevacizumab. Kulke et al (Abstract #4125) reported the results of a clinical trial utilizing an antibody targeting the insulin growth factor receptor. Finally, Vinik et al. (Abstract #4118) provided updated survival data form the seminal phase III trial that led to approval of sunitinib in the treatment of pNET. The authors review and summarize these abstracts in this article. 

Neuroendocrine tumors (NETs) describe a heterogeneous group of tumors with a wide range of morphologic, functional, and behavioral characteristics. These tumors are often indolent but they have the potential to cause symptoms through release of hormones and through local or distant spread. Pancreatic neuroendocrine tumors (pNET) represent a subset of NETs and they have a unique pattern of symptoms and disease progression. Due to the heterogeneity of this disease it is important to identify reliable markers to help guide prognosis and predict response to therapy. The recent approval of two new agents in the treatment of advanced pNET has raised additional interest in the significance of molecular markers in this disease. At the 2012 American Society of Clinical Oncology (ASCO) Annual Meeting, several investigators reported on collaborative efforts to develop clinically useful biomarkers for this disease. Choti et al. (Abstract #4126) reported data about the functional characteristics of NETs and pNETs among a multi-institutional cohort finding that a substantial minority of patients have functional symptoms even when the disease is localized. Faggiano et al. (Abstract #1604) looked at a wide spectrum of NETs in several referral centers and reported on predictors of both short term and long term survival in this setting. Yao et al. (Abstract #4014) reported analysis of predictive biomarkers among patients in the RADIANT-2 trial which looked at the role of the mTOR inhibitor, everolimus compared to placebo in NET. Fischer et al. (Abstract #4128) looked at a novel biomarker, placental growth factor (PlGF) and evaluated the role of serum and tissue levels of this protein as a predictive marker. Finally, Khan et al. (Abstract #4123) investigated the role of circulating tumor cells in NET (and pNET) and found that this may have potential as a prognostic marker and an early marker of response to therapy. The authors review and summarize these abstracts in this article.

Neuroendocrine tumors (NETs) describe a heterogeneous group of tumors with a wide range of morphologic, functional, and behavioral characteristics. These tumors are generally slow growing and behave in an indolent fashion. However, they have the potential to spread, primarily to the liver and when they do, they can be life threatening and difficult to treat with current modalities. A subset of NETs, the pancreatic neuroendocrine tumors (pNET) represent a small percentage of all pancreatic tumors (1.3%) but their incidence is rising. Prior to 2011, the only approved agent for unresectable pNETs was streptozocin (often used in combination with doxorubicin) but the efficacy of this drug was questionable. In 2011, the landscape of treatment for pNET was changed with the approval of the first new agents in 20 years, sunitinib and everolimus, that demonstrated improvement in time to progression in patients with progressive pNET. Sunitinib is a multikinase inhibitor and everolimus is an inhibitor of the mammalian target of rapamycin (mTOR) pathway. These drugs were approved by the Food and Drug Administration (FDA) on the basis of separate large randomized placebo-controlled trials. Data from these two trials and an additional phase III trial looking at everolimus in other neuroendocrine tumors has generated intense interest in this challenging disease. At the 2012 American Society of Clinical Oncology (ASCO) Gastrointestinal Cancers Symposium, several researchers presented updated data regarding the risk stratification, treatment, and outcome for patients with pNET in the new era of targeted therapy. Choti et al. (Abstract #187) reviewed demographic data from a large set of patients who presented to National Comprehensive Cancer Network (NCCN) sites with neuroendocrine tumors. Casciano et al. (Abstract #226) and Signorovitch et al. (Abstract #237) presented post-approval analysis of the relative role of everolimus and sunitinib in the treatment of pNET. Alistar et al. (Abstract #166) explored predictive biomarkers in pNET, and Yao et al. (Abstract #157) conducted multivariate analysis of patients treated with everolimus in the phase III, RADIANT-2 trial which included the identification of relevant biomarkers. Hobday et al. (Abstract #260) and Bergsland et al. (Abstract #285) reported phase II data from two clinical trials looking at novel targeted combinations for the treatment of pNET. Finally the role of treatment for poorly differentiated NETs (including pNETs) remains ill-defined and Yamaguchi et al. (Abstract #274) presented a report reviewing the experience at 23 centers in Japan in treating this population. The authors review and summarize these abstracts in this article.