Faculty Bibliography

Intraductal papillary mucinous neoplasms (IPMN) are cystic precursors to pancreatic cancer believed to arise within a widespread neoplastic field defect. The tendency for some patients to present with multifocal disease and/or develop additional lesions over time argues in favor of a field defect and complicates surgical management decisions. Surgery usually consists of partial pancreatic resection, which leaves behind a pancreatic remnant at risk for recurrent disease and progression to cancer. As an alternative, total pancreatectomy (TP) provides the most complete oncologic resection, but postoperative morbidity and quality of life (QoL) issues have generally limited its use to only the highest risk patients. Significant progress has been made in the management of the post-TP apancreatic state and studies now show less morbidity with acceptable QoL comparable to type 1 diabetic and post-pancreaticoduodenectomy patients. These improvements do not yet justify the routine use of TP, but they have opened the door for expansion to additional subsets of non-invasive IPMN. Here, we have identified several groups of patients that we believe would benefit from TP over partial resection based on the most current literature.

Our neoadjuvant clinical trial of a GM-CSF secreting allogeneic pancreas tumor vaccine (GVAX) revealed the development of tertiary lymphoid aggregates (TLAs) within the pancreatic ductal adenocarcinoma (PDA) tumor microenvironment 2 weeks after GVAX treatment. Microarray studies revealed that multiple components of the TGF-β pathway were suppressed in TLAs from patients who survived greater than 3 years and who demonstrated vaccine-enhanced mesothelin-specific T cell responses. We tested the hypothesis that combining GVAX with TGF-β inhibitors will improve the anti-tumor immune response of vaccine therapy. In a metastatic murine model of pancreatic cancer, combination therapy with GVAX vaccine and a TGF-β blocking antibody improved the cure rate of PDA-bearing mice. TGF-β blockade in combination with GVAX significantly increased the infiltration of effector CD8+ T lymphocytes, specifically anti-tumor-specific IFN-g producing CD8+ T cells, when compared to monotherapy controls (all p < 0.05). TGF-β blockade alone did not deplete T regulatory cells (Tregs), but when give in combination with GVAX, GVAX induced intratumoral Tregs were depleted. Therefore, our PDA preclinical model demonstrates a survival advantage in mice treated with an anti-TGF-β antibody combined with GVAX therapy and provides strong rational for testing this combinational therapy in clinical trials.

The majority of patients with curative resection of pancreatic ductal adenocarcinoma recur within 5 years of resection. However, the prognosis associated with different patterns of recurrence has not been well studied. A retrospective review of patients who underwent curative surgical resection of pancreatic cancer was performed. Of the 209 patients, 174 patients developed recurrent disease. Of these 174, 28(16.1%) had recurrent disease limited to lung metastases, 20(11.5%) had recurrence in the lung plus one or more other sites excluding the liver, 73(42.0%) had liver metastasis alone or liver metastasis with any other site except lung, 28(16.1%) local recurrence only, and 25(14.3%) peritoneal recurrence alone or together with local recurrence. Patients with recurrence limited to lung had a 8.5 months(Mo) median survival from recurrence to death, which was significantly better than the survival associated with recurrence in the liver(5.1Mo), in the peritoneum(2.3Mo) or locally(5.1Mo) in multivariable analyses. Among all groups, the time from surgery to the diagnosis of recurrence in patients who recurred in only in the lung was also the longest. However, 75% of patients were found to have indeterminate lung nodules on their surveillance CT scans prior to the diagnosis of recurrence in lung. This delayed diagnosis of lung recurrence may have a negative impact on survival after recurrence. In conclusion, pancreatic cancer with lung recurrence has a significantly better prognosis than recurrence in other sites. Further studies are needed to investigate how different diagnostic and treatment modalities affect the survival of this unique subpopulation of pancreatic cancer patients.