The management of small asymptomatic pancreatic neuroendocrine tumors: A matched case-control study.

Abstract

239 Background: Overdiagnosis and overtreatment has become an evolving challenge for several cancer sub-types. We hypothesized that a substantial portion of incidentally diagnosed small pancreatic neuroendocrine tumors(PanNET) are overtreated as a result of overdiagnosis and that non-operative management may be reasonable for selected patients. Methods: Consecutive patients evaluated for incidentally discovered, sporadic, stage I-II PanNET were analyzed retrospectively. Diagnosis was determined either by pathology or unequivocal imaging characteristics. Patients selected for radiographic surveillance (RS) were matched with patients who underwent resection based on tumor size at initial imaging. Clinicopathological characteristics were compared between the groups. Results: During the study period (2000-2013), RS was recommended for 80 patients, and 79 matched patients underwent resection (resection group). Pathologic diagnosis was obtained in 42 (53%) of the 80 RS patients. Median initial tumor size was similar between the RS vs resection groups (1.2cm (0.8-1.7) vs 1.3 cm (1-1.9), respectively, p=0.4). The resection group was younger and had a longer median follow-up compared to the RS group (58 vs 65 years, p<0.001; 50 vs 29 months, p=0.006; respectively). At the time of last follow-up of the RS group, median tumor size had not changed (1.2cm, p=0.4), no patient had developed metastases, and no patient had experienced radiographic changes in the primary tumor that prompted resection. Within the resection group, low-grade (G1) pathology was recorded in 74 (95%) tumors, one patient had node positive disease, and five developed recurrence (6%). The postoperative complication rate was 36%. No patient in either group died from disease. Death from other causes occurred in 7 out of 159(4%) patients. Conclusions: In this study, no patient who was selected for observation developed metastases or died from disease after a median follow-up of almost 2.5 years.Radiographic surveillance for stable, small, incidentally discovered PanNETs is reasonable in selected patients.