Surgical treatment and clinical outcome of nonfunctional pancreatic neuroendocrine tumors: a 14-year experience from one single center

Abstract

Our primary aim of the present study was to analyze the clinical characteristics and surgical outcome of nonfunctional pancreatic neuroendocrine tumors (non-F-P-NETs), with an emphasis on evaluating the prognostic value of the newly updated 2010 grading classification of the World Health Organization (WHO).Data of 55 consecutive patients who were surgically treated and pathologically diagnosed as non-F-P-NETs in our single institution from January 2000 to December 2013 were retrospectively collected.This entirety comprised of 55 patients (31 males and 24 females), with a mean age of 51.24 ± 12.95 years. Manifestations of non-F-P-NETs were nonspecific. Distal pancreatectomy, pancreaticoduodenectomy, and local resection of pancreatic tumor were the most frequent surgical procedures, while pancreatic fistula was the most common but acceptable complication (30.3%). The overall 5-year survival rate of this entire cohort was 41.0%, with a median survival time of 60.4 months. Patients who underwent R0 resections obtained a better survival than those who did not (P < 0.005). As for the prognostic analysis, tumor size and lymph invasion were only statistically significant in univariate analysis (P = 0.046 and P < 0.05, respectively), whereas the newly updated 2010 grading classification of WHO (G1 and G2 vs G3), distant metastasis, and surgical margin were all meaningful in both univariate and multivariate analysis (P = 0.045, 0.001, and 0.042, respectively).Non-F-P-NETs are a kind of rare neoplasm, with mostly indolent malignancy. Patients with non-F-P-NETs could benefit from the radical resections. The new WHO criteria, distant metastasis and surgical margin, might be independent predictors for the prognosis of non-F-P-NETs.

FIGURE 1

Overall 5-year survival rate of patients with non-F-P-NETs who underwent an operation was 41.0%, with a median overall survival time of 60.4 months (95% confidence interval, 20.9–99.8 months).

FIGURE 2

Comparison of survival for non-F-P-NETs with different resections. Survival time of patients who underwent R0 resection was statistically longer than that of patients who did not, whose median survival time was 60.43 and 7.40 months, respectively (P < 0.001).

FIGURE 3

Comparison of survival for p-NETs in different stage. Survival time of patients in stage I was longer than those in stages III and IV (P = 0.049 and 0.034, respectively), while no notable differences were found between stages I and II (P = 0.705). Also, patients in stage II obtained better survival than those in stages III and IV (P < 0.005 and P < 0.005, respectively), as well as that between stages III and IV (P = 0.042).

FIGURE 4

Comparison of survival for non-F-P-NETs with different WHO new grading classifications. Survival time of patients between NET G1 and NEC G3, NET G2 and NEC G3 were significant (P = 0.029 and 0.021, respectively), whereas that between NET G1 and NET G2 present no significant difference (P = 0.146).