High rate of Ki‐67 increase in entero‐pancreatic NET relapses after surgery with curative intent.

Neuroendocrine neoplasms (NENs) present with advanced disease at diagnosis in up to 28% of cases, precluding the possibility of curative‐intent surgery. Histopathological heterogeneity of this disease can be observed inter‐individually as well as intra‐individually during disease course. The present study aimed to assess the frequency of Ki‐67 change after radical surgery, in a series of patients with radically resected entero‐pancreatic neuroendocrine tumors (EP‐NETs). We present the analysis of a multicenter, retrospective, series of EP‐NETs G1–G2 recurring after radical resection and with histological re‐evaluation at disease recurrence (DR). The primary endpoint was the description of Ki‐67 change at DR compared to time of surgery. The secondary endpoint was assessment of recurrence‐free survival (RFS) rates. In total, 47 patients had a second histological evaluation and could be included in the present study. Median Ki‐67 at surgery was 3% (range 1–15%) but, at DR, a significant increase in the value was observed (7%, range 1–30%; p <.01) and involved 66.0% of cases, with a corresponding increase in tumor grading in 34.0% (p =.05). Median RFS of the overall population was 40 months, and was worse when Ki‐67 increased at DR vs. stable Ki‐67 value (36 vs. 61 months, respectively; p =.02). In conclusion, in more than half of the cases with relapse after radical surgery, a higher proliferative index with a potentially more aggressive potential was observed. Therefore, histological reassessment should be considered on DR because tailored therapeutic strategies may be required for these patients. [ABSTRACT FROM AUTHOR]