Borderline resectable pancreatic cancer: conceptual evolution and current approach to image-based classification.
OBJECTIVE To evaluate the outcome of preoperative gemcitabine-based chemoradiation therapy (CRT) for resectable and borderline resectable pancreatic cancer (PC), with a focus on the differences in surgical outcomes and patterns of recurrence between these 2 categories. BACKGROUND Various multimodal treatment strategies have been proposed to improve the surgical outcomes of PC. Preoperative CRT and subsequent surgery is one of the promising strategies for resectable (PC-R) and borderline resectable (PC-BR) PC. METHODS A total of 268 patients with PC-R and PC-BR received preoperative gemcitabine-based CRT. The numbers of PC-R and PC-BR cases were 188 and 80, respectively. We evaluated the following comparisons between patients with PC-R and those with PC-BR: (1) resection rate, (2) rate of margin-negative resection, (3) survival, and (4) pattern of the treatment failure, including local recurrence, peritoneal dissemination, and distant metastasis. RESULTS The resection rate of patients with PC-R (87%) was higher than that of patients with PC-BR (54%) (P < 0.001). Pathological margin-negative resection was achieved in 99% and 98% of the patients with PC-R and PC-BR, respectively. The 5-year survival rates of the PC-R and PC-BR cases were 57% and 34%, respectively (P = 0.029). Although the 5-year cumulative incidence of local recurrence was comparable in both groups (15% and 13%, respectively; P = 0.508), the 5-year cumulative incidence of peritoneal and distant recurrence was significantly higher in the patients with PC-BR (43 and 76%) than in the patients with PC-R (17% and 43%). CONCLUSIONS In the resected cases, the locoregional control was comparable between patients with PC-R and PC-BR after preoperative CRT. The survival rate for the patients with PC-BR was lower than the rate for those with PC-R due to a higher incidence of peritoneal and distant recurrence in the patients with PC-BR. (UMIN000001804).