Potential risk of residual cancer cells in the surgical treatment of initially unresectable pancreatic carcinoma after chemoradiotherapy

Hironobu Takano, Takahiro Tsuchikawa, Toru Nakamura, Keisuke Okamura, Toshiaki Shichinohe, Satoshi Hirano

With development of chemoradiotherapy for pancreatic carcinoma, borderline resectable or initially unresectable cases sometimes become operable after long-term intensive chemoradiotherapy. However, there is no established strategy for adjuvant surgery with respect to whether the surgical resection should be extensive or downsized accordingly with diminished disease areas following response to chemoradiotherapy. The clinical and pathological aspects of 18 patients with initially unresectable pancreatic cancer who underwent adjuvant surgery after chemo(radio)therapy in our department from 2007 were evaluated. Overall survival from initial treatment was much better for patients with R0 resection than for patients with R1/2 resection. In two of three patients who had complete improvement of plexus (PL) invasion after chemo(radio)therapy, there had still remained pathological plexus invasion. It was shown that tumors did not shrink continuously from the tumor front, but parts remained discontinuously at the distal portion in the process of tumor regression by chemo(radio)therapy. In adjuvant surgery for patients with locally advanced pancreatic cancer, the potential risk of residual cancer in the regression area following chemoradiotherapy should be considered. Achieving R0 resection will lead to an improved prognosis, and it is necessary to consider how well the extent of resection is after a favorable response to chemoradiotherapy.