Four cases of pancreatic acinar cell carcinoma treated with gemcitabine or S-1 as a single agent.

Pancreatic acinar cell carcinoma (ACC) is a comparatively rare tumor and account for approximately 1% of all cases of pancreatic cancer. Clinical presentation is usually related to either local spread or metastasis. The clinical features, especially those related to the prognosis and treatment outcomes, have not yet been fully clarified. There are no established treatments for unresectable pancreatic ACC. We administered gemcitabine monotherapy to four patients with ACC; however, the results were not satisfactory. Disease control without obvious tumor shrinkage was observed in one patient. Another patient showed severe renal damage caused by gemcitabine. On the other hand, fluoropyrimidine-based chemotherapy may have some activity against this tumor, because one of the three patients who received S-1 as second-line chemotherapy showed a partial response. Prospective clinical trials are necessary to confirm the effectiveness of fluoropyrimidine for the treatment of pancreatic ACC.