ABSTRACT
An advanced small bowel mucinous adenocarcinoma with Peutz-Jeghers syndrome was resected, and we started capecitabine plus oxaliplatin (CapeOX) as adjuvant therapy. However, local recurrence was noted, and the tumor increased even after CapeOX plus bevacizumab and fluorouracil plus leucovorin plus irinotecan plus panitumumab (FOLFIRI plus panitumumab). Pembrolizumab was administered after confirming high-frequency microsatellite instability, and the tumor shrank markedly and remained shrunk for 20 months.
Subject(s)
Adenocarcinoma, Mucinous , Colorectal Neoplasms , Peutz-Jeghers Syndrome , Adenocarcinoma, Mucinous/drug therapy , Antibodies, Monoclonal, Humanized , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Bevacizumab/therapeutic use , Camptothecin/therapeutic use , Fluorouracil/therapeutic use , Humans , Leucovorin/therapeutic use , Neoplasm Recurrence, Local , Peutz-Jeghers Syndrome/drug therapyABSTRACT
BACKGROUND & AIMS: Peutz-Jeghers syndrome (PJS) is typically manifested as severe gastrointestinal polyposis. Polyps in PJS patients and in Lkb1(+/-) mice that model PJS polyposis are frequently characterized by elevated cyclooxygenase-2 (COX-2). This study was designed to determine whether COX-2 inhibition would reduce tumor burden in Lkb1(+/-) mice or Peutz-Jeghers patients. METHODS: Genetic interactions between Cox-2 and Lkb1 in polyp formation were analyzed in mice with combined deficiencies in these genes. Pharmacologic inhibition of COX-2 was achieved by supplementing the diet of Lkb1(+/-) mice with 1500 ppm celecoxib between 3.5-10 and 6.5-10 months. In PJS patients, COX-2 was inhibited with a daily dose of 2 x 200 mg celecoxib for 6 months. RESULTS: Total polyp burden in Lkb1(+/-) mice was significantly reduced in a Cox-2(+/-) (53%) and in a Cox-2(-/-) (54%) background. Celecoxib treatment initiating before polyposis (3.5-10 months) led to a dramatic reduction in tumor burden (86%) and was associated with decreased vascularity of the polyps. Late treatment (6.5-10 months) also led to a significant reduction in large polyps. In a pilot clinical study, a subset of PJS patients (2/6) responded favorably to celecoxib with reduced gastric polyposis. CONCLUSIONS: These data establish a role for COX-2 in promoting Peutz-Jeghers polyposis and suggest that COX-2 chemoprevention may prove beneficial in the treatment of PJS.