A case of cT4b recto-sigmoidal cancer obtained pathological complete response by preoperative chemotherapy with 4 cycles of mFOLFOX6 plus panitumumab

We present a case of recto-sigmoidal cancer obtained pathological complete response as a result of laparoscopic surgery after chemotherapy concomitant use of panitumumab for the purpose of tumor shrinkage. A 64-year-old woman visited an emergency clinic complaining with continuous lower abdominal pain. She was diagnosed as a recto-sigmoidal cancer cT4b (right ureter and right ovary), N0, M0, cStage IIC. Preoperative chemotherapy was scheduled to expect tumor shrinkage. Based on the results of wild type gene concerning both RAS and BRAF, the modified 5-fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) plus panitumumab were administrated. After 4 cycles of treatment, since a down-stage to ycT3 was recognized, laproscopic high anterior resection with D3 lymphadenectomy was performed. She was judged in her primary lesion as a pathological complete response (pCR) by preoperative chemotherapy. Since her postoperative course was uneventful. No symptoms of relapse have been observed without adjuvant chemotherapy. A case of pCR after neoadjuvant treatment with mFOLFOX6 plus panitumumab followed by laparoscopic curative resection was reported. Further research is needed to confirm the appropriate indications for neoadjuvant therapy concomitant use of anti-EGFR antibody for patients with RAS wild typed locally advanced colon cancer.