[Two Cases of Locally Advanced Lower Rectal Cancer with Pathological Complete Response after Cetuximab plus SOX as Neoadjuvant Chemotherapy].

We have introduced neoadjuvant chemotherapy(NAC)for locally advanced lower rectal cancer(LARC)since 2014. We report 2 LARC cases in which a pathological complete response(pCR)was obtained by using cetuximab(Cmab)plus oxaliplatin plus S-1(SOX)for NAC. Case 1: A 68-year-old woman underwent 4 courses of Cmab plus SOX for Rb rectal cancer (well-differentiated adenocarcinoma, cStage Ⅲc: cT4b[vagina]N3M0). Lap posterior pelvic exenteration was performed. The pathological findings of the resected specimen revealed no carcinoma and we diagnosed it as pCR. As of 31 months after the operation, she is alive without recurrence. Case 2: A 72-year-old man underwent 4 courses of Cmab plus SOX for middle and lower rectal cancer(Rab, moderately differentiated tubular adenocarcinoma, cStage Ⅲc: cT3N3M0). After NAC, with the diagnosis of ycT3N0M0, laparoscopic-assisted(Lap)super-low anterior resection with bilateral lateral pelvic node dissection was performed. The pathological findings of the resected specimen revealed no carcinoma and we diagnosed it as pCR. As of 37 months after the operation, he is alive without recurrence. NAC with Cmab plus SOX may be an effective treatment for LARC.