[A Case of Stage IV Rectal Cancer Achieving Long-Term Stable Disease Treated with Chemotherapy and Residual Tumor Resection]

We herein report a Stage IV case ofrectal cancer in a patient who achieved stable disease and was treated monthly with fluorouracil(FU)monotherapy plus bevacizumab(Bmab)against relapse after residual tumor resection and withdrawal because ofref usal to continue chemotherapy, even though a marked response was obtained with standard chemotherapy. A 73-year-old woman visited a former hospital in 2014, and was diagnosed with rectal cancer with liver and lung metastases (diagnosed with Rb, T3, M1b[liver, lung]cStage IV). Chemotherapy(mFOLFOX6 plus Bmab)was initiated with a consideration of conversion. After 5 courses, she moved to our hospital. Since she was not aggressive to chemotherapy from the beginning, an imaging examination was performed after 9 courses. The primary lesion and lung metastases had disappeared, and there was only one liver metastasis. Partial hepatic resection was performed to attempt chemotherapy withdrawal following informed consent. Six months after surgery with no therapy, since relapse in the rectum and lungs was confirmed, laparoscopic rectal amputation was performed to control the primary tumor. Chemotherapy containing FU monotherapy plus Bmab was reinitiated after 15 months of withdrawal because liver and lung metastases increased 5 months after rectal amputation. Two months after resuming chemotherapy, the metastatic lesion decreased in size, and the tumor marker level normalized. The same regimen is continued monthly, and the response has been maintained for 17 months(infusions of 5-FU/LV plus Bmab, 18 courses).