[A case of a geriatric patient with stage IV anal canal cancer showing complete response to chemoradiation therapy].

We present a case in which chemoradiation therapy was effective in a geriatric patient with Stage IV anal canal cancer. The patient is an 81-year-old woman who complained of proctorrhagia and anal pain. She was referred to us by her family doctor who suspected rectal cancer. Tumors as large as 6.5 cm in diameter mainly on the right side of the rectum as well as 2 palpable enlarged lymph nodes on the right inguinal area, were found during the initial physical examination. Squamous cell carcinoma was elevated to 16 ng/mL. A CT scan revealed that irregularly shaped masses as large as 7 cm in diameter were externally exposed on the right side of the rectum along with enlarged lymph nodes on the right inguinal area and metastasis at S7 lesion in the liver. Squamous cell carcinoma was diagnosed from biopsy results. Due to her age, the chemotherapy regimen was S-1+CDDP with radiation therapy and 4-port irradiation (50.4 Gy) of the primary tumor, interior of the pelvis, and inguinal lymph nodes. Partial response was observed upon completion of treatment, and complete response was obtained after 6 months. She is currently an outpatient taking S-1: 60 mg/day orally. There is no indication of cancer recurrence after 1 year and 3 months, and she continues to visit an outpatient clinic for regular follow-ups. These results demonstrate the effectiveness of chemoradiation therapy for geriatric patients with Stage IV anal canal cancer.