[Clinicopathological study on rectal cancer after sphincter-saving operation in conjunction with preoperative radiation therapy].

In an attempt to clarify the effect of preoperative radiation on rectal cancer after sphincter-saving resection, radiation group (10 cases) and non-radiation group (22 cases) were studied clinicopathologically. A rate of local recurrence was 36.4% and 10.0% in radiation and non-radiation group, respectively. In cumulative 5-year-survival, non-radiation group showed 70.7%, however, all cases were alive in radiation group. Histological examination demonstrated that such factors predictive of local recurrence as depth of invasion a2, ew (distance between tumor invasion and surgical surface) less than 2 mm, have reduced in radiation group. As a result, it was shown that irradiation had an effect of lowering local recurrences even in cases with high risk factors of local recurrence prescribed above. On the contrary, AW (distance between tumor invasion and anal stump) and frequency of lymph node metastasis had no association with local recurrence, and have not changed favorably even after irradiation. It was also thought to be important to avoid radiation colitis as carefully as possible in radiation therapy for rectal cancer.