ABSTRACT
Total of 53 patients of unresectable and recurrent rectal cancer treated with neutron beam during the period from Oct. 1987 to Apr. 1992 were analyzed. Dose fractionation for the neutron only group was 1.5 Gy per fraction, 3 fraction per week, 21 Gy/41/2 wks for 42 patients out of 53(76%). Neutron only but modified fractionation schedule (10% more or less of total dose) was applied for 9 patients, and mixed team (neutron boost) was for 4 patients. Complete tumor response was obtained in 40 patients(76% response rate). Local control rate was 28 out of 53(53%). Statistically significant better prognostic factors for local control were age below 49 years old (15/22, 68%) than above 50 years old (13/31, 42%), male (20/32, 63%) than female(8/21, 38%), tumor size less than 5 cm and non-metastatic(16/24, 67%) than size more than 5 cm or metastatic(12/29, 4l%). Major complication had developed in 7 patients (13%). Two year overall survival rate by Kaplan-Meier method was 30%, but it was rised to, 47% when the tumor was less than 5cm non-metastatic.