TITLE:
Adjuvant Therapy on Cancer of the Lower Rectum. Evaluation of the Effects of Preoperative Radiotherapy on the Prognosis of Patients with Cancer of the Lower Rectum
AUTHORS:
Jose Alfredo Reis Neto, Jose Alfredo Reis Junior, Odorino Kagohara, Joaquim Simões Neto, Sérgio O. Banci, Luciane H. Oliveira
KEYWORDS:
Rectal Cancer; Cancer of the Lower Rectum; Irradiation; Preoperative Radiotherapy; Local Recurrence; Mortality; Survival
JOURNAL NAME:
Journal of Cancer Therapy,
Vol.3 No.6A,
November
30,
2012
ABSTRACT: Aims: The prognosis on treatment of the cancer of the rectum has not changed in the last fifty years. Survival rates of 50 to 55% seems immutable in several published series. The main cause for those results is the high incidence of recurrence, either local or widespread. Local recurrence is directly related to the number of undifferentiated cells and to the grade of wall invasion. Widespread recurrence depends specifically on the lymphatic and vascular spreading. So any kind of treatment that would diminish the number of undifferentiated cells and the size or the tumor wall penetration would certainly decrease the local recurrence rate, lengthening the interval free from cancer and, perhaps, modifying the long term survival rate. Between 1978 and 2009, a total of 538 patients with adenocarcinoma of the lower rectum (from the pectinate line to 10 cm above) were treated by preoperative radiotherapy. Methodology: The same protocol was used in all the patients – 400 cGy, 200 cGy/day, during 4 consecutive weeks (anterior and posterior pelvic fields) by means of a Linear Megavoltage Accelerator (25 MeV). Surgery was performed 2 months after completion of the radiotherapy. Results: Statistical analysis of the whole group showed that preoperative radiotherapy does decrease frequency of undifferentiated cells. Moreover, the incidence of local recurrence diminished after irradiation by 3.4%. Preoperative radiotherapy reduces tumor volume (ERUS) and wall invasion, as well as the mortality rate due to local recurrence (2.4%) and alters long-term survival rate (80.1%). Conclusion: Preoperative radiotherapy is really effective in reducing the number of undifferentiated cells and in diminishing the tumor volume and the carcinomatous infiltration of the rectal wall.