THE ADVERSE EFFECT OF TREATMENT PROLONGATION IN CERVICAL-CARCINOMA

Purpose: Proliferation of surviving tumor clonogens during a course of protracted radiation therapy may be a cause of local failure in cervi cal carcinoma. The affect of total treatment time was analyzed retrosp ectively in relation to pelvic control and overall survival for squamo us cell carcinomas of the uterine cervix. Methods and Materials: Two h undred and nine patients (Stage IB-IIIB) treated with a combination of external beam and low dose rate intracavitary irradiation were evalua ble for study. Multivariate analysis and Kaplan-Meier statistical meth ods were used to del:ermine the effect of treatment time on pelvic con trol and survival at 5 years. Results: The median treatment duration w as 55 days. For all stages combined, the 5-year survival and pelvic co ntrol rates were significantly different with treatment times < 55 day s vs. greater than or equal to 55 days: 65 and 54% (p = 0.03), 87 and 72% (p = 0.006), respectively. By stage, a shorter treatment duration (i.e., < 55 days vs. greater than or equal to 55 days) was significant for 5-year overall survival and pelvic control for Stages IB/IIA and III, but not for Stage IIIB: Stage IB/IIA (81 and 67%, 96 and 84%), St age III disease (52 and 42%, 76 and 55%) and Stage IIB (43 and 50%, 74 and 80%, respectively). Survival decreased 0.6%/day and pelvic contro l decreased 0.7%/day for each additional day of treatment beyond 55 da ys for all stages of disease. Additionally, significant late complicat ions were not influeuced by treatment time. Conclusion: These results suggest-that prolongation of treatment time is associated with decreas ed local control and survival in patients with cervical carcinoma. Thi s is consistent with emerging data from other institutions. Therapeuti c implications include avoidance of unnecessary treatment breaks, the design of fractionation schemes that decrease treatment duration, and possibly the use of tumor cytostatic drugs during conventional radiati on.