Increasing Brachytherapy Dose Predicts Survival for Interstitial and Tandem-Based Radiation for Stage IIIB Cervical Cancer

Purpose:

To evaluate factors affecting survival and toxicity in patients with stage IIIB cervical cancer treated with external-beam radiotherapy and low-dose-rate brachytherapy.

Materials and Methods:

Seventy patients with stage IIIB cervical cancer treated between 1980 and 2000 were identified. A total of 51 patients had a tandem placed; 19 had interstitial brachytherapy only with no tandem placed. Univariate and multivariate analyses assessed factors potentially associated with survival and long-term complications.

Results:

Kaplan-Meier estimates for overall survival (OS) for the entire population at 2, 3, and 4 years were 43%, 29%, and 27%, respectively. Overall survival differed significantly between those treated with a tandem versus those treated without (log rank P < 0.0001). Significant predictors of OS on univariate Cox regression were presence of a tandem (hazards ratio [HR], 0.31; P = 0.0001) and cumulative dose to point A (HR, 0.95; P = 0.0001). Multivariate regression showed that the presence of a tandem was the only significant predictor of OS (HR, 0.46; P = 0.04). There were no significant predictors of complications.

Conclusions:

The dose to point A of approximately 85 Gy as associated with tandem use was a significant predictor of survival in patients with stage IIIB cervical carcinoma, indicating the significance of the central location of the high dose provided by the tandem. Patients selected for interstitial brachytherapy alone must receive sufficient dose, and a tandem should be placed whenever feasible for all patients with an intact uterus treated for locally advanced cervical cancer.