Transperineal low-dose rate iridium-192 interstitial brachytherapy in cervical carcinoma Stage IIB

Purpose: To assess local control, survival and complications in patients wi th cervical carcinoma Stage IIB treated radically with transperineal Iridiu m-192 Low-dose rate interstitial brachytherapy following external beam radi otherapy. Patients and Methods: 65 women (age 25-70 years, mean 47 years) with cervic al carcinoma Stage IIB were initially treated with external beam radiothera py on a telecobatt or 6 MV linear accelerator to a dose of 50 Gy delivered in 5-6 weeks. After 2-3 weeks of completing external radiation, patients re ceived interstitial brachytherapy with Iridium-192 (activity 0.5-1 mCi/ cm) using a Syed-Neblett perineal template. The median dose delivered to the i mplant volume was 24 Gy (range 20-32 Gy) delivered at an average dose rate of 0.70 Gy/h (range 0.40-1.20 Gy/h). A point defined at 1.5 cm lateral to t he central uterine tandem at the level of os was taken as a representative for assessing the dose to the cervix. Mean doses delivered by interstitial brachytherapy to point A, cervix, point B and rectum were 38 Gy, 34 Gy, 16 Gy and 16 Gy, respectively. Results: At a median follow-up of 53 months, the actuarial disease free sur vival and overall survival for 65 patients at both 5 and 10 years was 64% a nd 44%, respectively. Response to radiotherapy was a strong predictor of lo cal control with 82% of patients continuing to have pelvic control after in itial complete response. Overall, nine (14%) patients had persistent diseas e, ten (15%) developed a central recurrence after initial control and three patients developed distant metastasis on follow-up. No patient had any imm ediate treatment-related complication. Late toxicity included grade I-II re ctal reactions in five patients and grade IV bladder complication (vesico-v aginal fistula) in two patients. 5 years after treatment, one patient devel oped intestinal obstruction, which was relieved after conservative manageme nt. Two patients developed vaginal stenosis. The 5- and 10-year disease fre e survival was 48% in patients aged Less than 45 years as compared to 80% i n patients of more than 45 years (p = 0.009). Dose to the cervical point wa s a prognostic indicator with 5- and 10-year disease free survival of 47 lo in patients who received < 35 Gy in comparison to 80% in patients who had > 35 Gy (p = 0.03). There was no difference in local control and survival i n patients with minimal and moderate parametrial involvement. Bulky disease (> 4 cm) at presentation and a longer gap between external radiation and b rachytherapy showed a trend towards inferior local control. Conclusions: Interstitial brachytherapy after external beam irradiation in patients with cervical carcinoma Stage IIB results in acceptable local cont rol, survival and complication rates. Increased dose to the cervical diseas e results in improved Local control and survival and should therefore be co nsidered while optimizing brachytherapy treatment plans. Comparison of the results with those of standard intracavitary therapy remains to be proven i n a randomized trial.