Template-based high-dose-rate interstitial brachytherapy in gynecologic cancers: a single institutional experience

To report the outcome and toxicities of radical external beam radiotherapy (EBRT) and template-based high-dose-rate interstitial brachytherapy (ISBT) in patients diagnosed with cervical cancer undergoing inadvertent surgery, vault cancers, and vaginal cancers at our institution.

Between January 2000 and December 2008, 113 patients (37 patients of cervical cancer post-inadvertent surgery, 57 patients with vault cancers, and 19 patients with primary vaginal cancers) were treated with Martinez Universal Perineal Interstitial Template brachytherapy boost after EBRT. The median EBRT dose was 50 Gy, median ISBT dose was 20 Gy, whereas median total dose was 73 Gy equivalent dose at 2 Gy per fraction in all three groups.

Median followup of surviving patients for the whole group was 43 months (interquartile range, 19-67 months). The 3-year actuarial disease-free survival and overall survival for three groups was 61%, 61%, 59% and 64%, 64%, and 56%, respectively. Grade III/IV rectal toxicity was seen in 11 (10%) patients, bladder toxicity in 5 (4.5%) patients, whereas 7 (6%) patients developed Grade III small bowel toxicity. Residual disease at brachytherapy had significant impact on DFS and OS. Other factors such as age, disease volume, parametrial extension, and vaginal extension did not impact the survivals.

Martinez Universal Perineal Interstitial Template-based high-dose-rate ISBT boost in gynecologic cancer results in a reasonable outcome in terms of survivals with acceptable late toxicities. The use of template-based ISBT is associated with a definite learning curve.