HDR brachytherapy applied to cervical carcinoma with moderate lateral expansion: modified principles of treatment

Background and purpose: In order to meet the deficiencies of endocavitary a pplications, a combined technique was introduced with the aim of achieving better target coverage for improvement of loco-regional tumour control. In high dose rate (HDR) endocavitary applications with tandem and ovoids, enla rgement of the distance between the ovoids, shifting of dwell times and als o optimization often fail to achieve sufficient expansion of the cervical p arametrial area encompassed by the reference isodose. Materials and methods: The Deventer method, whereby HDR endocavitary and HD R interstitial brachytherapy are applied in the same session, was applied f or tumours with a lateral expansion of 25 mm or more from the axis of the c ervical canal. For the addition of HDR interstitial brachytherapy, each ovo id was provided with a channel which allowed insertion of an afterloading n eedle into the cervix up to a fixed depth. The dose specifications and dosi metry in neighbouring organs are presented in detail. Results: Seventy-six combined applications were given to 41 patients. The f ollow-up averaged at 23 months, with a maximum of 59 months. No severe earl y or persistent late complications were observed. In stage IIB tumours, the most important evaluation of the merits of this technique, the disease-fre e S-year survival determined with the Kaplan-Meier method was 75% (n = 20). Conclusions: The Deventer method of HDR endocavitary and HDR interstitial b rachytherapy applied in the same session is a feasible method for enlargeme nt of the reference isodose envelope in the cervical parametrial area. The 3-year disease-free survival in stage IIB patients and the low complication rates in all stages together, justify its continuation. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.