Application of three different kinds of local boost techniques in radiotherapy for locally advanced cervical cancer

Objective: To investigate the dosimetry differences in the treatment of locally advanced cervical cancer with intracavitary/interstitial brachytherapy (IC/IS BT), intracavity brachytherapy combined with intensity modulated radiotherapy (ICBT + IMRT) and simple IMRT. Methods: Totally 16 patients with local advanced cervical cancer were retrospectively selected, which were treated by three-dimensional brachytherapy. On the basis of the original three-dimensional intracavitary/interstitial brachytherapy plan, ICBT + IMRT and IMRT plans were designed respectively to study the dosimetry differences of target and different organs at risk for the three kinds of plans. Results: A total of 75 brachytherapy treatment plans were designed, including 25 IC/IS BT, 25 ICBT + IMRT and 25 IMRT. There was not statistically significant difference of target dose parameters between ICBT + IMRT and IC/IS BT plan (P > 0.05). ICBT + IMRT plans had better OAR sparing than IC/IS BT. The doses of OARs in the IMRT plans were relatively large and the volume irradiated to more than 60 Gy (V₆₀) was significantly higher (t = 6.77, 10.37, 4.61, 2.83, P < 0.05). Conclusions: The ICBT + IMRT technique not only provides better target coverage, but also maintains low doses to the OARS, which can be used as an alternative treatment to IC/IS BT. Although the target coverage of IMRT is better, the protection of OARs is not satisfied, so it is not suitable for local boost therapy of advanced cervical cancer. (authors)