Dose escalation in image-guided, intensity-modulated radiotherapy of carcinoma prostate: Initial experience in India

Background : Increasing incidence and significant stage migration from distant metastases to a localized disease, due to screening application of PSA, is taking place in carcinoma prostate. Also, role of radiotherapy is increasing in carcinoma prostate due to rapid strides in technology.
Aim: The present retrospective study, evaluates escalating the dose in the treatment of localized carcinoma prostate using integration of multiple advanced techniques.
Settings and Design: The settings designed are: a) use of gold seed internal fiducial markers: b) clinical application of emerging Megavoltage Cone Beam Computed Tomography (MVCBCT) technology for Image Guided Radiotherapy (IGRT); c) Intensity Modulated Radiotherapy (IMRT); d) adopting biochemical method for follow-up.
Methods and Material: Twelve consecutive, biopsy proven localized cancer of prostate patients, treated with dose escalation IMRT& IGRT protocol between August 2006 and January 2008, were analyzed. Gold seed markers in prostate were used for daily localization with MVCBCT or Electronic Portal Imaging (EPI). All patients underwent clinical and biochemical follow-up.
Statistical Analysis& Results : Planned dose of 7740 cGy was delivered in 10 out of 12 patients (83%). While one patient had migration of maximum of 3 mm, two others had 1 mm migration of one seed during course of treatment. One patient (8%) developed Grade II proctitis at 12th month. During the mean follow-up duration of 12.2 months, 92% (11/12) had biochemical control within 3 months of treatment.
Conclusions: IGRT technique using MVCBCT for implanted fiducial gold seed localization was feasible for IMRT dose escalation in carcinoma prostate with excellent results.

Keywords
Dose escalation, gold seed markers, image guided intensity modulated radiotherapy, PSA.