Hypofractionated Simultaneous Integrated Boost (SIB) versus Conventional Fractionation in Localized Prostate Cancer:...

Radical prostatectomy or radiotherapy has comparable results in the treatment of localized prostate cancer. High dose external irradiation entails a prolonged 7-8 weeks of treatment with significant inconvenience to elderly patients. Hypofractionated regimen in prostate cancer depends on the distinctive radiobiological properties of prostate cancer cells; their relative low alpha beta ratio compared to that for late-reacting rectal tissue allows for significant dose escalation per fraction without expected increase in late normal tissue reaction.

Between July 2012 and December 2013, twenty patients were blindly randomized into two groups. The planning target volume in the study group received 65Gy to 67.5Gy/25 fractions over 5 weeks. The patients in the control arm received 74Gy to 78Gy in 2Gy/fraction. Cost-benefit was evaluated for both regimens.

Both groups were comparable regarding risk factors, with no significant statistical differences. Four patients in the study group developed grade 2 urinary toxicity and one patient had grade 3 during treatment. At six months no patient had urinary symptoms. In the control arm 4 patients have grade 2 toxicity during treatment which disappeared at six months. The two groups showed no statistical difference in the mean quality of life. Serum PSA reached a nadir value of 0.02 and 0.04 in the study and control groups respectively at 3 month post-treatment. The cost of treatment for the study group was 25000 L.E. per patient compared to 40000 L.E. in the control group. The hypofractionated group consumed 31138 MU compared to 45611 MU for the control group with a p-value of 0.015.

Hypofractionated IMRT with concomitant boost for localized cancer prostate is a feasible option with lesser cost and comparable toxicities. Longer followup is required to assess the late effects before recommending it as a standard of care.