Fine wine: The Old and the New in Radiation Therapy for Prostate Cancer (#89)
Radiation therapy is a primary curative treatment option for patients with localized prostate cancer and its use is supported by multiple randomized controlled trials. Although effective, radiation therapy can cause short term and long term morbidity. , which is attributed to incidental doses delivered to organs nearby the prostate. In the past two decades, multiple randomized trials demonstrated that dose- escalated radiation therapy compared to lower doses led to improved biochemical control and decreased clinical failures, but also increased treatment related morbidity because of higher doses to organs at risk. The challenge of increasing radiation dose for prostate cancer treatment while minimizing treatment related morbidity have been met with new radiation technologies such as image guided radiation therapy (IGRT), intensity modulated radiation therapy (IMRT), proton therapy. There is an ever increasing body of evidence showing benefit of these technologies in dosimetry, morbidity, quality of life and cancer control outcomes.
Better understanding of radiobiology of prostate cancers (low alpha/beta ratio -indicating better response with hypofractionation) has led to use of other technologies such as high dose rate brachytherapy and stereotactic body radiation therapy (SBRT) where large dose per fractions are delivered. This is possible because of the ability to “sculpt” out high dose radiation doses confined to prostate and low dose to surrounding organs at risk. There are now large series with long term follow up showing improved cancer outcomes and decreased morbidity with HDR brachytherapy as boost in intermediate and high risk prostate cancer compared to the past. The use of SBRT (where treatment is given in 5-7 fractions compared to conventional way of 38-40 fractions) in prostate cancer( esp low to intermediate risk prostate cancer) is in its early stages of evolution with early data showing very good cancer control outcomes.