SAN FRANCISCO, CA USA (UroToday.com) - Deborah Kuban, MD provided an excellent review of the last 10 years of advancements in the treatment of prostate cancer using radiation therapy (RT). She highlighted several phase III trials which have helped the radiation oncology community make decisions regarding treatment choices, dosimetry, duration of androgen deprivation (ADT), timing of postoperative RT, and comparative effectiveness research.
Regarding therapy decisions, she highlighted the Institute for Clinical and Economic Review report which demonstrated that for low-risk prostate cancer, active surveillance, brachytherapy, intensity-modulated radiotherapy, and radical prostatectomy can be considered equivalent in terms of cancer control, but do differ in terms of side effects. This was substantiated in retrospective analysis of patients in the PCOS and EPIC prospective observational studies.
Dr. Kuban went on to show that higher doses do perform better in terms of biochemical recurrence (BCR), metastasis, prostate cancer-specific mortality (PCSM), and local recurrence. ADT has also been optimized over the last decade. Based on several phase III trials, we now know that for high-risk prostate cancer, longer-term androgen deprivation (2-3 years) is better than 6 months of ADT, and that for intermediate-risk disease, shorter ADT duration (6 months) is preferable. We also now know that for low-risk prostate cancer, ADT is not necessary.
One question Dr. Kuban highlighted, that is being addressed, is whether higher doses of RT for intermediate risk will be equivalent to lower doses combined with ADT. Regarding the timing of postoperative radiation, she highlighted the trials showing that adjuvant RT decreased PCSM and increased overall survival compared to salvage RT but also noted that there were known flaws with regard to the PSA at the time of salvage RT. Based on retrospective studies, salvage RT when PSA is low (< 0.5 ng/mL) seems to perform as well as planned adjuvant RT and would obviously prevent the over treatment and toxicity of unnecessary RT. She mentioned that a trial comparing salvage with a designated PSA cut-off is in the works.
Lastly, regarding comparative effectiveness of the different types of RT, she cited a recent study showing that IMRT seemed to be superior to conformal RT in terms of cancer control, and also had better toxicity profile compared to proton beam and conformal RT.
She closed by noting that we started the last decade by deciding which type of RT was better in terms of cancer control, and we begin the next decade by trying to decide which one is the most cost effective.
Highlights of a presentation by Deborah A. Kuban, MD, FACR, FASTRO at the 2014 Genitourinary Cancers Symposium - January 30 - February 1, 2014 - San Francisco Marriott Marquis - San Francisco, California USA
The University of Texas M. D. Anderson Cancer Center, Houston, TX USA
Written by Phillip Abbosh, MD, PhD, medical writer for UroToday.com
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