According to an international study led by Alan Pollack, M.D., Ph.D., chair and professor of radiation oncology at Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine, and published in The Lancet, adding short-term hormone therapy (ADT) and pelvic lymph node radiotherapy to standard of care prostatectomy surgical bed treatment benefits prostate cancer patients whose PSA levels are rising post-prostatectomy.
According to Dr. Pollack, a rising PSA following prostatectomy for prostate cancer is a sign of a recurrence, which happens in more than half of men with negative surgical pathology. Dr. Pollack also said, "the PSA indicates that the cancer has returned, but it does not reveal where it is coming from — the prostate surgical bed, the pelvic lymph nodes, or elsewhere in the body."
Salvage radiation is the only curative option for such individuals, and the standard of care has been to treat only the prostate surgery bed. The SPPORT study (RTOG/NRG Oncology 0534) was designed to see if adding short-term hormone therapy or short-term hormone therapy plus pelvic lymph node radiation significantly lowers recurrence and the risk of cancer spreading.
The SPPORT trial, financed by the National Cancer Institute, included men from 283 radiation oncology cancer treatment sites in the United States (including Sylvester), Canada, and Israel who had prostatectomy but had PSAs ranging from 0.1 to 2.0 ng/mL. The men were randomly assigned to one of three treatments: prostate bed radiotherapy alone, prostate bed radiotherapy plus four to six months of hormone therapy (ADT) or the two treatments plus pelvic lymph node radiotherapy.
The researchers chose five-year independence from prostate cancer progression as their primary outcome for the various treatment arms. They discovered that there was an incremental advantage at each therapy intensification level.
The most intensive treatment, which included the removal of the pelvic lymph nodes and ADT, performed much better than the others. In an unplanned subgroup analysis based on PSA level at protocol entry, all the men improved significantly from the addition of ADT, regardless of their actual PSA numbers.
Five-year freedom from progression was 70.9 percent in the group that had only prostate bed radiation, compared to 81.3 percent in the group that also received ADT.
Adding pelvic lymph node radiation resulted in 87.4 percent patient benefit. Still, this advantage was most significant for individuals with higher PSAs at protocol entrance.
New Medical Standard of Care
According to Dr. Pollack, the SPPORT trial validates and extends the findings of two prior randomized trials of prostate bed radiotherapy plus hormone therapy. It is the first randomized study to indicate additional benefits from the addition of pelvic lymph node radiotherapy.
Dr. Pollack indicated that the SPPORT trial findings are consistent with modern PET imaging modalities that show lymph node recurrences following prostatectomy are significantly higher than previously thought. The results set a new standard of care for salvage radiation.
