BOSTON—Early-stage prostate cancer treated with radiation therapy should begin hormone therapy immediately if their PSA level rises quickly and doubles within six months after treatment; however patients should forego hormones if PSA levels do not rise as quickly, according to research presented Tuesday at the 50th annual meeting of the American Society for Therapeutic Radiology and Oncology (ASTRO).
“We've been using PSA doubling time to help guide our decision about when to begin hormone therapy, but this study gives us new and critical information that suggests we should start therapy sooner than previously thought for some patients and delay treatment for others,” said the study’s lead author Eric Horwitz, MD, acting chairman and clinical director of the radiation oncology department at Fox Chase Cancer Center in Philadelphia. “While hormone therapy can have side effects such as hot flashes, decreased libido and osteoporosis, it can help prevent the cancer from spreading to the bones, causing pain and leading to an earlier death from the disease.”
The researchers said that previous studies indicated an increased likelihood that the cancer had spread if the PSA doubling time occurred within 12 months, and thus a potential benefit from receiving hormone therapy.
However, they noted the effectiveness of a newly validated formula, Phoenix definition, used by physicians demonstrates a more accurate way of determining biochemical failure. Using the new formula, the Fox Chase team said it was able to determine when earlier action needs to be taken.
“What we now know is that when the PSA rises and doubles within six months, versus 12 months, we need to act,” Horwitz said. “Our study suggests that these are the men who will benefit most from hormone therapy.”
He also said that the study helps identify who is less likely to benefit from hormone therapy, which may indicate a necessary change in current practice. “Men whose PSA rises, but does so over a longer period of time may not benefit from hormones,” he added.
The authors concluded that both findings suggest a change in the practice of prescribing hormones is warranted.