Promising therapy if PSA rises after prostate cancer surgery

Research shows a promising new option for men who experience rising PSA after radical prostatectomy.

Many men who undergo surgical treatment for prostate cancer (radical prostatectomy) live their lives without recurrence of the disease. But 20% to 40% of them will experience a rise in prostate-specific antigen (PSA) levels within 10 years after surgery. PSA should be undetectable in the blood if the prostate has been removed, so elevated levels mean the cancer may have returned. Doctors call this a biochemical recurrence and usually treat it by irradiating the bed of the prostate where the prostate was before it was removed. Called pelvic bed radiation therapy, or PBRT, this type of treatment often manages to bring PSA back down to zero within years.

Now a large study shows that PBRT is even more effective when combined with other treatments. The findings are a potential game changer for men who experience biochemical recurrence after radical prostatectomy.

Funded by the National Cancer Institute, the SPPORT phase 3 clinical trial was conducted at nearly 300 medical centers in the United States, Canada and Israel. A total of 1,797 men were enrolled between 2008 and 2015, all with postoperative PSA levels ranging between 1 and 2 nanograms per milliliter (ng/mL).

Subjects were randomly assigned in approximately equal numbers to one of three groups. Men in group 1 received PBRT alone, while men in group 2 received PBRT combined with four to six months of androgen deprivation therapy, or ADT. (Also known as hormone therapy, ADT blocks testosterone, a hormone or androgen that fuels growing prostate tumors.) Men in group 3 received PBRT, ADT, and also radiation to the pelvic lymph nodes, where prostate cancer usually goes first. if it starts to spread. The researchers wanted to know which of these three strategies was most effective in halting disease progression.

Results, side effects and what’s next

According to their results, more intensive treatment leads to better results. Just over 70% of men in group 1 still avoided disease progression after five years, compared with 80.3% of men in group 2 and 87.4% of men in group 3. Specifically, 145 of the men in group 1 developed additional PSA increases during the follow-up period, compared with 104 men in group 2 and 83 men in group 3. Similar trends were seen in how many men developed metastases or cancer that became resistant to hormone therapy. therapy once it starts to spread.

More intensive treatments also have more short-term side effects, especially diarrhea. But the differences in side effects between the three groups disappeared after three months.

The authors emphasize that longer follow-up is still needed to confirm whether the addition of ADT and pelvic nodal radiation to PBRT actually prolongs survival. Also, the study did not evaluate a newer therapeutic strategy for biochemical recurrence, in which doctors use new imaging methods to find extremely small metastases throughout the body, which they treat directly with radiation.

Dr. Mark Garnick, Gorman Brothers Professor of Medicine at Harvard Medical School and Beth Israel Deaconess Medical Center and editor of Harvard Health Publishing Annual Report on Diseases of the Prostate, says it’s important for men to understand that any measurable amount of PSA after radical prostatectomy is abnormal and requires further evaluation. “The time-honored normal PSA range of 0 to 4 ng/mL no longer applies when men have their prostates surgically removed,” he says. “The evidence for additional benefit from the addition of ADT and pelvic radiation during this trial was substantial. Whether this represents a new standard of care for biochemical relapse requires further follow-up.”

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