In a recent study that the authors describe as "practice-changing," researchers from Cedars-Sinai Cancer Center found that a combination of androgen deprivation therapy and pelvic lymph node radiation kept nearly 90 percent of clinical trial patients' prostate cancer at bay for 5 years. Published in The Lancet, the study also showed that patients with prostate cancer who didn't receive androgen deprivation therapy and who did not receive pelvic lymph node radiation had a 5-year survival rate of 70 percent (2022; https://doi.org/10.1016/S0140-6736(21)01790-6).
Prostate cancer is the most common non-skin cancer in the U.S., with roughly 1 out of every 8 men receiving a prostate cancer diagnosis in their lifetime, according to American Cancer Society (ACS) statistics. The ACS also estimates there will be about 268,490 new cases of prostate cancer in 2022, and approximately 34,500 prostate cancer deaths in the same time frame. Prostate cancer is the second-leading cause of cancer death in American men, behind only lung cancer.
As the authors point out, there are rarely early warning signs of prostate cancer. There is, however, a robust screening test that can detect the disease in its earliest stages, with diagnosis usually accompanying an elevated level of prostate-specific antigen (PSA).
Many men diagnosed with prostate cancer will undergo a prostatectomy. A man's PSA level after surgery should be near zero, but some start to see their PSA levels rise several years after surgery. This increase typically indicates the need for radiation therapy, according to the Cedars-Sinai researchers, who point out that men with postoperative prostate cancer can have excellent outcomes, especially if radiation is given early and in combination with proven therapies.
The Cedars-Sinai research suggests as much. For their study, the investigators enrolled 1,716 patients between March 2008 and March 2015. Eligible patients, age 18 and older, were those who had a persistently detectable or an initially undetectable and rising PSA between 0.1 and 2.0 ng/mL after prostatectomy for adenocarcinoma of the prostate.
Patients with and without lymphadenectomy were eligible if there was no clinical or pathological evidence of lymph node involvement. Other eligibility criteria included pT2 or pT3 disease, prostatectomy Gleason score of 9 or less, and a Zubrod performance status of 0-1.
Patients meeting enrollment criteria were ultimately divided into three groups. The first group received salvage prostate bed radiotherapy, a standard radiation targeted to the area in which the prostate used to exist before being surgically removed. Patients in this group had a median 5-year survival of 71 percent. Patients in the second group received the standard radiation treatment, combined with androgen deprivation therapy. These patients showed a median 5-year survival rate of 81 percent.
Those in the third group were administered salvage prostate bed radiotherapy, androgen deprivation therapy, and pelvic lymph node radiation. Patients in this third group showed "a 5-year freedom from progression of just over 87 percent," according to the authors.
In undertaking this research, "we believed that adding short-term hormonal therapy and pelvic nodal irradiation would lead to better outcomes compared to standard treatment, which was prostate bed radiation alone," stated Howard Sandler, MD, Chair of the Department of Radiation Oncology, Professor of Medicine at Cedars-Sinai Cancer Center, and a co-author of the study.
"The study showed improved outcomes, notably among the patients who were treated both with nodal radiation and hormonal therapy," he stated, noting that hormonal therapy has been beneficial when used in combination with radiation in a number of prostate cancer cases. As such, "this finding was not a major surprise. The benefit of nodal radiation was somewhat surprising, but it is probably a result of the radiation treating small amounts of prostate cancer that has metastasized to regional lymph nodes."
According to Sandler, "this study establishes pelvic nodal radiation combined with short-term hormonal therapy for many patients who are candidates for postoperative radiation. Candidates for postoperative radiation are mostly those patients with elevated PSA levels at some point following radical prostatectomy. This is a pretty common situation, and so this trail could have an impact on many prostate cancer patients."
Mark McGraw is a contributing writer.