Experimental Model Finds High PSA Levels After Prostate Cancer Surgery May Not Lead To Metastasis

Experimental Model Finds High PSA Levels After Prostate Cancer Surgery May Not Lead To Metastasis

shutterstock_171525971Recent findings published in the Clinical Cancer Research journal, show that some prostate cancer patients who present elevated levels of prostate-specific antigen (PSA) after a radical prostatectomy (RP), may die of causes unrelated to prostate cancer long before they are diagnosed with prostate cancer metastasis.

The study, titled “Overdetection of Recurrence after Radical Prostatectomy: Estimates Based on Patient and Tumor Characteristics” estimated the chance that an untreated PSA-recurrence  (PSA-R) would not progress to clinical metastasis within the patient’s lifetime, leading researchers to conclude that in this population, treatment for recurrence may not be beneficial.

“Previous studies have indicated that the interval from PSA recurrence to metastasis is quite long, with a median of more than eight years, even in the absence of any treatment for the recurrence,” Ruth Etzioni, PhD, full member of the Public Health Sciences Division at Fred Hutchinson Cancer Research Center in Seattle, Washington and senior author in the study, said in an American Association for Cancer Research (AACR) press release. “Given that the majority of prostate cancer patients are older, we expect that many would die of other causes before reaching the point of metastasis. Much like the issues with PSA screening and overdetection of prostate cancer, overdetection of recurrence after primary treatment poses some concerns as well. We have attempted to quantify the risk associated with overdetection of recurrence,” added Dr. Etzioni.

The authors designed a simulation model to estimate times from PSA-R to metastasis using data from 441 patients with RP treated at Johns Hopkins University who did not receive salvage treatment at PSA-R, data from 4,455 patients from the Cancer of the Prostate Strategic Urologic Research Endeavor database, and data from the Surveillance, Epidemiology, and End Results (SEER) registry.

They found that at least 9.1% and 15.6% of prostate cancer patients whose PSA levels increase after 5 and 10 years of initial treatment, may not suffer from metastasis throughout their lifetime, and are overdetected for recurrence.

Furthermore, in men older than 70 with a PSA recurrence within 10 years of first diagnosis, the experimental model predicted that 31.4% were overdetected.

“Salvage therapy for prostate cancer patients includes radiation therapy, which has side effects such as bowel problems and urinary symptoms, and hormone therapy, which can cause hot flashes, fatigue, loss of libido, and in the long run, has been linked with osteoporosis, heart disease, and even diabetes,” Dr. Etzioni explained in the press release. “Our findings are in line with treatment studies showing that immediate salvage therapy following detection of rising PSA levels is not the right thing for everyone. We need to develop ways to determine who needs salvage therapy and when to give it.”