After surgery to remove a cancerous prostate gland, some men experience biochemical reoccurrence, meaning prostate-specific antigen (PSA) becomes detectable of their blood. Since only the prostate releases PSA, removing the gland should leave the protein at undetectable levels within the body. PSA detection can indicate that prostate cancer cells are late, and latest tumors are forming before they will be seen with advanced imaging technology. PSA just isn’t all the time reliable for screening for cancer, nevertheless it is a really sensitive marker of recent cancer growth after early treatment.
Doctors often treat biochemical reoccurrence by irradiating the prostate bed, or the world where the gland was once. Studies show that this treatment, called salvage radiation, helps reduce the chance that prostate cancer will return and spread, or metastasize. But when to begin salvage radiation is an open query, because PSA may even rise if a small amount of benign prostate tissue is left behind after surgery. Many times, doctors don't know if a biochemical reoccurrence is definitely cancer, so that they wait to see if the PSA level rises again.
In October, researchers reported Salvage radiation as soon as PSA is detected can significantly reduce the risk of metastasis.. “We found that early intervention with radiation can potentially improve cure rates,” said Rahul Tendulkar, MD, a radiation oncologist on the Cleveland Clinic, and first writer of the study. “There is no need to wait until the PSA crosses the discretionary threshold.”
Tendulkar and his colleagues checked out nearly 2,500 patients treated after surgery at 10 different teaching hospitals between 1987 and 2013. Of these men, 599 had cancers that were at low risk of developing, while the others had high-risk disease. Some cases spread to nearby tissues. Some men also had positive surgical margins, meaning cancer cells should still be lurking where the prostate was removed.
According to their results, the incidence of metastasis at five years after surgery was 9% in men who received salvage radiation for PSA levels of 0.01 to 0.2 nanograms per milliliter (ng/mL). In contrast, the incidence rate of metastasis in men treated for PSA levels of 0.2 to 0.5 ng/mL was 15%. Both the American Urological Association and the American Society of Radiation Oncology recommend that salvage radiation be given when the PSA level reaches or exceeds 0.2 ng/mL. But Tendulkar says that level was defined years ago, before highly sensitive methods for detecting PSA were widely available.
“In this new era of highly sensitive PSA testing, we didn't know whether giving low-level salvage radiation would make a difference,” Tendulkar said. “Now we know it does.”
Tendulkar says the choice to start salvage radiation could also be influenced by other aspects, corresponding to age, other health problems, and the aggressiveness of the cancer he was diagnosed with.
But the study doesn't address a crucial query: Should men with high-risk cancer consider getting radiation after surgery even before an increase in PSA is detected? Studies designed to reply this query are actually underway.