Following surgery to remove a cancerous prostate gland, some men experience a biochemical recurrence, meaning that prostate-specific antigen (PSA) has become detectable in their blood. Since only the prostate releases PSA, removing the gland should drop this protein to undetectable levels in the body. Detecting PSA could signify that prostate cancer cells are lingering, and forming new tumors before they can be seen with modern imaging technology. PSA isn’t always reliable for cancer screening, but it is a very sensitive marker of new cancer growth after initial treatment.
Doctors usually treat biochemical recurrence by irradiating the prostate bed, or the area where the gland used to be. Studies have shown that this treatment, which is called salvage radiation, helps to minimize the risk that prostate cancer will return and spread, or metastasize. But when to initiate salvage radiation has been open question, since PSA will also rise if small amounts of benign prostate tissue have been left behind after surgery. Many times, doctors don’t know if biochemical recurrence is really cancer, so they wait to see if the PSA levels will rise any further.
In October, researchers reported that giving salvage radiation as soon as PSA is detected could substantially reduce the risk of metastasis. “We found that early intervention with radiation could potentially improve cure rates,” said Rahul Tendulkar, M.D., a radiation oncologist at the Cleveland Clinic, and the study’s first author. “There’s no need to wait until PSA crosses an arbitrary threshold.”
Tendulkar and his colleagues combined nearly 2,500 post-surgical patients treated with salvage radiation at 10 different academic hospitals between 1987 and 2013. Of those men, 599 had cancers with a low risk of progression, while the others had higher-risk disease that was in some cases spreading into nearby tissues. Some of the men also had positive surgical margins, meaning that cancer cells might still be lurking next to where the prostate was removed.
According to their results, the incidence of metastases at five years following surgery was 9% among men given salvage radiation for PSA levels ranging from 0.01 to 0.2 nanograms per milliliter (ng/mL). By contrast, the metastasis incidence rate was 15% among men treated for PSA levels of 0.2 to 0.5 ng/mL. Both the American Urological Association and the American Society of Radiation Oncology recommend that salvage radiation be given when PSA levels reach or exceed 0.2 ng/mL. But Tendulkar says that level was defined years ago, before ultra-sensitive methods for detecting PSA became widely available.
“In this newer era of ultra-sensitive PSA testing we didn’t know if giving salvage radiation at lower levels would make a difference or not,” Tendulkar said. “Now we know that it does.”
Tendulkar says the decision to initiate salvage radiation can also be influenced by other factors, such as age, other health problems, and the aggressiveness of the cancer he was diagnosed with.
In an accompanying editorial, Paul Nguyen, M.D., a radiation oncologist at Dana Farber Cancer Institute, in Boston, MA, and an associate professor at Harvard Medical School, wrote that Tendulkar’s study “will become the gold standard” for men considering salvage radiation after surgical treatment for prostate cancer.
But the study doesn’t address an important question: Should men with high-risk cancer consider getting radiation after surgery even before PSA increases are detected? Studies designed to answer that question are now ongoing.
“This important study provides some much needed guidance that comports with my own clinical experience,” said Dr. Marc Garnick, the Gorman Brothers Professor of Medicine at Harvard Medical School and Beth Israel Deaconess Medical Center, and editor in chief of HarvardProstateKnowledge.org. “Patients should be aware that complications such as erectile problems and urinary side effects will likely worsen with salvage radiation.”
Bible verses for today’s meditation and inspiration: Matthew E. McLaren
Matthew 22:37 ESV And he said to him, “You shall love the Lord your God with all your heart and with all your soul and with all your mind.
Isaiah 43:18-19 ESV “Remember not the former things, nor consider the things of old. Behold, I am doing a new thing; now it springs forth, do you not perceive it? I will make a way in the wilderness and rivers in the desert.
Psalm 119:1-176 ESV Blessed are those whose way is blameless, who walk in the law of the Lord! Blessed are those who keep his testimonies, who seek him with their whole heart, who also do no wrong, but walk in his ways! You have commanded your precepts to be kept diligently. Oh that my ways may be steadfast in keeping your statutes! …
Philippians 2:13 ESV For it is God who works in you, both to will and to work for his good pleasure.
Psalm 19:14 ESV Let the words of my mouth and the meditation of my heart be acceptable in your sight, O Lord, my rock and my redeemer.
Psalm 131:1-3 ESV A Song of Ascents. Of David. O Lord, my heart is not lifted up; my eyes are not raised too high; I do not occupy myself with things too great and too marvelous for me. But I have calmed and quieted my soul, like a weaned child with its mother; like a weaned child is my soul within me. O Israel, hope in the Lord from this time forth and forevermore.
1 John 4:8 ESV Anyone who does not love does not know God, because God is love.
Psalm 90:12 ESV So teach us to number our days that we may get a heart of wisdom.
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