When Should Prostate Cancer Patients Receive Adjuvant Radiation Therapy?

When Should Prostate Cancer Patients Receive Adjuvant Radiation Therapy?

shutterstock_171518414According to results from two studies conducted by University of Virginia School of Medicine researchers, in order to prevent side effects from radiation it is better to postpone radiation therapy following prostatectomy in patients with prostate cancer.

“The common teaching has been, without clear evidence, that urinary incontinence and erectile function are worse when radiation is delivered earlier rather than later, but we didn’t see any protective effect of delayed radiation compared to earlier radiation,” said radiation oncologist Timothy N. Showalter, MD, of the UVA Cancer Center in a recent news release. “It contradicts the clinical principle of delaying radiation as long as possible for the sake of the patient’s side effects. It really speaks against that, and that ought not to be used for a reason to delay radiation.”

These results are still considered controversial, as some clinicians opt to give to their patients adjuvant radiotherapy right after prostate removal to eradicate potential remaining tumor cells, while other doctors opt for salvage therapy, exposing patients to radiation only when the results from prostate-specific antigen tests indicate in that direction. “Urologists tend to prefer to forgo adjuvant radiation therapy, because they fear the side effects, and radiation oncologists tend to prefer offering adjuvant radiation therapy because they fear the risk of metastasis [cancer spreading to other sites in the body],” Dr. Showalter said.

“There’s this commonly held belief that the longer you delay radiation therapy, the more opportunity a patient has for recovery from prostatectomy, and therefore the better long-term function in terms of urinary and bowel function — the longer you delay it, the better they’ll function,” he said. “A lot of clinicians believe that if you wait six months, 12 months, 18 months, that each additional step gets you some benefit in terms of toxicity. That didn’t make sense to me from a medical perspective, because I can’t think of any other surgery where we think recovery requires a year or more. We often, for other cancers, deliver post-operative radiation very soon,” he added, concluding that both studies can provide clinicians with key information for making decisions about the best treatment options for their patients.

The results were retrieved from a review of clinical outcomes of about 16,000 patients and disclosed the adverse events of exposure to radiation therapy after prostatectomy. “What we found is that the addition of radiation therapy after prostatectomy does lead to a noticeable increase in GI [gastrointestinal] and GU [genitourinary] side effects. However, delaying radiation therapy offers no protective benefit and in fact may increase the risk of GI complications,” Dr. Showalter explained.

Importantly, the results revealed that erectile dysfunction rates did not increase with the use of adjuvant therapy.

According to Showalter, patients should discuss with their clinicians the best treatment options for their case. “If someone’s at generally low risk of prostate cancer reoccurrence and they have low-grade disease, it’s probably still reasonable to take a delayed salvage radiation therapy approach,” Dr. Showalter said. “Once there’s a real, compelling reason to deliver radiation, there doesn’t seem to be a benefit to delaying their radiation in terms of avoiding complications. And we know from other studies, the earlier radiation is delivered, the more effective it is for these patients. The more likely it is to cure them.”

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