Similar Outcomes Yielded Between Surgery and Radiation in Low-Risk Prostate Cancer

Both prostatectomy and radiation therapy are highly effective treatments for prostate cancer, with no difference in survival outcomes for patients with low- or favorable-risk disease, Dr. Tyler M. Seibert stated during a presentation at CURE’s Educated Patient® Prostate Cancer Summit.

Seibert is an assistant professor in the Division of Radiation Oncology and a member of the RMAS Center for Precision Radiation Medicine.

For patients with higher-risk cancer, the treatment choice requires more careful consideration. Surgery may still need to be followed by radiation, which can lead to more side effects, while radiation may require a longer course of hormone therapy.

The ProtecT trial was a large clinical study that compared surgery, radiation and active monitoring for prostate cancer. In the trial, 1,643 patients were assigned to one of three groups: surgery (radical prostatectomy), radiation with three to six months of hormone therapy, or active monitoring with regular PSA checks. Most participants had low-risk or favorable-intermediate risk disease. Patients were enrolled from 1999 to 2009, allowing for long-term follow-up, though treatments have advanced since then.

During the presentation Seibert said, “So, the first and most important question of the trial: is it safe to monitor cancers for favorable or low risk? Yes, very safe, and that should be your number one choice if you have a favorable or low risk cancer. Absolutely, ask if this is an option for you.”

Safety Profile and Common Side Effects

Some patients may experience urinary incontinence, or leakage of urine. Patients may need to wear a pad if this occurs. Patients are more likely to wear a pad for urine leakage after surgery.

Nocturia — waking up at night, more than twice, to urinate — is a common side effect during radiation therapy; however, in the long term, nocturia is less common after surgery than after radiation.

Loose stool are somewhat common during radiation, and some men may continue to have loose stool for a year or more after radiation.

Fecal incontinence — fecal leakage once or more a week — is an uncommon side effect overall but more common after radiation, and modern radiation substantially reduces dose to rectum.

Only a small proportion of men will have firm erections during treatment and recovery. Sexual function can better be preserved after radiation than after surgery.

Types of Radiation Therapy

There are several main types of radiation therapy for cancer that Seibert discusses during his presentation. External beam radiation therapy uses high-energy x-rays aimed at the tumor to damage the DNA of cancer cells.

Proton beam therapy works in a similar way but uses protons, which can more precisely target the tumor while sparing nearby healthy tissue.

Another type is brachytherapy, which places radioactive seeds inside the body near or in the tumor. These seeds can be left in place permanently (low dose rate) or temporarily inserted and then removed (high dose rate).

Radiation therapy uses several specialized techniques. Intensity-modulated radiation therapy adjusts the intensity of radiation beams to match the shape of a tumor. Volumetric modulated arc therapy delivers radiation in a continuous arc around the patient. Image-guided radiation therapy uses imaging during treatment to target tumors more accurately. Another technique, stereotactic body radiation therapy — also called stereotactic ablative radiotherapy — delivers very high doses to small tumors with precision. CyberKnife is one brand of machine used for this approach.

Length of Treatment

The length of radiation treatment depends on the schedule used. Conventional treatment involves 35 to 45 daily sessions at 2 grays per day. Moderate hypofractionation shortens this to 20 to 28 treatments with doses of 2.5 to 3 grays per day. The shortest approach is SBRT, or stereotactic body radiation therapy, also called ultrahypofractionation, which typically uses five treatments given every other day at doses of 7.25 to 9 grays per session.

For more news on cancer updates, research and education, don’t forget to subscribe to CURE®’s newsletters here.