Stereotactic body radiotherapy achieves low toxicity and maintains QoL

MedWire News: Stereotactic body radiotherapy (SBRT) achieves low toxicity and maintains quality of life (QoL) in patients with localized prostate cancer, researchers report.

Alan Katz (Winthrop University Hospital, Mineola, New York, USA) and colleagues performed SBRT on 304 low-, intermediate-, and high-risk patients with clinically localized prostate cancer. Fifty patients received five 7-Gy fractions for a total dose of 35 Gy, and 254 patients received five fractions of 7.25 Gy for a total dose of 36.25 Gy.

In all, 280 patients presented with clinical stage T1cN0M0 and 24 patients presented with clinical stage T2aN0M0 as determined by physical exam, bone scan, and computed tomography scans. The median prostate-specific antigen level at presentation was 5.8 ng/ml. Fifty-seven patients received neoadjuvant hormonal therapy.

No patients given the 35-Gy regimenhad experienced biochemical failure by a median follow-up of 30 months. Acute grade II urinary and rectal toxicities occurred in 4% of patients with no higher rade acute toxicities. One grade II late urinary toxicity occurred with no other Grade II or higher late toxicities.

Among patients given the 36.25-Gy regimen, two low- and two high-risk patients experienced biochemical failure after a median of 17 months.

Acute grade II urinary and rectal toxicities occurred in 4.7% and 3.6% of these patients, respectively. For patients with a minimum of 12 months of follow-up, 5.8% had late grade II urinary toxicity and 2.9% had late grade II rectal toxicities. One late grade III urinary toxicity occurred, but no grade IV toxicities occurred.

For both regimens, Expanded Prostate Cancer Index Composite (EPIC) questionnaires completed at a median of 17 months demonstrated that bowel and urinary QoL returned to baseline values while sexual QoL decreased by 10%.

Katz et al comment in Biomed Central Urology: “At a median 30-month follow-up for the 35-Gy level, the long-term urinary and rectal toxicity are both low. EPIC QoL questionnaires also suggest that urinary, rectal and sexual QoL following SBRT may be comparable, if not better than that for external beam radiotherapy, brachytherapy, and radical prostatectomy.”

The researchers conclude: “Longer term follow-up and additional studies are needed to confirm the durability of biochemical control, toxicity and QoL with SBRT of prostate cancer.”

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