Radical prostatectomy and radiotherapy curb CA spread

NEW YORK (Reuters Health) - In clinically localized prostate cancer, both radical prostatectomy and external beam radiotherapy inhibit metastatic progression, but prostatectomy seems more effective in high-risk patients, researchers report.

Dr. Michael J. Zelefsky and colleagues at Memorial Sloan-Kettering Cancer Center, New York treated 2,380 patients with clinical stages T1c-T3b disease with either open radical prostatectomy or intensity-modulated external beam radiotherapy at a minimum of 81 Gy.

Both cohorts included patients treated for biochemical or locoregional failure with salvage radiotherapy or androgen-deprivation therapy - although salvage was delivered after a median of 13 months in the radiotherapy patients compared to 69 months in the prostatectomy group.

In a February 16th online paper in the Journal of Clinical Oncology, the researchers report that the 8-year probability of freedom from metastatic progression was 97% for prostatectomy patients and 93% for radiation patients.

Despite the overall similarity, "in high-risk patients, our data highlight the most significant difference between the groups," the authors said.

After adjustment for preoperative risk probability, age, and treatment year, the surgery group had a lower risk of metastasis (hazard ratio, 0.35). There were similar findings for prostate cancer-specific mortality.

Over 8 years, there was a 1.9% difference in metastasis-free survival in favorable-risk patients, a 3.3% difference in intermediate-risk patients and a 7.8% difference in high-risk patients.

Among the limitations of these findings, the researchers point out, are that older patients and those with higher biopsy Gleason scores were preferentially treated with radiation.

A possible explanation for these findings is that a radiation dosage of 81 to 86 Gy is not enough to eradicate local disease in high-risk patients, the authors suggest.

Dr. Zelefsky told Reuters Health by email that "when external beam radiotherapy is used for high-risk prostate cancer, improved outcomes are more likely...when high radiation doses are delivered in conjunction with elective irradiation of lymph node regions and...long-term hormonal therapy."

His group, he added, "favors the use of combined brachytherapy and intensity-modulated radiotherapy approaches for high-risk patients, which effectively delivers much higher radiation dose levels to the prostate, or surgery followed by adjuvant radiotherapy in selected patients."

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