External beam radiotherapy improved progression outcomes vs. watchful waiting
2011 ASTRO Annual Meeting
MIAMI - Compared with watchful waiting, external beam radiotherapy significantly reduced both distant and clinical progression in patients with early localized prostate cancer, according to data from a late-breaking clinical abstract presented here.
In 1986, Anders Widmark, MD, and colleagues began a randomized trial to examine PFS and OS among 214 patients with early localized prostate cancer who were assigned to external beam radiotherapy (EBRT) or watchful waiting. From 1986 to 1993, radiotherapy was given with four-field-box EBRT, 64 Gy/32 fractions with a 2 cm margin, and 4-field CRT 64-68 Gy with a 1.5 cm margin thereafter, according to Widmark, of the departments of radiation sciences and oncology at Umea University in Sweden. Hormonal treatment was given upon objective progression in both arms; EBRT was administered in some patients in the watchful waiting group. The primary endpoint was PFS and overall mortality.
Median follow-up was 16 years, during which time 74 patients in the watchful waiting arm and 64 in the EBRT arm died, resulting in an OS of 0.31 (95% CI, 0.22-0.42) for the watchful waiting group and 0.35 (95% CI, 0.25-0.48) for the EBRT arm. After 15 years, prostate-cancer-specific death occurred among 25 patients in the watchful waiting group and 19 in the EBRT group, yielding prostate-cancer-specific survival of 0.72 (95% CI, 0.63-0.83) for watchful waiting and 0.79 (95% CI, 0.71-0.89) for EBRT.
Distant progression occurred in 31% of the watchful waiting arm and 17% of the EBRT arm, yielding a 15-year recurrence-free survival rate of 0.66 (95% CI, 0.57-0.77) for watchful waiting and 0.81 (95% CI, 0.74-0.90) for EBRT.
Both biochemical and local progression rates favored the EBRT arm: Treatment change due to clinical progression occurred among 58% of those in the watchful waiting arm and 29% in the EBRT arm. This yielded a 15-year recurrence-free survival rate of 0.40 (95% CI, 0.31-0.51) in the watchful waiting arm and 0.67 (95% CI, 0.58-0.78) in the EBRT arm.
"In this randomized trial of external beam radiotherapy vs. watchful waiting for patients with localized prostate cancer, external beam radiotherapy significantly reduced distant progression and prolonged PFS," Widmark said during his presentation.
For more information:
- Widmark A. LB 1. Presented at: the 2011 ASTRO Annual Meeting; Oct. 2-6; Miami.
Disclosure: The researchers report no relevant financial disclosures.
Patients placed on surveillance in the Widmark trial, starting in 1986, are very different than patients enrolled on surveillance in the PSA era, thus caution is warranted in interpreting these results.
- Oliver Sartor, MD
Medical Director, Tulane Cancer Center;
Director, Prostate Cancer Program
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