Watchful waiting vs. external beam radiation: 15-year data from a randomized trial


According to a report presented today at the annual meeting of the American Society for Radiation Oncology (ASTRO) in Miami Beach, Florida, men with localized prostate cancer who were treated 15 years ago with external beam radiation therapy had no significant survival benefit compared to men followed with watchful waiting.

As reported in greater detail in a report on the Medscape Oncology web site, Widmark et al. provided an update, at 15 years of follow-up, from a randomized clinical trial of 214 men initially diagnosed with clinical stage T1b-T2N0M0.

The specific data reported by Widmark et al. are as follows:

  • 214 patients were recruited in Sweden, Denmark, and Norway between 1986 and 1993..
    • 166 patients were recruited from northern Sweden.
    • Just 48 patients were recruited from Denmark and Norway.
  • 107 men (of median age 69.4 years) were randomized to receive radiation therapy (mostly with a radiation dose of just 64 to 68 Gy, although some later patients did receive up to 78 Gy).
  • 107 men (of median age 67.7 years) were randomized to watchful waiting.
  • At objective disease progression, all patients were treated with hormonal therapy.
  • At an average (median) 15 years of follow-up
    • The rate of biochemical and local progression-free survival (PFS) for men treated with radiation therapy was 65 percent.
    • The rate of biochemical and local PFS for men managed with watchful waiting was 36 percent.
    • The rate of biochemical and local PFS was significantly better for the men treated with radiation therapy (P < 0.0001).
    • The rate of metastasis-free survival for men treated with radiation therapy was 81 percent.
    • The rate of metastasis-free survival for men treated with watchful waiting was 65 percent.
    • The rate of metastasis-free survival was significantly better for the men treated with radiation therapy (P <0.022).
    • There was no statistically significant overall or prostate cancer-specific survival benefit associated with radiation therapy compared to watchful waiting.

These trial results can be seen as justifying many different perspectives.

According to Dr. Widmark, these results are highly comparable to those reported by Bill-Axelson et al. from the Scandinavian Prostate Cancer Group Study Number 4 (SPCG-4) and “we still can’t tell which individual patient will benefit.”

On the other hand, to quote Dr. Alan Pollack from the University of Miami Miller School of Medicine in Florida, “It’s a fantastic study, … We need comparative data on the efficacy of interventions in early prostate cancer.”

It is important for readers to understand, however, that the patients enrolled into this trial (as was the case for patients enrolled into the SPCG-4 trial) were all initially diagnosed with clinically evident disease and without the advantages of PSA testing. In other words, when compared to the average man getting diagnosed in America (and much of Europe) today, most of these men were really at significant risk for having locally advanced as opposed to truly localized disease. It is therefore hardly surprising that the men who received radiation therapy had better rates of progression-free and metastasis-free survival over a 15-year period.

To quote Widmark again, “The big issue is to find the guys who really need treatment. That is the Nobel Prize question.”

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