Source: DGNews  |  Posted 9 years ago

FAIRFAX, VA -- September 24, 2002 -- The level of prostate-specific antigen (PSA) in the blood of prostate cancer patients five years after radiation treatment can help predict their disease-free survival for the next several years, according to the October 2002 issue of the International Journal of Radiation Oncology, Biology and Physics, the official journal of ASTRO, the American Society for Therapeutic Radiology and Oncology.

Researchers have discovered that patients who maintain very low five-year PSA levels have a very low probability of relapse at 10 years and beyond.

The study identified 328 men treated with external beam radiation therapy to the prostate who were biochemically disease-free five years after treatment. The median follow-up was 7.4 years. The patients were divided into four groups according to their PSA values five years after treatment: PSA less than or equal to 0.5, 0.5 to 1.0, 1.0 to 2.0 and 2.0 to 4.0 ng/mL. PSA progression-free rates were calculated in each subgroup at 10 years after treatment.

The PSA progression-free survival rate was 87 percent, 79 percent and 67 percent, respectively, 8, 10 and 13 years after treatment in patients biochemically free of disease five years after treatment. The progression-free rates at 10 years after treatment according to the PSA level at five years was 92 percent for PSA less than or equal to 0.5 ng/mL, 71 percent for PSA 0.5 to 1.0 ng/mL, 78 percent for PSA 1.0 to 2.0 ng/mL and 56 percent for PSA 2.0 to 4.0 ng/mL. The lower the PSA level at five years, the more durable the probability of maintained biochemical disease-free survival.

Researchers concluded that when PSA levels remain low (less than 2 ng/mL) five years after external beam radiation therapy, the great majority of patients will be biochemically disease-free at 10 years. The hazard rates of biochemical progression in the 6 to 10 years after treatment are low and are comparable to rates seen when prostatectomy (surgical removal of the prostate) is the chosen treatment modality.

"This study reinforces the fact that radiation therapy should be used to achieve low PSA levels early in treatment, and those low levels should be maintained to five years and beyond," said Anthony L. Zietman, M.D., of the Department of Radiation Oncology at Massachusetts General Hospital and co-author of the study. "If this can be achieved, the long-term outlook for prostate cancer patients treated with radiation therapy will be good."

The American Society for Therapeutic Radiology and Oncology is the largest radiation oncology society in the world, with 7,000 members who specialize in treating patients with radiation therapies. As a leading organization in radiation oncology, biology and physics, the Society's mission is to advance the practice of radiation oncology by promoting excellence in patient care, providing opportunities for educational and professional development, promoting research and disseminating research results and representing radiation oncology in a rapidly evolving socioeconomic healthcare environment.

SOURCE: The American Society for Therapeutic Radiology and Oncology