PSA era exclipses family history in predicting cancer

The study's lead author, Patrick A. Kupelian, MD, radiation oncologist, director of clinical research, department of radiation oncology, M.D. Anderson Cancer Center, Orlando, FL, and colleagues published a similar study in the Journal of Urology in 1997 (158:2197-201) involving 720 men with prostate cancer treated between 1987 and 1996. In that paper, the authors reported that the 5-year biochemical relapse-free survival rate for patients with a negative family history was 66% versus 46% for those with a positive family history.

They found that 16% of the cohort had a positive family history, defined as a brother or father with history of prostate cancer.

"When we looked at the initial group of patients treated between 1986 and 1992, what we published in 1997 still held up. Patients who had a positive family history had worse outcomes. But when we looked at all the other patients who have been treated since then, we did not find that much of a difference," Dr. Kupelian said.

For the early PSA period, the 10-year biochemical relapse-free survival rate for those with a negative family history was 45% versus 34% among subjects with a positive family history (p=.015). That gap closed to a 10-year biochemical relapse-free survival in the late PSA period of 61% for those with a negative family history versus 67% for a positive family history (p=.54).

The multivariate analysis does not suggest that family history is an independent predictor of relapse, the authors reported.

Family history is still useful

The discrepancy between the early and late PSA eras makes sense, Dr. Kupelian said.

"Patients who have a positive family history are a minority of the whole group with prostate cancer. The cure rates of prostate cancers have improved. We believe that the impact of family history on cure rates is relatively small. As we continue to pick up these cancers at early stages, the differences in clinical outcomes between those with a family history and those without a family history are going to be miniscule," he said.

Peter C. Albertsen, MD, professor of surgery and chief of urology at the University of Connecticut Health Center, Farmington, agrees.

"The fact that the researchers did not find a significant family link does not surprise me," Dr. Albertsen said. "What has been happening is that more men are undergoing repeat PSA tests, and, over the last decade, we have been selecting more men with smaller foci of relatively indolent prostate cancer. The many new cases we are finding are being driven primarily by small increases in PSA values. We are slowly drowning out the familial cancers by a larger number of patients who have low-grade cancer," Dr. Albertsen said.

Dr. Kupelian emphasized, however, that this study does not refute the belief that underlying genetic factors might affect prostate cancer behavior, and those should be investigated further.