Men with non-aggressive prostate cancer who were treated with hormones or took no action at all are unlikely to die of the disease even 20 years later, new research shows.
Conversely, the disease is likely to be deadly for men with signs of more aggressive cancer treated with hormones or just observation.
The new study, with an average follow-up of 24 years, suggests men with low-grade, localized cancers might do well with little or no treatment, avoiding the surgery or radiation that can cause impotence and incontinence.
"There does not appear to be any higher risk of developing aggressive prostate cancer for men with low-grade tumors," Dr. Peter Albertsen, Chief of Urology at the University of Connecticut Health Center, told CBS radio affiliate WTIC. "Obviously, the men with high-grade tumors, this was already a lethal disease if left untreated, and we would recommend treatment for those men."
The findings are the latest to support a cautious approach in treating some prostate cancers, although there is still debate about how to define the riskiest cases. Prostate cancer is the most common major cancer, and a man's lifetime odds of getting it are 1 in 6.
The research, led by Albertsen, appears in Wednesday's Journal of the American Medical Association. It involves 767 Connecticut men aged 55 to 74 who were diagnosed between 1971-84 with cancer that had not spread beyond the prostate gland and who received either hormone therapy or observation — sometimes called "watchful waiting."
Prostate cancer ended up killing 228 men, mostly within the first 15 years after diagnosis; most of those men had high-grade tumors — those with cells that looked very abnormal under a microscope.
The study contrasts with a smaller, Swedish study published in JAMA last year suggesting that untreated, slow-growing localized tumors could turn deadly after 15 years.
The new study casts doubt on the earlier findings and suggests that "if you survive 15 years, it is unlikely that the tumor will turn ugly and progress," Albertsen said.
However, Dr. Peter Gann of Northwestern University, who co-wrote a JAMA editorial, cautioned that the studies aren't directly comparable because the Swedish men might have had different types of tumors and received hormone treatment later.
Gann said the new study reinforces the importance of measuring tumor grade in predicting outcomes for men with localized disease that has not spread. In the study, only 7 percent of the men with low-grade tumors died of prostate cancer during the study, compared with 66 percent of men with high-grade.
By Lindsey Tanner