This week in The New England Journal of Medicine is the second of two major studies showing a reduction in prostate cancer incidence from a drug in the 5-alpha-reductase inhibitor class. The drug Avodart, commonly used to treat enlarged prostates, was shown to reduce the incidence of prostate cancer from 25% to 20% over 4 years in men with an elevated PSA but no prostate cancer on biopsy. With the results of this study, the drug maker, Glasko Smith Kline, is now seeking FDA approval for the drug for this indication. However, the results are far from a slam-dunk and the implications are controversial.
Adding to the contoversy are several factors: 1) no studies have shown a decrease in deaths from prostate cancer; 2) the side effects of the drug are significant (including a troubling finding of increased risk of heart failure); 3) lowering PSA levels is not necessarily of benefit; it just proves that the drug acts to shrink the prostate; and 4) the costs of the drug are huge – at $4 a day, it could cost up to $500,000 to prevent one case of prostate cancer (https://www.healthnewsreview.org/blog/2009/05/a-half-million.html).
This story does a nice job of describing the current study, quantifiying the benefits and discussing the controversy. It provides balance by quoting independent experts with no financial or personal interests in the results and by fully disclosing the potential harms of the drug.
There’s a big push for so-called "chemoprevention" of prostate cancer. But evidence – not intuition – must guide that push. This story did a decent job explaining the controversies.
At the end of the story, an expert is quoted accurately describing the cost of the drug as $4 a day, which is expensive given that it should be taken daily for many years. The article does note that insurance companies would not pay for using dutasteride for chemoprevention unless the FDA approves the indication. The article does note that finasteride, a comparable drug, is now available as a generic.
The story quantifies the potential benefits of Avodart in both relative and absolute terms. (However, we wish the absolute data had been described more clearly and with more emphasis.) First, the story describes the benefits in relative terms by stating that Avodart reduced the chance of developing prostate cancer by 23% in men with an elevated PSA but no prostate cancer on biopsy. Then it provides the same information in absolute terms by describing the incidence of cancer as 20% in the Avodart group and 25% in the placebo group. These two sets of numbers provide different perspective on the potential benefits of the drug.
The story does a good job of describing and quantifying the potential harms of the drug, which are significant.
The story adequately describes the design of the current study. The story could have mentioned that although the study was designed to perform biopsies on all subjects at the end of years 2 and 4–or when clinically indicated. The article did not note that 1393 (17%) of study subjects were never biopsied which could have biased study results.
Several times the story mentions that it is unknown if preventing these cancers would result in preventing deaths from those cancers. The story could have been more explicit about the fact that prostate cancer is slow growing and most men with prostate cancer die from other things. Thus, preventing low-risk cancers may not, in fact, save lives.
The story quotes several independent sources, including an expert from the American Cancer Society.
The story mentions finasteride as the primary alternative to Avodart for chemoprevention of prostate cancer.
Avodart, a drug commonly used to treat enlarged prostate, is clearly available.
Clearly, Avodart is not a new drug, however, the idea that it could be used to prevent prostate cancer is relatively new.
Because the story quotes experts other than simply the study investigators, the reader can assume the story did not rely on a press release as the sole source of information.