Prostate cancer prevention and screening: an ASCO update

Your editor was unable to attend the session on prostate cancer prevention and screening at the recent annual meeting of the American Society for Clinical Oncology (ASCO) because he is still working on how to be in two places at once. However, it was clearly a well structured session, and the following content has been summarized from a full report appearing on the UroToday web site.

Dr. Ian Thompson chaired the session and started by emphasizing that prostate cancer is a significant public health problem, with a lifetime risk of prostate cancer diagnosis in the USA of 1 in 6, and a mortality rate representing 10 percent of all cancer deaths in U.S. men. He also noted the well-known issues of racial, educational, and health insurance disparity that profoundly impact prostate cancer prevention and care. He went on to define three public health strategies for prostate cancer management:

  • Wait until symptoms develop and treat at this point.
  • Detect prostate cancer early, and treat while it is curable.
  • Prevent the disease from occurring whenever possible.

He ruled out the first option as being unacceptable because > 30 percent of men would only be diagnosed when they already had metastatic disease, and the remainder of the session focused on the second and third strategies.

Dr. Otis Brawley then addressed the rationale for prostate cancer screening, making the following points:

  • After lung cancer, prostate cancer is the second most common cause of cancer death in American men.
  • When it is diagnosed early, prostate cancer is curable.
  • Men with metastatic cancer commonly die of their disease.
  • Screening tests certainly do exist for prostate cancer (albeit not perfect ones).
  • There is a significant potential for over-detection (and therefore over-treatment) of clinically insignificant prostate cancer.
  • Among men who die of prostate cancer, > 60 percent have Gleason score 8-10 disease which may not be curable at the time of diagnosis.
  • There are significant morbidities associated with all forms of definitive prostate cancer therapies.

Dr. Brawley addressed data demonstrating differences in screening and treatment patterns across America using King County, Washington and the state of Connecticut as examples. The risk of being diagnosed with prostate cancer in Seattle is 14.7 percent compared to just 6.8 percent in Connecticut; rates of radical prostatectomy in Seattle are five times higher than in  Connecticut, but mortality rates in the two areas are not appreciably different.

Finally he talked about the data from the two major US and European screening studies published earlier this year, making the points that the US study didn’t show any significant benefit from screening and that the European study did, but that both studies  had major methodological flaws making accurate interpretation of the results extremely difficult.

Dr. Brawley concluding by giving a personal perspective of the critical issues that should be taken into account by physicians when considering prostate cancer screening for their patients. In his opinion:

  • Prior to obtaining a PSA, physicians should discuss the pros and cons of screening and treatment with each individual patient.
  • Physicians should routinely provide patients with an individualized estimate of risk for prostate cancer and their risk of high grade disease using risk assessment tools.
  • Physicians should always assess patient age and life expectancy when making decisions regarding prostate cancer screening and treatment.

In the final lecture, Dr. Eric Klein reviewed what we now know about the potential ability to prevent prostate cancer (at least in a proportion of the population). His talk included the following “take home” messages:

  • Many risk factors for prostate cancer are not modifiable, including age, race and genetics.
  • The absolute benefit of screening on mortality remains controversial.
  • All prostate cancer treatments are associated with significant morbidity.
  • The SELECT trial showed no significant reduction in prostate cancer for men taking vitamin E, selenium or both.
  • The PCPT trial demonstrated a 25 percent reduction in risk for men taking finasteride.
  • The REDUCE trial recently has shown a 23 percent reduction in risk among men taking dutasteride

Dr. Klein also pointed out that additional benefits of finasteride treatment demonstrated in the PCPT trial include:

  • A 20 percent reduction in risk of high-grade PIN
  • Fewer symptoms of urinary problems
  • Reduced risk of urinary retention
  • Avoidance of the burden of cure for low-risk cancers
  • Improved diagnostic accuracy of PSA.

At the end of the session Dr. Klein concluded that we now have effective primary prevention methods for prostate cancer.

The “New” Prostate Cancer InfoLink believes that these presentations represent a fair and accurate analysis of the data now available to us. The critical issue, in out opinion, is how to use these data and perceptions to be able to focus clinical practice on the early diagnosis, treatment, and (potentially) the cure of prostate cancer in men who are at high risk for clinically significant and progressive disease, and the minimization of unnecessary treatment in men who are likely to have indolent disease.

3 Responses

  1. Thank you for all the ASCO updates, very interesting.

    Do you know when this video on Dr. Catalona’s web site was produced/posted and have you any comments relating to the video?

  2. Mick:

    Re Dr. Catalona’s video … I have no idea when it was made or posted, but I would guess it was several years ago when he left Washington University and moved to Northwestern and needed to promote his new practice. It seems very “dated.”

  3. “Dated”, that’s what I was thinking after I posted. Thank you.

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