Patient life expectancy and application of radical prostatectomy in Ontario, Canada


An interesting epidemiological study just published on line in the Journal of Urology suggests that urologic surgeons in Ontario, Canada, are rather good at at estimating which patients diagnosed with prostate cancer have a life expectancy of 10+ years, making them reasonable candidates for radical prostatectomy.

We do have to be very careful not to over-assess the value of this study, because it is impossible to know whether all the patients included in this study really needed immediate treatment at all. In other words, we don’t know how many of these patients might have done just as well, over the following 10 years, on some form of expectant management (e.g., active surveillance). However, with that provision, let’s look at the details of the study.

Lavallée et al. were able to use a number of Ontario-specific databases to identify the following information:

  • Every man diagnosed with prostate cancer in Ontario between 1992 and 2011
  • Every man diagnosed with prostate cancer who then had a radical prostatectomy within 6 months of diagnosis (including their ages at time of diagnosis and treatment)
  • The long-term survival times of all of these men

They were then able to use sophisticated statistical methods to compare the rates of 10-year survival of these men to the average rates of 10-year survival of all men of comparable age in Ontario over the same time period. To do this they used well-validated population life-tables and a tool known as the Aggregated Diagnosis Group (ADG) Score (an accurate, validated index that predicts mortality risk based on patient comorbidities).

So here is what Lavallée et al. found:

  • 174,047 men were diagnosed with prostate cancer in Ontario between 1992 and 2011.
  • 36,045 of those men (20.7 percent) received a radical prostatectomy within 6 months of their diagnosis.
    • 266/36,045 of these patients (0.7 percent) exceeded 75 years of age.
    • 35,136 of these patients (97.4 percent) had their diagnosis made based on histological and pathological data from prostate biopsy or radical prostatectomy specimens.
    • The average (median) age of these men was 62 years.
    • The average (median) follow-up period for these men was 8.1 years.
  • The actual, observed 10-year survival rate for the patients was 88.9 percent (i.e., 4,001 deaths within 10 years of treatment).
  • The projected, expectable 10-year survival rate based on population life-tables was 83.3 percent (i.e., 6,020 deaths within 10 years of treatment).
  • The projected, expectable 10-year survival rate based on ADG Score was 76.0 percent (i.e., 8,651 deaths within 10 years of treatment).
  • The actual, observed 10-year survival rate was significantly higher than either of the projected, expectable rates.

The authors conclude that men undergoing radical prostatectomy in Ontario between 1992 and 2011 had

a 10-year survival that significantly exceeds the population and people with similar comorbidities. This indicates that physicians and patients involved in deciding who should undergo radical prostatectomy have done an excellent job at identifying prostate cancer patients with high survival.

These data have several potential implications which the authors discuss at length. Specifically, they state the following:

  • That those involved in deciding whether or not a man with prostate cancer should undergo radical prostatectomy (i.e., urologists, referring physicians, and the patients themselves) were able to accurately identify men with an excellent likelihood of 10-year survival.
  • That the high level of prognostic accuracy was probably accomplished without any use of objective tools (since most physicians informally prognosticate patient survival), which leads one to wonder whether prognostication  would (or would not) be significantly better if informal experience was combined with more formal prognostic models.
  • That clinicians’ ability to prognosticate life expectancy might actually be significantly better than other  published literature has suggested.

The authors are also very careful to emphasize that they have no opinion on the applicability of their data to decision-making about the value of radical prostatectomy outside the province of Ontario.

We would simply conclude by repeating the point we made early on. The authors recognize that, because they did not have access to accurate diagnostic data on all these patients, they have no idea of the patients’ individual risk level, nor, therefore, of how many of these patients who were given a radical prostatectomy might reasonably have been managed with non-invasive methods (e.g., active surveillance). However, it is worth noting that only just over 20 percent of all the prostate cancer patients diagnosed in Ontario in this 20-year period were actually treated by immediate radical prostatectomy, suggesting that the application of various forms of expectant management in Ontario was relatively high during that time frame.

 

7 Responses

  1. I find this kind of analysis useless because it is not stratified on the basis of risk factors. Where am I wrong?

  2. Dear Bob:

    It may feel “useless” to you on an individual basis … but that doesn’t make it “useless” to everyone.

    Some will see in these data further justification for the premise that early intervention is likely to extend life in younger patients — regardless of their risk factors. Is that necessarily true? I can’t answer that question (yet).

    What I see in data like these is further justification for a high quality prostate cancer registry initiative here in America that allows us to track detailed data (including data that do include risk-related information) over time.

  3. I was just about to ask Bob’s question about risk. I am glad that such a registry exists here in Sweden, less that 1 kilometre from my home.

  4. Assuming that guys don’t agree to RP unless they feel that they are at risk, it can be inferred that their lives were indeed extended as a result of RP. So this is indeed good news.

  5. Dear Bob:

    Actually I don’t think that yours is a justifiable conclusion. A 72-year-old man with a single, tiny, Gleason 6 tumor may consider that he is “at risk” and decide to have a radical prostatectomy. That is his right, with appropriate guidance from his doctors. However, I know of no evidence whatsoever that a radical prostatectomy (or any other form of treatment) can be expected to extend the life of such a patient; inded, there are a lot of data to suggest that it would not have that effect at all.

    You need to note that the average (median) age of the patients in this study was 62 years. If their median age had been more like 65 or 70 one might not have seen this outcome at all.

  6. Sitemaster:

    I would hope that guys are more educated than that, but perhaps not. I suppose that there are those who, at the mention of the C word, want it out at all costs, but I sense that, from reading posts on Healing Well, today men do a lot of due diligence before deciding on treatment — partly because there are many good treatments today. Going forward, with more emphasis on AS for low-risk patients, I would hope that unnecessary RPs or for that matter, other treatments, would decline. At any rate, as you know, there have been a number of studies that show disease-free progression by stage and Gleason score (i.e., risk) by type of treatment, or no treatment. I think these studies are more meaningful than the subject study.

    Bob

  7. Bob:

    Much as I would like it not to be the case, you might be surprised just how many men react exactly how you describe when they hear the C word. And many of them do very little research at all.

    Far more men in Europe and Canada are willing consider active surveillance than here in America as well. And most men never find out about being able to make outcome projections based on Gleason scores and other factors until after their treatment.

    In general, my experience is that “the average American male” is still very poorly informed when it comes to prostate cancer. And as a consequence decisions get made on the basis of whatever they saw on TV or heard from a friend (regardless of the quality of that information).

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: