Mirror, mirror, on the wall, …

For years, physicians and their patients diagnosed with low-risk prostate cancer believed that those patients were at high risk for progressive disease over time. And physicians and their patients diagnosed with a form of breast cancer known as ductal carcinoma in situ or DCIS had similar beliefs.

It is now becoming much clearer that, just as most low-risk, Gleason 6 prostate cancer patients are at minimal risk for progression to metastatic prostate cancer and consequent, prostate cancer-specific mortality, most patients with DCIS (also known as stage 0 breast cancer) will never progress to have metastatic breast cancer either. A newly published report in JAMA Oncology, based on  an analysis of data from > 100,000 women diagnosed with DCIS seems to show very clearly that only about 3 percent of those women went on to die from breast cancer, implying that > 95 percent of those women were at risk for over-treatment.

If you think that the furore over active surveillance as a sound methodology for managing the risks associated with low-risk prostate cancer was bad, wait until you see the one that is likely to blow up over this set of findings. But the principle makes perfect sense to your sitemaster (as he has suggested previously).

What Narod and his colleagues have actually shown is the following:

  • A cohort of 108,196 women were diagnosed with DCIS between 1988 and 2011.
  • Their average (mean) age at diagnosis was 53.8 years (range, 15 to 69 years).
  • The average (mean) duration of follow-up post treatment was 7.5 years (range, 0 to 23.9 years).
  • At 20 years of follow-up, the breast cancer-specific mortality rate was
    • 3.3 percent overall
    • Higher for women diagnosed at < 35 years of age compared with older women (7.8 vs 3.2 percent; hazard ratio [HR] = 2.58; P < 0.001)
    • Higher for black women than for non-Hispanic whites (7.0 vs 3.0 percent; HR = 2.55; P  < 0.001).
  • The risk of dying of breast cancer increased among women experiencing a subsequent diagnosis of invasive breast cancer in the same breast (HR = 18.1; P < 0.001).
  • 517 women died of breast cancer after diagnosis with DCIS without experiencing an in-breast invasive cancer prior to their death (mean follow-up, 7.5 years; range, 0 to 23.9 years).
  • Among patients diagnosed with DCIS who received lumpectomy, radiotherapy was associated with
    • A reduction in the risk for ipsilateral invasive recurrence at 10 years (2.5 vs 4.9 percent; adjusted HR = 0.47; P < 0.001)
    • No reduction in risk for breast cancer-specific mortality at 10 years (0.8 vs 0.9 percent; HR = 0.86; P = 0.22)

Are you seeing a similar pattern here to what we see in men diagnosed with low-risk prostate cancer?

While there is truth to the suggestion that these data need to be confirmed by data from a randomized clinical trial (see this article in today’s New York Times), the ability to actually conduct such a trial effectively in America is open to considerable question (not least because of the type of comment made by the chief breast cancer surgeon at Memorial Sloan-Kettering Cancer Center referenced in the same article).

We are seeing almost identical “gut” reactions to the new information published by Narod and his colleagues as were exhibited by many in the urology community when Albertsen and colleagues first published their data on mortality rates of men with low- and high-risk prostate cancer back in 1998. It took us the best part of 15 years after that to really understand that active surveillance/expectant management was a highly effective first-line process for the management of men with low-risk prostate cancer — because it improved patients’ quality of life without increasing their risk for prostate cancer-specific mortality. It is profoundly to be hoped that it won’t take us as long to understand that a similar approach is likely to be highly effective in the management of women diagnosed with DCIS. Some of those women will quite certainly need treatment over time as they are carefully followed. But many — and most likely the majority — won’t, and their quality of life will be the better for it.

If your wife/partner was to be diagnosed with DCIS tomorrow, what would you tell her?

2 Responses

  1. Did the study distinguish between low grade and high grade DCIS? They behave differently.

  2. Mark:

    The full text of the paper is available on line. I honestly don’t know and I certainly don’t pretend to be any sort of authority on breast cancer.

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