Technical vs. conventional wisdom

If you're into the breast cancer rates of recurrence conversation (as I am), check out these two articles for some totally different takes.


The full Medscape article is here.

The Mystery of a Common Breast Cancer Statistic -- Solved?
Nick Mulcahy
August 18, 2015

A commonly cited breast cancer statistic — that 30% of all early-stage breast cancers will progress, despite treatment, to deadly metastatic disease — appears to have no strong contemporary evidence to back it up. 

Nonetheless, the statistic appears widely. For example, it is cited in an academic report (J Intern Med. 2013;274:113-126), in a breast cancer charity report, in a pharmaceutical marketing piece, and on a major cancer center website. 

In short, the 30% figure is conventional wisdom — despite the absence of an authoritative epidemiologic source. 

But is that statistic accurate and reflective of current clinical reality? And should clinicians repeat it to patients? Perhaps more importantly, does the statistic really matter? After all, the treatment of women with early-stage disease will not change whatever the statistic is, correct? 

Medscape Medical News went in search of answers to these questions and found angry patients, a clinician author trusted blindly by a lot of people, and special access to a common database that, in fact, appears to solve the mystery of the proportion of early-stage patients who progress to metastatic disease. 

Our story begins with multiple women with metastatic breast cancer who are dismayed or angry about the fuzziness and mystery of the 30% statistic, and have said so online.

I would like to know the true stats of how many breast cancers come back no matter what the hell we do for treatment.

For example, in a 2013 post on the breastcancer.org bulletin board, "SusansGarden" from Gig Harbor, Washington, wrote: "I would like to know the true stats of how many breast cancers come back no matter what the hell we do for treatment." 

The topic has been discussed repeatedly by "metsers" for a few years, but a recent blog post got a lot of attention. 

On July 21, metastatic breast cancer patient and blogger Ann Silberman, from Sacramento, California, examined the 30% statistic. For the individual patient, "none of this matters," she wrote. "You will relapse or you won't." But Silberman, who unsuccessfully looked for a credible source for the statistic for 7 months, added that "it's harmful to mis-state things, use scare tactics, and otherwise try to make a bad thing worse." 

The post, with its reference to scare tactics by prominent breast cancer organizations, including Komen for the Cure, prompted a response from the Metastatic Breast Cancer Network (MBCN), a respected patient advocacy group. (continues on pages 2 and 3.)

NOTE: This next article is NOT the  2005 CME review on metastatic disease referred to above and published in the Oncologist by prominent medical oncologist Joyce O'Shaughnessy, MD, from Baylor University in Houston, which is quoted above.

Images from the full scientific abstract from PubMed are here. 

Breast Cancer Res Treat. 2013 Jan;137(2):449-55. doi: 10.1007/s10549-012-2366-0. Epub 2012 Dec 6.
Effect of HER2 status on distant recurrence in early stage breast cancer.
Hess KR1, Esteva FJ.Author informationAbstract
It has long been recognized in breast cancer that the effect of hormone receptor (HR) status on recurrence rates varies over time and with the site of recurrence. However, there is relatively little in the literature on the effect of human epidermal growth factor receptor 2 (HER2) on recurrence patterns. We wanted to assess whether the effect of HER2 status on the risk of distant recurrence changed over time and/or with HR status and whether these relationships varied with site of recurrence. We retrospectively studied 11,011 women diagnosed with stage I, II, or III breast cancer after 1997 who had data on HR status and HER2 status. 20 % were HR negative and HER2 negative (so-called "triple-negatives"), 7 % were HR negative and HER2 positive, 64 % were HR positive and HER2 negative, and 10 % were HR positive and HER2 positive. The estimated overall cumulative incidence of developing distant metastases is 20 % at 4 years, 30 % at 8 years, and 36 % at 12 years. The 12-year cumulative incidence was 23 % for bone, 16 % for liver, 14 % for lung, 13 % for distant lymph node, 10 % for brain, and 8 % for pleura. After adjusting for potential confounding factors, the nature of the effect of HER2 on recurrence rates was found to differ markedly across the sites of recurrence. For brain and pleura recurrences, the effect of HER2 depended on HR status in ways that significantly changed over time. For bone recurrences, the effect of HER2 did not depend on HR status, but did change significantly over time. For liver and distant lymph node recurrences, there was a significant effect of HER2 status that did not change with time or HR status. For lung recurrences, rates did not significantly vary with HER2 status.PMID:

 

23225147

 

[PubMed - indexed for MEDLINE] 

PMCID:

 

PMC3544467