CORRESPONDENCE

Re: Detection of Ductal Carcinoma In Situ in Women Undergoing Screening Mammography

Daniel B. Kopans

Correspondence to: Daniel B. Kopans, M.D., F.A.C.R., Avon Foundation Comprehensive Breast Evaluation Center, Wang Ambulatory Care Center, Suite 240, 15 Parkman St., Boston, MA 02114 (e-mail: kopans.daniel{at}mgh.harvard.edu).

I was surprised to read that Ernster et al. (1) thought that they were the first to discover that the rate of screen-detected ductal carcinoma in situ (DCIS) increases with age while DCIS accounts for a progressively smaller percentage of the total cancers detected (i.e., invasive plus DCIS). We actually made this observation in 1996 when we were discussing the artifactual results that are created by grouping women aged 40–49 years and comparing them with all women aged 50 years and older (2). One explanation for these rates of discovery of DCIS and invasive cancers is that DCIS is the precursor of many invasive cancers. It would therefore stand to reason that DCIS would form a higher percentage of the total number of cancers among younger women, but as these DCIS lesions become invasive, the percentage of total cancers that are DCIS would decrease. The absolute increase in the number of DCIS lesions that occurs with increasing age likely reflects the greater chance for malignant transformation that occurs with DNA "aging."

In the same issue of the Journal, the Stat Bite, unfortunately, reflects the main point of our 1996 article (2). The Stat Bite is misleading by suggesting that there is a large increase in breast cancer incidence at the age of 50 years by comparing the incidence of breast cancer among women aged 50 years and older with the total incidence. This use of age 50 years as a cutoff suggests that the incidence of breast cancer must be low among women aged 49 years and younger. However, as we have previously pointed out (24), it is greatly misleading to group women aged 50 years and older as if they are a uniform group and to compare them with women aged 49 years and younger as if they were a uniform group. If age groups must be made, then the age increments should be the same. Thus, if the Stat Bite had compared women by decade of age, it would have shown a steady increase in breast cancer incidence with age. The Journal should cease giving the unsupportable impression that the age of 50 years has some biologic or screening significance. There are no data that show any abrupt change in any parameters of mammographic screening (e.g., recall rates, rates of recommendation for biopsy, percentages of biopsies yielding cancers, and cancer detection rates) that occurs at the age of 50 years. The age of 50 years is merely an arbitrary age chosen by health planners and has no medical or scientific importance.

REFERENCES

1 Ernster VL, Ballard-Barbash R, Barlow WE, Zheng Y, Weaver DL, Cutter G, et al. Detection of ductal carcinoma in situ in women undergoing screening mammography. J Natl Cancer Inst 2002;94:1546–54.[Abstract/Free Full Text]

2 Kopans DB, Moore RH, McCarthy KA, Hall DA, Hulka CA, Whitman GJ, et al. The positive predictive value of breast biopsy performed as a result of mammography: there is no abrupt change at age 50 years. Radiology 1996;200:357–60.[Abstract]

3 Kopans DB, Halpern E, Hulka CA. Statistical power in breast cancer screening trials and mortality reduction among women 40–49 with particular emphasis on the national breast screening study of Canada. Cancer 1994;74:1196–203.[Medline]

4 Kopans DB. The breast cancer screening controversy: lessons to be learned. J Surg Oncol 1998;67:143–50.[CrossRef][Medline]



             
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