© 2004 by Oxford University Press
© 2004 Oxford University Press
CORRESPONDENCE |
RESPONSE: Re: Estrogen Receptor Status of Primary Breast Cancer Is Predictive of Estrogen Receptor Status of Contralateral Breast Cancer
Affiliations of authors: Cancer Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD (SMS), National Surgical and Adjuvant Breast and Bowel Project, Biostatistical Center and University of Pittsburgh, Pittsburgh, PA (JWW).
Correspondence to: Sandra M. Swain, MD, Cancer Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 8901 Wisconsin Ave., Bldg. 8, Rm. 5101, Bethesda, MD 20889 (e-mail: swains{at}mail.nih.gov)
Foulkes presents the hypothesis that the median interval between the primary and contralateral breast cancer of the women in our study (1) will be shorter in women aged younger than 50 years who had concordant estrogen receptor (ER)-negative tumors than in women with concordant ER-positive tumors or those who had discordant tumors. However, among our cohort, the median time to contralateral breast cancer was 5.08 years for women who had concordant ER-negative tumors (n = 19) and 4.76 years (n = 31) for women with concordant ER-positive tumors. Among women in the discordant groups, the median time to a second primary tumor was 4.14 years (n = 8) for women who presented with an ER-negative primary tumor and 2.99 years (n = 4) for women who presented with an ER-positive primary tumor. These results suggest that there is no difference in the time of presentation of concordant contralateral breast cancer according to the ER status of the primary tumor, and that of discordant tumors present at an earlier time, suggesting different etiologies.
To explore the relationship between concordance and time, we divided patients into three groups according to time from diagnosis of the primary tumor to time of diagnosis of the contralateral tumor: less than 3 years (n = 19), from 3 to 6 years (n = 23), and more than 6 years (n = 20). There was no evidence for an association between time of diagnosis and concordance (P = .56 by Fisher’s exact test and P = .63 by linear trend test). In fact, the lowest concordance rate was in the earliest time period, not in the latest. We found similar results in an analysis that was based on five time periods instead of three. Although these very exploratory analyses are intriguing and many speculations can be made, the numbers are very small, and prospective evaluations of these questions along with molecular analyses are critical to clarifying this issue.
REFERENCE
1 Swain S, Wilson JW, Mamounas EP, Bryant J, Wickerham DL, Fisher B, et al. Estrogen receptor status of primary breast cancer is predictive of estrogen receptor status of contralateral breast cancer. J Natl Cancer Inst 2004;96:516–23.
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J Natl Cancer Inst 2004 96: 1040-1041.
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