CORRESPONDENCE

RESPONSE: Re: Trends in Use of Adjuvant Multi-Agent Chemotherapy and Tamoxifen for Breast Cancer in the United States: 1975–1999

Angela Mariotto, Eric J. Feuer, Jeffrey Abrams

Affiliations of authors: A. Mariotto, E. J. Feuer (Cancer Surveillance Research Program, Division of Cancer Control and Population Sciences), J. Abrams (Cancer Therapy Evaluation Program, Division of Cancer Treatment and Diagnosis), National Cancer Institute, National Institutes of Health, Bethesda, MD.

Correspondence to: Angela Mariotto, Ph.D., National Cancer Institute, National Institutes of Health, 6166 Executive Blvd., Suite 504, MSC 8317, Bethesda, MD 20892–8317 (e-mail: mariotta{at}mail.nih.gov).

We appreciate the findings and comments of Du, who used a different source of information—Medicare claims linked to the SEER1 database—to estimate temporal changes in the use of adjuvant chemotherapy for breast cancer and obtained findings that are very similar to ours. He observes that both Mariotto et al. (1) and Du and Goodwin (2) estimate an increase in the use of adjuvant chemotherapy for women diagnosed with breast cancer stages II and IIIA from 1991 to 1996. However, he may have overinterpreted our figures when he says that, in contrast to his results, we showed an increase over time in the use of adjuvant chemotherapy from 1991 to 1996 among older women with stage I breast cancer. Using our model, we estimated that, from 1991 through 1996, the use of adjuvant chemotherapy among women diagnosed with stage I breast cancer at ages 50–69 years and ages 70 years or older increased slightly, from 9% to 11% and from 0.2% to 0.3%, respectively. However, we do not know if these small increases are statistically significant, especially because the number of older women with stage I breast cancer receiving adjuvant chemotherapy is still quite small.

As mentioned by Du, Medicare claims have proven to be an important resource for estimating chemotherapy use (3). Patterns of care (POC) data, which are based on medical record review, contain more accurate information than claims data on first-line therapy from hospitals and treating physicians from a sample of SEER patients. The drawbacks of POC data are that the sample size is small, especially for older patients, and that these data are not available for all years. The SEER-Medicare linked database thus provides a useful complement to the POC data.

In regard to the comments by Jordan and Morrow, we thank them for a plausible and more detailed explanation for the decline in tamoxifen usage observed in our data during the 1990s. Although we do not have data to support their explanation, the timing of the decline does coincide with the debate over tamoxifen endometrial toxicity reports, and we agree that this debate was exacerbated because of a misunderstanding of the role of tamoxifen in prevention and treatment. Better education of physicians and the public has likely led to a reversal of these trends, but we must await evidence from newer SEER studies before we can confirm this. However, it is also noteworthy that tamoxifen is now used only in women with ER-positive breast cancer, which undoubtedly also played a role in its decreased overall usage (4,5).

NOTES

1 Editor’s note: SEER is a set of geographically defined, population-based, central cancer registries in the United States, operated by local nonprofit organizations under contract to the National Cancer Institute (NCI). Registry data are submitted electronically without personal identifiers to the NCI on a biannual basis, and the NCI makes the data available to the public for scientific research. Back

REFERENCES

1 Mariotto A, Feuer EJ, Harlan LC, Wun LM, Johnson KA, Abrams J. Trends in use of adjuvant multi-agent chemotherapy and tamoxifen for breast cancer in the United States: 1975–1999. J Natl Cancer Inst 2002;94:1626–34.[Abstract/Free Full Text]

2 Du XL, Goodwin JS. Increase of chemotherapy use in older women with breast carcinoma from 1991 to 1996. Cancer 2001;92:730–7.[CrossRef][Medline]

3 Warren JL, Harlan LC, Fahey A, Virnig BA, Freeman JL, Klabunde CN, et al. Utility of the SEER-Medicare data to identify chemotherapy use. Med Care 2002;40(8 Suppl): IV-55–61.

4 Eifel P, Axelson JA, Costa J, Crowley J, Curran WJ Jr, Deshler A, et al. National Institutes of Health Consensus Development Conference Statement: adjuvant therapy for breast cancer, November 1–3, 2000. J Natl Cancer Inst 2001;93:979–89.[Abstract/Free Full Text]

5 Goldhirsch A, Glick JH, Gelber RD, Coates AS, Senn HJ. Meeting highlights: International Consensus Panel on the Treatment of Primary Breast Cancer. Seventh International Conference on Adjuvant Therapy of Primary Breast Cancer. J Clin Onc 2001;19:3817–27.



             
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