Chemotherapy in Women with Breast Cancer

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The summary below is from the full report titled "Discrepancy between Consensus Recommendations and Actual Community Use of Adjuvant Chemotherapy in Women with Breast Cancer." It is in the 21 January 2003 issue of Annals of Internal Medicine (volume 138, pages 90-97). The authors are XL Du, CR Key, C Osborne, JD Mahnken, and JS Goodwin.

What is the problem and what is known about it so far?

After surgery to remove breast cancer, patients frequently receive chemotherapy. Chemotherapy after surgery is known as adjuvant chemotherapy. An increasing number of studies show that women with early breast cancer do better if they receive adjuvant chemotherapy rather than surgery alone. The National Institutes of Health (NIH) periodically convenes expert panels to review evidence about which women with breast cancer are most likely to benefit from adjuvant chemotherapy, and it issues reports known as consensus statements. The NIH recommends adjuvant chemotherapy for all women whose breast cancer has spread to lymph nodes and for all women who have a tumor larger than 1 cm in size. These recommendations apply to postmenopausal women and to women in whom the tumor has chemical markers indicating that hormones can control tumor growth rate. Little is known about how closely doctors follow these recommendations.

Why did the researchers do this particular study?

The researchers wanted to find out whether the NIH consensus panel recommendations were being followed and whether a patient's age affects use of adjuvant chemotherapy.

Who was studied?

More than 5000 women with early-stage breast cancer who were 20 years of age or older (range, 20 to 98 years). All women were entered into the New Mexico Tumor Registry from 1991 to 1997.

How was the study done?

The researchers performed a computer analysis of data in the Registry to answer three questions: 1) What percentage of women with breast cancer received adjuvant chemotherapy? 2) For each age group [measured in 5-year intervals], what were the chances that chemotherapy was being administered? and 3) Do factors other than patient age affect chemotherapy use?

What did the researchers find?

Overall, 29% of the entire study group received adjuvant chemotherapy. The older a woman was, the less likely she was to receive adjuvant chemotherapy. Specifically, 66% of women younger than 45 years of age, 44% of women age 50 to 54 years, 31% of women age 55 to 59 years, 18% of women age 60 to 64 years, 12% of women age 65 to 69 years, and 3% of women older than age 75 years received adjuvant chemotherapy. The researchers could not detect any other factors that explained why older women were less likely than younger women to receive chemotherapy.

What were the limitations of the study?

The researchers could not be sure that all cases of breast cancer were being reported to the Registry. Also, they did not have any information on whether the patients who received adjuvant chemotherapy actually did any better than those who did not.

What are the implications of the study?

The NIH consensus panel recommendations are not being followed in most women with early-stage breast cancer, especially women older than 45 years of age. The reasons for this failure to treat are not clear, but doctors may be missing the opportunity to treat many women with early-stage breast cancer more effectively.