The older a woman is, the less likely she is to receive recommended chemotherapy after breast cancer surgery. This is a finding of a new study reported in the Annals of Internal Medicine (2003:138;90-7), in which the authors say there is “a clear divergence between consensus recommendations and clinical practice.”
The journal editors say (in the “Editors' notes” box accompanying the article): “Since only a minority of postmenopausal women receive adequate treatment for breast cancer, many unnecessary deaths could probably be prevented by following the National Institutes of Health guidelines.”
The study used data from the state-wide, population based New Mexico tumour registry, an original member of the surveillance, epidemiology, and end results (SEER) registry. It included 5101 women in the state aged 20 to 98 with stage I, II, or IIIA breast cancer between 1991 and 1997. Their mean age was 61.
During the study period, women should have been treated in accordance with the 1990 National Institutes of Health recommendations, an update of the 1985 guidelines. Chemotherapy was recommended for both premenopausal and post-menopausal women who had lymph nodes positive for cancer or had cancer confined to the breast but with poor prognostic signs, such as a large size of tumour or a tumour negative for hormone receptors. (In 2000, the National Institutes of Health recommended chemotherapy for all women with tumours larger than 1 cm in diameter, regardless of menopausal or hormone receptor status.)
However, only 29% of the 5101 women received chemotherapy, and the proportion declined with age. Whereas 66% of women aged under 45 received chemotherapy, only 3% of those women aged 75 and older did. For other groups the figures were 55% of women aged 45-49; 44% of those aged 50 to 54; 31% of those aged 55 to 59; 18% of those aged 60 to 64; 12% of those aged 65 to 69; and 7% of those aged 70 to 74. Eleven per cent of women with stage I cancer, 47% with stage II, and 68% with stage IIIA. received chemotherapy.
Women whose cancer had spread to the lymph nodes or was negative for hormone receptors were more likely to receive chemotherapy, but their numbers decreased substantially with age.
The percentage of women who received chemotherapy plus hormone therapy (usually tamoxifen) or chemotherapy alone decreased with age, but the use of hormone therapy alone increased with age. The percentage of women who received neither chemotherapy nor hormone therapy increased with age.
“Women with large tumours or tumours negative for hormone receptors should receive chemotherapy, but it won't be 100%. Some may refuse, for example, but we expected a higher percentage than what we saw,” said the lead author, Dr Xianglin Du, assistant professor of medicine and geriatrics at the Texas centre, even though the efficacy of chemotherapy decreases with age.
“Oncologists' attitudes and patient preferences were never measured. Doctors may have perceptions that older individuals are less tolerant of toxicity or that toxicity increases with age, but that may not be true. It's a question whether the recommendations are overly aggressive or oncologists are too conservative,” he said.