Effect of season and climate on choice of therapy for breast cancer in older women.

OBJECTIVES

We and others have previously found a relative underutilization of breast-conserving surgery with adjuvant radiation therapy in older women diagnosed with early stage breast cancer. Because adjuvant radiotherapy involves daily trips to a facility for 6 weeks, we reasoned that season and climate might influence choice of therapy. Specifically we hypothesized that in northern states, a lower proportion of women would receive breast-conserving surgery plus radiation in the winter months than in summer, whereas in sunbelt states there would be no relationship between season and therapy.

DESIGN

Analysis of national Medicare billing tapes for 1990 and SEER tumor registry data for 1983-1990.

PARTICIPANTS

43,083 women aged 65 to 79, diagnosed with local or regional breast cancer in 50 states or Washington, DC, who underwent mastectomy or breast-conserving surgery in 1990, and 32,502 women aged 65 to 79 who underwent mastectomy or breast-conserving surgery from 1983 to 1989 at any of the nine SEER sites.

RESULTS

Using a variety of analytical approaches, we could find no consistent effect of cold winter climate on choice of breast cancer therapy.

CONCLUSION

Bad weather does not appear to discourage the choice of breast-conserving treatment. It is not known if bad weather influences actual receipt of radiotherapy.