Breast cancer in women 65-74 years old: earlier detection by mammographic screening

Our objective was to investigate the value of screening mammography in 65- to 74-year-old women by determining differences in various prognostic indicators in screened and nonscreened groups.

We reviewed 103 malignant breast tumors detected in 102 women 65-74 years old over a period of 73 consecutive months (February 1988-March 1994). A screening interval of less than 18 months was chosen to separate the screened from the nonscreened populations. Mammographic, histologic, and clinical features were reviewed. Statistically significant differences were calculated using Fisher's exact test and Wilcoxon's rank sum test.

Thirty-two patients were in the screened population; 70 patients were in the nonscreened population. Ninety-nine percent (102/103) of the carcinomas were apparent mammographically. We found significant differences between the screened and the non-screened groups with respect to the size of lesions revealed by mammography (11 mm versus 21 mm; p = .0002) and the incidence of minimal tumors (20/32 (63%) versus 26/70 (37%), p = .0198). The incidence of lymph node metastases was 3/27 (11%) for the screened group versus 14/47 (30%) for the nonscreened group (p = .0875). The overall positive predictive value of mammography for the 65- to 75-year-old patients was higher than in our general population, 47% versus 28%.

Screening mammography revealed significantly smaller and earlier stage tumors in 65- to 74-year-old women. This finding inferentially supports the efficacy of screening in this age population.