The impact of mammography in 1096 consecutive patients with breast cancer, 1979-1993: equal value for patients younger and older than age 50 years.

BACKGROUND

Although the benefit of screening mammography in healthy women younger than age 50 remains controversial, few studies have addressed the impact of mammography over time and by patient age, on means of diagnosis and stage of disease among women with breast cancer.

METHODS

One thousand ninety-six consecutive patients with operable breast cancer (both invasive and noninvasive intraductal) treated in this practice between 1979 and 1993 were stratified by primary means of diagnosis (patient, physician, or mammography), age < 50 years, 50 years and older), and time period (1979-83, 1984-88, and 1989-93). Tumor size, lymph node status, and tumor type were compared among these groups.

RESULTS

(1) Mammography was the primary means of diagnosis in 28.8% of younger and 42.4% of older patients treated most recently (1989-1993), significantly more often than in the past (P < 0.0005). (2) For cancers diagnosed primarily by either patients or physicians, there was not significant change over time (for either younger or older patients) in clinical presentation, tumor size, lymph node status, or histology. (3) For cancers diagnosed primarily by mammogram, i) 95% of patient self-exams and 56% of physician exams were negative, ii) tumor size was significantly smaller (P < 0.00005), iii) lymph nodes more often were negative (P = 0.0002), and d) histology was more likely to be either in-situ or microinvasive (P < 0.00005). These findings were equally true for younger and older patients.

CONCLUSION

Increased use of mammography, rather than improvement in patient or physician breast examination, explains the progressively earlier stage of breast cancers found in recent years, a benefit equally apparent in patients younger and older than age 50.