Risk of breast cancer in relation to cigarette smoking.

To provide additional data on the smoking-breast cancer association, a case-control study of 456 cases of breast cancer and 1693 matched controls was conducted among participants in a cancer screening program. The adjusted risk of breast cancer for current smokers was 1.38 (95% confidence interval, 1.01 to 1.90). Analysis of smoking habits restricted to premenopausal women revealed a risk estimate of 2.33 (confidence interval, 1.10 to 4.96) among current smokers and increasing linear trends in risk for number of cigarettes smoked per day and for number of years of smoking. Although smokers had an earlier natural menopause than nonsmokers, there was no evidence of a protective effect of early menopause after adjustment for other factors. These findings suggest that smoking may increase the incidence of breast cancer, especially in premenopausal women.

Breast cancer detected by screening: the importance of long-term follow-up.

This study updates a 10- to 15-year follow-up of 136 patients with breast cancer among 10,187 symptom-free participants in a screening program. Mammography was the sole detection modality in 76 (56%) patients. The combination of mammography and physical examination revealed 41 (30%) cancers, whereas 19 (14%) were detected on physical examination alone. There were 26 (19%) noninvasive and 110 (81%) invasive neoplastic lesions. Positive axillary nodes were found in 34 (25%) patients, and 102 (75%) patients had negative nodes. For the entire group 5- and 10-year survival rates were 84.5% and 75%, respectively. After a minimum follow-up of 10 years and a median of 13.5 years, 102 patients are alive; one of these has a recurrence of cancer. Among the 34 patients who are no longer living, 14 died of causes unrelated to breast cancer. Two patients in the group in which diagnosis was based on mammography alone died of breast cancer, for a breast cancer-related fatality rate of 2.6% (2/76). By contrast, the breast cancer-related mortality of patients whose tumors were palpable at the time of detection was 30% (18/60) (p = 0.00001). This study suggests that long-term survival of patients whose breast cancer is detected by screening is, in large measure, dependent on the ability to detect malignant lesions before they become palpable.

Cancer of the breast. Mammography and thermography.

Quality mammography with knowledgeable interpretation is now a widely utilized and reliable procedure. It permits clinically occult lesions to be detected and clinically obvious or indeterminate lesions to be managed more intelligently. Abnormal mammographic signs are well defined, as are their differential diagnoses. Thermography of the breast is a younger science than mammography and must mature before its full potential can be realized. It is clear that thermography today cannot be considered an adequate prescreening technique to obviate further examination, as was once anticipated. Used in conjunction with physical examination and mammography it can serve to reinforce suspicions, and the high acceptability of the examination is an impetus to further clarify its role in detection.

Cancer of the breast. Screening.

Screening is a more complicated issue than has been indicated in this chapter. Long-term followup is essential to exclude misleading initial impressions, and survival predictions must stand this test. The problem of interval cancers must be acknowledged, and methods of developing more cost-effective systems that might provide even broader coverage of the population at risk have to be considered. Suffice it to say that mass screening for breast cancer can be accomplished. Large numbers of American women are sufficiently concerned about this disease to participate, as evidenced by the success of the National Cancer Institute/American Cancer Society Breast Cancer Detection Demonstration Projects. It has been demonstrated that breast cancers so small that they would previously be considered a pathological curiosity are detected with surprising frequency. The ultimate effect on survival time by this screening can of course only be determined after passage of time, but there is every reason to believe that it represents one of the really great advances in detection-diagnosis in recent history. The chief detection modality is mammography, and it is to be expected that technological advances in this area will permit images of even greater reliability and resolution at a level of radiation exposure that will be acceptable to everyone. The definitive role of thermography in detection of breast disease has yet to be fully determined. The maximal scientific benefit and the true impact of the screening demonstration projects will be realized only after long-term followup of the 280,000 participants.

The impact of breast cancer screening on survival. A 5- to 10-year follow-up study.

The Missouri Breast Cancer Detection Demonstration Project (BCDDP) at the Cancer Research Center in Columbia, Missouri, detected 136 malignant lesions among 10,187 asymptomatic participants between 1974 and 1980. Mammography was the sole detection modality in 76 or 56% of cases (Group 1). Mammography combined with physical examination revealed 41 (30%) additional cases (Group 2). Physical examination alone detected 19 (14%) cases (Group 3). Follow-up was complete in all cases. There were 26 (19%) noninvasive and 110 (81%) invasive lesions. Positive axillary nodes were found in 34 (25%) cases, and 102 (75%) patients had negative nodes. The overall 5-year survival was 84.5%. After a minimum follow-up of 5 years and a median follow-up of 8.5 years, 108 patients are alive, 5 of whom have recurrences. Among 28 deceased patients, 9 died of causes unrelated to breast cancer. The 5-year survival of Group 1 was 95% (72/76). Among this group of patients, 84% (64/76) had negative lymph nodes. At 5 to 10 years follow-up, there have been no breast cancer-related deaths among this group, and only one patient has recurrent disease 91 months after mastectomy. Furthermore, 85% (22/26) of all noninvasive lesions were found in this group. Of the remaining 12 patients diagnosed by mammography alone but who had positive nodes, the 5-year survival was 75% (9/12). By contrast, patients diagnosed by mammography plus physical examination (Group 2) experienced a survival of 71% (29/41) at 5 years. Sixty-three percent of patients diagnosed by physical examination had negative lymph nodes. Their 5-year survival was 84%, which contrasts with a 50% 5-year survival for patients with positive nodes. In Group 3, 79% (15/19) had negative nodes. The 5-year survival rate of this group was 74% (14/19), and the 5-year survival rate of the node-negative patients with invasive disease in this group was 29% and 21% lower than that of the node-negative patients with invasive disease of Groups 1 and 2, respectively (P less than 0.01). This study suggests that improved survival in breast cancer screening program is in large measure dependent on the ability to detect lesions before they become palpable. The authors conclude that mammography is a determining factor in early diagnosis, and at 5 to 10 years contributes significantly to improved 5- and 10-year survival rates.