Age-related lobular involution and risk of breast cancer.

BACKGROUND: As women age, the lobules in their breasts undergo involution or regression. We investigated whether lobular involution in women with benign breast disease was associated with subsequent breast cancer risk. METHODS: We examined biopsy specimens of 8736 women in the Mayo Benign Breast Disease Cohort from whom biopsy samples were taken between January 1, 1967, and December 31, 1991. Median follow-up for breast cancer outcomes was 17 years. We classified lobular involution in the background breast tissue as none (0% involuted lobules), partial (1%-74%), or complete (> or = 75%). Subsequent breast cancer events and data on other risk factors were obtained from medical records and follow-up questionnaires. To estimate relative risks (RRs), standardized incidence ratios were calculated by use of incidence rates from the Iowa Surveillance, Epidemiology, and End Results (SEER) Registry. All statistical tests were two-sided. RESULTS: Distribution of extent of involution was none among 1627 (18.6%) women, partial among 5197 (59.5%), and complete among 1912 (21.9%). Increased involution was positively associated with increased age and inversely associated with parity (both P<.001). The relative risk for the entire cohort of 8736 women, compared with the Iowa SEER population, was 1.40 (95% CI = 1.30 to 1.51). Risk of breast cancer was associated with the extent of involution (for no involution, RR [i.e., observed versus expected] = 1.88, 95% confidence interval [CI] = 1.59 to 2.21; for partial involution, RR = 1.47, 95% CI = 1.33 to 1.61; and for complete involution, RR = 0.91, 95% CI = 0.75 to 1.10; test for heterogeneity P<.001). Lobular involution modified risk in all subsets (e.g., among women with atypia, for no involution, RR = 7.79, 95% CI = 3.56 to 14.81; for partial involution, RR = 4.06, 95% CI = 3.03 to 5.33; and for complete involution, RR = 1.49, 95% CI = 0.41 to 3.82; P = .003). CONCLUSIONS: In this large cohort of women with benign breast disease, lobular involution was associated with reduced risk of breast cancer. Aberrant involution may be a biologically important phenomenon in breast cancer biology.

Leadership and professionalism curriculum in the Gross Anatomy course.

INTRODUCTION: Today's physicians must demonstrate both professionalism and leadership skills in order to succeed in largely team-based healthcare environments. The purpose of this study was to determine if professionalism attributes, leadership style, and leadership style adaptability are associated with academic performance among first-year students early in their medical curriculum. MATERIALS AND METHODS: Students were divided into 4-member dissection groups for the duration of the Gross and Developmental Anatomy course. Leadership responsibility was randomly assigned to a team member on a rotating basis every 5 weeks. After each 5-week block, student performance was measured by written and practical examinations, and each student assessed their leader's or their own professionalism attributes and leadership style using validated survey instruments. RESULTS: Most students demonstrated either a "selling" only (57%) or "participating" only (30%) leadership style with low to moderate leadership adaptability. "Participating" and "delegating" leadership styles have the highest average group written exam scores (89.4%, P <0.008). "Telling" only or "selling" only leaders have the lowest average group exam scores (83.5%, P <0.001). "Selling" and "participating" leaders have significantly lower average group practical exam scores than other styles (81.5%, P <0.007). Positive associations were observed between the written and practical examination scores and the leader's integrity (P = 0.003, P = 0.002) and responsibility (P <0.001, P = 0.037). CONCLUSIONS: This study demonstrates that various situational leadership styles and aspects of professionalism are associated with written and practical examination scores in the Gross and Developmental Anatomy course. Furthermore, it demonstrates that first-year medical students are in need of leadership skill development.