Parity association with clinicopathological factors in invasive breast cancer: a retrospective analysis

Ranking of Modifiable Lifestyle Risk Factors for Breast Cancer in Saudi Women: Population Attributable Risk and Nomogram

Purpose

Breast cancer is the most common cancer among women in the Saudi Arabia, and over 50% of the cases are detected at a late stage. This study aimed to estimate population attributable risk percentage (PAR%) of modifiable lifestyle risk factors for breast cancer in Saudi Arabia.

Patients and Methods

A secondary analysis of previously published papers was performed . Relative risks (RR) and odds ratios (OR) were obtained from published international epidemiological studies, and the prevalence of each risk factor in Saudi Arabia was obtained from various sources (eg, national surveys and published literature) to calculate PAR%. A nomogram was used to visually translate the RRs/ORs and their prevalence into PAR% using a practical tool.

Results

Seven modifiable lifestyle risk factors for breast cancer were identified in Saudi Arabia. The identified risk factors included lack of physical activity (sedentary lifestyle), oral contraception (current use), obesity (postmenopausal), hormone replacement therapy (current use), passive smoking, age at first birth (≥ 35 years), and tobacco smoking (current or daily smoking). The PAR% for these risk factors ranged from 0.5% for tobacco smoking to 23.1% for a lack of physical activity. Few modifiable lifestyle risk factors were excluded from this study, due to limited nor unavailable data in Saudi Arabia (eg, alcohol consumption, breastfeeding patterns and childbearing patterns, obesity according to menopausal status, and night-shift work).

Conclusion

Physical inactivity has the most significant modifiable health impact and is a major risk factor for breast cancer. Removing this risk factor would reduce the prevalence of breast cancer in the Saudi population by 23%. There is an immense need to prioritize cancer control strategies based on local needs, current data on cancer risk factors, and the disease burden.

Epidemiologic risk factors for in situ and invasive ductal breast cancer among regularly screened postmenopausal women by grade in the Cancer Prevention Study-II Nutrition Cohort

PURPOSE

Histopathologic grade provides an integrated measure of biologic features which affects cancer prognosis. In invasive ductal breast cancer (IDBC), the grade of the ductal carcinoma in situ (DCIS) and invasive components are usually concordant, suggesting grade is established early in tumorigenesis and may be linked to etiologic factors. In this study, we used prospectively collected data from postmenopausal women in the Cancer Prevention Study-II (CPS-II) Nutrition Cohort to compare risk factor associations among low-grade and high-grade DCIS, as well as low-grade and high-grade IDBC.

METHODS

Among 73,825 cancer-free women at enrollment in the CPS-II Nutrition Cohort in 1992-1993 (mean age: 62.1 years), we verified 802 diagnosed with DCIS (C50 8500/2; n = 430 low-grade and 372 high-grade) and 3,125 with IDBC (C50 8500/3; n = 2,221 low-grade and 904 high-grade) through June 2013. Person-time contribution was conditional on screening mammograms self-reported on biennial surveys. Multivariable-adjusted joint Cox proportional hazards regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

A personal history of benign breast disease was more strongly associated with higher risk of low-grade DCIS (HR = 2.20, 95% CI 1.81-2.67; p for heterogeneity = 0.0004) than high-grade DCIS. Consumption of two or more alcoholic drinks/day was only associated with a higher risk of low-grade IDBC (HR = 1.58, 95% CI 1.33-1.88; p for heterogeneity = 0.005).

CONCLUSIONS

These results suggest heterogeneity by grade for breast cancer etiology. Identification of potential risk factor differences among low-grade and high-grade DCIS and IDBC may help to clarify associations, and ultimately, improve breast cancer risk prediction models.