Risk of breast cancer in relation to reproductive factors in North-West of Iran, 2013-2014.

More than one million new patients suffer from breast cancer annually in the world. In developed countries, breast cancer is the most common malignancy diagnosed among women, and in developing regions, it often ranks second to cervical cancer. This study aimed to investigate the relationship between incidence of breast cancer and reproductive factors in North-West of Iran. This retrospective analytical control-case study was conducted with 235 breast cancer patients and 235 women in the control group. Data collection tools included a set of questions with interviews and patient medical records. Data were analyzed using statistical tests: t-test, Chi-square, Fisher, and Pearson correlation coefficient. Significantly increased risks were associated between breast cancer and older age at first pregnancy, age at menopause and history of contraceptive use. A trend for decreasing risk were observed with increasing parity. Findings of this study showed no association between breast cancer and age at menarche. The study results suggested that physiological and reproductive factors may play important roles in the development breast cancer among Iranian women.

Risk of cancer with combined oral contraceptive use among Iranian women.

Oral contraceptive use is the most common type of contraception. More than 300 million women worldwide take oral contraceptives every day. However, there is a concern about the relationship with the incidence of cancer. This analytical retrospective study aimed to investigate the relationship between the incidence of cervical and breast cancers and oral contraceptive use in 128 Iranian patients with cervical cancer, 235 with breast cancer and equal numbers of controls. Data were collected through interviews with an organized set of questions. Details were also extracted from patient files. Data were analyzed using Student's t-test, chi-square and Fisher's exact tests, and Pearson's correlation analysis. The result revealed correlations between both cervical and breast cancers and history of contraceptive pills use. While cervical cancer significantly correlated with duration of use of pills, breast cancer had significant correlations with the type of oral contraceptive and age at first use. No significant relationships were found between the two types of cancer and age at discontinuation of oral contraceptives, patterns of use, and intervals from the last use. The use of oral contraceptives may triple the incidence of cervical cancer and doubles the incidence of breast cancer. Therefore, performing Pap smears every six months and breast cancer screening are warranted for long-term oral contraceptive users.