INVESTIGATING THE IMPACT OF AGE AND PARITY ON BREAST CANCER RISK: A STUDY AT KTH PESHAWAR

Abstract

Background: Breast cancer is the most prevalent cancer in women all over the world, and one of the major causes of cancer deaths. Although age and parity are the most known risk factors that have been well studied in the Western population, its use in low and middle-income countries such as Pakistan is unclear. It is worth mentioning that regional clinical observation indicates that breast cancer is very prevalent in grand multiparous women and this observation contradicts the perceived protective effect of multiparity. Purpose: The study was aimed at evaluating the parity and age relations with breast cancer risk and stage at diagnosis among women in northwestern Pakistan. Methods: The study was a prospective descriptive study that was performed in Khyber Teaching Hospital, Peshawar, on a population of 163 women with primary breast cancer. Demographic, reproductive, and tumor data determined such as age, parity, age at which a child was born, and Ki-67 proliferation index were obtained through a semi-structured proforma. Categorical variables were analyzed relating to AJCC stage descriptively and by post-stratification chi-square test with the use of significance levels of p ≤ 0.05. Findings: Mean age at diagnosis was 48.29 years (SD=10.24), with the most frequent at the end of the forties and the beginning of the fifties. The mean parity was 2.6 (SD = 1.7), the mean number of pregnancies was 3.9 (SD = 2.1), which means that reproductive exposure was more moderate than in the previous studies. The age of first birth was 18.8 years (SD = 8.63), indicating that there was a high degree of variability in age of first birth which was very early. The levels of Ki-67 indicated intermediate-to-high proliferation (mean = 37.96, SD = 22.17). The Chi-square test demonstrated that there were significant relationships among AJCC stage and both age group ( 2 = 18.456, 9 -1, p = 0.0302) and age at first birth group ( 2 = 17.717, 9 -1, p = 0.0386), but not between parity group (p = 0.1872). Conclusion: This cohort of breast cancer is more common among midlife women who are moderately parity and very young at the time of first birth (~18.8 years). Although total parity is not a significant predictor of the disease stage, older age and earlier age at first childbirth are still found to be significantly correlated with higher AJCC stages.