Publication: Survival analysis of pregnancy associated breast cancer in Kelantan: a hospital-based retrospective cohort study
Date
2023-07
Authors
Abrar, Syed Sana
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Abstract
According to the World Health Organization, breast cancer was diagnosed in
2.3 million women in 2020, and approximately 6,85,000 deaths were recorded
worldwide. The number of breast cancer patients in Malaysia is increasing at an
alarming rate, with almost half of all breast cancer patients aged < 50 years. Breast
cancer that develops during pregnancy or within 12-24 months of delivery is known
as pregnancy-associated breast cancer (PABC). PABC patients may have poor clinical
results and survival. Research exploring survival outcomes in pregnant breast cancer
patients is limited, especially in Asian countries. The objective of this study was to
compare the survival probability in PABC and non-PABC patients and identify if
pregnancy is an independent prognostic factor in PABC. The study design was
retrospective cohort. Two cohorts of breast cancer women, one pregnant cohort and
another non-pregnant cohort, were followed for the survival outcome. Patients’ data
from the Universiti Sains Malaysia (USM) and Hospital Raja Perempuan Zainab
(HRPZ) II database from 1st January 2001 until 31st December 2020 was reviewed,
and relevant information was extracted and recorded in a data collection form. The
survival of the two groups of patients were analysed following the Kaplan-Meier method and compared using the Mantel-Cox log-rank method. Prognostic factors were
analysed using Cox proportional hazard regression. A total of 35 patients in the PABC
group were analysed and matched with 35 non-PABC patients in the 1:1 group and 70
non-PABC patients in the 1:2 group on the basis of age and year of diagnosis. The
median (IQR) follow-up times were 30.93 (42.20), 25.17 (29.55), and 36.57 (58.25)
months for the PABC, non-PABC (1:1), and non-PABC (1:2) groups, respectively.
The median survival time in the PABC group was 40.32 months (95% confidence
interval (CI), 0.00-94.18), 26.29 months in the 1:1 matched non-PABC group (95%
CI 22.45-30.13; p=0.080) and 43.59 months in the 1:2 matched non-PABC group was
(95% CI, 0.00-89.92; p=0.941). The 5-year survival of PABC, non-PABC (1:1), and
non-PABC (1:2) was 47.54%, 25.69%, and 45.11%, respectively. There were no
significant differences between groups; p=0.080 for 1:1 group and p=0.941 for 1:2
group. Pregnancy was not found to be an independent significant prognostic factor;
adjusted hazard ratio (AHR) 0.56, 95% CI: 0.30, 1.03, p=0.063 for the 1:1 group and
AHR 0.72, 95% CI (0.39, 1.28), p=0.266 for 1:2 group. The findings show that women
diagnosed with PABC had non-significant difference of overall survival compared to
non-PABC. Pregnancy is not an independent prognostic factor for the survival of
breast cancer. This information may be useful when women with breast cancer are
counselled and supports the option of beginning treatment with pregnancy
continuation. However, due to the small sample size and low power of the study, the
outcomes should be interpreted with caution.
Description
Keywords
Breast cancer , Pregnancy