Survival probabilities and prognostic factors of pregnancy-associated breast cancer in Malaysian women.

Objective: Pregnancy-associated breast cancer (PABC) is a rare cancer. This study aimed to determine the survival probabilities and prognostic factors in patients with PABC.

Methods: A retrospective cohort study was conducted in two tertiary care hospitals in Kota Bharu. We included all patients with breast cancer who were diagnosed by histopathology while pregnant or within 2 years post-partum from 2001 through 2020. We matched patients with PABC to non-pregnant patients with breast cancer by age and year of diagnosis. The data were analyzed using Cox proportional hazard regression.

Results: A total of 35 cases of PABC and 70 non-PABC controls were recruited. The 3-year, 5-year, and 10-year survival probabilities for patients with PABC were 58.6%, 47.54%, and 38.03%, respectively. The patients with PABC had a non-significant difference in survival probabilities compared with non-PABC patients. The significant prognostic factors of PABC were age (adjusted hazard ratio [aHR], 0.91; 95% confidence interval [CI], 0.86-0.96; P=0.001), advanced stage of cancer (aHR, 9.97; 95% CI, 3.96-25.2; P<0.001), and no surgery (aHR, 3.16; 95% CI, 1.01-9.85; P=0.047). Pregnancy was not found to be an independent factor in the prognosis of PABC (aHR, 0.72; 95% CI, 0.39-1.28; P=0.266).

Conclusion: Women diagnosed with PABC had similar survival probabilities compared with non-PABC patients. Pregnancy was not an independent prognostic factor for breast cancer. This information can be useful when women with breast cancer are counseled and supported with the option of beginning treatment with pregnancy continuation.