ABSTRACT
Introduction:
GLOBOCAN 2020 estimates the incidence rate of breast cancer (BC) in Indonesia is 40.3 in 100.000 women with a mortality rate of 16.6 in 100.000 women.1,2 The development and progressivity of BC depend on steroid hormone activity, namely estrogen, progesterone, and androgen, along with their respective receptors.3 Local and regional recurrence commonly occur in approximately 35% of patients in ten years after mastectomy, in which local recurrence rate for patients undergoing mastectomy is 8.9% with 5-year disease-free survival rate of 73%.4 This study was conducted to investigate the 5-year survival rate, progression-free survival (PFS), and effect of progesterone level changes on the progressivity of Luminal B BC.

Methods:
This study was a quantitative, prospective cohort observational study in Luminal B BC patients who had undergone mastectomy, received chemotherapy (ChT), and had hormonal therapy (HT). These patients had their progesterone levels examined in 2016 and reexamined in 2021, the hormone level changes were evaluated along with the patients' clinical symptoms whether they developed progressivity, i.e., local-regional recurrence or distant metastasis. In addition, bivariate analysis by utilizing Chi Square/Fischer's Exact Test on risk factors as confounding factors including age, use of contraception, family history of BC, number of parity, histological grading, and progesterone level bivariate/multivariate analysis was performed to investigate the effect of progesterone level changes on disease progressivity.

Results:
The five-year survival rate of Luminal B BC was 63.5% (2016–2021). Bivariate analysis by utilizing Chi-Square/Fischer's Exact Test on risk factors as confounding factors including age, use of contraception, family history of BC, number of parity, and histological grading showed no significant effect on the progressivity of BC (p value>0.05). In contrast, bivariate and multivariate analysis on progesterone levels showed a significant effect on the progressivity of BC, in which an increase of progesterone level was a risk factor of disease progressivity (p value<0 Rank=14.732;>

Conclusion:
This study showed the significant effect of progesterone blood level changes in patients with Luminal B BC who had undergone definitive surgery, received chemotherapy, and hormonal therapy on BC disease progressivity. Patients with elevated progesterone levels had the risk of disease progressivity about 26.25-fold with 5-year survival rate of 63.5% (2016–2021). The Progression-Free Survival rate of patients with stable and elevated progesterone levels were 78.9% and 12.5%, respectively.