Association of progesterone receptor status with 21-gene recurrence score and survival among patients with estrogen receptor-positive breast cancer

BACKGROUND

Progesterone receptor (PR)-negative tumors have been shown to have worse prognosis and were underrepresented in recent trials on patients with estrogen receptor (ER)-positive breast cancer. The role of PR-negative status in the context of 21-gene recurrence score (RS) and nodal staging remains unclear.

METHODS

The National Cancer Database (NCDB) was queried for women diagnosed between 2010 and 2017 with ER-positive, human epidermal growth factor receptor 2 (HER2)-negative, pT1-3N0-1a breast cancer. Logistic and Cox multivariable analyses (MVA) were performed to identify association of PR status with high RS (> 25) and overall survival (OS), respectively.

RESULTS

Among 143,828 women, 130,349 (90.6%) and 13,479 (9.4%) patients had PR-positive and PR-negative tumors, respectively. Logistic MVA showed that PR-negative status was associated with higher RS (> 25: aOR 16.15, 95% CI 15.23-17.13). Cox MVA showed that PR-negative status was associated with worse OS (adjusted hazards ratio [aHR] 1.20, 95% CI 1.10-1.31). There was an interaction with nodal staging and chemotherapy (p = 0.049). Subgroup analyses using Cox MVA showed the magnitude of the chemotherapy benefit was greater among those with pN1a, PR-negative tumors than pN1a, PR-positive tumors (PR-positive: aHR 0.57, 95% CI 0.47-0.67; PR-negative: aHR 0.31, 95% CI 0.20-0.47). It was comparable among those with pN0 tumors regardless of PR status (PR-positive: aHR 0.74, 95% CI 0.66-0.82; PR-negative: aHR 0.63, 95% CI 0.51-0.77).

CONCLUSION

PR-negative tumors were independently correlated with higher RS and were associated with greater OS benefits from chemotherapy for pN1a tumors, but not pN0 tumors.

KLP-PI: a new prognostic index for luminal B HER-2-negative breast cancer

Luminal B HER-2-negative (LBHN) subtype is one of the major subtypes of breast cancer according to different features, clinical behaviors, and treatment response. The LBHN subtype shows a poor prognosis and is insensitive to endocrine therapy. Our work aim is to investigate the prognostic factor in the LBHN subgroup and, meanwhile, try to obtain an optimal prognostic index (PI) contrapose LBHN subgroup which helps to guide chemotherapy. A total of 515 female LBNH patients who underwent diagnosis and surgery at our hospitals from August 2008 to August 2018 were enrolled. Clinical-pathological information was obtained and immunohistochemistry result was available. From these cases, a 30% Ki-67 LI was employed to divide LBHN into two groups with low and high levels; high Ki-67 LI was associated with GIII tumor grade (P < 0.001), positive axillary lymph nodes (ALN) status (P = 0.018) and negative PR status (P = 0.016), and also seemed to be related to T2-T3 tumor size (P = 0.058). High Ki-67 level (HR = 3.30; P < 0.011), positive ALN (HR = 7.29; P < 0.001) and PR negative (HR = 2.63; P = 0.034) significantly associated with poor 5-year DFS in multivariate Cox's proportional hazard regression model. A novel prognosis prediction model (KLP-PI), based on Ki-67 LI, ALN and PR status, showed a better discriminatory ability compared with traditional Nottingham prognostic index targeted to LBHN breast cancer. Our study highlights that high Ki-67 LI, positive ALN and negative PR status were associated with poor outcome in LBHN patients, and composed by these prognostic factors, KLP-PI improves the prognostic assessment using the Nottingham Prognostic Index when aiming at LBHN subtype.