The 21-gene recurrence score in early non-ductal breast cancer: a National Cancer Database analysis

Jiyue Qin,Della Makower,Xiaonan Xue,Joseph A Sparano,Juan Lin

doi:10.1038/s41523-021-00368-9

Jiyue Qin, Della Makower + Show 3 more

Open Access

https://doi.org/10.1038/s41523-021-00368-9

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Abstract

The 21-gene recurrence score (RS) is prognostic for recurrence and predictive of chemotherapy benefit in early estrogen receptor-positive (ER +) HER2-negative (HER2-) breast cancer (BCA). We evaluated clinicopathologic characteristics, RS and chemotherapy benefit in invasive ductal carcinoma (IDC), invasive lobular carcinoma (ILC), and carcinomas of mixed histologies (ductal + lobular (DLC), ductal + other (DOC), lobular + other (LOC)). Women diagnosed between 1/1/2010 and 1/1/2014 with ER + HER2- BCA, measuring <5 cm, with 0–3 involved axillary nodes, surgery as first treatment, and available RS, were identified from the NCDB. Associations between categorical variables were examined using chi-square test. Cox proportional hazards model was used to examine overall survival (OS) differences among histology subtypes. IDC was associated with smaller size, high grade, and RS > 26. ILC was associated with larger size, and least likely to be high grade (p < 0.0001). Lobular histology was associated with lower incidence of RS > 26. IDC patients (pts) were more likely to receive chemotherapy than pts with other histologies (p < 0.0001). OS for IDC, ILC and DOC were similar. DLC was associated with improved OS (HR 0.82, p = 0.02). Adjuvant chemotherapy was associated with improved OS in IDC (HR = 0.76, p < 0.0001) but not in ILC (HR = 0.99, p = 0.93), DLC (HR = 1.04, p = 0.86), DOC (HR = 0.87, p = 0.71), or LOC (HR = 2.91, p = 0.10). Lobular and mixed BCA histologies have distinct clinicopathologic features compared with IDC, and are less likely to have high RS. OS is similar for IDC and ILC. Although chemotherapy benefit was seen only in IDC, benefit for ILC with RS > 26 cannot be excluded.

Highlights

Breast cancer is a heterogenous disease, which includes several histologic morphologies[1]
invasive ductal carcinoma (IDC) was associated with smaller tumor size. 79.2% of IDC measured 20 mm or less, compared with 65.5% of invasive lobular carcinoma (ILC), 71.2% of DLC, 74.7% DOC, and 70.4% LOC (p < 0.0001)
The majority of clinical trials which inform breast cancer (BCA) management do not distinguish between BCA subtypes, and their findings are likely driven by the behavior of IDC

Summary

INTRODUCTION

Breast cancer is a heterogenous disease, which includes several histologic morphologies[1]. Invasive ductal carcinoma (IDC), the most common form of breast cancer (BCA), comprises ~80% of cases. Invasive lobular carcinoma (ILC), the second most prevalent BCA histology, represents about 10–15% of cases[2,3]. ILC is more difficult to detect mammographically than IDC5, and advanced ILC is associated with a predilection for metastases to the peritoneum, gastrointestinal tract, and meninges[4,6,7]. Despite these differences, IDC and ILC are typically managed . We sought to evaluate differences in clinicopathologic characteristics, RS and chemotherapy benefit between IDC, ILC, and carcinomas of mixed histologies

RESULTS

DISCUSSION

Makower et al 5

24. NCCN Clinical Practice Guidelines in Oncology