Clinical and Demographic Factors, Treatment Patterns, and Overall Survival Associated With Rare Triple-Negative Breast Carcinomas in the US

Abstract

IMPORTANCE Triple-negative breast cancers are known collectively to demonstrate a more aggressive clinical course and earlier recurrence than cancers of other histological subtypes.However, the literature on rare triple-negative breast cancers and the association of histological type with survival and risk of metastasis is sparse.OBJECTIVE To present the clinical and demographic characteristics, treatment patterns, and overall survival (OS) for histologically rare (<10% of breast cancers) triple-negative breast cancer types: medullary carcinoma, adenoid cystic carcinoma, and metaplastic breast carcinoma. DESIGN, SETTING, AND PARTICIPANTSThis cohort study was performed in the US using data reported by the National Cancer Database between 2010 and 2016. Confirmed cases of medullary carcinoma, adenoid cystic carcinoma, and metaplastic breast cancer were analyzed. Univariable analyses and multivariable Cox regression models were performed. Data analysis was performed from April to May 2020. MAIN OUTCOMES AND MEASURES The primary outcome was 5-year OS. Secondary outcomes included site of metastasis, effect of immunohistochemistry, management, and 2-year mortality. RESULTS A total of 8479 patients with breast cancer (mean [SD] age; 62.6 [14.3] years; 8435 women [99.48%]) were analyzed. Metaplastic carcinoma was the most commonly diagnosed histological type in this cohort, with 6867 patients (81%), followed by 1357 (16%) with adenoid cystic carcinoma and only 255 (3%) with medullary carcinoma. Medullary carcinoma presented earlier in life, at a median (interquartile range) age of 53 (45-62) years, compared with 62 (53-72) years for patients with adenoid cystic carcinoma and 63 (52-74) years for patients with metaplastic carcinoma. The proportion of tumors with triple-negative immunohistochemistry varied by histological type for medullary carcinoma (57 patients [22.4%]), adenoid cystic carcinoma (653 patients [48.1%]), and metaplastic carcinoma (3637 patients [53.0%]). Patients with adenoid cystic carcinoma were less likely to receive radiotherapy (711 patients [52.4%]) and chemotherapy (175 patients [12.9%]) compared with patients with medullary carcinoma (radiotherapy, 156 patients [61.2%]; chemotherapy, 190 patients [74.5%]) and metaplastic carcinoma (radiotherapy, 3416 patients [49.7%]; chemotherapy, 4709 patients [68.6%]). The 5-year OS rate was superior for patients with medullary (91.7%) and adenoid cystic carcinoma (88.4%) compared with patients with metaplastic carcinoma (63.1%). The 5-year mortality rate for adenoid cystic carcinoma was 8.33% vs 36.91% for metaplastic carcinoma. CONCLUSIONS AND RELEVANCENationally, over the course of 7 years, medullary carcinoma was most common and metaplastic carcinoma had the worst 5-year OS among the rare histological breast cancer subtypes analyzed. Factors associated with a poor prognosis for metaplastic carcinoma included advanced stage, lung metastasis, older age, and not receiving chemotherapy or radiation (continued) Key Points Question Do all triple-negative breast ca...

Triple-Negative Breast Cancer Histological Subtypes with a Favourable Prognosis

“…The myoepithelial/abluminal cells express p63, smooth muscle actin and basal CKs: CK5/6, CK14, CK17. CAdCC generally displays a triple-negative immunophenotype, although ER-positive cases also occur ( Supplementary Table S2 ) [ 46 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 ]. CAdCC frequently expresses EGFR, an immunohistochemical marker of the “basal-like” phenotype, without gene amplification [ 69 ].…”

“…Taking account of the publications to date, the median age of patients with AdCC ranged from 58 to 66 years. Data on the ethnical differences are limited, but larger registry-based series suggest that approximately 85% of patients diagnosed in the USA were whites [ 46 , 48 , 50 , 52 , 53 ]. The majority of patients presented with a palpable mass (85.7%) and underwent lumpectomy, breast-conserving surgery (BCS) or mastectomy.…”

Unique clinicopathological characteristic and survival rate of metaplastic breast cancer;a special subtype of breast cancer a 5 year cohort study in single referral centre in North Borneo

“…One patient from our case series who presented with lung metastasis was received palliative chemotherapy (4 cycles of FEC regimen, and 2 cycles of docetaxel) and also received second line chemotherapy paclitaxel, experienced no reduction in tumor size along with worsening lung metastasis. Although evidence shown little benefit of systemic therapy in metastatic disease of MBC, it was also demonstrated that those who did not received chemotherapy or undergo any surgical treatment over the site of primary tumor, was associated with decreased survival outcome [ 16 ]. Corso et al found that patients who received CMF/CMF like regimen showed better prognosis and improved overall survival [ 5 ].…”

“…Zhang et al revealed that the 5 year overall survival rate of MBC patients was shorter compared to that of invasive ductal carcinoma patient group and triple negative subtype of invasive ductal carcinoma patients (78.7% vs 93% vs 90.6%) [ 3 ]. Elimimian et al demonstrated inferior prognosis of MBC patient group compared to 2 other special type of breast carcinoma, which is adenoid cystic carcinoma and medullary carcinoma (5 year overall survival rate: 63.1% cs 88.4% vs 91.7%) [ 16 ].…”

Evaluation of Adjuvant Treatments for Adenoid Cystic Carcinoma of the Breast: A Population-Based, Propensity Score Matched Cohort Study from the SEER Database

“…In the rare breast ACC cases without the MYB-NFIB gene fusion, additional genomic alterations have been detected, including MYB gene amplification and MYBL1 gene rearrangement [ 6 ]. Although the immunohistochemical phenotype of most ACC of the breast is triple-negative, the prognosis is better than that of other triple-negative breast cancer [ 7 ].…”