Title
Clinical course and treatment outcomes in solid-basaloid adenoid cystic
carcinoma of the breast: A systematic review and case report
Authors
Stephanie Kim, Kyle Sheth, Xiaoying, Laura Porterfield, Elizabeth M. Vaughan
Journal
Cancer Treatment Review
Background
Adenoid Cystic Carcinoma (ACC) is a rare, indolent subtype of triple-negative breast cancer, accounting
for < 0.1 % of cases. The solid-basaloid subtype (SBACC), comprising approximately one-quarter of
breast ACCs, has a poorer prognosis. While ACC is typically managed with surgery and is chemo-resistant, SBACC
is more aggressive and often treated with chemotherapy and, more recently, immunotherapy—though supporting
evidence remains limited.
Aim
To assess clinical characteristics and treatment outcomes of SBACC of the breast.
Methods
This study presents a case of breast SBACC and a systematic review of five databases (inception–September
10, 2024). Eligible studies reported clinical course, treatment, and outcomes. Exclusions included duplicates,
non-SBACC focus, animal studies, and those lacking clinical or with only pathological data. Descriptive
statistics were used for binary and categorical variables. Risk of bias was assessed using JBI tools, following
PRISMA 2020 guidelines. The review is registered in PROSPERO.
Results
Nineteen studies and one new case (134 patients, aged 19–89) were included. Except for three patients
who had with metastatic disease at diagnosis, the rest (97 %) were treated with surgery; 55.6 % received
chemotherapy. Among nine patients given neoadjuvant chemotherapy and/or immunotherapy, none achieved
complete pathological response, and most had poor outcomes. In non-metastatic cases with reported treatment
(n =99), younger age predicted recurrence (p =0.032) but not chemotherapy receipt (p =0.082). Chemotherapy
did not reduce recurrence risk (p =0.819). Mastectomy versus breast-conserving surgery with radiation
had similar outcomes (p =0.197).
Conclusion
Although limited data are available for this rare cancer, evidence for the efficacy of chemotherapy
and immunotherapy for SBACC treatment is lacking. Treatment plans should be individualized to reduce the
physical, psychological, and financial burdens on both patients and healthcare systems.