# Adenoid Cystic Carcinoma of the Breast: Clinicopathological Features, Therapy Strategy, and Prognosis

## TL;DR

This study examines a rare type of breast cancer called adenoid cystic carcinoma, focusing on its features, treatment, and outcomes in 22 patients.

## Contribution

The study provides a detailed clinicopathological analysis of a rare breast cancer subtype, offering insights into its management and prognosis.

## Key findings

- Most patients had triple-negative breast cancer and were diagnosed at early stages.
- The 5-year disease-free survival rate was 95.4%, indicating a relatively good prognosis.
- Definitive diagnosis of adenoid cystic carcinoma relies on histopathological and immunohistochemical methods.

## Abstract

Adenoid cystic carcinoma (ACC) of the breast is a special subtype of breast cancer.

This study aimed to systematically characterize the clinicopathologic features, treatment patterns, and prognostic indicators of breast ACC, with the overarching goal of enhancing clinical understanding and optimizing management strategies for this rare malignancy.

We conducted a retrospective investigation of 22 patients with breast ACC treated at The West China Hospital of Sichuan University between March 2009 and January 2021. Clinical manifestations, therapy strategies, pathological characteristics, and follow‐up information were systematically observed and analyzed. This study retrospectively analyzed 22 female patients with breast ACC, with ages ranging from 31 to 75 years. Notably, 54.5% (12/22) of the patients were postmenopausal. A palpable breast mass was the most common initial presenting symptom, observed in 95.5% (21/22) of cases. In terms of molecular subtype, triple‐negative breast cancer (TNBC) was identified in 77.3% (17/22) of patients. Conversely, the remaining 22.7% (5/22) of cases showed positive expression for estrogen receptor (ER), progesterone receptor (PR), or human epidermal growth factor receptor 2 (HER2). All patients received surgical treatment, which included simple mastectomy, breast‐conserving surgery (BCS), or modified radical mastectomy. The surgical procedures were optionally accompanied by axillary lymph node dissection (ALND) or sentinel lymph node biopsy (SLNB). The majority of patients, 90.9% (20/22), were diagnosed at early stages (Stage I or II), while only 2 patients were in Stage III. For postoperative adjuvant therapy, 6 patients underwent radiotherapy, 16 received chemotherapy, 2 received hormonal modulation, and 1 advanced‐stage patient participated in a clinical trial with bevacizumab therapy. During the follow‐up period, 4 patients (19%) developed distant metastasis. The 5‐year disease‐free survival rate was 95.4%, with 21 out of 22 patients remaining free from disease recurrence. Remarkably, all patients survived until the end of the last follow‐up, suggesting a relatively good prognosis for breast ACC in this cohort.

Breast ACC is a rare type of TNBC that reportedly has indolent biologic behavior. Definitive preoperative diagnosis remains challenging using imaging modalities alone, as conclusive identification relies heavily on histopathological and immunohistochemical examinations.