Solid-basaloid variant of adenoid cystic carcinoma of the breast with near complete response to neoadjuvant chemotherapy

Solid basaloid adenoid cystic carcinoma of the breast: A high-grade triple negative breast carcinoma which rarely responds to neoadjuvant chemotherapy

Solid basaloid adenoid cystic carcinoma of the breast (SB-AdCC) is an exceedingly rare but important entity that warrants clear separation from classic AdCC (C-AdCC) for optimal treatment. This case series retrospectively reviewed the diagnosis and treatment of 20 breast AdCCs. While four breast pathologists reached consensus on the diagnosis of all C-AdCCs, there was considerable disagreement when diagnosing pure SB-AdCCs. The morphology and immunohistochemical profiles of SB-AdCC closely resemble those of basaloid triple-negative breast carcinoma (TNBC). Molecular profiling of SB-AdCC revealed frequent mutations in the Notch pathway and alterations in chromatin modifiers, such as CREBBP and KMT2D. MYB-NFIB fusion was rare and detected in only 2 of 9 (22.2 %) SB-AdCCs. Axillary lymph node metastasis was present in 2 of 10 patients with SB-AdCC at the time of surgery. During a median follow-up of 27 months, one patient with SB-AdCC developed axillary recurrence. Moreover, 6 of 12 (50.0 %) patients with SB-AdCC developed distant metastases. Of the three patients who underwent neoadjuvant chemotherapy for SB-AdCC, one achieved near-complete pathological response, while the remaining two had minimal response. In conclusion, this series underscores the aggressive clinical course of SB-AdCC, similar to conventional TNBC. Pathologically, SB-AdCC also closely mimics conventional TNBC. It is imperative for pathologists to clearly indicate C-AdCC or SB-AdCC or give a percentage of each component to ensure appropriate treatment strategies and avoid both over-treatment and under-treatment.

Personalized treatment strategies for breast adenoid cystic carcinoma: A machine learning approach

BACKGROUND

Breast adenoid cystic carcinoma (BACC) is a rare subtype of breast cancer that accounts for less than 0.1 % of all cases. This study was designed to assess the efficacy of various treatment approaches for BACC and to create the first web-based tool to facilitate personalized treatment decisions.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was used for this study's analysis. To identify the prognostic variables, we conducted Cox regression analysis and constructed prognostic models using five Machine Learning (ML) algorithms to predict the 5-year survival. A validation method incorporating the area under the curve (AUC) of the receiver operating characteristic (ROC) curve was used to validate the accuracy and reliability of ML models. We also performed a Kaplan-Meier (K-M) survival analysis.

RESULTS

This study included 1212 patients. The median age was 60 years, with most tumors being localized and less than 2 cm in size. The 5-year overall survival (OS) rates were highest for surgery + radiotherapy (RT) (94.9 %) and lowest for surgery + chemotherapy (CTX) + RT (80.1 %). Positive estrogen receptor (ER) status and younger age were associated with better survival outcomes. ML models identified key predictive features for survival, including age, nodal status, and ER status.

CONCLUSION

Age, lymph node metastasis, and ER status are crucial prognostic indicators for BACC. Although postoperative RT enhances survival, the advantages of adjuvant CTX are uncertain, implying that it may be eschewed to avert adverse effects. Our online tool offers essential resources for prognostication and treatment optimization.

Locoregional Recurrence in Adenoid Cystic Carcinoma of the Breast: A Retrospective, Multicenter Study (KROG 22-14)

PURPOSE

This study aims to evaluate the treatment approaches and locoregional patterns for adenoid cystic carcinoma (ACC) in the breast, which is an uncommon malignant tumor with limited clinical data.

MATERIALS AND METHODS

A total of 93 patients diagnosed with primary ACC in the breast between 1992 and 2022 were collected from multi-institutions. All patients underwent surgical resection, including breast-conserving surgery (BCS) or total mastectomy (TM). Recurrence patterns and locoregional recurrence-free survival (LRFS) were assessed.

RESULTS

Seventy-five patients (80.7%) underwent BCS, and 71 of them (94.7%) received post-operative radiation therapy (PORT). Eighteen patients (19.3%) underwent TM, with five of them (27.8%) also receiving PORT. With a median follow-up of 50 months, the LRFS rate was 84.2% at 5 years. Local recurrence (LR) was observed in five patients (5.4%) and four cases (80%) of the LR occurred in the tumor bed. Three of LR (3/75, 4.0%) had a history of BCS and PORT, meanwhile, two of LR (2/18, 11.1%) had a history of mastectomy. Regional recurrence occurred in two patients (2.2%), and both cases had a history of PORT with (n=1) and without (n=1) irradiation of the regional lymph nodes. Partial breast irradiation (p=0.35), BCS (p=0.96) and PORT in BCS group (p=0.33) had no significant association with LRFS.

CONCLUSION

BCS followed by PORT was the predominant treatment approach for ACC of the breast and LR mostly occurred in the tumor bed. The findings of this study suggest that partial breast irradiation might be considered for PORT in primary breast ACC.

Locally Advanced Adenoid Cystic Carcinoma of the Breast-A Case Report with a Review of the Literature

Breast cancer (BC) is a heterogeneous disease distinguished by four main subtypes based on the expression of estrogen, progesterone receptors, and human epidermal growth factor-2 on the cancer cells. Triple-negative breast cancer (TNBC) consists of approximately 10-20% of all BCs and is characterized by a poor prognosis. Adenoid cystic carcinoma (ACC) of the breast is a rare, special type of TNBC with low metastatic potential and usually favorable prognosis. There are no established recommendations concerning systemic therapy in advanced ACC. We present a case of a 70-year-old woman with locally advanced ACC with progression after radical mastectomy, and review the literature concerning the treatment of metastatic disease focused on systemic therapy.

Solid-basaloid variant of adenoid cystic carcinoma of the breast unresponsive to neoadjuvant chemotherapy: Case report

INTRODUCTION AND IMPORTANCE

Adenoid cystic carcinoma (ACC) is a rare triple-negative breast cancer, accounting for only 0.1 % of all primary breast carcinomas. At variance with the classic variant, the solid-basaloid variant of ACC (SB-ACC) is clinically more aggressive and has different molecular features. There is, currently, no consensus regarding the treatment of SB-ACC of the breast, especially the use of neoadjuvant chemotherapy.

CASE PRESENTATION

Here, we present a rare case of SB-ACC in an elderly female patient, with no history of breast carcinoma, who presented with a 4.5 cm central round mass invading the nipple. Given the locally advanced triple negative breast cancer and the invasion of the nipple-areolar complex, the patient has received neoadjuvant chemotherapy followed by surgical treatment. On histopathological examination, the diagnosis of SB-ACC, non-responsive to neoadjuvant chemotherapy, with absence of rearrangement of the MYB gene was retained. The patient received adjuvant radiation therapy and was ambulatory followed without recurrence at the 12-month follow-up.

DISCUSSION/CONCLUSION

This case provided direct evidence that SB-ACC of the breast wasn't responsive to neoadjuvant chemotherapy but cannot allow for definitive conclusions on chemotherapy recommendations. For this reason, more data must be published to investigate the real value of neoadjuvant chemotherapy in SB-ACC.

Rare subtypes of triple negative breast cancer: Current understanding and future directions

Rare subtypes of triple-negative breast cancers (TNBC) are a heterogenous group of tumors, comprising 5-10% of all TNBCs. Despite accounting for an absolute number of cases in aggregate approaching that of other less common, but well studied solid tumors, rare subtypes of triple-negative disease remain understudied. Low prevalence, diagnostic challenges and overlapping diagnoses have hindered consistent categorization of these breast cancers. Here we review epidemiology, histology and clinical and molecular characteristics of metaplastic, triple-negative lobular, apocrine, adenoid cystic, secretory and high-grade neuroendocrine TNBCs. Medullary pattern invasive ductal carcinoma no special type, which until recently was a considered a distinct subtype, is also discussed. With this background, we review how applying biological principals often applied to study TNBC no special type could improve our understanding of rare TNBCs. These could include the utilization of targeted molecular approaches or disease agnostic tools such as tumor mutational burden or germline mutation-directed treatments. Burgeoning data also suggest that pathologic response to neoadjuvant therapy and circulating tumor DNA have value in understanding rare subtypes of TNBC. Finally, we discuss a framework for advancing disease-specific knowledge in this space. While the conduct of randomized trials in rare TNBC subtypes has been challenging, re-envisioning trial design and technologic tools may offer new opportunities. These include embedding rare TNBC subtypes in umbrella studies of rare tumors, retrospective review of contemporary trials, prospective identification of patients with rare TNBC subtypes entering on clinical trials and querying big data for outcomes of patients with rare breast tumors.