Mammary analog secretory carcinoma in adults: A systematic review.

Abstract

e18076 Background: Mammary analog secretory carcinoma (MASC) is a rare malignant salivary gland tumor of the head and neck region that was first described by Skálová et al. in 2010. It histologically mimics breast secretory carcinoma and parotid acinic cell carcinoma, and characterized by ETV6-NTRK3 fusion gene. This review aims to investigate the clinicopathologic features, treatment, and outcomes of MASC in adults. Methods: PubMed search for MASC adults (18+ years) from data inception through 2021, pooled with a case from our institution. Kaplan-Meier analysis was used to plot survival curves. Results: Of the 254 included cases, female:male ratio 1.02:1 with a mean age at diagnosis (±SD, range) of 50.1 (±16.7, 18–86) years. In terms of location, 143 (56.3%) occurred in the parotid gland, 21 (8.3%) in the submandibular gland, 21 (8.3%) in the lip, 15 (5.9%) in the thyroid gland–all (100%) had a component of classical type papillary carcinoma, 15 (5.9%) were cutaneous, 13 (5.1%) in the buccal mucosa, 12 (4.7%) split between hard and soft palate, 4 (1.6%) in the nasal mucosa, 2 (0.8%) in the lung, and remaining 8 (3.1%) each in the conjunctiva, tongue, minor salivary gland, submaxillary gland, maxillary sinus, ethmoid sinus, upper esophagus, and mandible. Patients mostly presented with swelling or growing mass in 95.4% (out of which, 93.3% were painless), followed by a painful ulcer in 1.8%. Median tumor size was 1.9 cm (range 0.3cm–8.5cm). Median duration of symptoms at time of presentation was 12 (range 1-360) months. Tumors were T1 (49.7%), T2 (23.9%), T3 (20.3%), and T4 (6.1%), N0 (81.9%), N1 (10.7%), N2 (7.4%), M0 (97.4%), and M1 (2.6%). Most patients (70.7%) presented as early stage (I or II) which was associated with a high survival probability based on a log-rank test (p-value: 0.0007). All patients had surgical resection, mostly combined with neck dissection (ND) in11.4%, radiation (RT) in 7.8%, ND+RT in 4.7%, ND with platinum-based chemoradiation in 1.0%, and one case reported use of Crizotinib followed by Entrectinib with disease progression at 4.5 and 7 months, respectively. Among patients with reported outcomes, 92.2% were alive with a median follow-up of 26 (range 1-228) months, and 7.8% deceased with a median time-to-death of 29 (range 1-107) months. Eleven (4.3%) reported a high-grade MASC and 18.5% of patients lived for over five years after their diagnosis. Conclusions: Early stage was a notable predictor of higher survival probability in MASC patients. Its rarity, heterogeneity of clinical behaviors, and variable outcomes make it even more challenging. This review serves as real-world evidence to further our understanding of this rare entity and shed light on prospective clinical trial design.