P2.04-033 Primary Salivary Gland Tumors of the Lung: A Systematic Review and Pooled Analysis: Topic: Esophageal Cancer and Other Malignancies

Abstract

Salivary gland type neoplasms are known to occur at multiple organ sites in view of basic structural homology among exocrine glands in these anatomic sites. Primary salivary gland type tumors of lung (PSGTTL) are rare intra-thoracic malignant neoplasm. They are believed to arise from the sub-mucosal glands of the trachea-bronchial tree. Their description in literature is largely limited to a few case series/case reports. A greater awareness of PSGTTL is essential for accurate diagnosis and proper clinical management. A systematic review and pooled analysis of previously reported cases of PSGTTL is presented here. We searched the electronic database of Pubmed using key words (“lung neoplasm” [Mesh] AND “salivary gland tumors” [Mesh] to identify the papers documenting the PSGTTL. Filters (publication date from 1900/01/01 to 2015/12/31, Humans, and English) were applied to refine the search. All the articles which were single case reports or had exclusively presented one pathological type of PSGTTL were not included in the review. A pooled analysis of clinical, pathological, treatment and survival data was performed. The present systematic review included 5 studies and a total of 233 patients. Mean age of the patients was 41 years (range 6-80 years) and there was a male preponderance (1.3:1). Common pathological types were mucoepidermoid (MEC) (56.6%), adenoid cystic (ACC) (39.5%), and epithelial-myoepithelial cancer (3.8%). Tumors were located in central airways (trachea and major bronchi) in 43.3% patients. Mean tumor size was 4.2 cm. Surgery was the primary treatment undertaken in 82.4% patients while radiotherapy and chemotherapy was also used in 15.9% and 9.4% patients. Lymph node involvement was seen in 15.2% patients. Disease recurrences were observed in 21.1% patients (12.9% and 37.5% in MEC and ACC respectively). 3-year, 5-year, and 10-year weighted overall survival was 86.4%, 81.4%, and 73.6% (93.8%, 90.0% and 85.0% respectively for MEC; 76.7%, 62.8% and 50.5% respectively for ACC). Surgery is the primary treatment of PSGTTL resulting in good long-term survival. ACC histological type has a poor prognosis with more disease recurrences compared to MEC. Role of chemotherapy and radiotherapy in the management of PSGTTL warrants further studies.