Survival rates and oncologic outcomes of adeno squamous carcinoma of oral cavity: A systematic review

Background: Adenosquamous carcinoma (ASC) of the oral cavity is an uncommon and aggressive malignancy characterized by squamous and glandular histologic components. Due to its rarity, clinical behavior and oncologic outcomes remain poorly defined. Methods: A systematic literature review was conducted according to PRISMA 2020 guidelines. Comprehensive searches of Embase, PubMed, Scopus, and Cochrane Library identified studies published between 1968 and 2025. Results: Sixty-one patients were included. The most frequent subsites were tongue (43 %) and floor of mouth (31 %). Transoral surgery was performed in 93 % of cases, with neck dissection in 50 %. Adjuvant therapy was administered in 27 %. Despite 57 % presenting with early-stage disease, recurrence occurred in 42 %: local (36 %), regional (20 %), and distant (10 %). Local recurrence was significantly associated with advanced stage (p = 0.007) and subsite (p = 0.028), highest in floor of mouth (59 %) and gingiva (50 %). Perineural invasion (PNI), lymphovascular invasion (LVI), and positive margins correlated with recurrence and reduced time to recurrence (TTR), disease-specific survival (DSS), and overall survival (OS) (p < 0.001). Two-year TTR, DSS, and OS rates were 47 %, 74 %, and 70 %, respectively—lower than reported for conventional oral squamous carcinoma. Because oral ASC is rare, the evidence is primarily derived from case reports and small retrospective series. Conclusions: Oral ASC demonstrates high recurrence and poor survival, even in early-stage disease. Prognosis is strongly influenced by PNI, LVI, and margin status, as well as tumor subsite. These findings highlight oral ASC as a distinct and particularly aggressive entity.