Adenosquamous carcinoma of the lung: surgical management, pathologic characteristics, and prognostic implications

Adenosquamous carcinoma (ASC) is a mixed glandular and squamous cell carcinoma with a more aggressive behavior than the other histologic subtypes of lung cancer. We revisited the pathologic characteristics and surgical results associated with ASC.

Patients who underwent surgical resection of non-small cell lung cancer in two French centers were retrospectively reviewed. Patients presenting with ASC (n=141) were compared to those with adenocarcinomas (AC, n=2415) and squamous cell carcinomas (SCC, n=2662) regarding preoperative data, histologic characteristics, and outcome.

The frequency of ASC and SCC decreased over time. ASC patients were similar to AC patients regarding age, sex, and smoking habits. The type of resections performed in ASC patients was intermediary between SCC (more pneumonectomy) and AC (more lobectomy) patients. ASC was associated with larger size, more frequent visceral pleura invasion, microinvasion of the lymphatic vessels, and ipsilateral second nodules, compared with SCC and AC. Among the 135 patients with documented ASC, 48% presented with a combination of AC and SCC tumor cells ranging between 40% and 60% of each component, and 55% of cases were associated with undifferentiated large cells. ASC was associated with a lower 5-year survival rate (37%) than SCC and AC (43.4% and 42.8%, respectively, p=0.017). For ASC patients, survival was better during the last decade or in cases of balanced AC/SCC components.

ASC is characterized by both histologic aggressiveness and adverse prognosis. In this setting, the impact of adjuvant therapies needs to be reevaluated.