Clinicopathological features of small-sized peripheral squamous cell lung cancer.

Recent advances in imaging technology have enhanced the detection rate of small-sized peripheral lung cancers. The present study aimed to identify the clinicopathological differences between patients with small-sized peripheral squamous cell carcinoma (SCC) and adenocarcinoma (ADC). Patients with lung cancer who underwent radical surgical resection at Gunma University Hospital between July 2007 and October 2012 were retrospectively analyzed. Patients who exhibited small-sized peripheral tumors (pathological size, ≤2 cm) located within the outer-third of the lung field on preoperative computed tomography were enrolled in the present study. A total of 26 patients were diagnosed with SCC and 214 with ADC. The results revealed that patients with SCC exhibited higher rates of pleural invasion, vascular invasion and lymphatic invasion compared with ADC patients. Additionally, the rate of postoperative recurrence was higher in patients with SCC compared with ADC patients. Patients with ADC were subsequently into two groups: Solid ADCs (sADC) and non-solid ADCs (nsADC), which included pure ground glass nodules and part-solid ADCs. The results revealed that the incidence of pleural invasion, vascular invasion and lymphatic invasion, and the rate of postoperative recurrence in patients with sADCs were similar to those with SCC, but were also significantly higher when compared with nsADC patients. The present study concluded that patients with SCC and sADC may not be suitable candidates for sublobar resection, despite exhibiting small tumors that are located in the peripheral lung.