A better survival outcome is associated with low blood levels of squamous cell carcinoma antigen, or absence of tumor invasion either into the space between the lungs and chest wall or into blood vessels of individuals with a peripheral squamous cell carcinoma, a type of non-small cell lung cancer (NSCLC).

Lung cancer is the most common cause of cancer-related death worldwide and lung squamous cell carcinomas (SCC) account for 20-30% of all NSCLC. SCC can be classified as either central (c-SCC) or peripheral (p-SCC) depending on the primary location. While c-SCC is the most prevalent, the incidence of p-SCC is increasing and the clinical and biological behaviors of p-SCC remain unclear.

Researchers from Keio University School of Medicine and Saiseikai Utsunomiya Hospital in Japan evaluated several clinical and pathological variables in 280 patients with surgically removed p-SCC in order to identify potential prognostic factors.

Results published in the Journal of Thoracic Oncology, the official journal of the International Association for the Study of Lung Cancer (IASLC), show that low preoperative levels of squamous cell carcinoma antigen in the serum or either absence of tumor invasion into the pleura (the space between the lungs and chest wall) or tumor vasculature are independent prognostic factors for patients with any stage of p-SCC. These patients had an extended period without disease recurrence and longer overall survival. The same was also seen for the sub-group of patients with early stage I disease.

The authors note that "our study revealed that p-SCCs with pleural or vascular invasion or high serum SCC antigen are more likely to recur than those without it; even in stage I patients. Pleural and/or vascular invasion are thought to be essential steps in the progression and metastasis of p-SCCs and high serum SCC antigen may suggest micro-metastases at the time of surgery." The authors propose that "patients with high serum SCC levels, vascular invasion or pleural invasion should have their tumor stage upgraded in order to reflect the clear differences in survival. Clinical trials should be performed to evaluate if postoperative chemotherapy would benefit these patients who typically may not receive chemotherapy because of their early stage."