Historically, adenocarcinoma was more often seen peripherally in the lungs than SCLC and squamous-cell lung cancer, both of which tended to be more often centrally located. Recent studies, though, suggest that the "ratio of centrally to peripherally occurring" lesions may be converging toward unity for both adenocarcinoma and squamous-cell carcinoma. Squamous-cell lung carcinoma
Squamous-cell carcinoma (SCC) of the lung is more common in men than in women. It is closely correlated with a history of tobacco smoking, more so than most other types of lung cancer. According to the Nurses Health Study, the relative risk of SCC is around 5.5, both among those with a previous duration of smoking of 1 to 20 years, and those with 20 to 30 years, compared to "never smokers" (lifelong nonsmokers). The relative risk increases to about 16 with a previous smoking duration of 30 to 40 years, and roughly 22 with more than 40 years. Large-cell lung carcinoma
Large-cell lung carcinoma (LCLC) is a heterogeneous group of undifferentiated malignant neoplasms originating from transformed epithelial cells in the lung. LCLCs have typically comprised around 10% of all NSCLC in the past, although newer diagnostic techniques seem to be reducing the incidence of diagnosis of "classic" LCLC in favor of more poorly differentiated SCCs and adenocarcinomas. LCLC is, in effect, a "diagnosis of exclusion", in that the tumor cells lack light microscopic characteristics that would classify the neoplasm as a small-cell carcinoma, squamous-cell carcinoma, adenocarcinoma, or other more specific histologic type of lung cancer.
Multiple phase 3 clinical trials utilizing immunotherapy in the first line for treatment of NSCLC were published, including Pembrolizumab in KEYNOTE-024, KEYNOTE-042, KEYNOTE-189 and KEYNOTE-407; Nivolumab and Ipilimumab in CHECKMATE-227 and CHECKMATE 9LA; and Atezolizumab in IMpower110, IMpower130 and IMpower150.In 2015, the US Food and Drug Administration (FDA) approved the anti-PD-1 agent nivolumab for advanced or metastatic SCC.In 2015, FDA also approved the anti-EGFR drug necitumumab for metastatic SCC.2 October 2015, the FDA approved pembrolizumab for the treatment of metastatic NSCLC in patients whose tumors express PD-L1 and who have failed treatment with other chemotherapeutic agents.October 2016, pembrolizumab became the first immunotherapy to be used first line in the treatment of NSCLC if the cancer overexpresses PDL1 and the cancer has no mutations in EGFR or in ALK; if chemotherapy has already been administered, then pembrolizumab can be used as a second-line treatment, but if the cancer has EGFR or ALK mutations, agents targeting those mutations should be used first. Assessment of PDL1 must be conducted with a validated and approved companion diagnostic. The prognosis of patients with non-small-cell lung cancer improved significantly with the introduction of immunotherapy.