Primary lung signet-ring cell carcinoma: a national analysis

Background: Primary lung signet-ring cell carcinoma (LSRCC) is a rare form of aggressive lung cancer whose clinical features remain inadequately discerned. The objective of this study was to evaluate the clinicopathological characteristics and independent prognostic factors of primary LSRCC. Methods: Overall survival (OS) of patients with LSRCC, lung adenocarcinoma (LAC), and lung mucinous adenocarcinoma (LMAC) in the National Cancer Database from 2004 to 2018 was evaluated using KaplanMeier and multivariable Cox proportional hazards modeling. Independent prognostic indicators for patients with LSRCC were determined using multivariable Cox proportional hazards analysis. Results: A total of 1,705 LSRCC, 504,006 LAC, and 15,883 LMAC patients were included in our analysis. LSRCC histology was significantly associated with younger age, male sex, larger and more poorly differentiated tumors, later American Joint Committee on Cancer (AJCC) stage disease, higher clinical T, N, and M status, more use of chemotherapy, and less use of surgery when compared to LAC and LMAC patients. In unadjusted analysis, patients with LSRCC had significantly worse OS when compared to patients with LAC and LMAC. In multivariable analysis, patients with LSRCC experienced significantly worse OS when compared to only patients with LAC. Independent predictors of survival for patients with LSRCC were younger age, later year of diagnosis, lower Charlson/Deyo comorbidity condition scores, lower AJCC stage, higher income, smaller tumors, treatment with surgery, and receipt of chemotherapy. Conclusions: In this national analysis, LSRCC was found to be associated with distinct clinicopathological characteristics from those of LAC.