Clinical significance of tumor necrosis and viability in non-small cell lung cancer

Background: We included tumor necrosis (TN) and tumor viability (TV) in our prognostic assessment of patients with non-small cell lung cancer (NSCLC) and investigated their clinical significance. Methods: Medical records of all consecutive subjects who underwent a lobectomy with standard mediastinal lymph node dissection for NSCLC between 2015 to 2016, were reviewed retrospectively. We analyzed the associations of TN and TV with various parameters associated with prognosis as well as survival in NSCLC patients. All analyses were performed regarding neoadjuvant therapy status [the group without neoadjuvant therapy (WON) vs. the group with neoadjuvant therapy (WN)]. Results: A consecutive 154 patients (mean age: 65.0 +/- 10.1 years) were included into the present study. Fifteen patients underwent neoadjuvant therapy. Final pathologic stages were IA1 (n=13), IA2 (n=30), IA3 (n=32), IB (n=40), IIA (n=9), IIB (n=18), and IIIA (n=12). WN significantly showed higher TN (P=0.005) and lower TV (P<0.001) than WON. Tumors with vascular, lymphatic, and perineural invasion showed significantly lower TV and higher TN than cases without these features (P=0.014, P=0.019, and P=0.012 for TV; P=0.001, P<0.001, and P<0.001 for TN, respectively). Tumors with poorer differentiation had lower TV (P<0.001) and higher TN (P<0.001) than more differentiated tumors. There was a positive correlation between TN and tumor size (P<0.001) and a negative correlation between TV and tumor size (P=0.031). TN significantly increased as pathologic stage increased (P=0.001), and TV significantly decreased as pathologic stage increased (P=0.038). The group without TN survived significantly longer than the group with TN (P=0.016) in N0 disease and presence of TN and pT stage were independent prognostic factors for survival in N0 disease (P=0.037 and P=0.021, respectively). There was a positive correlation between TN and Ki-67 level (P=0.027). In WN, TN was significantly associated with differentiation (P=0.035), tumor size (P=0.008), and pT stage (P=0.031) but not overall pathologic stage or survival. Conclusions: Presence of histological TN was associated with prognosis of NSCLC, especially in N0 disease, and its usage as a diagnostic or prognostic tool and determination of resection extent could potentially provide prognostic information that can facilitate better management of NSCLC.