In the new 8th TNM classification, stage III non-small cell lung cancer (NSCLC) is divided into three subgroups. Stage IIIA includes T4 N0 M0 and T3/4 N1 M0 tumours as well as T1/T2 N2 M0 tumours. Stage IIIB tumours are either T3/T4 N2 M0 or T1/T2 N3 M0. Stage IIIC involves T3/T4 N3 M0 tumours. Beside new IIIC stage, the greatest change is reclassification of T category based on dimension. Tumours larger than 7 cm that were previously T3 are now staged T4. The anatomic extent of disease is the base of the TNM classification with impact on survival. The aim of this analysis was to determine applicability of the new 8th TNM edition on survival of stage III NSCLC treated with combined radiochemotherapy between 2005 and 2010 in our institution.
A total of 101 patient with stage III NSCLC treated between September 2005 and November 2010 with induction chemotherapy and radiochemotherapy were included in long term survival analysis of TNM restaging. Results of survival are presented for the 7th and 8th edition in view of the revised T stage.
After a median follow up of 117.5 months, median overall survival (mOS) of stage IIIA patients according to the 7th TNM classification was significantly longer than those of stage IIIB patients (30.8 months and 19.0 months, p = 0.005). Redefinition of the stages according to the new 8th TNM classification showed similar mOS for patients in stage IIIA and stage IIIB (21.6 months and 24.9 months), but much shorter mOS for stage IIIC patients with 6.6 months (p = 0.885). Of 101 patient 13 were up-graded from T3 to T4 according to new TNM classification. In the 7th TNM classification T3N2 was in stage IIIA and T4N2 in stage IIIB, while in 8th TNM classification both are in stage IIIB. According to 7th TNM classification, mOS of patients in stage T3N2 was significantly longer with 60.0 months than in stage T4N2 with 19.2 months (p = 0.004). After the revision there is no difference, mOS of patients with T3N2 was 28.4 months and with T4N2 was 31.4 months (p = 0.478).
The statistical difference in survival between subgroups of stage III shown in the old TNM classification did not appear in the new classification. Other factors could affect prognosis that are patient, tumour and treatment related.
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