Multifocal T4 non-small cell lung cancer: a subset with improved prognosis.

Objective: T4-disease for non-small cell lung cancer (NSCLC) includes different conditions: mediastinal invasion, neoplastic pleural cytology, and multifocal disease in the same lobe; regarding the last category, no strict criteria allow to differentiate satellite nodules from synchronous multiple primary tumours.

Methods: Retrospective study of 56 patients who underwent a complete resection from 1985 to 2006 of a NSCLC graded pT4N0 due to multifocal disease. A small nodule (<1cm) closed to the primary tumour, in a same pulmonary segment with an identical histology was considered as a satellite nodule (pT4sn). Multiple tumours, sized more than 1cm, with an identical histology, located in the same lobe but in different segment were considered as synchronous cancers (pT4sc).

Results: There were 44 males and 12 females: 35 patients were graded T4sn and 21 patients T4sc. The median age was 62.5 years. The two groups were similar for sex, age, tobacco consumption, ASA score, NYHA, Charlson's index, spirometric parameters, cardiovascular comorbidity and history of previous extra-thoracic malignancies. All had a complete anatomic resection with mediastinal lymphadenectomy. Thirty-day mortality rate was 3.6%. Overall 5-year and 10-year survival rates were 48.2% and 29.9%, respectively. There was a non-significant trend for a worse survival in T4sn group patients when compared to that of T4sc group patients: 42.9% vs 52.3% at 5 years, and 25% vs 34.9% at 10 years (p=0.62).

Conclusions: Multifocal T4 stage IIIB disease is a heterogeneous category where overall prognosis is far better than those of other T4 subgroups. Survival rates associated with pT4sn and pT4sc look roughly similar because of the small size of the subgroups usually submitted to comparison in most series. In the present experience, respective survival figures diverge, suggesting different biological behaviours.