Study objective: To assess the outcome of lung cancer with invasion beyond interlobar pleura and to clarify whether it should be treated in the same way as invasion to the parietal pleura or to other visceral pleura. Design: Retrospective analysis. Setting: Tokyo Medical College Hospital. Patients: Eighteen resected non-small cell lung cancers with invasion beyond interlobar pleura were studied. The outcomes of those patients, those with parietal pleural invasion, and those with other visceral pleural invasion were compared. Patients with rib invasion, mediastinal organ invasion, or distant metastasis were excluded. Results: The 5-year survival rate for patients with invasion beyond interlobar pleura was 34.2% and the median survival time was 56.5 months. The outcome was significantly better than that of patients with parietal pleural invasion. There was no significant difference between the outcome of invasion beyond interlobar pleura and that of other visceral pleural invasion. In patients without lymph node metastasis, similar results were obtained. There was no difference between the outcome of patients with invasion beyond interlobar pleura, who undergo lobectomy with a parietal resection of the invaded lobe, and that of patients with visceral pleural invasion, who undergo lobectomy, Conclusions: The behavior of patients with invasion beyond interlobar pleura is different from that of patients with parietal pleural invasion and should be categorized as T2, The optimum operative method was lobectomy with only parietal resection of the invaded lobe to preserve the pulmonary function.
