Background: Therapeutic principles for managing subclinical pleural cancer found unexpectedly during intraoperative examination are unclear. We analyzed prognostic factors including the tumor proliferative marker Ki-67 in these circumstances.
Methods: The cases of 65 surgically treated patients with lung cancer and subclinical T4 pleural cancer, microscopic in 25 and macroscopic in 40, were reviewed.
Results: The overall 5-year survival rate of patients undergoing lobectomy was 14.3%. For patients with T4 NO disease, the 5-year survival rate was 46.7%. In patients with a low Ki-67 labeling index, the 5-year survival rate was 28.6%. The Ki-67 labeling index was a significant (p < 0.05) indicator of survival. Multivariate analysis demonstrated Ki-67 labeling index, lymph node involvement, and tumor differentiation to be the most influential prognostic factors for postoperative survival (p < 0.01).
Conclusions: In the treatment of lung cancer patients with subclinical pleural cancer found at thoracotomy, tumor resection is not necessarily contraindicated. Resection appears to be beneficial in patients with no nodal involvement or a low tumor Ki-67 labeling index. This index is a good therapeutic indicator for lung cancer patients.