Grading of tumor regression in non-small cell lung cancer after neoadjuvant therapy

In the scope of a multi-center-study 35 resection specimens from patients with locally advanced non-small cell lung cancer after neoadjuvant chemotherapy and radiation were processed histologically and graded according to the following regression grading system: grade I: no or only slight, in general spontaneous tumor regression, grade II a: incomplete tumor regression with more than 10% and grade II b less than 10% vital tumor tissue as well as grade III: complete tumor regression. In 15 patients with grade II a to III tumor regression roughly concentric foci of various size with a sequence of central tumor necrosis, narrow foam cell rim, vascular granulation tissue and peripheral scar formation were demonstrated as characteristic feature of response to neoadjuvant therapy. In patients with grade II b to III tumor regression (''responders'') median survival time of 27.9 months was significantly longer than in patients with grade I to II a tumor regression (''non-responders'') with a median survival time of 12.7 months.