“…In a combined series of 4,953 patients with primary bronchial carcinoma, positive mediastinal biopsies were obtained in 39% of cases (Jepson and Rahbek, 1970). In more recent series, 2848% of presumably operable patients have yielded positive mediastinal biopsies (Ashraf et al, 1980;Fishman and Bronstein, 1975;Gibbons, 1972;Kirschner, 1971;Larsson, 1976;Otto, Zaslonska and Lukianski, 1972), this proportion representing 80-90%7o (sensitivity) of all patients found to have mediastinal disease at thoracotomy (Jepson and Rahbek, 1970;Larsson, 1976;Pearson, 1968;Pearson et al, 1972). Positive findings, as denoted by the presence ofpathologically identifiable tumour in mediastinal biopsies, provide a highly specific diagnosis and for practical purposes the specificity of mediastinoscopy can be assumed to be 100%.…”