THE RELIABILITY OF PRESURGICAL PATHOLOGIC AL DIAGNOSIS IN PRIMARY BRONCHOGENIC-CARCINOMA

BACKGROUND: The specific cell type in primary lung cancer (LC) has imp ortant consequences, both for treatment and prognosis. Our objective h as been to evaluate the degree of accuracy of several preoperative tec hniques in the LC diagnosis. PATIENTS AND METHODS: We have studied 442 diagnostic techniques realized in 360 patients who underwent thoracot omy for LC in our hospital (1988-1994). Twelve sputum cytologies, 93 t ransthoracic neddle biopsies (TNB), 73 bronchial aspirated cytologies, 30 bronchial brushing, 205 bronchial biopsies (BB) and 29 transbronch ial biopsies were included. In each case the cellular type of LC, obta ined through these techniques, was compared with the result derived fr om the study of surgical piece (reference diagnosis). To calculate the degree of concordance between both diagnoses we used the Kappa coeffi cient (K). RESULTS: The overall concordance between the cellular type observed in the different preoperative techniques and the definitive r esult obtained by thoracotomy was 0.61. The worst test was TNB (K = 0. 41). Sputum cytology and BB presented a good histopathological precisi on (K = 0.75 and 0.70 respectivelly). The rest of techniques showed mo derate results. On the different histologies, the best result was obta ined in squamous carcinoma (K = 0.68) and the worst in undifferentiate d large cell carcinoma (LCC) (K = 0.39). Small-cell lung cancer only s howed a moderate concordance (K = 0.58). The coexistence and coinciden ce of two or more tests with the same cellular type were associated wi th a higher proportion of accuracy (0.97 vs 0.73; p = 0.00002; odds ra tio: 12.02). CONCLUSIONS: The preoperative histopathological diagnoses should be interpreted with caution, especially those obtained by TNB and those where it is implied the LCC. In these two circunstances and in cases in which the knowledge of the cellular type have relevance, w e think that the initial diagnosis should be reinforced with a second result. The precision of the preoperative diagnoses in small-cell lung cancer must be reevaluated.