Comparison of survival in nonresected well differentiated and poorly differentiated adenocarcinoma of the lung.

One hundred nineteen cases of advanced adenocarcinoma of the lung were divided into well differentiated adenocarcinoma (72 cases) and poorly differentiated adenocarcinoma (47 cases) histologically and/or cytologically. The median survival of 72 cases of well differentiated adenocarcinoma (7.9 months) was significantly (P less than 0.025) longer than that of poorly differentiated adenocarcinoma (4.9 months) irrespective of stage, difference in treatment regimen, or response to treatment. In 9 evaluable cases, the objective response rate to chemotherapy was 25% (6/24) in poorly differentiated adenocarcinoma and 11.3% (8/71) in well differentiated adenocarcinoma, respectively. In 45 patients who received a combination of chemotherapy and radiotherapy, the median survival of 22 well differentiated adenocarcinomas (11.8 months) was significantly (P less than 0.05) longer than than of 23 poorly differentiated adenocarcinomas (5.6 months). The same tendency was observed in 74 patients who received chemotherapy alone. Analysis based on the grade of differentiation is essential for the accurate assessment of the efficacy of treatment in adenocarcinomas of the lung.