Prognostic Factor Analysis of Small Cell Lung Cancer: Appropriateness of Two Staging System / 대한암학회지

ABSTRACT

PURPOSE: The two staging system, which divides the tumors into limited disease (LD) and extensive disease (ED) has been widely accepted as a major prognostic determinant in small cell lung cancer (SCLC). However this system has provoked several controversial issues in defining stage categories, for instance, ipsilateral pleural effusion as LD or ED. Furthermore, identification of favorable subgroups in the same stage has been recognized as an important factor to determine appropriate treatment strategies. In this study, we performed a retrospective analysis in an attempt to resolve the controversial issues about staging and identify the patient group with favorable prognosis based on this two staging system. MATERIALS AND METHODS: The clinical data of 233 patients with SCLC treated from 1990 to 1996 at Korea Cancer Center Hospital were retrospectively analyzed for this study. All patients were treated with chemotherapy containing cisplatin and/or radiotherapy. The independent prognostic factors for survival were identified by multivariate analysis using Cox's proportional hazards model. RESULTS: Performance status (relative risk of death [RR]2.89), number of metastasis (RR2.2), response to treatment (RR2.2) as well as stage (RR1.77) were identified as independent prognostic factors for survival in patient with SCLC. The median survival of patients with ipsilateral pleural effusion (13 months) which was categorized as ED was similar to that of patients with contralateral mediastinal or supraclavicular lymph nodes (13.8 months) or other LD patients (13.7 months). This result suggests that ipsilateral pleural effusion should be categorized as LD. In LD, response to treatment was the only independent prognostic factor (RR2.34) and thoracic radiotherapy moderately improved survival as compared with combination chemotherapy alone (17.7 months vs. 10.4 months, p=0.06). In ED, the patient group with a good performance status (ECOG 0-1), normal range of serum alkaline phophatase, and metastasis less than 2 sites showed significantly prolonged survival, comparing with other ED patients (11.2 months vs. 7.2 months, p=0.0001). CONCLUSION: As a result of survival analysis, we confirmed independent prognostic factors such as stage and performance status in SCLC. We could recommend that LD category include patients with ipsilateral pleural effusion as well as those with contralateral lymphadenopathy. In ED, the survival in patients with favorable prognostic factors was comparable to LD, suggesting this patient group may be a candidate for aggressive therapy.