Small cell lung cancer (SCLC): Intrathoracic lymph node enlargement as an indicator of prognosis

Abstract

7273 Background: Although radiologic-prognostic correlates for non-SCLC have been extensively studied in the CT era, such correlates for CT assessment of SCLC have received little attention. The purpose of the present analysis was to determine whether assessment of intrathoracic lymph node (LN) enlargement on chest CT scans would allow further stratification of prognosis beyond the classifications of limited-stage and extensive-stage disease. Methods: A retrospective review of chest CT scans was performed for 52 consecutive patients (mean age 69 years old, 32 female, 20 male) from 1998 to 2002 with histologically or cytologically proven SCLC. Three chest radiologists assessed intrathoracic LN enlargement on each CT scan. The presence or absence of extrathoracic metastatic disease and patient survival from time of diagnosis were recorded. Data analysis used the Kaplan-Meier method and multivariate Cox regression model. Results: The number of enlarged intrathoracic LN and evidence of extrathoracic metastasis were each an independent prognostic indicator (p <0.001). As expected, patients without extrathoracic metastasis (limited stage) (n=26) had longer survival than patients with extrathoracic metastasis (extensive stage) (n=26) (median survival 1.6 years versus 0.6 years, p=0.002). In patients without extrathoracic metastasis, those with 0–2 enlarged intrathoracic LN (n=13) had a significantly longer survival than those with 3 or more enlarged intrathoracic LN (n=13) (median survival 3.9 years versus 1.3 years, p=0.03). In patients with extrathoracic metastasis, those with 0–2 enlarged intrathoracic LN (n=11) also had a significantly longer survival than those with 3 or more enlarged intrathoracic LN (n=15) (median survival 1.1 years versus 0.6 years, p=0.02). The primary tumor size was not a statistically significant prognostic indicator. Conclusion: In this retrospective study, the presence and extent of intrathoracic LN enlargement, as assessed by CT scan, correlated significantly with survival in both limited and extensive disease SCLC patients. Chest CT evaluation of the number of enlarged intrathoracic LN allows stratification of prognosis in patients with SCLC. No significant financial relationships to disclose.