Examining time intervals between diagnosis and treatment in the management of patients with limited stage small cell lung cancer

Abstract

Objective: To examine time intervals between diagnosis and treatment of limited stage small cell lung cancer (L-SCLC) and to evaluate its effect on clinical outcomes.

Materials and methods: Data on 166 patients with L-SCLC referred to a regional cancer center between January 1991 and December 1999 were analyzed. The time intervals studied were defined as: interval A, first abnormal chest x-ray to pathologic diagnosis: interval B, diagnosis to first oncology consultation; interval C, oncology consultation to first day of thoracic radiotherapy (RT); interval D, oncology consultation to first day of chemotherapy; and interval E, first day of chemo to first day of RT. Cox proportional hazards models were used to examine associations between the time intervals and thoracic relapse (TR) and overall survival (OS) outcomes. Logistic regression analysis was used to model associations between time and complete response (CR) rates.

Results: The median time duration of intervals A to E were 20, 12, 63.5, 15, and 48 days, respectively. When time was analyzed as a continuous variable, no statistically significant association between the interval lengths and outcomes studied was observed. Dichotomizing each interval using the median value as cut-off revealed that interval A >20 days was significantly associated with improved CR (odds ratio = 3.573; P = 0.027) whereas interval B >12 days was associated with a trend toward lower CR (odds ratio = 0.348; P = 0.073).

Conclusions: Short median times from first abnormal chest x-ray to diagnosis and from diagnosis to oncology consultation indicate that L-SCLC patients were diagnosed and referred promptly in the community setting. OS and TR appeared independent of the time intervals analyzed. Individual variations in disease presentation and tumor biology may explain the observed associations between early pathologic diagnosis and inferior CR rates.