[Value of C-reactive protein determination in small cell lung cancer]

A prospective analysis of serum levels of C-reactive protein (CRP) has been conducted on a series of 39 small cell lung cancer (SCLC) patients during the first course of chemotherapy in order to evaluate the predictive value of this marker on tumoral extension at diagnosis and response to therapy. Serum levels of CRP were measured before chemotherapy (day 0) and during the first two days of treatment (day 1, day 2). Twenty-three of 32 evaluable patients (71%) had extensive disease. The mean pre-treatment CRP level was significantly higher in this group than in the group of patients with limited disease (52.3 mg/l vs 15.8 mg/l, P = 0.02). Twenty-three patients responded to treatment and nine did not. The evolution of serum CRP levels in both groups was compared between day 0 and day 2. A more than two-fold increase of initial CRP levels showed a 100% predictive value for response. On the other hand, a decrease by more than 50% of initial serum levels was associated with a negative predictive value of 75% for response. We conclude that the follow-up of CRP levels during initial chemotherapy of SCLC might be useful in the initial evaluation of tumoral extension and in the early prediction of response to therapy.