Flow cytometric analysis of tumor DNA profile related to response to treatment and survival in small-cell lung cancer.

Flow cytometric (FCM) analysis of tumor DNA ploidy and S-phase fraction (SPF) has been widely used to predict prognosis and treatment response in many malignant tumors, but rarely in small-cell lung cancer (SCLC). In the present study, tumor DNA ploidy and SPF were measured from paraffin-embedded tumor biopsy samples of 36 small-cell lung cancer patients treated with combination chemotherapy and radiotherapy. Aneuploidy was detected in 69% of the tumors. There was a statistically non-significant trend towards more aneuploidy among extensive disease (ED) patients as compared to patients with limited disease (LD): 80% versus 65%, respectively (p = 0.69). The mean SPF was 21.3% (+/-7.6) in patients with LD and 29.0% (+/-5.3) in patients with ED, the difference (7.6%) being statistically significant (p = 0.008, 95% CI for the difference 2.2-13.1). No significant differences was detected in the survival of aneuploid and diploid patients or patients with low (< or = 24.9%) and high (> 24.9%) SPF. Similarly, no significant difference was observed between aneuploid and diploid cases in relation to response to treatment or response duration. It is concluded that the difference detected in the SPF with LD and ED of SCLC may indicate the biological aggressiveness of extensive SCLC.