Cytogenetic effects of multiagent chemotherapy on the peripheral lymphocytes of patients with small cell lung cancer.

Peripheral lymphocytes of 8 patients with small cell lung cancer (SCLC), who received combination chemotherapy consisting of cisplatin and VP-16 (PVP), were examined for frequency of sister chromatid exchange (SCE) and chromosomal aberrations. Three of the 8 patients were treated with the PVP regimen only; however, the others had previously been treated with multiagent chemotherapy consisting of a cyclophosphamide, adriamycin, and vincristine (CAV) regimen or a cyclophosphamide, ACNU and vincristine (CAV') regimen with or without radiotherapy. Significantly increased SCE frequency was observed in previously untreated patients 3 or 4 days after PVP treatment, compared with the pretreatment values. The earlier analysis in the previously treated patients also showed increased SCE frequency, which seemed to return to the normal value as time elapsed after PVP. In addition, abnormal chromosome count distribution and/or increased incidence of structural changes were observed in cultures from all the patients. In general, striking changes in chromosomes were observed in previously treated patients. The aberrations observed in pretreated patients consisted of chromatid gaps and breaks, exchanges, fragments and dicentric chromosomes. In addition to these abnormalities, double minutes like microchromosomes were seen irrespective of radiotherapy. Further studies are needed to elucidate whether any of the chromosomal aberrations observed in this study could participate in the induction of secondary neoplasms.