Although DNA aneuploidy and high proliferative activity (S-phase fraction,
SPF) of tumour cells, measured by flow cytometry, have proved to be indicat
ors of poor prognosis in most solid tumours, there have been conflicting re
sults in lung cancer studies. During a four-year period we studied the prog
nostic significance of DNA ploidy and SPF in 99 surgically treated lung can
cer patients. Flow cytometric analysis was done from archival, formalin-fix
ed, paraffin-embedded tumour specimens. DNA index and SPF were determined,
using MultiCycle software with sliced nuclear correction to compensate for
debris. There were 61 DNA diploid and 38 DNA aneuploid tumours. The median
SPF was 10.2%. Neither ploidy nor SPF was associated with previously known
prognostic factors. Survival was poorer in patients with aneuploid tumours
than in the other patients, but the difference was not statistically signif
icant. DNA ploidy and SPF thus do not seem to be useful prognostic indicato
rs in surgically treated lung cancer.