Age and bromodeoxyuridine labelling index as prognostic factors in high-grade gliomas treated with surgery and radiotherapy

Aims: To determine the prognostic value of proliferative potential and DNA ploidy in 72 brain tumours (36 grade III and 36 grade IV astrocytomas) using bromodeoxyuridine (BrdUrd) incorporation and flow cytometry. Material and methods: All 72 patients underwent excision, mostly incomplete of the tumour. After surgery, eight patients received conventionally fractionated radiotherapy, 11 patients received accelerated radiotherapy, and 53 patients received hypofractionated radiotherapy. Tumour samples taken during surgery from each patient were incubated in vitro for 1 h at 37 degrees C with BrdUrd using the high pressure oxygen method. The percentage of BrdUrd-labelled cells (BrdUrd labelling index [BrdUrd LI]), and the total DNA content were evaluated. Results: The tumours showed variability in the BrdUrd LI values, which ranged from 0.3 to 19.1%. No difference was observed in mean BrdUrd LI between grade III and grade IV sub-groups. A significantly higher percentage of DNA aneuploidy was observed in grade III gliomas (69.4%) than in grade IV gliomas (52.8%). Univariate analysis showed that younger patients (<= 51 years) (P = 0.021) with grade III gliomas (P = 0.030) and low tumour proliferation rate (BrdUrd LI <= 2.7%, P = 0.028) had significantly higher 5-year survival rates. Tumour ploidy had no influence on patients' survival (P = 0.591). However, Cox multi-variate analysis showed that only age over 51 years, and high tumour proliferation rate (BrdUrd LI > 2.7%), were significant unfavourable prognostic factors in patient survival. Conclusion: In this study, independent prognostic factors for patients with high-grade gliomas treated with surgery and post-operative radiotherapy are age and tumour proliferation rate assessed according to the BrdUrd LI.