Prognostic Significance of Flow Cytometric Nuclear DNA Content and S-phase Fraction in Non-small Cell Lung Cancer

Kang, Suck Min; Kim, Joo Hang; Kim, Sung Kyu; Lee, Won Young; Jung, Kyong Young; Lee, Yi Hyeong

Abstract

OBJECTIVES
In surgically treated non-small cell lung cancer, patients have a wide difference in prognosis even though they may be in the same stage. Therefore it is difficult to establish the prognosis for individual lung cancer patients. In this study, by using flow cytometric analysis of nuclear DNA content and S-phase fraction(SPF) of surgically treated non-small cell lung cancer patients, we proposed to establish other prognostic factors and their validity in comparison with the existing ones.
METHODS
Paraffin-embedded tissue specimens from 81 surgically treated patients, diagnosed with non-small cell lung cancer ranging from stage I to stage IIIa, were analyzed by flow cytometrically determined nulear DNA content and S-phase fraction. Cellular DNA content stained with propidium iodide was analyzed by flow cytometry: histograms with a coefficient of variation exceeding 8% were not used.
RESULTS
1) DNA content analysis was carried out for 59 of 81 patients. Of the 59 patients who were investigated by flow cytometry, 45 (76.3%) of the tumors were DNA aneuploidy and 14 (23.7%) were DNA diploidy. The proportion of DNA aneuploidy tumors showed no significant difference between cell types or stage. 2) S-phase fraction was evaluated for 36 of 81 patients. Mean value of SPF was 19.2% (+/-12.62)%. The value of SPF had nothing to do with stage. 3) The proportion of the high SPF group (more than 10% of cell proliferation cycle) was 75% With advance staging, the proportion of the high SPF group increased. 4) Significant difference in the median survival time was observed between the low SPF group and the high SPF group (32 months in low SPF, 12 months in high SPF) (p<0.05). No significant difference in the median survival time was observed between the aneuploidy group and the diploidy group (19 months in aneuploidy, 34 months in diploidy). 5) Significant difference in the disease free median survival time was observed between the low SPF group and the high SPF group (5 months in low SPF, 19 months in high SPF) (p<0.05). No significant difference in the disease free median survival time was observed between the aneuploidy group and the diploidy group (12 months in aneuploidy, 34 months in diploidy). 6) Upon multivariate analysis, stage and high SPF (more than 10% of cell proliferation cycle) were significant prognostic factors in surgically treated non-small cell lung cancer patients.
CONCLUSION
The TNM stage and high SPF were significant as prognostic factors in surgically treated non-small cell lung cancer patients. Therefore new treatment plan should be needed in the patients who have high SPF.