前立腺癌におけるFlow cytometric DNA analysisの臨床的有用性

Abstract

予後の明らかな前立腺癌患者54例を対象として, 経尿道的前立腺切除術によってえられた組織のパラフィン包埋切片を用いてFCM-DNA分析を行い, 組織型, 病期と比較しながら, FCM-DNA分析の臨床的有用性について検討した.1) ploidy分類と組織学的分類の間には有意な関連性はみられなかったが, 組織学的分化度が低い程aneuploidが増える傾向があった.2) ploidy分類と病期分類の間にも有意な関連性はみられなかったが, 病期が進行する程aneuploidが増える傾向があった.3)生存曲線についてみると, 組織学的分類, 病期分類よりも, ploidy分類の方が生命予後とよく相関している傾向があった.4) near diploid patternと判定された症例は全例5年以上生存しており, aneuploidと判定された症例は全例3年6ヵ月以内に死亡していた.tetraploidと判定された症例はproliferation index (P.I.)が65以下で病期がC以下であれば生命予後は良好であった

Flow cytometry was used to measure the DNA content in archival paraffin-embedded prostatic cancer specimens from 54 patients with known outcomes. The specimens were obtained by transurethral resection of the prostate. DNA ploidy as a predictor of prognosis was compared with histological grade and clinical stage. Although no significant correlation between histological grade or clinical stage and ploidy pattern was demonstrated, an increased percentage of DNA aneuploid tumors was seen in higher histological grade and in advanced clinical stage. The survival rate calculated by Kaplan-Meier analysis showed that DNA ploidy pattern was a more reliable indicator to predict survival probability than histological grade or clinical stage. All patients with a near diploid pattern (11 patients) survived more than 5 years, whereas all those with an aneuploid pattern (21 patients) died within 3.5 years. Of 22 patients with a tetraploid pattern, 15 died of tumor progression within 5 years. The remaining 7 patients with favorable outcome had a relatively lower proliferation index (less than 65) in DNA histogram and none of them suffered from stage D disease. In conclusion, the results from this retrospective study suggest that flow cytometric DNA analysis in prostatic cancer would be useful as a means of providing prognostic information.