無治療早期前立腺癌症例の臨床的検討

Abstract

前立腺癌と診断され, 臨床病期T1cあるいはT2と診断され, 6ヵ月以上の無治療期間があった33例(54～87歳)を対象に, PSAの推移と, それに影響する因子, 無治療経過観察例の臨床像について検討した.PSA上昇例7例と, 非上昇例21例の2群間において, 年齢, 診断時PSA値, PSA密度, Gleasonスコア, 癌陽性コア数, 癌占拠率のいずれの因子においても両群間に有意差はみられなかった.無治療経過観察の際に, その後の病勢, PSA増加を予測しうる因子はなく, 早期前立腺癌の進展, あるいは自然史の複雑性がうかがわれた.このことから, 早期前立腺癌の無治療経過観察期間中は, PSA推移のみで病勢を判断すべきでなく, 直腸診, TRUS, MRIなどの定期的臨床検査を施行することが必要と思われた

To search for a more suitable qualification indicating watchful waiting, we performed a retrospective study against early-stage prostate cancer patients managed without initial treatment. Thirty-three patients who had not been treated for more than 6 months after diagnosed as T1c or T2 prostate cancer were studied. The median values of total observation period, age at diagnosis, and initial PSA were 27.0 months, 69.0 years old, and 7.0 ng/ml, respectively. Among 28 patients who had had measurement of serum PSA at least three times, seven patients showed a significant PSA elevation when transition of PSA level was analyzed using linear regression analysis. The other patients had been stable or PSA level declined. Between these two groups, there was no significant difference regarding age, initial PSA, PSA density, Gleason score, number of cancer-positive core, and cancer-occupying rate in biopsy specimen. The median PSA doubling time in patients showing PSA elevation was 36.3 months. There were no patients showing PSA elevation among those with a cancer-occupying rate of less than 5%. Clinical disease progression was obviously observed in two cases although one did not show PSA elevation. During the observation period, treatment was eventually started in seven patients. The 5-year rate of no treatment was 53.8%. Although a significant independent factor predicting the future treatment was not identified, univariate analysis revealed that the initial PSA value in patients undergoing treatment was significantly higher than that of those without treatment (p = 0.032). We concluded that early-stage prostate cancer has clinical variability, and regular clinical evaluations as digital rectal examination should be performed when the patient was managed with watchful waiting.