Critz F A, Levinson A K, Williams W H, Holladay C T, Griffin V D, Holladay D A
Radiotherapy Clinics of Georgia, Decatur, USA.
J Urol. 1999 Apr;161(4):1199-203; discussion 1203-5.
The role of prostate specific antigen (PSA) nadir in the definition of disease freedom after radiotherapy of prostate cancer is controversial. We evaluate post-irradiation PSA nadir in men apparently cured of this disease.
From 1984 to 1993, 354 men with clinical stage T1T2N0 prostate cancer were treated with radioactive 125iodine prostate implant followed by external beam radiation. Median pretreatment PSA was 8.4 ng/ml (range 0.3 to 188). Of these men 250 are disease-free and median pretreatment PSA was 6.5 ng/ml (range 0.3 to 123). Treatment failure is defined as 3 consecutive PSA increases above nadir. Median followup is 7 years (range 5 to 14 years) for the 250 disease-free men and 6 years (range 0.5 to 14) for all 354 men.
PSA nadir 0.5 ng/ml or less was achieved by 98% of all disease-free men (244 of 250) with minimum 5-year followup, including 87% (217) who achieved nadir 0.2 ng/ml or less. All 27 disease-free men with minimum 10-year followup had a PSA nadir of 0.5 ng/ml or less. PSA nadir significantly correlated with disease-free survival by receiver operator characteristics curve analysis (0.93 area under the curve) in all 354 men.
PSA nadir is the fundamental measurement that determines possible cure after radiotherapy. Except for perhaps rare occasions, men must at least achieve a nadir of 0.5 ng/ml. or less to be cured of prostate cancer by irradiation. However, the prognostic value of this nadir level depends on most men achieving a nadir of 0.2 ng/ml or less. Disease freedom for radiotherapy, defined as achievement and maintenance of PSA nadir 0.5 ng/ml or less, is reasonable.
前列腺特异性抗原（PSA）最低点在前列腺癌放疗后疾病无进展定义中的作用存在争议。我们评估了表面上已治愈该疾病的男性患者放疗后的PSA最低点。
1984年至1993年，354例临床分期为T1T2N0的前列腺癌男性患者接受了放射性125碘前列腺植入，随后进行外照射。治疗前PSA中位数为8.4 ng/ml（范围0.3至188）。这些患者中250例疾病无进展，治疗前PSA中位数为6.5 ng/ml（范围0.3至123）。治疗失败定义为PSA连续3次升高超过最低点。250例疾病无进展患者的中位随访时间为7年（范围5至14年），354例所有患者的中位随访时间为6年（范围0.5至14年）。
所有疾病无进展患者（250例中的244例）中有98%在至少5年的随访后PSA最低点达到0.5 ng/ml或更低，其中87%（217例）最低点达到0.2 ng/ml或更低。所有27例至少随访10年的疾病无进展患者PSA最低点均为0.5 ng/ml或更低。通过接受者操作特征曲线分析，在所有354例患者中，PSA最低点与疾病无进展生存期显著相关（曲线下面积为0.93）。
PSA最低点是放疗后确定可能治愈的基本指标。除了可能的罕见情况外，男性患者要通过放疗治愈前列腺癌，PSA最低点必须至少达到0.5 ng/ml或更低。然而，这个最低点水平的预后价值取决于大多数男性患者最低点达到0.2 ng/ml或更低。将放疗后的疾病无进展定义为PSA最低点达到并维持在0.5 ng/ml或更低是合理的。
