Kupelian Patrick, Kuban Deborah, Thames Howard, Levy Larry, Horwitz Eric, Martinez Alvaro, Michalski Jeff, Pisansky Thomas, Sandler Howard, Shipley William, Zelefsky Michael, Zietman Anthony
Department of Radiation Oncology, M. D. Anderson Cancer Center Orlando, Orlando, FL 32806, USA.
Int J Radiat Oncol Biol Phys. 2005 Feb 1;61(2):415-9. doi: 10.1016/j.ijrobp.2004.05.018.
To study the radiation dose-response as determined by Kaplan-Meier prostate-specific antigen (PSA) disease-free survival (PSA-DFS) estimates in patients with stage T1-T2 prostate cancer treated within a 2-year period (1994-1995).
Nine institutions combined data on 4839 patients with stage T1 and T2 adenocarcinoma of the prostate who received > or =60 Gy external beam radiation therapy (RT) as sole treatment. No patient received neoadjuvant androgen deprivation or planned adjuvant androgen deprivation. Of the 4839 patients, 1325 were treated in 1994 and 1995; 1061 were treated with <72 Gy and 264 with > or =72 Gy. The median RT doses for the <72 Gy and the > or =72 Gy groups were 68.4 Gy and 75.6 Gy, respectively. The median follow-up for the <72 Gy and the > or =72 Gy groups were 5.8 and 5.7 years, respectively. Risk groups, defined on the basis of T stage, pretherapy PSA level, and biopsy Gleason score (GS), were as follows: low risk--T1b, T1c, T2a, GS < or =6 and PSA < or =10 ng/mL; intermediate risk--T1b, T1c, T2a, GS < or =6 and PSA >10 ng/mL but < or =20 ng/mL or T2b, GS < or =6 and PSA < or =20 ng/mL or GS 7 and PSA < or =20 ng/mL; high risk--GS 8-10 or PSA >20 ng/mL. The endpoint for outcome analysis was PSA-DFS at 5 years after therapy using the American Society for Therapeutic Radiology and Oncology failure definition.
Patients receiving > or =72 Gy had significantly more advanced cancers. The proportion of stage T2b/T2c cancers in the > or =72 Gy group was 42% compared with 32% in the <72 Gy group (p = 0.027). The mean pretherapy PSA was 11.4 ng/mL in the > or =72 Gy group compared with 10.7 ng/mL in the <72 Gy group (p = 0.001). The proportion of GS > or =8 cancers in the > or =72 Gy group was 9% compared with 7% in the <72 Gy group (p = 0.309). Overall, 15% of patients receiving <72 Gy had high-risk disease, compared with 22% of patients receiving > or =72 Gy (p = 0.034). The > or =72 Gy group had a greater number of follow-up PSA levels (mean 10.6/patient) compared with the <72 Gy group (mean 9.6/patient) (p = 0.007). For all 1325 patients, the 5- and 8-year PSA-DFS estimates were 64% and 62%, respectively. The 5-year PSA-DFS estimates for <72 Gy vs. > or =72 Gy were 63% vs. 69%, respectively (p = 0.046). Multivariate analysis for factors affecting PSA-DFS was performed for all cases using the following variables: pretherapy PSA (continuous), biopsy GS (continuous), stage (T1 vs. T2), radiation dose (continuous), and radiation technique (three-dimensional conformal vs. conventional). Pretreatment PSA (p < 0.001, chi-square 112.2), GS (p < 0.001, chi-square 12.8), radiation dose (p < 0.001, chi-square 13.5), and stage (p = 0.007, chi-square 7.2) were independent predictors of outcome. Radiotherapy technique was not (p = 0.50).
Differences in PSA-DFS estimates observed in multiple retrospective series have been attributed to differences in follow-up duration between patients treated to conventional doses (longer follow-up intervals) and those treated to higher doses (shorter follow-up intervals). In this report, the median follow-up duration in the > or =72 Gy group was essentially identical to the <72 Gy group, because the study included a large number of patients treated consecutively during a narrow time range (1994-1995). With similar follow-up duration, higher than conventional radiotherapy doses were associated with improved PSA-DFS when controlled for the influence of pretreatment PSA levels, biopsy GS, and clinical T stage.
通过卡普兰 - 迈耶前列腺特异性抗原（PSA）无病生存期（PSA - DFS）评估，研究1994 - 1995年这两年间接受治疗的T1 - T2期前列腺癌患者的放射剂量反应。
9家机构汇总了4839例T1和T2期前列腺腺癌患者的数据，这些患者接受了≥60 Gy的外照射放疗（RT）作为唯一治疗。没有患者接受新辅助雄激素剥夺或计划中的辅助雄激素剥夺。在4839例患者中，1325例在1994年和1995年接受治疗；1061例接受<72 Gy的放疗，264例接受≥72 Gy的放疗。<72 Gy组和≥72 Gy组的中位放疗剂量分别为68.4 Gy和75.6 Gy。<72 Gy组和≥72 Gy组的中位随访时间分别为5.8年和5.7年。根据T分期、治疗前PSA水平和活检Gleason评分（GS）定义的风险组如下：低风险——T1b、T1c、T2a，GS≤6且PSA≤10 ng/mL；中风险——T1b、T1c、T2a，GS≤6且PSA>10 ng/mL但≤20 ng/mL或T2b，GS≤6且PSA≤20 ng/mL或GS 7且PSA≤20 ng/mL；高风险——GS 8 - 10或PSA>20 ng/mL。结局分析的终点是使用美国放射肿瘤学会失败定义，治疗后5年的PSA - DFS。
接受≥72 Gy放疗的患者癌症进展程度明显更高。≥72 Gy组中T2b/T2c期癌症的比例为42%，而<72 Gy组为32%（p = 0.027）。≥72 Gy组治疗前的平均PSA为11.4 ng/mL，<72 Gy组为10.7 ng/mL（p = 0.001）。≥72 Gy组中GS≥8的癌症比例为9%，<72 Gy组为7%（p = 0.309）。总体而言，接受<72 Gy放疗的患者中有15%患有高风险疾病，接受≥72 Gy放疗的患者中这一比例为22%（p = 0.034）。≥72 Gy组的随访PSA水平数量更多（平均每位患者10.6次），而<72 Gy组为（平均每位患者9.6次）（p = 0.007）。对于所有1325例患者，5年和8年的PSA - DFS评估分别为64%和62%。<72 Gy组与≥72 Gy组的5年PSA - DFS评估分别为63%和69%（p = 0.046）。使用以下变量对所有病例进行影响PSA - DFS因素的多变量分析：治疗前PSA（连续变量）、活检GS（连续变量）、分期（T1与T2）、放射剂量（连续变量）和放射技术（三维适形与传统）。治疗前PSA（p < 0.001，卡方值112.2）、GS（p < 0.001，卡方值12.8）、放射剂量（p < 0.001，卡方值13.5）和分期（p = 0.007，卡方值7.2）是结局的独立预测因素。放射治疗技术不是（p = 0.50）。
多个回顾性系列中观察到的PSA - DFS评估差异归因于接受传统剂量治疗的患者（随访间隔较长）和接受较高剂量治疗的患者（随访间隔较短）之间随访持续时间的差异。在本报告中，≥72 Gy组的中位随访持续时间与<72 Gy组基本相同，因为该研究纳入了大量在狭窄时间范围内（1994 - 1995年）连续接受治疗的患者。在相似的随访持续时间下，当控制治疗前PSA水平、活检GS和临床T分期的影响时，高于传统放疗剂量与改善的PSA - DFS相关。
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