Aims

Intermediate-risk prostate cancer is heterogenous. The absolute percentage of biopsied tissue positive for Gleason pattern 4 disease (APP4) is a possible prognostic measure. Here we sought to determine the impact of APP4 in a prospective multi-institutional pooled analysis of men with intermediate-risk prostate cancer treated with stereotactic body radiotherapy (SBRT).

Materials and methods

Patients with intermediate-risk prostate cancer treated with SBRT (40 Gy in five fractions or 26 Gy in two fractions) with or without androgen deprivation therapy treated on prospective clinical trials were included. Pathology reports were queried to obtain APP4, calculated as the percentage of Gleason pattern 4 disease within the tumour(s) multiplied by the percentage of total biopsied tissue positive for disease divided by 100. The optimal APP4 cut-off points for biochemical failure and distant metastasis were calculated and used as a stratification in the cumulative incidence of biochemical failure and distant metastasis. Multivariable competing risk models were developed.

Results

In tota, 227 patients were included. The median follow-up was 56.5 months. The optimal APP4 cut-off points were 5% for biochemical failure and 20% for distant metastasis. At 4 years, the cumulative incidence of biochemical failure was 23.6% and 2.3% for APP4 >5% and $\le$ 5%, respectively (P < 0.0001). The cumulative incidence of distant metastasis was 12.5% for APP4 >20% and 1% for APP4 $\le$ 20% (P = 0.02). APP4 sub-stratified favourable intermediate-risk prostate cancer and unfavourable intermediate-risk prostate cancer into groups at similarly low and similarly high risk of biochemical failure and distant metastasis. On multivariable competing risk analysis, APP4 >5% (P = 0.0004) was significantly associated with biochemical failure, but APP4 (log) was not for distant metastasis (P = 0.08).

Conclusion

APP4 may be an easily accessible promising prognostic measure for patients with intermediate-risk prostate cancer treated with SBRT. Incorporation of APP4 into prospective trials will help to determine its value.

中文翻译：

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4 型疾病的绝对百分比作为立体定向放射治疗中危前列腺癌的预后指标

目标

中危前列腺癌是异质的。Gleason 4 型疾病 (APP4) 阳性活检组织的绝对百分比是一种可能的预后指标。在这里，我们试图确定 APP4 在对接受立体定向放射治疗 (SBRT) 治疗的中危前列腺癌男性的前瞻性多机构汇总分析中的影响。

材料和方法

纳入前瞻性临床试验中接受或不接受雄激素剥夺治疗的 SBRT（5 次 40 Gy 或 2 次 26 Gy）治疗的中危前列腺癌患者。查询病理学报告以获得 APP4，计算方法为肿瘤内 Gleason 模式 4 疾病的百分比乘以疾病阳性活检组织的百分比除以 100。生化失败和远处的最佳 APP4 截止点计算转移并用作生化失败和远处转移的累积发生率的分层。开发了多变量竞争风险模型。

结果

共纳入 227 名患者。中位随访时间为 56.5 个月。最佳的 APP4 截止点是生化失败的 5% 和远处转移的 20%。4 年时，生化失败的累积发生率分别为 23.6% 和 2.3%，APP4 >5% 和$\le$分别为 5% ( P < 0.0001)。APP4>20% 远处转移的累积发生率为 12.5%，APP4 为 1%$\le$20% ( P = 0.02)。APP4 将有利的中危前列腺癌和不利的中危前列腺癌细分为生化失败和远处转移风险相似的低和相似高的组。在多变量竞争风险分析中，APP4 >5%（P = 0.0004）与生化失败显着相关，但APP4（log）与远处转移无关（P = 0.08）。

结论

对于接受 SBRT 治疗的中危前列腺癌患者，APP4 可能是一种容易获得的有前途的预后指标。将 APP4 纳入前瞻性试验将有助于确定其价值。