Introduction

The International Duration Evaluation of Adjuvant Therapy (IDEA) collaboration in 2017 established 3 months of adjuvant therapy as an alternative to 6 months of therapy for stage III colon cancer. We determined the association between the IDEA publication, changes in clinical practice, and prescriber variation.

Patients and Methods

Using linked databases, we identified Ontarians aged ≥18 years at diagnosis of stage III colon cancer between 2007 and 2019 who received oxaliplatin-containing adjuvant therapy. The outcome was duration of therapy, categorized as ≤25%, >25% to ≤50%, >50% to ≤75%, and >75% of a 6-month course of therapy to approximate treatment durations in the IDEA collaboration. We examined trends in duration over time using an interrupted time series regression model. We analyzed treatment duration after accounting for patient and prescriber characteristics, using multivariable mixed effects logistic regression models to quantify between-prescriber variation.

Results

We included 4695 patients with stage III colon cancer who received oxaliplatin-containing adjuvant chemotherapy, of whom 77.5% initiated treatment pre-IDEA and 22.5% initiated treatment post-IDEA. Post-IDEA, there was a 16.4% (95% CI, 12.5%-20.3%) absolute increase in the proportion of patients treated with ≤50% of a maximal course of therapy. This trend was greatest among patients with low-risk tumors. Prescriber variation increased pre-IDEA to 15.6% post-IDEA (variance partition coefficient 5.4% pre-IDEA and 15.6% post-IDEA).

Conclusion

The publication of IDEA was associated with increases in short duration adjuvant therapy and prescriber-level practice variation for stage III colon cancer. Clinicians should be better supported to make consistent recommendations about adjuvant duration under conditions of uncertainty and trade-offs.

中文翻译：

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2007 年至 2019 年 III 期结肠癌含奥沙利铂辅助化疗持续时间的趋势和处方者变化：一项基于人群的回顾性队列研究

介绍

2017 年国际辅助治疗持续时间评估 (IDEA) 合作确定了 3 个月的辅助治疗作为 III 期结肠癌 6 个月治疗的替代方案。我们确定了 IDEA 出版物、临床实践的变化和处方者变化之间的关联。

患者和方法

使用链接数据库，我们确定了 2007 年至 2019 年间诊断为 III 期结肠癌时年龄≥18 岁且接受含奥沙利铂辅助治疗的安大略人。结果是治疗持续时间，分为 6 个月疗程的 ≤25%、>25% 至 ≤50%、>50% 至 ≤75% 和 >75%，以近似 IDEA 合作中的治疗持续时间。我们使用中断时间序列回归模型检查了持续时间随时间的趋势。我们在考虑患者和处方者特征后分析了治疗持续时间，使用多变量混合效应逻辑回归模型来量化处方者之间的差异。

结果

我们纳入了 4695 名接受含奥沙利铂辅助化疗的 III 期结肠癌患者，其中 77.5% 在 IDEA 前开始治疗，22.5% 在 IDEA 后开始治疗。IDEA 后，接受最大疗程≤50% 治疗的患者比例绝对增加了 16.4%（95% CI，12.5%-20.3%）。这种趋势在低风险肿瘤患者中最为明显。IDEA 前处方者变异增加至 IDEA 后 15.6%（IDEA 前变异分配系数为 5.4%，IDEA 后为 15.6%）。

结论

IDEA 的发布与 III 期结肠癌短期辅助治疗和处方者水平实践变化的增加有关。应更好地支持临床医生在不确定和权衡的情况下就辅助治疗持续时间提出一致的建议。