再挑战，一般指使用以前用过的方案再次治疗，是结直肠癌系统治疗中后续线治疗时的一种治疗策略。包含两个要素，一是发生在后续线治疗时；二是选用的方案在前面的“线” 中使用过，并且此方案治疗是有效的，停用的原因不是因为疾病进展，而是其他的原因非进展原因（例如：用作辅助治疗，累积毒性，治疗中断，患者偏爱），可以选择再挑战。

若以前的方案在使用过程中疾病进展，则再挑战不能选此方案。

再挑战所选方案不限于化疗方案，也包括靶向治疗（例如EGFR抑制剂）。

【1】Due to few efficacious options in later lines of therapy, there has been considerable interest in the possibility of retreating with a systemic therapy used during an earlier line of treatment. Most studies that have reported on this approach have been retrospective, detailing institutional experiences retreating with chemotherapeutics566-568 or targeted therapies (eg, EGFR inhibitors)566,569-573 and concluded that a retreatment approach was feasible, based on response and/or toxicity data. However, these studies were mainly small and did not differentiate between patients who stopped therapy due to progression compared to other reasons, limiting the quality of these data. The randomized FIRE-4 trial (NCT02934529) is currently under recruitment and will seek to address this question.

由于在后线治疗中几乎没有有效的选择，人们对用前线治疗中使用的系统治疗方案进行再治疗的可能性相当感兴趣。大多数报道这种方法的研究都是回顾性的，详细介绍了使用化疗或靶向治疗（例如 EGFR 抑制剂）进行再治疗的机构经验，并得出结论，基于反应和/或毒性数据，再治疗方法是可行的。然而，这些研究主要是小规模的，与其他原因相比，没有区分因进展而停止治疗的患者，限制了这些数据的质量。随机 FIRE-4 试验 (NCT02934529) 目前正在招募中，将寻求解决这个问题。

【2】Therefore, until stronger data become available, the panel agrees that for patients who had therapy stopped for a reason other than progression (eg, use as adjuvant therapy, cumulative toxicity, treatment break, patient preference), rechallenge with this therapy would be an option. However, based on the current lack of evidence, retreatment with a therapy following progression on that regimen is not recommended.

因此，在获得更有力的数据之前，专家组一致认为，对于因进展以外的原因（例如，用作辅助治疗、累积毒性、治疗中断、患者偏好）而停止治疗的患者，再挑战将是一种选择。然而，基于目前缺乏证据，不推荐在使用某方案进展后再次使用该方案。