Division of Medical Senology, European Institute of Oncology, Via Ripamonti 435, 20141 Milan, Italy.
Breast. 2013 Aug;22 Suppl 2:S161-4. doi: 10.1016/j.breast.2013.07.031.
There is a biological rationale for expecting benefit from longer duration therapy in the subpopulation of patients with endocrine non-responsive disease. Such tumors have a rapid cell proliferation and are associated with a high risk of relapse despite adjuvant chemotherapy. Moreover, prolonged duration of chemotherapy may be particularly relevant for patients with triple negative disease to inhibit the growth of tumors that are not susceptible to the effects of endocrine therapies due to lack of steroid hormone receptors, or to the effects of anti-HER2 target treatment.
The question of duration of adjuvant chemotherapy for breast cancer has been directly addressed in several trials herein presented. Most of these were small and, therefore, unsuitable for detecting differences of modest magnitude in intrinsic biological subtypes. In addition, a number of trials examine regimens which differ in duration of therapy, but also in the drugs given. In these trials the effects of duration and choice of drug are inextricably confounded. However incremental chemotherapy strategies, compared with less extensive therapies, were more effective in past studies particularly in patients with endocrine non-responsive disease.
The evidence resulting from past trials indicates that conventional-dose chemotherapy for 4-6 months is an adequate option in patients whose tumors present a low or no expression of steroid hormone receptors. These tumor subtypes are part of a highly heterogeneous subgroup (e.g., basal-like, molecular apocrine, claudin-low, HER-enriched). Tailored research through international cooperation is key to solidify consensus on how to treat individual patients with endocrine non-responsive breast cancer.
对于内分泌治疗无反应疾病患者亚群，从延长治疗持续时间中获益存在生物学依据。这些肿瘤具有快速的细胞增殖，并且尽管接受了辅助化疗，但仍存在较高的复发风险。此外，对于三阴性疾病患者，延长化疗持续时间可能特别重要，以抑制因缺乏甾体激素受体而对内分泌治疗不敏感的肿瘤，或因抗 HER2 靶向治疗而不敏感的肿瘤的生长。
本文介绍的几项试验直接探讨了乳腺癌辅助化疗持续时间的问题。这些试验大多规模较小，因此不适合检测内在生物学亚型中适度差异的差异。此外，一些试验检查了持续时间和治疗药物不同的方案，但这些方案中药物的持续时间和选择的药物的效果是不可分割的。然而，与范围较小的治疗方法相比，递增化疗策略在过去的研究中，特别是在内分泌治疗无反应疾病患者中，更为有效。
过去试验的结果表明，对于肿瘤表达低水平或无甾体激素受体的患者，4-6 个月的常规剂量化疗是一种可行的选择。这些肿瘤亚型是高度异质性亚组的一部分（例如，基底样、分子大汗腺、claudin-low、HER 富集）。通过国际合作进行有针对性的研究是确定如何治疗内分泌治疗无反应性乳腺癌患者的关键，以达成共识。
