Background The aim of the study was to evaluate the independent prognostic role of PIK3CA activating mutations and an association between PIK3CA activating mutations and efficacy of adjuvant endocrine therapy (ET) in patients with operable invasive lobular carcinoma (ILC). Patients and methods A single institution study of patients with early-stage ILC treated between 2003 and 2008 was performed. Clinicopathological parameters, systemic therapy exposure and outcomes (distant metastasis-free survival [DMFS] and overall survival [OS]) were collected based on presence or absence of PIK3CA activating mutation in the primary tumor determined using a quantitative polymerase chain reaction (PCR)-based assay. An association between PIK3CA mutation status and prognosis in all patient cohort was analyzed by Kaplan-Meier survival analysis, whereas an association between PIK3CA mutation and ET was analyzed in estrogen receptors (ER) and/or progesterone receptors (PR)-positive group of our patients by the Cox proportional hazards model. Results Median age at diagnosis of all patients was 62.8 years and median follow-up time was 10.8 years. Among 365 patients, PIK3CA activating mutations were identified in 45%. PIK3CA activating mutations were not associated with differential DMFS and OS (p = 0.36 and p = 0.42, respectively). In patients with PIK3CA mutation each year of tamoxifen (TAM) or aromatase inhibitor (AI) decreased the risk of death by 27% and 21% in comparison to no ET, respectively. The type and duration of ET did not have significant impact on DMFS, however longer duration of ET had a favourable impact on OS. Conclusions PIK3CA activating mutations are not associated with an impact on DMFS and OS in early-stage ILC. Patients with PIK3CA mutation had a statistically significantly decreased risk of death irrespective of whether they received TAM or an AI.

中文翻译：

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PIK3CA激活突变与接受辅助全身治疗的早期浸润性小叶乳腺癌的结局之间的关联

背景 本研究的目的是评估以下因素的独立预后作用：PIK3CA激活突变和之间的关联PIK3CA可手术的浸润性小叶癌（ILC）患者的激活突变和辅助内分泌治疗（ET）的疗效。患者和方法 对 2003 年至 2008 年间接受治疗的早期 ILC 患者进行了一项单一机构研究。根据使用定量聚合酶链式反应 (PCR) 确定的原发肿瘤中是否存在 PIK3CA 激活突变，收集临床病理学参数、全身治疗暴露和结果（无远处转移生存期 [DMFS] 和总生存期 [OS]）。为基础的测定。通过 Kaplan-Meier 生存分析分析了所有患者队列中 PIK3CA 突变状态与预后之间的关联，而我们通过 Cox 比例风险模型在雌激素受体 (ER) 和/或孕激素受体 (PR) 阳性患者组中分析了 PIK3CA 突变与 ET 之间的关联。结果所有患者诊断时的中位年龄为 62.8 岁，中位随访时间为 10.8 年。在 365 名患者中，45% 的患者发现了 PIK3CA 激活突变。PIK3CA 激活突变与差异 DMFS 和 OS 无关（分别为 p = 0.36 和 p = 0.42）。在 PIK3CA 突变患者中，与不接受 ET 治疗相比，每年接受他莫昔芬 (TAM) 或芳香酶抑制剂 (AI) 治疗的患者死亡风险分别降低 27% 和 21%。ET 的类型和持续时间对 DMFS 没有显着影响，但较长的 ET 持续时间对 OS 有有利的影响。结论 PIK3CA 激活突变与早期 ILC 中的 DMFS 和 OS 影响无关。PIK3CA 突变患者的死亡风险在统计学上显着降低，无论他们接受 TAM 还是 AI。