Geneva Cancer Registry, Global Health Institute, Geneva University, Geneva, Switzerland.
Cancer Survival Group, Faculty of Epidemiology and Population Health, Department of Non-Communicable Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK.
BMC Cancer. 2019 Jan 28;19(1):107. doi: 10.1186/s12885-019-5304-2.
Breast cancer prognosis has dramatically improved over 40 years. There is, however, no proof of population 'cure'. This research aimed to examine the pattern of long-term excess mortality due to breast cancer and evaluate its determinants in the context of cancer registry data.
We used data from the Geneva Cancer Registry to identify women younger than 75 years diagnosed with invasive, localised and operated breast cancer between 1995 and 2002. Flexible modelling of excess mortality hazard, including time-dependent (TD) regression parameters, was used to estimate mortality related to breast cancer. We derived a single "final" model using a backward selection procedure and evaluated its stability through sensitivity analyses using a bootstrap technique.
We analysed data from 1574 breast cancer women including 351 deaths (22.3%). The model building strategy retained age at diagnosis (TD), tumour size and grade (TD), chemotherapy and hormonal treatment (TD) as prognostic factors, while the sensitivity analysis on bootstrap samples identified nodes involvement and hormone receptors (TD) as additional long-term prognostic factors but did not identify chemotherapy and hormonal treatment as important prognostic factors.
Two main issues were observed when describing the determinants of long-term survival. First, the modelling strategy presented a lack of robustness, probably due to the limited number of events observed in our study. The second was the misspecification of the model, probably due to confounding by indication. Our results highlight the need for more detailed data and the use of causal inference methods.
40 多年来，乳腺癌的预后已显著改善。然而，目前尚无人群“治愈”的证据。本研究旨在通过癌症登记数据，探讨乳腺癌长期过度死亡的模式，并评估其决定因素。
我们使用日内瓦癌症登记处的数据，确定了 1995 年至 2002 年间诊断为浸润性、局限性和手术治疗的乳腺癌且年龄小于 75 岁的女性。采用灵活的超额死亡风险模型（包括时间依赖性（TD）回归参数）来估计与乳腺癌相关的死亡率。我们使用向后选择程序得出一个单一的“最终”模型，并通过使用自举技术进行敏感性分析来评估其稳定性。
我们分析了 1574 名乳腺癌患者的数据，包括 351 例死亡（22.3%）。构建模型的策略保留了诊断时的年龄（TD）、肿瘤大小和分级（TD）、化疗和激素治疗（TD）作为预后因素，而自举样本的敏感性分析确定了淋巴结受累和激素受体（TD）作为额外的长期预后因素，但没有确定化疗和激素治疗是重要的预后因素。
在描述长期生存的决定因素时，我们观察到两个主要问题。首先，模型构建策略缺乏稳健性，这可能是由于我们研究中观察到的事件数量有限。其次，模型的指定可能存在问题，这可能是由于混杂因素的影响。我们的结果强调了需要更详细的数据和使用因果推理方法。
