Centre for Population Health Data, Statistics Canada, Ottawa, Ontario.
Health Rep. 2023 Dec 20;34(12):17-26. doi: 10.25318/82-003-x202301200002-eng.
The validity of survival estimates from cancer registry data depends, in part, on the identification of the deaths of deceased cancer patients. People whose deaths are missed seemingly live on forever and are informally referred to as "immortals." Their presence in registry data can result in inflated survival estimates. This study assesses the issue of immortals in the Canadian Cancer Registry (CCR) using a recently proposed method that compares the survival of long-term survivors of cancers for which "statistical" cure has been reported with that of similar people from the general population.
Data are from the population-based CCR record linked to the Canadian Vital Statistics - Death Database and tax data. Yearly interval-specific relative survival (IRS) estimates were derived up to 15 years after diagnosis for colon cancer cases, and for colon, rectal and melanoma cancer cases combined, diagnosed from 1992 to 2002.
With increasing follow-up time since diagnosis, national colon cancer IRS estimates levelled off at 1.00, or slightly less, for each age group studied, indicating that survival did not exceed that of the general population. Similar results were obtained among males and females, and for colon, rectal and melanoma cancer cases combined. Provincial IRS point estimates for the three cancers combined also levelled off around 1.00, though with more variation in the estimates than at the national level.
Based on the results of this study, immortals do not appear to be an issue at either the national or the provincial level for survival estimates derived from CCR data.
癌症登记数据中生存估计的有效性部分取决于已死亡癌症患者死亡的识别。那些被漏报的死亡患者看似永远活着，他们被非正式地称为“不朽者”。他们在登记数据中的存在可能导致生存估计值膨胀。本研究使用最近提出的一种方法评估加拿大癌症登记处（CCR）中的不朽者问题，该方法比较了报告“统计”治愈的癌症的长期幸存者与来自普通人群的类似人群的生存情况。
数据来自基于人群的 CCR 记录，与加拿大生命统计-死亡数据库和税收数据相关联。根据诊断年份，从 1992 年至 2002 年，对结肠癌病例和结肠癌、直肠癌和黑色素瘤病例的每年间隔特定相对生存率（IRS）进行了估计，最长可达 15 年。
随着诊断后随访时间的增加，全国结肠癌 IRS 估计值在每个研究年龄组中稳定在 1.00 或略低，表明生存率未超过普通人群。在男性和女性中，以及在结肠癌、直肠癌和黑色素瘤病例中，均获得了类似的结果。三个癌症联合的省级 IRS 点估计值也稳定在 1.00 左右，尽管与国家水平相比，估计值的变化更大。
根据本研究的结果，在从 CCR 数据得出的生存估计中，不朽者似乎不是一个全国或省级水平的问题。
