Uhry Z, Remontet L, Grosclaude P, Velten M, Colonna M
Département des maladies chroniques et traumatismes, institut de Veille-Sanitaire (InVS), 94415 Saint-Maurice, France.
Rev Epidemiol Sante Publique. 2009 Oct;57(5):329-36. doi: 10.1016/j.respe.2009.05.004. Epub 2009 Aug 14.
Cancer incidence in France is monitored by district-level cancer registries, which cover only 15% of the population. Incidence at the national and regional level are estimated from mortality data by extrapolating the ratio between incidence and mortality observed in the districts covered by a cancer registry. Using the incidence/mortality ratio might not be relevant at the district-level (département). This study aims to produce district-level estimations of colorectal cancer incidence, using the ratio between incident cases from cancer registries and surgery admissions for colorectal cancer identified in the national hospital discharge database.
This ratio was studied for the period 1999-2003 in the 13 districts covered by a cancer registry. For each sex separately, the number of incident cases was analyzed according to the number of surgery admissions for resection of colorectal cancer using a Poisson model. Age was introduced in the model as a fixed effect and district as a random effect. The model's ability to predict incidence was tested through cross-validation. The model was then extrapolated in order to estimate incidence of colorectal cancer in all French districts.
In the districts covered by a cancer registry, cross-validation showed the model had a good predictive ability, except in men for one district where the difference between predicted and observed incidence reached 10%. Estimated incidence rates, age-standardized on the world population, ranged broadly from 29 to 44 per 100,000 in men and from 17 to 27 per 100,000 in women. Incidence did not show any clear geographical pattern.
Among districts covered by a cancer registry, cross-validation showed overall good accuracy of predicted incidence. Inclusion of several admissions per patient was certainly a minor source of error in these estimations. Indeed, our selection only included 2% of multiple admissions, without geographical variations, in 2002 and 2003, years for which patient identifiers were available in the hospital discharge database. Estimated incidence rates presented moderate geographical variations and their prediction intervals should be taken into account.
法国的癌症发病率由地区级癌症登记处监测，这些登记处仅覆盖15%的人口。国家和地区层面的发病率是通过外推癌症登记处覆盖地区观察到的发病率与死亡率之比，从死亡率数据估算得出的。在地区（省）层面使用发病率/死亡率之比可能并不合适。本研究旨在利用癌症登记处的发病病例与国家医院出院数据库中确定的结直肠癌手术入院病例之比，得出地区层面的结直肠癌发病率估计值。
对癌症登记处覆盖的13个地区1999 - 2003年期间的这一比例进行了研究。按性别分别使用泊松模型，根据结直肠癌切除手术入院病例数分析发病病例数。年龄作为固定效应引入模型，地区作为随机效应。通过交叉验证测试模型预测发病率的能力。然后对模型进行外推，以估计法国所有地区的结直肠癌发病率。
在癌症登记处覆盖的地区，交叉验证表明该模型具有良好的预测能力，但在一个地区的男性中除外，该地区预测发病率与观察发病率之间的差异达到10%。以世界人口为标准进行年龄标准化后的估计发病率，男性每10万人中广泛分布在29至44例之间，女性每10万人中在17至27例之间。发病率未显示出任何明显的地理模式。
在癌症登记处覆盖的地区中，交叉验证表明预测发病率总体准确性良好。每位患者纳入多次入院情况肯定是这些估计中一个较小的误差来源。实际上，我们的选择仅包括了2002年和2003年（医院出院数据库中有患者标识符的年份）2%的多次入院情况，且无地理差异。估计发病率呈现出适度的地理差异，应考虑其预测区间。
