质量控制贯穿肿瘤登记工作的全过程。肿瘤登记地区应在各个环节制定工作规范和质量控制程序，并严格执行。质量控制主要包括四个方面：可比性、有效性、完整性和时效性。

数据结果真实可比的基本先决条件是采用通用的标准或定义。通常而言，可比性是指发病率间的不同不是因各登记地区之间的数据质量和标准不同而产生。可比性涉及以下几个指标：对“发病”的定义、对原发、复发和转移的诊断标准、分类与编码、死亡证明等。

完整性是指在登记地区资料库的目标人群中发现所有发病病例的程度。常用的评价指标有死亡/发病比（M/I）、只有死亡证明比例（DCO%）、病理诊断比例（MV%）、病例的来源数与报告单数、不同时间发病率的稳定性、不同人群发病率的比较、年龄别发病率曲线、儿童癌症评价等。俘获/再俘获方法也用来评价登记报告资料的完整性。

有效性是指登记病例中具有给定特征（例如肿瘤部位、年龄）真正属性的病例所占的比例。再摘录与再编码方法是评价有效性的最客观方法，一般由另一个观察者完成对登记地区记录与相关病例文件间仔细比较。常用的评价指标有病理诊断比例（MV%），只有死亡证明比例（DCO%）、部位不明百分比，年龄不明百分比等。癌症登记地区至少进行诸如年龄/出生日期、性别/部位、部位/组织学以及部位/组织学/年龄、基本变量无遗漏信息的基本核对。

4　Quality control

The value of cancer registration relies on the data quality.This procedure aims at providing qualified cancer registration data with comparability，completeness，validity，and timeliness.

4.1　Comparability

Comparability is the extent to which coding and classification at a registry，together with the definitions of recording and reporting specific data items，adhere to standardized international guidelines.In the evaluation of the comparability of registration data，the following standards should be identical：the identification for tumor classification and coding，the definition of incidence，the identification of primary cancer and cancer recurrence or metastasis of an existing one，and the criteria of death certification.

4.2　Completeness

The completeness of cancer registry data refers to the extent of all the incident cancers occurring in the population included in the cancer registration database.It is an extremely important attribute of cancer registration data.The methods which provide indication of the completeness include the following：M/I ratio，DCO%，MV%，reporting avenues，stability of incidence rates over time，comparison of incidence rates in different populations，shape of age-specific curves and incidence rates of childhood cancers.The capture-recapture methods are also used to evaluate the completeness of registration data.

4.3　Validity

Validity is defined as the proportion of cases in a dataset with a given characteristic which truly have the attribute.Re-abstracting and re-coding are the principle methods which permit comparisons with respect to specified subsets of cases.Using diagnostic criteria（MV%and DCO%），missing information analysis and internal consistency methods，the validity of the cancer registration information can be verified.

时效性一般指发病日期（诊断日期）到数据被利用时（年报、研究报告、论文）的间隔。登记地区应及时报告和获取癌症信息。目前对时效性无统一的国际标准。为平衡与完整性和准确性的关系，国家癌症中心要求各登记地区于诊断年份后的30个月内提交数据。

4.4　Timeliness

Timeliness relates to the rapidity at which a registry can collect，process and report reliable and complete cancer data.It indicates the time to availability as the interval between date of diagnosis and the date the case was available in the registry for further use.The cancer registries should timely collect and report cancer statistics.NCC China requires the cancer registries should report cancer statistics in 30 months.