Evaluation of Data Quality of Four New Population Based Cancer Registries (PBCRs) in Chandigarh and Punjab, North India- A Quality Control Study

BACKGROUND: Population based Cancer Registries(PBCRs) are hallmark of cancer surveillance and cancer control activity .The value of cancer registries rely heavily on underlying quality of their data. Current study assessed data quality of four new PBCRs of Chandigarh, SAS Nagar, Mansa and Sangrur covering a total population of 4.5 millions on three quality parameters i.e. comparability, validity and completeness as recommended by International Agency of Research on Cancer(IARC), Lyon, France. METHODS: For assessing comparability, data of the registries were reviewed in terms of system of classification and coding, definition of incidence date and rule for multiple primaries. For assessing validity (Accuracy) four different methods i.e. re-abstraction and re-coding, percentage morphologically verified cases (MV%), percentage of death certificate only (DCO%) cases and percentage of cases with other and unspecified sites (O and U%) were used. For assessing completeness of coverage, different semi-quantitative methods were used. RESULTS: Re-abstraction done for 10% of the total incident cases yielded overall percentage agreement of 97.4%, 97.2%, 95.4% and 94.9% for PBCR Chandigarh, SAS Nagar, Mansa and Sangrur respectively. MV% was found to be 96.3% for PBCR Chandigarh, 92.8% for PBCR SAS Nagar , 89.3% for PBCR Mansa and 82.9% for PBCR Sangrur. Percentage of DCO cases and O and U cases were 1.4% and 2.8% for PBCR Chandigarh, 3.9% and 5.3% for SAS Nagar, 6.4% and 16.4% for Mansa and 6.3% and 8.3% for Sangrur. Completeness assessed through the various methods showed good level of completeness at PBCR Chandigarh and SAS Nagar and somewhat lower but acceptable level of completeness at PBCR Mansa and Sangrur. CONCLUSIONS: All the four PBCRs are comparable internationally. PBCR Chandigarh and SAS Nagar, predominantly urban registries, have higher accuracy of their data and good completeness levels as compared to predominantly rural registries of Mansa and Sangrur. Cancer estimates given by all the four registries are reliable and data from these registries can be utilized for planning cancer prevention and control activities in the region.