The reliability of Cancer Registry records

Data Reliability and Coding Completeness of Cancer Registry Information Using Reabstracting Method in the National Cancer Institute: Thailand, 2012 to 2014

PURPOSE

Data quality is a core value of cancer registries, which bring about greater understanding of cancer distribution and determinants. Thailand established its cancer registry in 1986; however, studies focusing on data reliability have been limited. This study aimed to assess the coding completeness and reliability of the National Cancer Institute (NCI) hospital-based cancer registry, Thailand.

METHODS

This study was conducted using the reabstracting method. We focused on seven cancer sites-the colon, rectum, liver, lung, breast, cervix, and prostate-registered between 2012 and 2014 in the NCI hospital-based cancer registry. Missing data were identified for coding completeness calculation among important variables. The agreement rate and κ coefficient were computed to represent data reliability.

RESULTS

For reabstracting, we retrieved 957 medical records from a total of 5,462. These were selected using the probability proportional to size method, stratified by topology, sex, and registered year. The overall coding completeness of the registered and reabstracted data was 89.9% and 93.6%, respectively. In addition, the overall agreement rate among variables ranged from 84.7% to 99.6%, and κ coefficient ranged from 0.619 to 0.995. The misclassification among unilateral organs caused lower coding completeness and agreement rate of laterality coding. The completeness of current residency could be improved using the reabstracting method. The lowest agreement rate was found among various categories of diagnosis basis. Sex misclassification for male breast cancer was identified.

CONCLUSION

The coding completeness and data reliability of the NCI hospital-based cancer registry met the standard in most critical variables. However, some challenges remain to improve the data quality. The reabstracting method could identify the critical points affecting the quality of cancer registry data.

Variability in date of prostate cancer diagnosis: a comparison of cancer registry, pathology report, and electronic health data sources

PURPOSE

The date of cancer diagnosis is a critical data element for clinical care and research. Because this date can be abstracted from various data sources, its comparability from source to source is unclear. This study compared the date of diagnosis from multiple sources within the same population of prostate cancer patients.

METHODS

We linked cancer registry, pathology report, and electronic health data sources from the Kaiser Permanente Southern California health data systems for a cohort of 22,666 members diagnosed with prostate cancer between 2000 and 2010. The magnitude and direction of the differences in date of diagnosis were assessed for each date pairwise comparison. We reviewed 454 medical records to determine reasons for date discrepancies.

RESULTS

Among the date pairwise comparisons, differences in date of diagnosis spanned from 9.6 years earlier to 10 years later than each other. However, the overall median difference ranged from 1 to 16 days, thus suggesting that the vast majority of the date differences were small. Chart review results identified major categories of date discrepancies.

CONCLUSIONS

These data demonstrate variability in date of diagnosis across these data sources. This variability may have implications for epidemiologic estimates or patient identification in research studies using different data sources.

Accuracy and completeness of the New Zealand Cancer Registry for staging of invasive breast cancer

PURPOSE

Population based cancer registries are an invaluable resource for monitoring incidence and mortality for many types of cancer. Research and healthcare decisions based on cancer registry data rely on the case completeness and accuracy of recorded data. This study was aimed at assessing completeness and accuracy of breast cancer staging data in the New Zealand Cancer Registry (NZCR) against a regional breast cancer register.

METHODOLOGY

Data from 2562 women diagnosed with invasive primary breast cancer between 1999 and 2011 included in the Waikato Breast Cancer Register (WBCR) were used to audit data held on the same individuals by the NZCR. WBCR data were treated as the benchmark.

RESULTS

Of 2562 cancers, 315(12.3%) were unstaged in the NZCR. For cancers with a known stage in the NZCR, staging accuracy was 94.4%. Lower staging accuracies of 74% and 84% were noted for metastatic and locally invasive (involving skin or chest wall) cancers, respectively, compared with localized (97%) and lymph node positive (94%) cancers. Older age (>80 years), not undergoing therapeutic surgery and higher comorbidity score were significantly (p<0.01) associated with unstaged cancer. The high proportion of unstaged cancer in the NZCR was noted to have led to an underestimation of the true incidence of metastatic breast cancer by 21%. Underestimation of metastatic cancer was greater for Māori (29.5%) than for NZ European (20.6%) women. Overall 5-year survival rate for unstaged cancer (NZCR) was 55.9%, which was worse than the 5-year survival rate for regional (77.3%), but better than metastatic (12.9%) disease.

CONCLUSIONS

Unstaged cancer and accuracy of cancer staging in the NZCR are major sources of bias for the NZCR based research. Improving completeness and accuracy of staging data and increasing the rate of TNM cancer stage recording are identified as priorities for strengthening the usefulness of the NZCR.

Agreement of Iranian breast cancer data and relationships with measuring quality of care in a 5-year period (2006-2011)

OBJECTIVES

To investigate data agreement of cancer registries and medical records as well as the quality of care and assess their relationship in a 5-year period from 2006 to 2011.

METHODS

The present cross-sectional, descriptive-analytical study was conducted on 443 cases summarized through census and using a checklist. Data agreement of Nemazi hospital-based cancer registry and the breast cancer prevention center was analyzed according to their corresponding medical records through adjusted and unadjusted Kappa. The process of care quality was also computed and the relationship with data agreement was investigated through chi-square test.

RESULTS

Agreement of surgery, radiotherapy, and chemotherapy data between Nemazi hospital-based cancer registry and medical records was 62.9%, 78.5%, and 81%, respectively, while the figures were 93.2%, 87.9%, and 90.8%, respectively, between breast cancer prevention center and medical records. Moreover, quality of mastectomy, lumpectomy, radiotherapy, and chemotherapy services assessed in Nemazi hospital-based cancer registry was 12.6%, 21.2%, 35.2%, and 15.1% different from the corresponding medical records. On the other hand, 7.4%, 1.4%, 22.5%, and 9.6% differences were observed between the quality of the above-mentioned services assessed in the breast cancer prevention center and the corresponding medical records. A significant relationship was found between data agreement and quality assessment.

CONCLUSION

Although the results showed good data agreement, more agreement regarding the cancer stage data elements and the type of the received treatment is required to better assess cancer care quality. Therefore, more structured medical records and stronger cancer registry systems are recommended.

Histological confirmation of breast cancer registration and self-reporting in England and Wales: a cohort study within the UK Collaborative Trial of Ovarian Cancer Screening

BACKGROUND

In research studies, accurate information of cancer diagnosis is crucial. In women with breast cancer (BC), we compare cancer registration (CR) in England/Wales and self-reporting with independent confirmation.

METHODS

In the UK Collaborative Trial of Ovarian Cancer Screening, notification of BC diagnosed between randomisation and 31 December 2009 was obtained through (1) CR (17 October 2011) and (2) self-reporting using postal-questionnaire. Breast cancer was confirmed using a detailed questionnaire (BC questionnaire BCQ) completed by the treating clinician (gold standard). Apparent sensitivity and positive-predictive value of CR/self-reporting vs BCQ were calculated.

RESULTS

Of 1065 women with possible BC notification, diagnosis was confirmed in 932 (87.5%). A total of 3.1% (28 out of 918) of BC CR and 12.4% (128 out of 1032) of women with self-reported BC only had in-situ carcinoma on BCQ. Another 4.6% (43 out of 932) of BCQ-confirmed cancer did not have a BC registration, and 3.6% (34 out of 932) did not self-report BC. Apparent sensitivity of CR and self-reporting vs BCQ were 95.4 and 96.4%, respectively. Positive-predictive value of self-reporting (87.1%) was significantly lower than that of CR (96.8%). Women aged<65 were more likely to over report in-situ carcinoma as BC. Overall, 73 (6.8%) women would have been misclassified/missed if CR, and 167 (15.6%) if self-reporting data alone was used.

CONCLUSION

This study confirms the reliability of BC registration in England/Wales and highlights the fact that 1 in 10 women self-reporting BC might only have in-situ breast carcinoma.

Misclassification of colorectal cancer stage and area variation in survival

We previously investigated the impact of health area of residence on colon and rectal cancer survival by estimating area-specific relative excess risk of death (RER), stratified by stage at diagnosis. The aims of this study were to quantify errors in colorectal cancer stage obtained from an Australian population-based cancer registry and assess the potential impact of errors in stage on these estimates. For a subset of cases, we compared the cancer registry stage with that from a survey of treating surgeons. We then randomly reallocated all cases to a simulated "corrected" stage according to the estimated misclassification probabilities and repeated the analysis of area variation stratified by simulated stage 1,000 times. We found 70% agreement between the Registry and Survey stage. This reallocation of the Registry cases by stage resulted in substantial variation in area-specific RERs across the simulated samples. Area variation in survival for localized colon and localized rectal cancer, which were previously statistically significant when classified using Registry stage, appeared no longer to be so. Misclassification of cancer registry stage can have an important impact on estimates of spatial variation in stage-specific colon and rectal cancer survival. If population-based cancer registry data are to be effectively used in evaluating and improving cancer care, the quality of the stage data may need to be improved.

Geographical inequalities in lung cancer management and survival in South East England: evidence of variation in access to oncology services?

This study aimed to determine whether the management and survival of patients with lung cancer varied among 26 health authorities in South East England. The Thames Cancer Registry identified patients diagnosed with lung cancer (ICD-10 codes C33-C34) between 1995 and 1999. After excluding death certificate only patients, 32,818 (81%) patients were analysed. The proportions of patients receiving active treatment varied among health authorities between 5 and 17% for non-investigative surgery, 4 and 17% for any chemotherapy, 8 and 30% for any radiotherapy and 15 and 42% for any active treatment. One-year patient survival ranged from 11 to 34%. There was evidence of health authority level variation even after adjusting for case mix. Patients whose first hospital attendance was at a radiotherapy centre were more likely to receive active treatment (OR 1.72, 95% CI 1.21-2.46), chemotherapy (1.38, 1.06-1.79) or radiotherapy (1.86, 1.28-2.71). There was some evidence that patients whose first hospital attendance was at a radiotherapy centre survived longer. This study shows there is geographical inequality in the treatment given to lung cancer patients and patient survival in South East England. There was some evidence to suggest that these inequalities might be explained by variations in access to oncology services. Future studies should investigate the pathways and barriers to specialist care in this condition.

Reliability of cancer registration data in Scotland, 1997

The aim of this study was to assess the reliability of cancer registration data in Scotland following a major re-organisation of the Scottish Cancer Registry. From a random sample of 3500 primary cancers (excluding non-melanoma skin cancers and death certificate only (DCO) registrations) diagnosed between April and September 1997, 3175 (90.7%) had medical records available for scrutiny. Data were re-abstracted by a team of trained medical coders and compared with information registered originally. Reliability was generally high for demographic, diagnostic, and fact of treatment details, but less reliable for grade of differentiation, staging variables and dates of treatment. Some discrepancies probably arose because of differing availability of information at the time of registration compared with the time of re-abstraction. Although data quality is high overall, further improvements might be achieved through continued training, structured recording of information by clinicians in medical records, and continued exploitation of the data.

Concordance on the recording of cancer in the Saskatchewan Cancer Agency Registry, hospital charts and death registrations

Accurate and complete registries are an important source of knowledge about cancer. The concordance of the recording of neoplasms in the Saskatchewan cancer registry with that in hospital charts and death registrations was evaluated for 368 patients. The agreement between registry and hospital charts or death registrations was excellent (kappa: 0.93; 95% confidence interval: 0.89, 0.97), with 91.3% of those with cancer having the same neoplasm recorded in their chart or death registration as in the registry. There was only one patient whose hospital chart indicated cancer who was not in the registry and one apparent major discrepancy relating to the cancer site, which was due to the recording of the primary site in the registry and a secondary in the hospital chart. Although based on a relatively small number of patients, these results suggest a high degree of consistency between cancer registry, hospital charts and death registrations in Saskatchewan.

Differences in treatment and survival rates of non-small-cell lung cancer in three regions of France

Treatment and survival rates of patients with non-small-cell lung cancer (NSCLC) were compared between three French Cancer Registries (Calvados, Doubs, Tarn). The methodological issues in such comparisons are discussed. The treatments for NSCLC differed between the regions: radiotherapy tended to be preferred in Calvados (73% vs 21.3% surgery), whereas surgery was more frequently employed in Doubs and Tarn (27.7% and 37% respectively). The percentage of cases receiving no therapeutic treatment ranged from 7.8% (Calvados) to 26% (Tarn). Despite the differences in treatment, the overall survival rates were similar in the three regions. Adjustment for treatment in such a descriptive study may be misleading since different therapeutic strategies in different regions may lead to selection of patients of systematically better or poorer prognosis in the various treatment groups.

Acquisition and use of clinical data for audit and research

Acquisition of adequate patient data for clinical management is hard enough, but higher quality patient data are needed for clinical audit and research. This article discusses some of the problems of using routine clinical data for audit and research, aspects of data quality, sources of audit or research data and their problems, methods for improving data quality, the benefits and problems of computer-based systems and current trends in the capture and processing of clinical data.

Reliability of data of the Thames cancer registry on 673 cases of colorectal cancer: effect of the registration process

OBJECTIVE

To measure the reliability of data collected by the Thames cancer registry and to identify factors in the registration process affecting reliability.

DESIGN

A retrospective study of data from the registry, including death certificate only registrations, and hospital case notes on cases of colorectal cancer diagnosed in 1983 or 1988.

SETTING

Four districts in South Thames region.

SUBJECTS

673 cases of colorectal cancer in resident patients.

MAIN MEASURES

Dates of birth, diagnosis of cancer, and death; sex; tumour site; whether treatment was given; type of treatment; and district of residence.

RESULTS

Among the 416 (62%) case notes retrieved, including 66 death certificate only registrations, full or high agreement between registry data and hospital notes was recorded for sex, district of residence, and dates of birth and death. Only 12% of cases had the same date of diagnosis, which may be due to failure of registry policy. Lower agreement rates occurred for tumour site (87%), whether treatment occurred (84%), and treatments administered (80%, 1983; 72%, 1988). 20% of surgical treatments and 37% of adjuvant therapy, radiotherapy, and chemotherapy were not recorded by the registry. Disagreements were common among death certificate only registrations. Such registrations accounted for 16(32%) disagreements over tumour site, 33(41%) major disagreements over date of diagnosis (difference > 30 days), and 47(44%) disagreements over treatment. In 65 cases the registry failed to capture all treatments carried out within the six month follow up period, 38(58%) of which were for death certificate only registrations. In 36% of death certificate only registrations the patients survived more than one year from diagnosis, indicating a failure of registry policy over retrospective follow up.

CONCLUSIONS

Registry data on district of residence; sex; dates of birth, diagnosis, and death are highly reliable, but treatment and tumour site data are less so. Lack of follow up in death certificate only registrations and failure to monitor treatments during follow up period seemed to be associated with disagreements.

Registration of lung cancer in Scotland: an assessment of data accuracy based on review of medical records

Lung cancer represents a major public health problem in Scotland. Cancer registration data permit the approximate incidence of this disease to be measured directly and the projected incidence to be modelled. Thus, in addition to epidemiologic studies and survival analyses, cancer registration data may be used for planning and monitoring relevant health services. Since the value of the data depends on their quality, we undertook a large-scale study of the accuracy of cancer registration data in Scotland. The medical records of a random sample of cancer registrations attributed to the year 1990 were sought. The sample contained 340 registrations of lung cancer, 309 (91 percent) of which had relevant medical records available for scrutiny. Registration details were reabstracted from available records and compared with data in the registry. Results revealed 19 discrepancies in identifying items of data (surname, forename, gender, and date of birth) involving 16 (5.2 percent) patients. Most were trivial and would not disturb record linkage. Discrepancy rates were found to be: 7.8 percent in postcode of residence at the time of diagnosis, 10 percent in 'anniversary date' (excluding differences of six weeks or less), 12.5 percent in histologic verification status; 4.2 percent in ICD-9 site code (the first three digits), and 15.5 percent in four digit ICD-O morphology code (excluding 'inferred' morphology codes). This relatively high level of accuracy gives weight to routinely published incidence figures and supports the use of these data for exploratory epidemiologic studies, assessment of health care needs, and calculation of survival.

Registration of colorectal cancer in Scotland: an assessment of data accuracy based on review of medical records

Colorectal cancer accounts for a substantial burden of morbidity and mortality in the population. While the need for reliable incidence data may be self-evident, the quality of cancer registration data has rarely been assessed. In Scotland during 1993, the medical records of a random sample of cancer registrations attributed to the year 1990 were sought. The sample contained 238 registrations of colorectal cancer, 217 (91%) of which had relevant medical records available for review. Registration details were reabstracted from available records and compared with data in the registry. Discrepancies in identifying items of data (surname, forename, sex and date of birth) were recorded in eight cases (3.7%, 95% confidence intervals 1.2-6.2%). None would have disturbed record linkage. Discrepancy rates of 3.7% (1.2-6.3%) in postcode of residence at the time of diagnosis (excluding differences arising through boundary changes), 8.3% (4.6-12.0%) in 'anniversary date' (excluding differences of 30 days or less), 2.8% (0.6-5.0%) in histological verification status and 13.5% (8.9-18.1%) in morphology code (excluding 'inferred' morphology codes) were recorded. Twelve cases (5.5%, 2.5-8.6%) were deemed not to warrant site codes for cancer of the colon (ICD-9 153) or rectum (ICD-9 154). In many respects, therefore, the data held about registrations of colorectal cancer in Scotland appear to show a high level of accuracy. Completeness of case ascertainment has still to be formally assessed.

How accurate are Scottish cancer registration data?

In order to assess the accuracy of Scottish cancer registration data, a random sample of 2,200 registrations, attributed to the year 1990, was generated. Relevant medical records were available for review in 2,021 (92%) cases. Registration details were reabstracted from available records and compared with data in the registry. Discrepancies in identifying items of data (surname, forename, sex and date of birth) were found in 3.5% of cases. Most were trivial and would not disturb record linkage. Discrepancy rates of 7.1% in post code of residence at the time of diagnosis (excluding differences arising through boundary changes), 11.0% in anniversary date (excluding differences of 6 weeks or less), 7.7% in histological verification status, 5.4% in ICD-9 site codes (the first three digits) and 14.5% in ICD-O morphology codes (excluding 'inferred' morphology codes) were recorded. Overall, serious discrepancies were judged to have occurred in 2.8% of cases. In many respects, therefore, Scottish cancer registration data show a high level of accuracy that compares favourably to the reported accuracy of the few other cancer registries undertaking such analyses.

Trends in primary cerebral lymphoma

Primary non-Hodgkin lymphoma of the brain is rare, representing only 1% of all non-Hodgkin lymphomas (NHLs), but its incidence has been increasing rapidly in south-east England since 1985. Among 17,322 cases of NHL registered during the 18 year period 1973-90, there were 210 cases of primary cerebral NHL, of which 179 (86%) were diagnosed in the last third of this period, 1985-90. This increase in cerebral lymphoma is not adequately explained by improvements in the precision of diagnosis or by changes in disease coding or cancer registration practice. While there has also been a rapid increase in Kaposi sarcoma, neither immunosuppression acquired through HIV infection nor the overall trend in non-Hodgkin lymphoma can satisfactorily explain the recent increase in cerebral lymphoma, which affects all ages and both sexes similarly. Other possible causes for a true increase in cerebral lymphoma should be sought.

Management of breast cancer in southeast England

OBJECTIVE

To examine the extent to which management of invasive breast cancer reflected consensus guidelines in the Thames regions in 1990.

DESIGN

Population based study of case notes.

SETTING

Thames Cancer Registry.

SUBJECTS

All women with breast cancer diagnosed in early 1990 (417 cases) resident in the four Thames regions. Hospital records were traced for 346 cases, of which 12 were ineligible because of misclassification in initial registration and were excluded from the analysis. 334 cases were analysed.

MAIN OUTCOME MEASURES

Investigations and treatment in the six months after diagnosis, stage of disease.

RESULTS

Of the 334 women identified, 86 were aged under 50. Three years after diagnosis, 74 were dead, seven (8%) aged under 50 and 67 (27%) aged 50 or over. Axillary surgery was used to stage cancer in only 155 cases (46%), although this is recommended in the guidelines. Only 79 (24%) case notes had any information recorded on stage. Stage could be determined reliably for only half of the sample. Treatment varied widely within the same age group and stage of disease. In particular, chemotherapy was not routinely given to patients under 50 with stage II disease. Only 17 records showed evidence that the patient was participating in a clinical trial.

CONCLUSIONS

There was a lack of consensus on the management of breast cancer among clinicians in 1990. More patients should be included in clinical trials.

A computerized data collection system for a cancer centre

A data system has been designed for a cancer centre and, with the close collaboration of staff, has been brought into use. Data are continuously gathered by doctors, nurses, radiographers and cancer registration staff for the contracting process, cancer registration, audit, research and development.