Anna Kemp | Ascertaining cases of invasive breast cancer in the 45 and Up Study: a validation...
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Transcript of Anna Kemp | Ascertaining cases of invasive breast cancer in the 45 and Up Study: a validation...
Ascertaining cases of invasive breast cancer in the 45 and Up Study: a validation study.
Kemp A, Preen DB, Saunders C, Holman CDJ, Bulsara M, Rogers K, Roughead EE.
Background
• Routinely-collected and self-reported health data are increasingly used to identify health status and service use
• State-based cancer registries are considered the ‘gold standard’ for identifying breast cancer cases for research purposes o However researchers conducting survey-based studies or
working with other datasets (e.g. hospital data) may need to identify cases without linkage to a cancer registry
o ‘Temporary’ access problems with cancer registrations in New South Wales (NSW)
Background continued
• Larger program of work examining use of prescription hormone therapies for invasive breast cancer in Australian practice (e.g. tamoxifen)
• Planned to identify cases of invasive breast cancer through the NSW Cancer Registry o Power calculations based on cases diagnosed 2003-2009
• We received all the datasets needed for the study except Cancer Registry records for 2009
• Can we ascertain 2009 cases of invasive breast cancer using information from the other available datasets?
Objective
• To determine the accuracy of hospital and outpatient services, prescription claims, and self-report for breast cancer in identifying cases of invasive breast cancer on the NSW Cancer Registry
Data sources
• NSW Cancer Registry (gold standard) o date of diagnosis for all invasive breast cancers in NSW
between 1 July 2004 to 31st December 2008
• 45 and Up Study baseline data o self-reported demographic and clinical information
• NSW Admitted Patients Data Collection o hospital separations for all public and private hospitals
• Pharmaceutical Benefits Scheme o claims for government-subsidised dispensed prescription
medicines • Medicare Benefits Schedule
o claims for government-subsidised outpatient procedures and procedures in private hospitals
Breast cancer ‘flags’
• Hospital diagnosis of invasive breast cancer o ≤ 6 months of diagnosis
• Breast cancer surgery o ≤12 months of diagnosis o mastectomy or lumpectomy
• Prescriptions dispensed o ≤18 months of diagnosis o tamoxifen, toremifene, anastrazole, exemestane, letrozole,
goserelin, trastubumab, lapatinib • Breast radiotherapy
o ≤18 months of diagnosis • Self-reported diagnosis breast cancer and age at diagnosis
o within 12 months of date of diagnosis o analysis restricted to self-reports before January 2006
Analyses
• Cases of invasive breast cancer recorded on the Cancer Registry during the study period were compared with flagged (suspected) cases
• Comparison included o flags from individual datasets (e.g. hospital diagnosis) o clinically meaningful combinations of flags (e.g. hospital
diagnosis and a dispensed medicine for breast cancer) • For each flag/s we calculated:
o positive predictive value (PPV) o sensitivity o Specificity
• We sought flags with high PPV (>90%) and within that, the highest specificity
Results
• Of 143,010 women in the 45 and Up Study, 2661 (1.9%) had a recorded invasive breast cancer on the Cancer Registry during the study period o 681 occurred between 1 July 2004 and 31st December
2005 (this subgroup was compared against self-reported breast cancer)
Results from individual datasets PPV Sensitivity Specificity
45 and Up Study baseline survey
Self-reported diagnosis (12 month window)
40.9% 73.0% 99.5%
Hospital data Inpatient primary diagnosis 80.3% 85.2% 99.7%
Lumpectomy 99.3% 61.3% 99.9%
Mastectomy 99.2% 35.2% 99.9%
Lumpectomy OR mastectomy 99.2% 86.3% 99.9%
Results from individual datasets PPV Sensitivity Specificity
45 and Up Study baseline survey
Self-reported diagnosis (12 month window)
40.9% 73.0% 99.5%
Self-reported diagnosis 72% of the ‘false positives’ had a record on the Cancer Registry for an earlier period
Hospital data Inpatient primary diagnosis 80.3% 85.2% 99.7%
Lumpectomy 99.3% 61.3% 99.9%
Mastectomy 99.2% 35.2% 99.9%
Lumpectomy OR mastectomy 99.2% 86.3% 99.9%
Results from individual datasets PPV Sensitivity Specificity
45 and Up Study baseline survey
Self-reported diagnosis (12 month window)
40.9% 73.0% 99.5%
Self-reported diagnosis 72% of the ‘false positives’ had a record on the Cancer Registry for an earlier period
Hospital data Inpatient primary diagnosis 80.3% 85.2% 99.7%
Lumpectomy 99.3% 61.3% 99.9%
Mastectomy 99.2% 35.2% 99.9%
Lumpectomy OR mastectomy 99.2% 86.3% 99.9%
Results from individual datasets
PPV Sensitivity Specificity
Pharmaceutical Benefits Scheme
Any dispensed medicine 88.5% 68.5% 99.9%
Medicare Benefits Schedule
Breast radiotherapy 95.8% 57.9% 99.9%
Results from 45 and Up Study, MBS and PBS data package
PPV Sensitivity Specificity
Breast radiotherapy AND dispensed medicine
95.8% 41.1% 99.9%
Breast radiotherapy OR dispensed medicine
89.9% 85.3% 99.9%
Breast radiotherapy AND self-reported diagnosis
70.2% 28.3% 99.9%
Breast radiotherapy AND dispensed medicine AND self-reported diagnosis
68.4% 19.4% 99.9%
(Breast radiotherapy OR dispensed medicine) AND self-reported diagnosis
67.8% 56.8% 99.9%
Breast radiotherapy OR dispensed medicine OR self-reported diagnosis
24.9% 94.1% 98.6%
Results from 45 and Up Study, MBS and PBS data package
PPV Sensitivity Specificity
Breast radiotherapy AND dispensed medicine
95.8% 41.1% 99.9%
Breast radiotherapy OR dispensed medicine
89.9% 85.3% 99.9%
Breast radiotherapy AND self-reported diagnosis
70.2% 28.3% 99.9%
Breast radiotherapy AND dispensed medicine AND self-reported diagnosis
68.4% 19.4% 99.9%
(Breast radiotherapy OR dispensed medicine) AND self-reported diagnosis
67.8% 56.8% 99.9%
Breast radiotherapy OR dispensed medicine OR self-reported diagnosis
24.9% 94.1% 98.6%
Results from hospital, 45 and Up Study, MBS and PBS datasets
PPV Sensitivity Specificity
(Lumpectomy or mastectomy) AND diagnosis of invasive breast cancer AND dispensed medicine
99.4% 56.7% 99.9%
(Lumpectomy or mastectomy) AND (diagnosis of invasive breast cancer OR breast radiotherapy)
96.8% 91.6% 99.9%
(Lumpectomy or mastectomy) AND (diagnosis of invasive breast cancer OR dispensed medicine)
91.2% 93.7% 99.9%
(Lumpectomy or mastectomy) AND (diagnosis of invasive breast cancer OR breast radiotherapy OR dispensed medicine)
90.8% 96.8% 99.9%
Results from hospital, 45 and Up Study, MBS and PBS datasets
PPV Sensitivity Specificity
(Lumpectomy or mastectomy) AND diagnosis of invasive breast cancer AND dispensed medicine
99.4% 56.7% 99.9%
(Lumpectomy or mastectomy) AND (diagnosis of invasive breast cancer OR breast radiotherapy)
96.8% 91.6% 99.9%
(Lumpectomy or mastectomy) AND (diagnosis of invasive breast cancer OR dispensed medicine)
91.2% 93.7% 99.9%
(Lumpectomy or mastectomy) AND (diagnosis of invasive breast cancer OR breast radiotherapy OR dispensed medicine)
90.8% 96.8% 99.9%
Strengths and weaknesses
• Strengths o Large, heterogeneous sample of women o Complete capture for all public and private inpatient
diagnoses and surgeries, subsidised outpatient procedures and medicines
• Weaknesses o We could not identify how many false positives were DCIS
vs. not breast cancer at all o The flags we have identified may not predict invasive
breast cancer as well in younger women o Validity of the flags examined here may change over time
with shifts in health service use
Conclusions
• Invasive breast cancer can be accurately ascertained through administrative datasets other than the Cancer Registry
• The most useful flags will depend on the research question and available datasets
• Self report with date restriction had moderate sensitivity and low PPV, however specificity was very high o Suitable for excluding cases of breast
cancer from a study sample
Conclusions
• We had access to 45 and Up Study baseline survey, hospital, MBS, and PBS data and needed to identify a sample
• The most useful flag or this purpose: o (Lumpectomy or mastectomy) AND (primary diagnosis of
invasive breast cancer or breast radiotherapy) o 97% of those identified are true positives o 92% of cases on the Cancer Registry
are identified
Acknowledgements
• Participants of the 45 and Up Study • The 45 and Up Study is managed by the Sax Institute in
collaboration with: • Cancer Council New South Wales (major partner) • National Heart Foundation of Australia (NSW Division) • NSW Ministry of Health • beyondblue: the national depression initiative • Ageing, Disability and Home Care NSW Family and
Community Services • Australian Red Cross Blood Service • UnitingCare Ageing
Acknowledgements
• Staff at the Centre for Health Record Linkage • Other data custodians:
o NSW Ministry of Health o Commonwealth Department of Human Services o NSW Cancer Institute
• The project was funded by: o Cancer Australia o National Breast Cancer Foundation
Questions