Cancer recurrence: an important but missing variable in national cancer registries

Cancer recurrence is a critically important outcome to patients and providers. However, no publicly available cancer registry data contain recurrence information. The National Cancer Data Base (NCDB) collects recurrence data; however, this information is not provided to researchers because of completeness and accuracy concerns. Our objective was to examine completeness of cancer recurrence information in the NCDB.

Stage I-III thyroid/colon/melanoma/pancreas/breast cancers diagnosed in 2002-2005 were identified. Recurrence status, recurrence type, and recurrence date were evaluated for data completeness. Patient, tumor, and hospital factors were examined using generalized linear mixed models. Pseudo-R (2) statistics estimated the relative contribution of patient and hospital factors.

Of 702,144 patients with thyroid/colon/melanoma/pancreas/breast cancers treated in 1405 hospitals, recurrence information was incomplete in 21.5/24.0/20.2/34.8/18.2 % of patients, respectively. On average, hospitals had incomplete recurrence information on 56.7-66.7 % of their patients. Patients with incomplete information had more comorbidities, a higher cancer stage, non-private insurance, and lived farther from the hospital. Hospitals with the poorest collection were larger tertiary hospitals serving higher-income patients. However, these patients and hospital factors explained less than 3 %, while unexplained hospital variation accounted for the largest part of the observed variation (%ΔR (2) = 84 %).

The majority of hospitals report incomplete recurrence information for more than half of their patients. The presence of incomplete recurrence information was largely dependent on undefined hospital factors, rather than patient or tumor characteristics. Attempts to improve cancer recurrence information should focus on hospital operational and process factors surrounding how the hospital tumor registries collect recurrence data.