Delay Databases by Stage
Databases that use delay adjustment factors and consider stage for prostate and breast cancers are released with the SEER Research Plus data. Stage was considered for prostate, breast, lung, and colorectal cancers, and while stage made only modest differences in delay for lung and colorectal cancers, it made more substantial differences for prostate and breast cancers. Therefore the databases that consider stage include only prostate and breast cancers. The stages include “un-staged”, “local”, “regional”, and “distant.” Stage was added as an additional stratification variable in addition to cancer site and registry, and the analyses proceeded otherwise the same as with the non-stage variables. Deriving delay-adjusted rates by stage for lung and colorectal cancers using factors unadjusted for stage should be reasonable since it has been determined that different factors are not needed.
Consistent staging was achieved using SEER Summary Stage 2000 for 2001-2003 and using Derived Summary Stage 2000 for 2004 forward. When the Derived Summary Stage 2000 was missing, the abstracted stage was used if the reporting source was deemed reliable. Although the delay factors are attached to cases based on summary stage, derivations by stage using any of the available staging systems (e.g. AJCC staging) should provide a reasonable approximation of delay adjusted rates by stage using that staging system.
For breast and prostate cancer, the delay factors for distant and unstaged disease were much larger than for local and regional disease. In fact, for prostate cancer the delay factors were found to be twice as large for distant and unstaged disease in comparison with local and regional disease. In the Annual Report to the Nation1 with a special section on recent changes in prostate cancer trends, it was stated that “in prostate cancer, patients with local and regional disease are more likely to undergo radical prostatectomy. Because the surgery is performed in a hospital setting whereas other treatment modalities are administered in outpatient centers, there might be a differential delay in reporting by stage based on the location of treatment.”
- Negoita S, Feuer EJ, Mariotto A, Cronin KA, Petkov VI, Hussey SK, Benard V, Henley SJ, Anderson RN, Fedewa S, Sherman RL, Kohler BA, Dearmon BJ, Lake AJ, Ma J, Richardson LC, Jemal A, Penberthy L. Annual Report to the Nation on the Status of Cancer, part II: Recent changes in prostate cancer trends and disease characteristics. Cancer. 2018;124(13):2801-2814. doi:10.1002/cncr.31549