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Abstract: Background and Objective: Period analysis provides more up-to-date estimates of cancer patient survival than traditional methods, but there is a trade-off between up-to-dateness and precision. Our objective was to compare the performance of period and complete analysis in terms of up-to-dateness and precision of survival estimates. Study Design and Setting: Five-year relative survival data actually observed for patients diagnosed with 1 of 20 common forms of cancer in Finland in 36 overlapping 5-year periods between 1958–1962 and 1993–1997 were compared with period estimates and various variants of complete estimates of 5-year relative survival potentially available during these periods. Results: At comparable levels of up-to-dateness, survival estimates from period analysis were more precise than survival estimates from complete analysis. At comparable levels of precision, period analysis provided more up-to-date survival estimates than did complete analysis. Conclusion: These results further encourage more widespread use of period analysis as a standard tool for up-to-date monitoring of cancer patient survival by population-based cancer registries. [Copyright &y& Elsevier]

Abstract: Selective under-ascertainment of cancer patients by cancer registries may bias population-based estimates of cancer patient survival. As prognosis is strongly age related for many forms of cancer, age adjustment of cancer survival rates, which is primarily used to enhance the validity of comparative analyses between cancer populations, might also effectively reduce this type of bias. We empirically assessed this potential “side-effect” of age adjustment using data from the Finnish Cancer Registry. Analyses of five-year absolute and relative survival for patients diagnosed in 1990–1994, and age adjustment to the age structure of patients diagnosed in 1985–1989, were used as examples. Various patterns of selective under-ascertainment were simulated, and the bias in crude and age adjusted five-year survival rates was compared. Age adjusted estimates were less biased in most scenarios, which may be an additional argument for application of age adjustment in the analysis and reporting of population-based cancer survival rates. [Copyright &y& Elsevier]

Abstract: Up-to-date monitoring of long-term survival is an important task of population-based cancer registries. Period analysis, a new method of survival analysis introduced a few years ago, has been shown to be particularly useful for that purpose. The “classical” period analysis uses a life-table approach which requires both the year and month of diagnosis for implementation in pertinent software programs. However, an increasing number of cancer registries remove the month of diagnosis from their datasets, mainly to ensure the highest possible protection against re-identification of patients. In this paper, we present modifications of period analysis that allow the application of this technique, while almost completely preserving its advantages, in datasets without the month of diagnosis. The modified techniques are illustrated and evaluated using examples from the Surveillance, Epidemiology, and End Results (SEER) programme of the United States (US) National Cancer Institute (NCI), which also has removed month of diagnosis from its most recently released public use database. [Copyright &y& Elsevier]

Up-to-date monitoring of long-term survival is an important task of population-based and clinical cancer registries. A few years ago, a new method of survival analysis, denoted period analysis, was introduced to provide more up-to-date estimates of long-term survival. However, a prototypical period analysis may not be applicable in situations with delayed recording of incident cases. We introduce herein a hybrid type of analysis that combines elements of both traditional and period analyses which may still be feasible in such settings. The performance of the hybrid type of analysis compared with other design options is empirically evaluated and illustrated for children diagnosed with cancer in the United States. The empirical evaluation indicates that hybrid analysis may be useful to derive more up-to-date estimates of long-term survival compared with traditional design options if there is a strong improvement of survival over time, even in situations with a substantial delay in recording of incident cases. [Copyright &y& Elsevier]