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Background: The proportion of cases notified by death certificate only (DCO) is a commonly used data quality indicator in studies comparing cancer survival across regions and over time. We aimed to assess dependence of DCO proportions on the age structure of cancer patients. Methods: Using data from a national cancer survival study in Germany, we determined age specific and overall (crude) DCO proportions for 24 common forms of cancer. We then derived overall (crude) DCO proportions expected in case of shifts of the age distribution of the cancer populations by 5 and 10 years, respectively, assuming age specific DCO proportions to remain constant. Results: Median DCO proportions across the 24 cancers were 2.4, 3.7, 5.5, 8.5 and 23.9% in age groups 15-44, 45-54, 55-64, 65-74, and 75+, respectively. A decrease of ages by 5 and 10 years resulted in decreases of cancer specific crude DCO proportions ranging from 0.4 to 4.8 and from 0.7 to 8.6 percent units, respectively. Conversely, an increase of ages by 5 and 10 years led to increases of cancer specific crude DCO proportions ranging from 0.8 to 4.8 and from 1.8 to 9.6 percent units, respectively. These changes were of similar magnitude (but in opposite direction) as changes in crude 5-year relative survival resulting from the same shifts in age distribution. Conclusions: The age structure of cancer patient populations has a substantial impact on DCO proportions. DCO proportions should therefore be age adjusted in comparative studies on cancer survival across regions and over time. [ABSTRACT FROM AUTHOR]

Abstract: Within the past 10–15 years, major advances in therapy have strongly improved prognosis of patients with chronic myelocytic leukaemia (CML). We estimated trends in 5- and 10-year relative survival of patients developing CML after a previous malignancy in the United States from 1990–1994 to 2000–2004. Period analysis was employed to disclose recent developments with minimum delay. Overall, 5- and 10-year relative survival increased from 17.6% to 37.7% (p <0.0001) and from 7.6% to 23.8% (p <0.0001), respectively. Improvements were particularly strong in younger age groups. Prognosis of CML patients with previous malignancy no longer lags behind prognosis of patients with primary CML. [Copyright &y& Elsevier]

Abstract: Period analysis has been shown to provide more up-to-date estimates of long-term cancer survival rates than traditional cohort-based analysis. Here, we provide detailed period estimates of 5- and 10-year relative survival by cancer site, country, sex and age for calendar years 2000–2002. In addition, pan-European estimates of 1-, 5- and 10-year relative survival are provided. Overall, survival estimates were mostly higher than previously available cohort estimates. For most cancer sites, survival in countries from Northern Europe, Central Europe and Southern Europe was substantially higher than in the United Kingdom and Ireland and in countries from Eastern Europe. Furthermore, relative survival was also better in female than in male patients and decreased with age for most cancer sites. [Copyright &y& Elsevier]

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]

Abstract: The measures of cancer prognosis most commonly reported by cancer registries are 5- or 10-year absolute or relative survival rates. Because cancer survival rates often vary by the age of cancer patients, and because the age structure of cancer patients often varies between populations, age adjustment is crucial for comparative analyses of cancer survival rates. However, traditional age adjustment often breaks down for long-term survival rates, particularly for sparse data, and it may provide inconsistent results for relative survival rates, even if age adjustment is made to the study population’s own age distribution. In this manuscript, we propose an alternative approach to age adjustment of both absolute and relative survival rates to overcome both the practical and conceptual problems inherent in traditional age adjustment. We outline the computational realisation of this approach, and we give an empirical illustration of its application using data from the nationwide Finnish Cancer Registry. [Copyright &y& Elsevier]

Relative survival rates, such as 5- or 10-year relative survival rates, which quantify “net survival” of cancer patients, are the most commonly reported measures of cancer outcome by cancer registries. Because relative survival rates vary with age for many forms of cancer, and because the age distribution of cancer patients varies between different populations or within one population over time, age adjustment of relative survival rates is often employed in international comparisons or in time series analyses of cancer patient survival. In this article, we show that derivation of crude and of age-adjusted relative survival rates in the traditional way is conceptually inconsistent, and that this inconsistency has important practical implications. We show ways to overcome this inconsistency in the derivation and interpretation of crude and age-adjusted relative survival rates. [Copyright &y& Elsevier]

Background: Previous population-based studies revealed major variation in survival for patients with colorectal cancer (CRC) in Europe by age and between different countries and regions, but also a sustained improvement in survival for patients with CRC in recent years. This EUROCARE-5 paper aims to update available knowledge from previous studies and to provide the latest survival estimates for CRC patients from Europe. Methods: The study analysed data of patients diagnosed with CRC from population-based cancer registries diagnosed in 29 European countries. Estimates of 1-year and 5-year relative survival (RS) were derived for patients diagnosed in 2000-2007 by European region, country and age at diagnosis. Additionally to these cohort estimates, time trends in 5-year RS were obtained for the calendar periods 1999-2001 and 2005-2007, using the period analysis methodology. Results: European average 5-year RS for patients diagnosed with colon and rectum cancer was 57% and 56%, respectively. The analyses showed persistent differences in cancer survival across Europe with lowest survival for CRC patients observed in Eastern Europe. The analyses further showed a strong gradient in age-specific survival. Even though the study revealed sustained improvement in patient survival between 1999-2001 and 2005-2007 (absolute increase of 4 and 6 percentage points for colon and rectum, respectively), the differences in the survival for CRC patients observed at the beginning of the millennium persisted over time. Conclusion: Although survival for CRC patients in Europe improved markedly in the study period, significant geographic variations and a strong age gradient still persisted. Enhanced access to effective diagnostic procedures and treatment options might be the keys to reducing the existing disparities in the survival of CRC patients across Europe. [ABSTRACT FROM AUTHOR]

Abstract: In international comparisons of cancer registry based survival it is common practice to restrict the analysis to first primary tumours and exclude multiple cancers. The probability of correctly detecting subsequent cancers depends on the registry’s running time, which results in different proportions of excluded patients and may lead to biased comparisons. We evaluated the impact on the age-standardised relative survival estimates of also including multiple primary tumours. Data from 2,919,023 malignant cancers from 69 European cancer registries participating in the EUROCARE-4 collaborative study were used. A total of 183,683 multiple primary tumours were found, with an overall proportion of 6.3% over all the considered cancers, ranging from 0.4% (Naples, Italy) to 12.9% (Iceland). The proportion of multiple tumours varied greatly by type of tumour, being higher for those with high incidence and long survival (breast, prostate and colon-rectum). Five-year relative survival was lower when including patients with multiple cancers. For all cancers combined the average difference was –0.4 percentage points in women and –0.7 percentage points in men, and was greater for older registries. Inclusion of multiple tumours led to lower survival in 44 out of 45 cancer sites analysed, with the greatest differences found for larynx (–1.9%), oropharynx (–1.5%), and penis (–1.3%). Including multiple primary tumours in survival estimates for international comparison is advisable because it reduces the bias due to different observation periods, age, registration quality and completeness of registration. The general effect of inclusion is to reduce survival estimates by a variable amount depending on the proportion of multiple primaries and cancer site. [Copyright &y& Elsevier]