REFERENCE ADJUSTED AND STANDARDIZED ALL-CAUSE AND CRUDE PROBABILITIES AS AN ALTERNATIVE TO NET SURVIVAL IN POPULATION-BASED CANCER STUDIES

BackgroundIn population-based cancer survival studies the most common measure to compare population groups is age standardized marginal relative survival, which under assumptions can be interpreted as marginal net survival; the probability of surviving if it was not possible to die of causes other than the cancer under study (if the age distribution was that of a common reference population). The hypothetical nature of this definition has led to confusion and incorrect interpretation. For any measure to be fair in terms of comparing cancer survival, then differences between population groups should depend only on differences in excess mortality rates due to the cancer and not differences in other cause mortality rates or differences in the age distribution.MethodsWe propose using crude probabilities of death and all-cause survival that incorporate reference expected mortality rates. This makes it possible to obtain marginal crude probabilities and all-cause probability of death that only differ between population groups due to excess mortality rate differences. Choices have to be made regarding what reference mortality rates to use and what age distribution to standardize to.ResultsWe illustrate the method and some potential choices using data from England for men diagnosed with Melanoma. Various marginal measures are presented and compared.ConclusionsThe new measures help enhance understanding of cancer survival and are a complement to the more commonly used measures.</p

Outcome for children treated for medulloblastoma and supratentorial primitive neuroectodermal tumor (CNS-PNET) – a retrospective analysis spanning 40 years of treatment

<p><b>Background:</b> Medulloblastoma (MB) and supratentorial primitive neuroectodermal tumor of the central nervous system (CNS-PNET) are among the most common pediatric brain tumors. The diagnosis, treatment, and outcome of MB/CNS-PNET patients treated during the last four decades at Oslo University Hospital (OUH) are described.</p> <p><b>Material and methods:</b> All patients younger than 20 years of age diagnosed and treated for MB/CNS-PNET at OUH between 1 January 1974 and 31 December 2013 were identified.</p> <p><b>Results:</b> We found 175 patients. In 13 of them, the diagnosis was changed upon histopathological review and in 4 patients part of the treatment was administered at other hospitals. Thus, 158 patients were included for further analysis. Eight patients did not receive adjuvant therapy because of a dismal clinical condition. The overall 5-year survival rate for MB and CNS-PNET was 54%, for MB 57%, and for CNS-PNET 41%. Gross total resection (GTR) was achieved in 118 patients and 5-year overall survival for patients with GTR versus those with non-GTR differed significantly with 64% versus 22%. Cytological examination of the cerebrospinal fluid was performed in 52 patients. A total of 126 patients received radiotherapy as part of the primary treatment and 24 did not due to young age. Median time from surgery to start of radiotherapy was 33 days. Duration of radiotherapy was more than 48 days in 22% of patients. At the time of analysis, 63 patients were alive and disease-free, one alive with disease, and 94 patients were deceased; 84 of these due to MB/CNS-PNET and 10 due to supposed late effects from the treatment.</p> <p><b>Conclusions:</b> Survival was comparable to data from other population-based studies. The importance of GTR for survival was corroborated. Reporting real-world data remains crucial to know the true outcome of patients treated outside clinical trials.</p

Progress in cancer survival, mortality, and incidence in seven high-income countries 1995–2014 (ICBP SURVMARK-2): a population-based study

BackgroundPopulation-based cancer survival estimates provide valuable insights into the effectiveness of cancer services and can reflect the prospects of cure. As part of the second phase of the International Cancer Benchmarking Partnership (ICBP), the Cancer Survival in High-Income Countries (SURVMARK-2) project aims to provide a comprehensive overview of cancer survival across seven high-income countries and a comparative assessment of corresponding incidence and mortality trends.MethodsIn this longitudinal, population-based study, we collected patient-level data on 3·9 million patients with cancer from population-based cancer registries in 21 jurisdictions in seven countries (Australia, Canada, Denmark, Ireland, New Zealand, Norway, and the UK) for seven sites of cancer (oesophagus, stomach, colon, rectum, pancreas, lung, and ovary) diagnosed between 1995 and 2014, and followed up until Dec 31, 2015. We calculated age-standardised net survival at 1 year and 5 years after diagnosis by site, age group, and period of diagnosis. We mapped changes in incidence and mortality to changes in survival to assess progress in cancer control.FindingsIn 19 eligible jurisdictions, 3 764 543 cases of cancer were eligible for inclusion in the study. In the 19 included jurisdictions, over 1995–2014, 1-year and 5-year net survival increased in each country across almost all cancer types, with, for example, 5-year rectal cancer survival increasing more than 13 percentage points in Denmark, Ireland, and the UK. For 2010–14, survival was generally higher in Australia, Canada, and Norway than in New Zealand, Denmark, Ireland, and the UK. Over the study period, larger survival improvements were observed for patients younger than 75 years at diagnosis than those aged 75 years and older, and notably for cancers with a poor prognosis (ie, oesophagus, stomach, pancreas, and lung). Progress in cancer control (ie, increased survival, decreased mortality and incidence) over the study period was evident for stomach, colon, lung (in males), and ovarian cancer.InterpretationThe joint evaluation of trends in incidence, mortality, and survival indicated progress in four of the seven studied cancers. Cancer survival continues to increase across high-income countries; however, international disparities persist. While truly valid comparisons require differences in registration practice, classification, and coding to be minimal, stage of disease at diagnosis, timely access to effective treatment, and the extent of comorbidity are likely the main determinants of patient outcomes. Future studies are needed to assess the impact of these factors to further our understanding of international disparities in cancer survival.</div