Calculating age-adjusted cancer survival estimates when age-specific data are sparse: an empirical evaluation of various methods

We evaluated empirically the performance of various methods of calculating age-adjusted survival estimates when age-specific data are sparse. We have illustrated that a recently proposed alternative method of age adjustment involving the use of balanced age groups or age truncation may be useful for enhancing calculability and reliability of adjusted survival estimates

Effect of an antepartum Pap smear on the coverage of a cervical cancer screening programme: a population-based prospective study

BACKGROUND: Almost one-third of Norwegian women aged 25–69 years invited to have a Pap smear do not attend during the recommended period, and thus constitute a population with high-risk of cervical cancer (CC). Since the incidence of precancerous lesions of the cervix peak with occurrence of pregnancies within the same decade in women aged 25 to 35 years of age, antepartum care presents an opportunity to offer a Pap smear thereby increasing the coverage of the programme. The study objective was to describe the effect of the antepartum Pap smear on the coverage of a cytological CC screening programme. METHODS: Among 2 175 762 women resident in Norway in 31.12.1996, all women who gave birth in 1996–7 were identified from the Medical Birth Registry of Norway. Attendance to the cervical cancer screening was assessed by linkage to the Cytology Registry separately for the pregnant and non-pregnant women cohorts. The results were stratified by age, history of previous Pap smear and history of invitation to the CC screening programme. Logistic regression was used to estimate the relative probabilities of having a Pap smear adjusted for age, screening history, and time since invitation, for pregnant and non-pregnant women, respectively. RESULTS: 69% of the pregnant women had a Pap smear during one year of follow-up since beginning of the pregnancy with the majority taken during the antepartum period. Irrespectively of age or history of having a Pap smear, pregnant women were 4.3 times more likely to have a Pap smear during follow-up compared to non-pregnant women. 63.2% of the pregnant women had a smear as response to the invitation letter compared to 28.7% of the non-pregnant women, OR = 2.1 (95% CI 1.9 to 2.4). As an indication of "over-screening", 5397 pregnant women (57.8%) with a smear shortly before the start of follow-up also had a new Papsmear, compared to 83 023 (32.3%) in non-pregnant. CONCLUSION: Pap smear screening during pregnancy increases the coverage of the CC screening programme. The contribution of the antepartum Pap smear to "over-screening" exists but its effect is modest in countries where women on average become pregnant after the start of recommended age of screening

Prognostic value of morphology and hormone receptor status in breast cancer - a population based study

We analysed the 5-year relative survival among 4473 breast cancer cases diagnosed in 1990-1992 from cancer registries in Estonia, France, Italy, Spain, the Netherlands and the UK. Among eight categories based on ICD-O codes (infiltrating ductal carcinoma, lobular plus mixed carcinoma, comedocarcinoma, 'special types', medullary carcinoma, not otherwise specified (NOS) carcinoma, other carcinoma and cancer without microscopic confirmation), the 5-year relative survival ranged from 66% (95% CI 61-71) for NOS carcinoma to 95% (95% CI 90-100) for special types (tubular, apocrine, cribriform, papillary, mucinous and signet ring cell); 27% (95% CI 18-36) for cases without microscopic confirmation. Differences in 5-year relative survival by tumor morphology and hormone receptor status were modelled using a multiple regression approach based on generalised linear models. Morphology and hormone receptor status were confirmed as significant survival predictors in this population-based study, even after adjusting for age and stage at diagnosis

Global surveillance of cancer survival 1995-2009: analysis of individual data for 25,676,887 patients from 279 population-based registries in 67 countries (CONCORD-2)

BACKGROUND: Worldwide data for cancer survival are scarce. We aimed to initiate worldwide surveillance of cancer survival by central analysis of population-based registry data, as a metric of the effectiveness of health systems, and to inform global policy on cancer control. METHODS: Individual tumour records were submitted by 279 population-based cancer registries in 67 countries for 25·7 million adults (age 15-99 years) and 75,000 children (age 0-14 years) diagnosed with cancer during 1995-2009 and followed up to Dec 31, 2009, or later. We looked at cancers of the stomach, colon, rectum, liver, lung, breast (women), cervix, ovary, and prostate in adults, and adult and childhood leukaemia. Standardised quality control procedures were applied; errors were corrected by the registry concerned. We estimated 5-year net survival, adjusted for background mortality in every country or region by age (single year), sex, and calendar year, and by race or ethnic origin in some countries. Estimates were age-standardised with the International Cancer Survival Standard weights. FINDINGS: 5-year survival from colon, rectal, and breast cancers has increased steadily in most developed countries. For patients diagnosed during 2005-09, survival for colon and rectal cancer reached 60% or more in 22 countries around the world; for breast cancer, 5-year survival rose to 85% or higher in 17 countries worldwide. Liver and lung cancer remain lethal in all nations: for both cancers, 5-year survival is below 20% everywhere in Europe, in the range 15-19% in North America, and as low as 7-9% in Mongolia and Thailand. Striking rises in 5-year survival from prostate cancer have occurred in many countries: survival rose by 10-20% between 1995-99 and 2005-09 in 22 countries in South America, Asia, and Europe, but survival still varies widely around the world, from less than 60% in Bulgaria and Thailand to 95% or more in Brazil, Puerto Rico, and the USA. For cervical cancer, national estimates of 5-year survival range from less than 50% to more than 70%; regional variations are much wider, and improvements between 1995-99 and 2005-09 have generally been slight. For women diagnosed with ovarian cancer in 2005-09, 5-year survival was 40% or higher only in Ecuador, the USA, and 17 countries in Asia and Europe. 5-year survival for stomach cancer in 2005-09 was high (54-58%) in Japan and South Korea, compared with less than 40% in other countries. By contrast, 5-year survival from adult leukaemia in Japan and South Korea (18-23%) is lower than in most other countries. 5-year survival from childhood acute lymphoblastic leukaemia is less than 60% in several countries, but as high as 90% in Canada and four European countries, which suggests major deficiencies in the management of a largely curable disease. INTERPRETATION: International comparison of survival trends reveals very wide differences that are likely to be attributable to differences in access to early diagnosis and optimum treatment. Continuous worldwide surveillance of cancer survival should become an indispensable source of information for cancer patients and researchers and a stimulus for politicians to improve health policy and health-care systems

Age-specific cancer survival in Estonia: recent trends and data quality

Kaire Innos,1 Katrin Lang,2 Kersti Pärna,2 Tiiu Aareleid11Department of Epidemiology and Biostatistics, National Institute for Health Development, Tallinn, Estonia; 2Department of Public Health, University of Tartu, Tartu, EstoniaBackground: A number of population-based studies have demonstrated lower cancer survival in elderly patients than among middle-aged or younger patients. Also, data quality in cancer registries has been shown to be associated with age. The objective of this study was to examine the recent age-specific cancer survival trends and age-specific quality of cancer data in Estonia.Methods: Using Estonian Cancer Registry data, we calculated relative survival ratios (RSRs) for eight common cancers in Estonia in 1995–1999 (cohort method) and 2005–2009 (period method) for four major age groups (15–54, 55–64, 65–74, and 75–84 years at diagnosis). The main data quality indicators were calculated, and the age-specific effect of missing death certificate initiated (DCI) cases on survival was estimated comparing 5-year RSRs computed from the complete data set with those from data set without DCI cases.Results: We observed overall rise in 5-year RSR for all eight cancers over the study period, with a considerable variation by age, with the lowest survival among the oldest patients. The widest age gradient in 5-year RSR was seen for bladder cancer (20% units in 2005–2009), followed by cancers of lung (16% units), kidney (15% units), breast and prostate (13% units), stomach and rectum (11% units), and colon (5% units). All data quality indicators, including proportion of cases with unknown stage showed a similar age-related pattern with the lowest quality in the oldest age group. The effect of missing DCI cases on survival estimates increased by age and was around 3% units for prostate and kidney cancers among the oldest patients.Conclusion: Young or middle-aged patients in Estonia experienced larger survival gain since the late 1990s than elderly patients. Decreasing quality of cancer registry data along with increasing patient age suggests less thorough clinical investigations in older age groups.Keywords: cancer registry, population-based, relative survival, age differences, data qualit