Impact of variation in cancer registration practice on observed international cancer survival differences between International Cancer Benchmarking Partnership (ICBP) jurisdictions

Identifying a common data dictionary across colorectal cancer outcome registries: A mapping exercise to identify opportunities for data dictionary harmonisation

IMPORTANCE

The development of colorectal cancer outcome registries internationally has been organic, with differing datasets, data definitions and infrastructure across registries which has limited data pooling and international comparison. Currently there is no comprehensive data dictionary identified as a standard. This study is part of an international collaboration that aims to identify areas of data capture and usage which may be optimised to improve understanding of colorectal cancer outcomes.

OBJECTIVE

This study aimed to compare and identify commonalities and areas of difference across major colorectal cancer registries. We sought to establish datasets comprising of mutually collected common fields, and a combined comprehensive dataset of all collected fields across major registries to aid in establishing a future colorectal cancer registry database standard.

DESIGN AND METHODS

This mixed qualitative and quantitative study compared data dictionaries from three major colorectal cancer outcome registries: Bowel Cancer Outcomes Registry (BCOR) (Australia and New Zealand), National Bowel Cancer Audit (NBOCA) (United Kingdom) and Dutch ColoRectal Audit (DCRA) (Netherlands). Registries were compared and analysed thematically, and a common dataset and combined comprehensive dataset were developed. These generated datasets were compared to data dictionaries from Sweden (SCRCR), Denmark (DCCG), Argentina (BNCCR-A) and the USA (NAACCR and ACS NSQIP). Fields were assessed against prominent quality indicator metrics from the literature and current case-use.

RESULTS

We developed a combined comprehensive dataset of 225 fields under seven domains: demographic, pre-operative, operative, post-operative, pathology, neoadjuvant therapy, adjuvant therapy, and follow up/recurrence. A common dataset was developed comprising 38 overlapping fields, showing a low degree of mutually collected data, especially in preoperative, post operative and adjuvant therapy domains. The BNCCR-A, SCRCR and DCCG databases all contained a high percentage of common dataset fields. Fields were poorly comparable when viewed form current quality indicator metrics.

CONCLUSION

This study mapped data dictionaries of prominent colorectal cancer registries and highlighted areas of commonality and difference The developed common field dataset provides a foundation for registries to benchmark themselves and work towards harmonisation of data dictionaries. This has the potential to enable meaningful large-scale international outcomes research.

Trends in survival for cancer patients aged 65 years or over from 1995 to 2014 in the United States: A population-based study

BACKGROUND

Adults aged 65 years and above account for over half of all cancer diagnoses in the United States, but little is known about trend of elderly cancer survival in the United States. We aimed to assess the survival trend for elderly cancer in the United States from 1995 to 2014.

METHODS

We used data from Surveillance, Epidemiology, and End Results 12 registries and included 1,112,441 eligible patients aged 65 years or older who were diagnosed between 1995 and 2014 with cancer and followed up until December 2019. Overall and stage-specific 5-year relative survival, ratio of observed survival to expected survival, with 95% confidence intervals (CIs) of elderly cancer patients stratified by age were estimated during four periods (1995-1999, 2000-2004, 2005-2009, and 2010-2014). Cox proportional hazards models were used to estimate hazard ratios for cancer-specific death among patients diagnosed during 2000-2004, 2005-2009, 2010-2014, compared diagnoses in 1995-1999. We also calculated stage distribution and treatment rate during four periods.

RESULTS

In the United States, 5-year relative survival for elderly cancer patients improved from 57.3% (95% CIs 57.0-57.5) in 1995-1999 to 60.7% (60.5-60.9) in 2010-2014. After controlling for sociodemographic and tumor characteristics, about a 19% reduction in cancer-specific deaths among diagnoses in 2010-2014 compared with 1995-1999. Cancer survival improved for elderly patients in all age groups, with exception of stable survival for patients aged 85 and above. Comparing 1995-1999 with 2010-2014, relative survival improved from 84.7% (84.3-85.1) to 86.7% (86.3-87.0) for localized stage and from 12.4% (12.1-12.7) to 18.7% (18.4-19.0) for distant stage for all cancers combined. The trends in stage distribution and treatment rate for all cancers combined were relatively stable.

CONCLUSIONS

In the United States, survival for elderly cancer patients has improved slightly from 1995 to 2014, possibly mainly due to advances in treatment. Further studies are warranted to explore interventions to improve elderly cancer survival.

Evaluation of the Effect of Carvedilol in Preventing Right Ventricular Dysfunction in Breast Cancer Patients Receiving Anthracycline

Background

Today, it has been shown that it is possible for right ventricular (RV) wall motion abnormalities or RV functional disorders to occur during cancer treatment. Now, considering the effect of carvedilol on beta 1, 2, and alpha receptors and its antioxidant properties, it seems that it can prevent RV abnormalities. Therefore, the aim of this study was to investigate the possible protective effects of carvedilol in preventing RV dysfunction in patients with breast cancer treated with anthracyclines.

Materials and Methods

The present single-blind clinical trial study was performed on 23 patients with breast cancer that 12 of them received only the anthracycline antineoplastic doxorubicin (Adriamycin^®) chemotherapy (control group) and 11 patients received carvedilol in addition to anthracycline. To evaluate the effect of carvedilol, patients underwent transthoracic echocardiography before intervention and 2 weeks after the end of treatment with anthracyclines.

Results

The two parameters of RV ejection fraction and RV fractional area change in the carvedilol group with a mean of 66.41% ± 8.10% and 51.85% ± 6.89% were slightly higher than the control group with a mean of 64.58% ± 6.83% and 50.48 ± 5.79%, respectively, which was not statistically significant (P > 0.05). In contrast, RV S wave tissue Doppler imaging (S-TDI) in the control group with a mean of 0.13 ± 0.02 m/s was significantly lower than the carvedilol group with a mean of 0.14 ± 0.02 m/s (P = 0.022).

Conclusion

According to the results of the present study, the effect of using carvedilol as a preservative on improving RV function was seen compared to the control group, although this difference was not statistically significant.

Paradoxes of breast cancer incidence and mortality in two corners of Europe

BACKGROUND

Breast cancer incidence is rising globally, while mortality rates show a geographical heterogenous pattern. Early detection and treatment have been proven to have a profound impact on breast cancer prognosis. The aim of his study was to compare breast cancer incidence, mortality, and survival rates in two contrasting corners of Europe, Sweden and Crete, to better understand cancer determinants with focus on disease burden and sociocultural factors.

METHODS

Breast cancer data from Sweden and Crete was derived from registries. Incidence and mortality were expressed as Age-Standardized Incidence Rates (ASIR), Age-Standardized Mortality Rates (ASMR).

FINDINGS

Breast cancer incidence has for decades risen in Sweden and on Crete. In 2019, ASIR was 217.5 in Sweden and 58.9 on Crete, (p < 0.001). Mortality rates showed opposite trends. ASMR in Sweden was reduced from 25.5 to 16.8 (2005-2019) while on Crete, ASMR increased from 22.1 to 25.3. A successive rise in survival rate in Sweden with a 5-year survival rate of 92% since 2015, but a converse development on Crete with 85% 5-year survival rate the same year.

INTERPRETATION

The incidence of breast cancer is slowly rising in both studied regions, but mortality increases on Crete in contrast to Sweden with sinking mortality rates. The interpretation of these findings is that differences in health care systems and health policies including differences in early detection like screening programs and early treatment, as well as sociocultural factors in the two countries might play an important role on the differences found in breast cancer burden.

Exploring the link between cancer policies and cancer survival: a comparison of International Cancer Benchmarking Partnership countries

Cancer policy differences might help to explain international variation in cancer survival, but empirical evidence is scarce. We reviewed cancer policies in 20 International Cancer Benchmarking Partnership jurisdictions in seven countries and did exploratory analyses linking an index of cancer policy consistency over time, with monitoring and implementation mechanisms, to survival from seven cancers in a subset of ten jurisdictions from 1995 to 2014. All ten jurisdictions had structures in place to oversee or deliver cancer control policies and had published at least one major cancer plan. Few cancer plans had explicit budgets for implementation or mandated external evaluation. Cancer policy consistency was positively correlated with improvements in survival over time for six of the seven cancer sites. Jurisdictions that scored the highest on policy consistency had large improvements in survival for most sites. Our analysis provides an important first step to systematically capture and evaluate what are inherently complex policy processes. The findings can help guide policy makers seeking approaches and frameworks to improve cancer services and, ultimately, cancer outcomes.

Five ways to improve international comparisons of cancer survival: lessons learned from ICBP SURVMARK-2

BACKGROUND

Comparisons of population-based cancer survival between countries are important to benchmark the overall effectiveness of cancer management. The International Cancer Benchmarking Partnership (ICBP) Survmark-2 study aims to compare survival in seven high-income countries across eight cancer sites and explore reasons for the observed differences. A critical aspect in ensuring comparability in the reported survival estimates are similarities in practice across cancer registries. While ICBP Survmark-2 has shown these differences are unlikely to explain the observed differences in cancer-specific survival between countries, it is important to keep in mind potential biases linked to registry practice and understand their likely impact.

METHODS

Based on experiences gained within ICBP Survmark-2, we have developed a set of recommendations that seek to optimally harmonise cancer registry datasets to improve future benchmarking exercises.

RESULTS

Our recommendations stem from considering the impact on cancer survival estimates in five key areas: (1) the completeness of the registry and the availability of registration sources; (2) the inclusion of death certification as a source of identifying cases; (3) the specification of the date of incidence; (4) the approach to handling multiple primary tumours and (5) the quality of linkage of cases to the deaths register.

CONCLUSION

These recommendations seek to improve comparability whilst maintaining the opportunity to understand and act upon international variations in outcomes among cancer patients.

Evaluation of Whole Brain Radiotherapy among Lung Cancer Patients with Brain Metastases in Relation to Health Care Level and Survival

Whole-brain radiotherapy (WBRT) as a treatment for brain metastases has been questioned over the last years. This study aimed to evaluate health care levels and survival after WBRT in a cohort of lung cancer patients with brain metastases receiving WBRT in Stockholm, Sweden, from 2008 to 2019 (n = 384). If the patients were able to come home again was estimated using logistic regression and odds ratios (OR) and survival by using Cox regression. The median age in the cohort was 65.6 years, the median survival following WBRT was 2.4 months (interquartile range (IQR) 1.2–6.2 months), and 84 (22%) patients were not able to come home after treatment. Significantly more males could come home again after WBRT compared to women (OR = 0.37, 95%CI 0.20–0.68). Patients with performance status scores WHO 3–4 had a median survival of 1.0 months, hazard ratio (HR) = 4.69 (95%CI 3.31–6.64) versus WHO score 0–1. Patients admitted to a palliative ward before WBRT had a median survival of 0.85 months, HR = 2.26 (95%CI 1.53–3.34) versus being at home. In conclusion, patients treated with WBRT had a short median survival and 20% could not be discharged from the hospital following treatment. Significantly more women did not come home again.

Comparison of liver cancer incidence and survival by subtypes across seven high-income countries

International comparison of liver cancer survival has been hampered due to varying standards and degrees for morphological verification and differences in coding practices. This article aims to compare liver cancer survival across the International Cancer Benchmarking Partnership's (ICBP) jurisdictions whilst trying to ensure that the estimates are comparable through a range of sensitivity analyses. Liver cancer incidence data from 21 jurisdictions in 7 countries (Australia, Canada, Denmark, Ireland, New Zealand, Norway and the United Kingdom) were obtained from population-based registries for 1995-2014. Cases were categorised based on histological classification, age-groups, basis of diagnosis and calendar period. Age-standardised incidence rate (ASR) per 100 000 and net survival at 1 and 3 years after diagnosis were estimated. Liver cancer incidence rates increased over time across all ICBP jurisdictions, particularly for hepatocellular carcinoma (HCC) with the largest relative increase in the United Kingdom, increasing from 1.3 to 4.4 per 100 000 person-years between 1995 and 2014. Australia had the highest age-standardised 1-year and 3-year net survival for all liver cancers combined (48.7% and 28.1%, respectively) in the most recent calendar period, which was still true for morphologically verified tumours when making restrictions to ensure consistent coding and classification. Survival from liver cancers is poor in all countries. The incidence of HCC is increasing alongside the proportion of nonmicroscopically verified cases over time. Survival estimates for all liver tumours combined should be interpreted in this context. Care is needed to ensure that international comparisons are performed on appropriately comparable patients, with careful consideration of coding practice variations.

Examining the Landscape of Prognostic Factors and Clinical Outcomes for Cancer Control

Prognostic factors have important utility in various aspects of cancer surveillance, including research, patient care, and cancer control programmes. Nevertheless, there is heterogeneity in the collection of prognostic factors and outcomes data globally. This study aimed to investigate perspectives on the utility and application of prognostic factors and clinical outcomes in cancer control programmes. A qualitative phenomenology approach using expert interviews was taken to derive a rich description of the current state and future outlook of cancer prognostic factors and clinical outcomes. Individuals with expertise in this work and from various regions and institutions were invited to take part in one-on-one semi-structured interviews. Four areas related to infrastructure and funding challenges were identified by participants, including (1) data collection and access; (2) variability in data reporting, coding, and definitions; (3) limited coordination among databases; and (4) conceptualization and prioritization of meaningful prognostic factors and outcomes. Two areas were identified regarding important future priorities for cancer control: (1) global investment and intention in cancer surveillance and (2) data governance and exchange globally. Participants emphasized the need for better global collection of prognostic factors and clinical outcomes data and support for standardized data collection and data exchange practices by cancer registries.

The validity of cancer information on death certificates in Norway and the impact of death certificate initiated cases on cancer incidence and survival

BACKGROUND

Death certificates are an important source of information for cancer registries. The aim of this study was to validate the cancer information on death certificates, and to investigate the effect of including death certificate initiated (DCI) cases in the Cancer Registry of Norway when estimating cancer incidence and survival.

METHODS

All deaths in Norway in the period 2011-2015 with cancer mentioned on the death certificates were linked to the cancer registry. Notifications not registered from other sources were labelled death certificate notifications (DCNs), and considered as either cancer or not, based on available information in the registry or from trace-back to another source.

RESULTS

From the total of 65 091 cancers mentioned on death certificates in the period 2011-2015, 58,425 (89.8%) were already in the registry. Of the remaining 6 666 notifications, 2 636 (2 129 with cancer as underlying cause) were not regarded to be new cancers, which constitutes 4.0% of all cancers mentioned on death certificates and 39.5% of the DCNs. Inclusion of the DCI cases increased the incidence of all cancers combined by 2.6%, with largest differences for cancers with poorer prognosis and for older age groups. Without validation, including the 2 129 disregarded death certificates would over-estimate the incidence by 1.3%. Including DCI cases decreased the five-year relative survival estimate for all cancer sites combined with 0.5% points.

CONCLUSION

In this study, almost 40% of the DCNs were regarded not to be a new cancer case, indicating unreliability of death certificate information for cancers that are not already registered from other sources. The majority of the DCNs where, however, registered as new cases that would have been missed without death certificates. Both including and excluding the DCI cases will potentially bias the survival estimates, but in different directions. This biases were shown to be small in the Cancer Registry of Norway.

Influence of age on surgical treatment and postoperative outcomes of patients with colorectal cancer in Denmark and Yorkshire, England

AIM

Denmark and Yorkshire are demographically similar and both have undergone changes in their management of colorectal cancer to improve outcomes. The differential provision of surgical treatment, especially in the older age groups, may contribute to the magnitude of improved survival rates. This study aimed to identify differences in the management of colorectal cancer surgery and postoperative outcomes according to patient age between Denmark and Yorkshire.

METHOD

This was a retrospective population-based study of colorectal cancer patients diagnosed in Denmark and Yorkshire between 2005 and 2016. Proportions of patients undergoing major surgical resection, postoperative mortality and relative survival were compared between Denmark and Yorkshire across several age groups (18-59, 60-69, 70-79 and ≥80 years) and over time.

RESULTS

The use of major surgical resection was higher in Denmark than in Yorkshire, especially for patients aged ≥80 years (70.5% versus 50.5% for colon cancer, 49.3% versus 38.1% for rectal cancer). Thirty-day postoperative mortality for Danish patients aged ≥80 years was significantly higher than that for Yorkshire patients with colonic cancer [OR (95% CI) = 1.22 (1.07, 1.38)] but not for rectal cancer or for 1-year postoperative mortality. Relative survival significantly increased in all patients aged ≥80 years except for Yorkshire patients with colonic cancer.

CONCLUSION

This study suggests that there are major differences between the management of elderly patients with colorectal cancer between the two populations. Improved selection for surgery and better peri- and postoperative care in these patients appears to improve long-term outcomes, but may come at the cost of a higher 30-day mortality.

Colon and rectal cancer survival in seven high-income countries 2010-2014: variation by age and stage at diagnosis (the ICBP SURVMARK-2 project)

OBJECTIVES

As part of the International Cancer Benchmarking Partnership (ICBP) SURVMARK-2 project, we provide the most recent estimates of colon and rectal cancer survival in seven high-income countries by age and stage at diagnosis.

METHODS

Data from 386 870 patients diagnosed during 2010-2014 from 19 cancer registries in seven countries (Australia, Canada, Denmark, Ireland, New Zealand, Norway and the UK) were analysed. 1-year and 5-year net survival from colon and rectal cancer were estimated by stage at diagnosis, age and country, RESULTS: (One1-year) and 5-year net survival varied between (77.1% and 87.5%) 59.1% and 70.9% and (84.8% and 90.0%) 61.6% and 70.9% for colon and rectal cancer, respectively. Survival was consistently higher in Australia, Canada and Norway, with smaller proportions of patients with metastatic disease in Canada and Australia. International differences in (1-year) and 5-year survival were most pronounced for regional and distant colon cancer ranging between (86.0% and 94.1%) 62.5% and 77.5% and (40.7% and 56.4%) 8.0% and 17.3%, respectively. Similar patterns were observed for rectal cancer. Stage distribution of colon and rectal cancers by age varied across countries with marked survival differences for patients with metastatic disease and diagnosed at older ages (irrespective of stage).

CONCLUSIONS

Survival disparities for colon and rectal cancer across high-income countries are likely explained by earlier diagnosis in some countries and differences in treatment for regional and distant disease, as well as older age at diagnosis. Differences in cancer registration practice and different staging systems across countries may have impacted the comparisons.

Estimates of lung and pancreatic cancer survival in Sweden with and without inclusion of death certificate initiated (DCI) cases

INTRODUCTION

International differences in cancer incidence and survival may partly reflect differences in cancer registration practices. As opposed to most other National Cancer Registries, Death Certificate Initiated (DCI) cases are not included in the Swedish Cancer Register. We characterized cases not reported to the Swedish Cancer Register and assessed the impact of inclusion of DCI cases on the completeness and estimates of one-year lung and pancreatic cancer survival.

METHODS

We used information in the Swedish Cause of Death Register to identify individuals in two Health Care Regions (West and Uppsala Örebro) with lung or pancreatic cancer as cause of death in 2013. These records were cross-linked to the Cancer Register to identify individuals without a corresponding cancer registration, i.e. Death Certificate Notified (DCN) cases. DCN cases were cross-linked to the Patient Register to retrieve hospital discharge information to confirm the diagnosis. In a separate step, trace-back of DCN cases was performed to access medical records to validate the diagnosis.

RESULTS

Following validity checks, an estimated 16% and 34% of individuals with a diagnosis of lung or pancreatic cancer, respectively, had not been reported to the SCR. Non-reported patients were older and had a considerable poorer survival than those included in the SCR. Inclusion of DCI cases decreased one-year lung cancer overall survival from 45% to 41%. The corresponding decrease for pancreatic cancer was five percentage points, from 29% to 24%.

CONCLUSIONS

Lung and pancreatic cancers are underreported to the SCR yielding too low incidence rates and upward biased survival estimates. We conclude that implementation of systematic death certificate processing with trace-back is feasible also within the Swedish system with regionalized cancer reporting. Verifying registrability by use of information in the Patient Register provided a good approximation of "corrected" survival estimates based on chart review.

Can different definitions of date of cancer incidence explain observed international variation in cancer survival? An ICBP SURVMARK-2 study

BACKGROUND

Differences in registration practices across population-based cancer registries may contribute to international variation in survival estimates. In particular, there are variations in recorded date of incidence (DOI) as cancer registries have access to different sources of information and use different rules to determine an official DOI. This study investigates the impact of different DOI rules on cancer survival estimates.

MATERIALS AND METHODS

Detailed data on dates of pathological confirmation and hospital admittance were collected from three registries participating in the ICBP SURVMARK-2 project (England, Northern Ireland and Norway). Multiple dates of incidence were determined for each cancer patient diagnosed during 2010-2014 by applying three sets of rules that prioritize either: a) histological date, b) hospital admittance date or c) the earliest date recorded. For each set of rules and registry, 1- and 5-year net survival were estimated for eight cancer sites (oesophagus, stomach, colon, rectum, liver, pancreas, lung and ovary).

RESULTS

The mean difference between different DOIs within a country and cancer site ranged from 0.1-23 days. The variation in 1- and 5-year net survival using different DOIs were generally small for all registries and cancer sites. Only for liver and pancreatic cancer in Norway and ovarian cancer in England, were larger 1-year survival differences, of 2-3 % found.

CONCLUSION

In the ongoing discussion of the comparability of survival estimates across registry populations, the use of different DOI definitions can be considered to have a very limited impact.

Longer-term (≥ 2 years) survival in patients with glioblastoma in population-based studies pre- and post-2005: a systematic review and meta-analysis

Translation of survival benefits observed in glioblastoma clinical trials to populations and to longer-term survival remains uncertain. We aimed to assess if ≥ 2-year survival has changed in relation to the trial of radiotherapy plus concomitant and adjuvant temozolomide published in 2005. We searched MEDLINE and Embase for population-based studies with ≥ 50 patients published after 2002 reporting survival at ≥ 2 years following glioblastoma diagnosis. Primary endpoints were survival at 2-, 3- and 5-years stratified by recruitment period. We meta-analysed survival estimates using a random effects model stratified according to whether recruitment ended before 2005 (earlier) or started during or after 2005 (later). PROSPERO registration number CRD42019130035. Twenty-three populations from 63 potentially eligible studies contributed to the meta-analyses. Pooled 2-year overall survival estimates for the earlier and later study periods were 9% (95% confidence interval [CI] 6-12%; n/N = 1,488/17,507) and 18% (95% CI 14-22%; n/N = 5,670/32,390), respectively. Similarly, pooled 3-year survival estimates increased from 4% (95% CI 2-6%; n/N = 325/10,556) to 11% (95% CI 9-14%; n/N = 1900/16,397). One study with a within-population comparison showed similar improvement in survival among the older population. Pooled 5-year survival estimates were 3% (95% CI 1-5%; n/N = 401/14,919) and 4% (95% CI 2-5%; n/N = 1,291/28,748) for the earlier and later periods, respectively. Meta-analyses of real-world data suggested a doubling of 2- and 3-year survival in glioblastoma patients since 2005. However, 5-year survival remains poor with no apparent improvement. Detailed clinically annotated population-based data and further molecular characterization of longer-term survivors may explain the unchanged survival beyond 5 years.

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

BACKGROUND

Population-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.

METHODS

In 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.

FINDINGS

In 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.

INTERPRETATION

The 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.

FUNDING

Canadian Partnership Against Cancer; Cancer Council Victoria; Cancer Institute New South Wales; Cancer Research UK; Danish Cancer Society; National Cancer Registry Ireland; The Cancer Society of New Zealand; National Health Service England; Norwegian Cancer Society; Public Health Agency Northern Ireland, on behalf of the Northern Ireland Cancer Registry; The Scottish Government; Western Australia Department of Health; and Wales Cancer Network.