Cancer incidence, stage shift and survival during the 2020 COVID-19 pandemic: A population-based study in Belgium.

The COVID-19 pandemic was associated with a profound decline in cancer diagnoses in 2020 in Belgium. Disruption in diagnostic and screening services and patient reluctance to visit health facilities led to fewer new cases and concerns that cancers may be diagnosed at more advanced stages and hence have poorer prognosis. Using data from mandatory cancer registration covering all of Belgium, we predicted cancer incidence, stage distribution and 1-year relative survival for 2020 using a Poisson count model over the preceding years, extrapolated to 2020 for 11 common cancer types. We compared these expected values to the observed values in 2020 to specifically quantify the impact of the COVID-19 pandemic, accounting for background trends. A significantly lower incidence was observed for cervical, prostate, head and neck, colorectal, bladder and breast cancer, with limited or no recovery of diagnoses in the second half of 2020 for these cancer types. Changes in stage distribution were observed for cervical, prostate, bladder and ovarian and fallopian tube tumours. Generally, changes in stage distribution mainly represented decline in early-stage than in late-stage tumours. One-year relative survival was lower than predicted for lung cancer and colorectal cancer. Stage shifts are hypothesised to result from alterations in access to diagnosis, potentially due to prioritisation of symptomatic patients, and patient reluctance to contact a physician. Since there were over 5000 fewer cancer diagnoses than expected by the end of 2020, it is critical to monitor incidence, stage distribution and survival for these cancers in the coming years.

Hospital Volume for Rectal Cancer Resection Plays a Pivotal Role in Improving Outcomes: A Population-based Analysis.

OBJECTIVE: Assessing the association between hospital surgical volume (SV) and outcomes after rectal cancer surgery (RCS), using national population-based data. SUMMARY BACKGROUND DATA: For RCS, the association of higher SV with improved short- and/or long-term outcomes remains controversial. METHODS: National cancer registry data and administrative data were used to select patients diagnosed with stage I-III rectal cancer in 2009-2018 and who underwent RCS. The average annual SV of RCS was categorised as low (<15; LV), medium (15-29; MV) or high (≥30; HV). The association between SV and 90-day and 1-year excess postoperative mortality (90DPM and 1YEPM) and 5-year observed survival (5YOS) was evaluated. RESULTS: From the 11,519 patients , RCS was performed in LV (4,088; 36%), MV (2,795; 24%) or HV (4,636; 40%) hospitals. Observed 90DPM was significantly better in HV (2.3% 95%CI[1.9,2.8]) than in LV (3.7% 95%CI[3.2,4.4]) and MV (3.5% 95%CI[2.9,4.3]) with adjusted OR 1.4, P<0.0001. Continuous regression analysis showed significantly higher 90DPM in annual SV <35 compared to ≥35 (OR 1.6 95%CI[1.21,2.11]; P=0.0009). Observed 1YEPM was significantly better in HV (2.9% 95%CI[2.2,3.6]) compared to LV (4.7% 95%CI [3.9,5.6]) with adjusted excess HR 1.31 95%CI[1.00,1.73] and P=0.05, and to MV (5.0% 95%CI[4.0,6.1]) with adjusted excess HR 1.45 95%CI[1.09,1.94] and P=0.01. The 5YOS was significantly better in HV (75.9% 95%CI[74.6,77.2]) than in LV (70.3% 95%CI[68.8,71.8]) and MV (71.5% 95%CI[69.7,73.2]) with adjusted HR 1.4 in both LV and MV versus HV, P≤0.003. CONCLUSIONS: This population-based study identified robustly superior outcomes at 90-days, 1-year and 5-years after RCS in hospitals with higher volumes.

Delayed treatment in breast cancer patients during the COVID-19 pandemic: a population health information research infrastructure (PHIRI) case study.

BACKGROUND: The indirect impact of the coronavirus disease 2019 pandemic on healthcare services was studied by assessing changes in the trend of the time to first treatment for women 18 or older who were diagnosed and treated for breast cancer between 2017 and 2021. METHODS: An observational retrospective longitudinal study based on aggregated data from four European Union (EU) countries/regions investigating the time it took to receive breast cancer treatment. We compiled outputs from a federated analysis to detect structural breakpoints, confirming the empirical breakpoints by differences between the trends observed and forecasted after March 2020. Finally, we built several segmented regressions to explore the association of contextual factors with the observed changes in treatment delays. RESULTS: We observed empirical structural breakpoints on the monthly median time to surgery trend in Aragon (ranging from 9.20 to 17.38 days), Marche (from 37.17 to 42.04 days) and Wales (from 28.67 to 35.08 days). On the contrary, no empirical structural breakpoints were observed in Belgium (ranging from 21.25 to 23.95 days) after the pandemic's beginning. Furthermore, we confirmed statistically significant differences between the observed trend and the forecasts for Aragon and Wales. Finally, we found the interaction between the region and the pandemic's start (before/after March 2020) significantly associated with the trend of delayed breast cancer treatment at the population level. CONCLUSIONS: Although they were not clinically relevant, only Aragon and Wales showed significant differences with expected delays after March 2020. However, experiences differed between countries/regions, pointing to structural factors other than the pandemic.

A Population-Based Study Using Belgian Cancer Registry Data Supports Centralization of Esophageal Cancer Surgery in Belgium.

BACKGROUND: Esophageal cancer surgery outcomes benefit from higher hospital volumes. Despite the evidence, organization of national health care often is complex and depends on various factors. The volume-outcome results of this population-based study supported national health policy measures regarding concentration of esophageal resections in Belgium. METHODS: The Belgian Cancer Registry (BCR) database was linked to administrative data on cancer treatment. All Belgian patients with newly diagnosed esophageal cancer in 2008-2018 undergoing resection were allocated to the hospital at which surgery was performed. The study assessed hospital volume association with 90-day mortality and 5-year overall survival, classifying average annual hospital volume of resections as low (LV, <6), medium (MV, 6-19), or high (HV, ≥20) and as a continuous covariate in the regression models. RESULTS: The study included 4156 patients who had surgery in 79 hospitals (2 HV hospitals [37% of all surgeries], 12 MV hospitals [30% of all surgeries], and 65 LV hospitals [33% of all surgeries]). Adjusted 90-day mortality in HV hospitals was lower than in LV hospitals (odds ratio [OR], 0.37; 95% CI, 0.21-0.65; p = 0.001). Case-mix adjusted 5-year survival was superior in HV versus LV (hazard ratio [HR], 0.43; 95% CI, 0.31-0.60; p < 0.001). The continuous model demonstrated a lower 90-day mortality (OR, 0.40; 95% CI, 0.23-0.71; p = 0.002) and a superior 5-year survival (HR, 0.45; 95% CI, 0.33-0.63; p < 0.001) in hospitals with volumes of 40 or more resections annually. CONCLUSION: Population-based data from the BCR confirmed a strong volume-outcome association for esophageal resections. Improved 5-year survival in centers with annual volumes of 20 or more resections was driven mainly by the achievement of superior 90-day mortality. These findings supported centralization of esophageal resections in Belgium.

The epidemiology of multiple primary cancers in Belgium (2004-2017): Incidence, proportion, risk, stage and impact on relative survival estimates.

BACKGROUND: As both life expectancy and cancer survival improve, the incidence of multiple primary cancer has augmented and is expected to further increase. This study describes for the first time the epidemiology of multiple invasive tumours in Belgium. METHODS: This nationwide study, based on all cancers diagnosed between 2004 and 2017 in Belgium, describes the proportion of multiple primary cancer, its evolution over time, the impact of inclusion or exclusion of multiple primary cancer on relative survival estimates, the risk of developing a second primary cancer, and the difference in stage between first and second primary cancer for the same patient. RESULTS: The proportion of multiple primary cancer increases with age, varies across cancer sites (from 4% for testis cancer to 22.8% for oesophageal cancer), is higher in men than in women, and has linearly increased over time. The inclusion of multiple primary cancer resulted in smaller 5-year relative survival and this impact is more pronounced in cancer sites with high relative survival. Patients with a first primary cancer have an increased risk to develop a new primary cancer compared to the population without a previous cancer history (1.27 and 1.59 times higher in men and women, respectively) and this risk depends on cancer site. Second primary cancers are associated with more advanced stages and more unknown stages than the corresponding first cancer diagnosis. CONCLUSIONS: This study describes multiple primary cancer according to several measures (proportion, standardised incidence ratio for an second primary cancer, impact of multiple primary cancer on relative survival and differences according to stage) for the first time in Belgium. The results are based on data of a population-based cancer registry with a relatively recent onset (2004).

Quality indicators in neuro-oncology: Review of the literature and development of a new quality indicator set for glioma care through a two-round Delphi survey.

BACKGROUND: Quality Indicators (QIs) are important tools to assess the quality and variability of oncological care. However, their application in neuro-oncology is limited so far. The objective of this study was to develop a set of QIs for glioma, covering process and outcome indicators. METHODS: A systematic review was conducted to identify both QIs in the field of adult glioma care, and guidelines or recommendations that could be translated into QIs. Also reports from national and international healthcare agencies and scientific associations ("grey literature") were taken into account. After conversion of these recommendations into QIs, merging with existing QIs found in the literature and rationalization, a two-round Delphi survey was conducted to gain consensus on relevance for the proposed QIs. RESULTS: In total 240 recommendations and 30 QIs were retrieved from the literature. After conversion, merging and rationalization, 147 QIs were evaluated in the Delphi survey and eventually consensus was gained on 47 QIs in the following 7 domains: Diagnosis and Imaging, Surgery, Pathology, Radio/Chemotherapy, Recurrence, Supportive Treatments (Epilepsy, Thromboembolism, Steroid Use and Rehabilitation) and Survival. CONCLUSION: This study defined a set of 47 QIs for assessing quality of care in adult glioma patients, distributed amongst 7 crucial phases in the patient's care trajectory. These QIs are readily applicable for use in diverse health care systems, depending on the availability of population-based health care data enabling (inter)national benchmarking.

Patterns and quality of care for head and neck cancer in Belgium: A population-based study.

OBJECTIVES: We evaluated the quality of care for patients with squamous cell carcinoma (SCC) of the oral cavity, oropharynx, hypopharynx or larynx in Belgium. METHODS: Data of the Belgian Cancer Registry were coupled with health insurance data and hospital discharge data. Quality of care and the association with hospital volume were evaluated based on six quality indicators. RESULTS: Half of the patients were treated with primary radiotherapy, with or without systemic therapy (49.7%) and 38.1% with surgery, with or without (neo)adjuvant therapy. Single-modality treatment was provided to 78.1% of early-disease patients. Of the patients with cN0 disease, 56.4% underwent neck dissection. Postoperative radiotherapy was completed timely in 48.5% of patients. Concomitant chemotherapy was administered to 58.2% of patients <70 years with locally advanced disease. Imaging of the neck after radiotherapy was performed appropriately in 32.7% of patients. Variability between centres was considerable. No clear relationship between hospital volume and results of the individual QIs was observed. CONCLUSIONS: Results show that for the measured QIs, targets are not met and variability between centres is considerable. Through individual feedback, centres are motivated to improve the quality of care for head and neck cancer patients in Belgium.

Development of paediatric non-stage prognosticator guidelines for population-based cancer registries and updates to the 2014 Toronto Paediatric Cancer Stage Guidelines.

Population-based cancer registries (PBCRs) generate measures of cancer incidence and survival that are essential for cancer surveillance, research, and cancer control strategies. In 2014, the Toronto Paediatric Cancer Stage Guidelines were developed to standardise how PBCRs collect data on the stage at diagnosis for childhood cancer cases. These guidelines have been implemented in multiple jurisdictions worldwide to facilitate international comparative studies of incidence and outcome. Robust stratification by risk also requires data on key non-stage prognosticators (NSPs). Key experts and stakeholders used a modified Delphi approach to establish principles guiding paediatric cancer NSP data collection. With the use of these principles, recommendations were made on which NSPs should be collected for the major malignancies in children. The 2014 Toronto Stage Guidelines were also reviewed and updated where necessary. Wide adoption of the resultant Paediatric NSP Guidelines and updated Toronto Stage Guidelines will enhance the harmonisation and use of childhood cancer data provided by PBCRs.

Benefits of switching from guaiac-based faecal occult blood to faecal immunochemical testing: experience from the Wallonia-Brussels colorectal cancer screening programme.

BACKGROUND: Faecal immunochemical tests (FITs) have replaced guaiac-based faecal occult blood test (gFOBTs) in several colorectal cancer (CRC) screening programmes. We aimed to evaluate the benefits of this transition based on the Wallonia-Brussels-organised CRC screening programme. METHODS: A total of 1,569,868 individuals aged 50-74 years, who were invited to screening during 2009-2017, were studied by linking their screening records with insurance, pathology and cancer data in the Belgian Cancer Registry. We compared neoplasm detection rates and positive predictive values (PPVs) of gFOBT and FIT at 15 µg haemoglobin per gram cut-off in screen-naive individuals. We furthermore examined the incidence rates of interval cancer in gFOBT- and FIT-based screening programme. RESULTS: Advanced neoplasms were detected less frequently by gFOBT (0.8%) than by FIT (1.3%), with a difference of 0.5% (P < 0.01). PPVs were lower for gFOBT (15.1%) than for FIT (21.7%) for advanced neoplasms (difference 6.6%, P < 0.01). Compared to participants with negative gFOBT, those with negative FIT were 77% less likely to develop interval cancer (incidence rate ratio 0.23, 95% confidence interval 0.16-0.33). CONCLUSION: Our study demonstrated that in an organised CRC screening programme, replacing gFOBT with FIT improved neoplasm detection rate and substantially reduced interval cancer incidence.

Resection of pancreatic cancer in Europe and USA: an international large-scale study highlighting large variations.

OBJECTIVE: Resection can potentially cure resectable pancreatic cancer (PaC) and significantly prolong survival in some patients. This large-scale international study aimed to investigate variations in resection for PaC in Europe and USA and determinants for its utilisation. DESIGN: Data from six European population-based cancer registries and the US Surveillance, Epidemiology, and End Results Program database during 2003-2016 were analysed. Age-standardised resection rates for overall and stage I-II PaCs were computed. Associations between resection and demographic and clinical parameters were assessed using multivariable logistic regression models. RESULTS: A total of 153 698 records were analysed. In population-based registries in 2012-2014, resection rates ranged from 13.2% (Estonia) to 21.2% (Slovenia) overall and from 34.8% (Norway) to 68.7% (Denmark) for stage I-II tumours, with great international variations. During 2003-2014, resection rates only increased in USA, the Netherlands and Denmark. Resection was significantly less frequently performed with more advanced tumour stage (ORs for stage III and IV versus stage I-II tumours: 0.05-0.18 and 0.01-0.06 across countries) and increasing age (ORs for patients 70-79 and ≥80 versus those <60 years: 0.37-0.63 and 0.03-0.16 across countries). Patients with advanced-stage tumours (stage III-IV: 63.8%-81.2%) and at older ages (≥70 years: 52.6%-59.5%) receiving less frequently resection comprised the majority of diagnosed cases. Patient performance status, tumour location and size were also associated with resection application. CONCLUSION: Rates of PaC resection remain low in Europe and USA with great international variations. Further studies are warranted to explore reasons for these variations.

Comorbidities, age and period of diagnosis influence treatment and outcomes in early breast cancer.

Survival for breast cancer (BC) is lower in eastern than northern/central Europe, and in older than younger women. We analysed how comorbidities at diagnosis affected whether selected standard treatments (STs) were given, across Europe and over time, also assessing consequences for survival/relapse. We analysed 7581 stage I/IIA cases diagnosed in 9 European countries in 2009-2013, and 4 STs: surgery; breast-conserving surgery plus radiotherapy (BCS + RT); reconstruction after mastectomy; and prompt treatment (≤6 weeks after diagnosis). Covariate-adjusted models estimated odds of receiving STs and risks of death/relapse, according to comorbidities. Pearson's R assessed correlations between odds and risks. The z-test assessed the significance of time-trends. Most women received surgery: 72% BCS; 24% mastectomy. Mastectomied patients were older with more comorbidities than BCS patients (p < 0.001). Women given breast reconstruction (25% of mastectomies) were younger with fewer comorbidities than those without reconstruction (p < 0.001). Women treated promptly (45%) were younger than those treated later (p = 0.001), and more often without comorbidities (p < 0.001). Receiving surgery/BCS + RT correlated strongly (R = -0.9), but prompt treatment weakly (R = -0.01/-0.02), with reduced death/relapse risks. The proportion receiving BCS + RT increased significantly (p < 0.001) with time in most countries. This appears to be the first analysis of the influence of comorbidities on receiving STs, and of consequences for outcomes. Increase in BCS + RT with time is encouraging. Although women without comorbidities usually received STs, elderly patients often received non-standard less prompt treatments, irrespective of comorbidities, with increased risk of mortality/relapse. All women, particularly the elderly, should receive ST wherever possible to maximise the benefits of modern evidence-based treatments.

Development and validation of a prognostic model to predict the prognosis of patients who underwent chemotherapy and resection of pancreatic adenocarcinoma: a large international population-based cohort study.

BACKGROUND: Pancreatic cancer (PaC) remains extremely lethal worldwide even after resection. PaC resection rates are low, making prognostic studies in resected PaC difficult. This large international population-based study aimed at exploring factors associated with survival in patients with resected TNM stage I-II PaC receiving chemotherapy and at developing and internationally validating a survival-predicting model. METHODS: Data of stage I-II PaC patients resected and receiving chemotherapy in 2003-2014 were obtained from the national cancer registries of Belgium, the Netherlands, Slovenia, and Norway, and the US Surveillance, Epidemiology, and End Results (SEER)-18 Program. Multivariable Cox proportional hazards models were constructed to investigate the associations of patient and tumor characteristics with overall survival, and analysis was performed in each country respectively without pooling. Prognostic factors remaining after backward selection in SEER-18 were used to build a nomogram, which was subjected to bootstrap internal validation and external validation using the European datasets. RESULTS: A total of 11,837 resected PaC patients were analyzed, with median survival time of 18-23 months and 3-year survival rates of 21-31%. In the main analysis, patient age, tumor T stage, N stage, and differentiation were associated with survival across most countries, with country-specific association patterns and strengths. However, tumor location was mostly not significantly associated with survival. Resection margin, hospital type, tumor size, positive and harvested lymph node number, lymph node ratio, and comorbidity number were associated with survival in certain countries where the information was available. A median survival time- and 1-, 2-, 3-, and 5-year survival probability-predictive nomogram incorporating the backward-selected variables in the main analysis was established. It fits each European national cohort similarly well. Calibration curves showed very good agreement between nomogram-prediction and actual observation. The concordance index of the nomogram (0.60) was significantly higher than that of the T and N stage-based model (0.56) for predicting survival. CONCLUSIONS: In these large international population-based cohorts, patients with resected PaC receiving chemotherapy have distinct characteristics independently associated with survival, with country-specific patterns and strengths. A robust benchmark population-based survival-predicting model is established and internationally validated. Like previous models predicting survival in resected PaC, our nomogram performs modestly.

Administration of adjuvant chemotherapy for stage II-III colon cancer patients: An European population-based study.

The advantage of adjuvant chemotherapy (ACT) for treating Stage III colon cancer patients is well established and widely accepted. However, many patients with Stage III colon cancer do not receive ACT. Moreover, there are controversies around the effectiveness of ACT for Stage II patients. We investigated the administration of ACT and its association with overall survival in resected Stage II (overall and stratified by low-/high-risk) and Stage III colon cancer patients in three European countries including The Netherlands (2009-2014), Belgium (2009-2013) and Sweden (2009-2014). Hazard ratios (HR) for death were obtained by Cox regression models adjusted for potential confounders. A total of 60244 resected colon cancer patients with pathological Stages II and III were analyzed. A small proportion (range 9-24%) of Stage II and over half (range 55-68%) of Stage III patients received ACT. Administration of ACT in Stages II and III tumors decreased with higher age of patients. Administration of ACT was significantly associated with higher overall survival in high-risk Stage II patients (in The Netherlands (HR; 95%CI = 0.82 (0.67-0.99), Belgium (0.73; 0.59-0.90) and Sweden (0.58; 0.44-0.75)), and in Stage III patients (in The Netherlands (0.47; 0.43-0.50), Belgium (0.46; 0.41-0.50) and Sweden (0.48; 0.43-0.54)). In Stage III, results were consistent across subgroups including elderly patients. Our results show an association of ACT with higher survival among Stage III and high-risk Stage II colon cancer patients. Further investigations are needed on the selection criteria of Stages II and III colon cancer patients for ACT.

Nonsurgical therapies for resected and unresected pancreatic cancer in Europe and USA in 2003-2014: a large international population-based study.

The role of chemotherapy in the treatment of pancreatic cancer (PaC) has been well-established, while radiation plays ambiguous roles. This international large-scale population-based study aimed to investigate the real-world application of chemotherapy and radiotherapy for resected and unresected PaC in Europe and USA. Population-based data from multiple European national cancer registries and the US Surveillance, Epidemiology and End Results (SEER)-18 database during 2003-2014 were analyzed. Temporal trends and geographical variations in the application rates of chemotherapy and radiotherapy were quantified using age standardization. Associations of treatment with demographic and clinical characteristics were assessed using multivariable logistic regression. A total of 141,533 PaC patients were analyzed. From 2003-2005 to 2012-2014, chemotherapy administration rates increased in most countries and more strongly among resected patients, while radiation rates were generally low with a slight decline or no obvious trend. In 2012-2014, 12.5% (Estonia) to 61.7% (Belgium) of resected and 17.1% (Slovenia) to 56.9% (Belgium) of unresected patients received chemotherapy. Radiation was administered in 2.6% (Netherlands) to 32.6% (USA) of resected and 1.0% (USA) to 6.0% (Belgium) of unresected patients. Strong temporal and geographical variations were observed. Patterns and strengths of associations of treatment administration with various demographic and clinical factors differed substantially between resected and unresected cancers and varied greatly across countries. Conclusively, administration of chemotherapy but not radiotherapy for PaC increased during the last decade in Europe and USA. Treatment rates were low and the uptake strongly varied across countries, highlighting the need for standardization in PaC treatment to improve patient care.

Stratified survival of resected and overall pancreatic cancer patients in Europe and the USA in the early twenty-first century: a large, international population-based study.

BACKGROUND: The prognosis of pancreatic cancer (PaC) strongly varies across different stages and age groups, which has unfortunately not been well recorded in the literature. This international population-based study aimed to provide tumor-node-metastasis (TNM) stage- and age-specific survival estimates and trends in resected and overall (resected and unresected) PaC in the early twenty-first century. METHODS: Using data from the US Surveillance, Epidemiology, and End Results-18 Program and the national cancer registries of the Netherlands, Belgium, Norway, and Slovenia, short-term and long-term overall survival results stratified by TNM stage and age in resected and overall primary PaC, irrespective of being microscopically confirmed or not, in 2003-2014 were computed using the Kaplan-Meier method. The temporal survival trends over three predefined periods (2003-2005, 2006-2008, and 2009-2011) were further examined using the log-rank test. RESULTS: In total, data for 125,183 patients were analyzed. Overall, age-stratified 3-year survival was 20-34% (< 60 years), 14-25% (60-69 years), and 9-13% (≥ 70 years) in stages I-II PaC; and 2-5% (< 60 years), 1-2% (60-69 years), and < 1-1% (≥ 70 years) in stages III-IV cancer. Patients who underwent operation had higher 3-year survival in each stage and age group (stages I-II: 23-39% (< 60 years), 16-31% (60-69 years), and 17-30% (≥ 70 years); stages III-IV: 5-19% (< 70 years) and 2-14% (≥ 70 years)). Perioperative survival also decreased with advancing stage and older age (stages I-II: 98-100% (< 60 years), 97-99% (60-69 years), and 94-99% (≥ 70 years); stages III-IV: 94-99% (< 70 years) and 81-96% (≥ 70 years)). Between 2003 and 2005 and 2009-2011, for overall PaC, both short-term and long-term survival improvements were observed in all countries except Belgium; for resected disease, short-term improvements were present only in the USA and Slovenia, but long-term improvements were observed in all countries except Slovenia, with stage-specific variations. CONCLUSIONS: Our large international study provides TNM stage- and age-specific population-based survival in overall and resected PaC that will facilitate clinical counseling. While the survival expectations for patients with resected PaC are substantially higher than the widely available and known dismal survival predictions for overall patients, conclusions on the benefits of resection cannot be made from this observational study. Patients with advanced-stage disease and/or older age should undergo careful risk assessment before treatment. Limited but inspiring improvement in survival is observed.

Burden and centralised treatment in Europe of rare tumours: results of RARECAREnet-a population-based study.

BACKGROUND: Rare cancers pose challenges for diagnosis, treatments, and clinical decision making. Information about rare cancers is scant. The RARECARE project defined rare cancers as those with an annual incidence of less than six per 100 000 people in European Union (EU). We updated the estimates of the burden of rare cancers in Europe, their time trends in incidence and survival, and provide information about centralisation of treatments in seven European countries. METHODS: We analysed data from 94 cancer registries for more than 2 million rare cancer diagnoses, to estimate European incidence and survival in 2000-07 and the corresponding time trends during 1995-2007. Incidence was calculated as the number of new cases divided by the corresponding total person-years in the population. 5-year relative survival was calculated by the Ederer-2 method. Seven registries (Belgium, Bulgaria, Finland, Ireland, the Netherlands, Slovenia, and the Navarra region in Spain) provided additional data for hospitals treating about 220 000 cases diagnosed in 2000-07. We also calculated hospital volume admission as the number of treatments provided by each hospital rare cancer group sharing the same referral pattern. FINDINGS: Rare cancers accounted for 24% of all cancers diagnosed in the EU during 2000-07. The overall incidence rose annually by 0.5% (99·8% CI 0·3-0·8). 5-year relative survival for all rare cancers was 48·5% (95% CI 48·4 to 48·6), compared with 63·4% (95% CI 63·3 to 63·4) for all common cancers. 5-year relative survival increased (overall 2·9%, 95% CI 2·7 to 3·2), from 1999-2001 to 2007-09, and for most rare cancers, with the largest increases for haematological tumours and sarcomas. The amount of centralisation of rare cancer treatment varied widely between cancers and between countries. The Netherlands and Slovenia had the highest treatment volumes. INTERPRETATION: Our study benefits from the largest pool of population-based registries to estimate incidence and survival of about 200 rare cancers. Incidence trends can be explained by changes in known risk factors, improved diagnosis, and registration problems. Survival could be improved by early diagnosis, new treatments, and improved case management. The centralisation of treatment could be improved in the seven European countries we studied. FUNDING: The European Commission (Chafea).

Cure of cancer for seven cancer sites in the Flemish Region.

Cumulative relative survival curves for many cancers reach a plateau several years after diagnosis, indicating that the cancer survivor group has reached "statistical" cure. Parametric mixture cure model analysis on grouped relative survival curves provide an interesting way to determine the proportion of statistically cured cases and the mean survival time of the fatal cases in particular for population-based cancer registries. Based on the relative survival data from the Belgian Cancer Registry, parametric cure models were applied to seven cancer sites (cervix, colon, corpus uteri, skin melanoma, pancreas, stomach and oesophagus), at the Flemish Regional level for the incidence period 1999-2011. Statistical cure was observed for the examined cancer sites except for oesophageal cancer. The estimated cured proportion ranged from 5.9% [5.7, 6.1] for pancreatic cancer to 80.8% [80.5, 81.2] for skin melanoma. Cure results were further stratified by gender or age group. Stratified cured proportions were higher for females compared to males in colon cancer, stomach cancer, pancreas cancer and skin melanoma, which can mainly be attributed to differences in stage and age distribution between both sexes. This study demonstrates the applicability of cure rate models for the selected cancer sites after 14 years of follow-up and presents the first population-based results on the cure of cancer in Belgium.

Facing further challenges in cancer data quality and harmonisation.

This article highlights the recent and ongoing activities of European population-based cancer registries (PBCRs) in data quality and harmonisation in the framework of the collaboration between the European Network of Cancer Registries (ENCR) and the Directorate-General Joint Research Centre (JRC), the science and knowledge centre of the European Commission. The article concludes the Frontiers in Oncology's Research Topic "Joining Efforts to Improve Data Quality and Harmonization Among European Population-Based Cancer Registries", which has been an opportunity for several European researchers to share their experience on cancer data quality and harmonisation. Such experience will be helpful for PBCRs in view of future challenges and opportunities in cancer epidemiology, with a few examples discussed in the present article.

Global Stage Distribution of Breast Cancer at Diagnosis: A Systematic Review and Meta-Analysis.

Importance: Stage at diagnosis is a key prognostic factor for cancer survival. Objective: To assess the global distribution of breast cancer stage by country, age group, calendar period, and socioeconomic status using population-based data. Data Sources: A systematic search of MEDLINE and Web of Science databases and registry websites and gray literature was conducted for articles or reports published between January 1, 2000, and June 20, 2022. Study Selection: Reports on stage at diagnosis for individuals with primary breast cancer (C50) from a population-based cancer registry were included. Data Extraction and Synthesis: Study characteristics and results of eligible studies were independently extracted by 2 pairs of reviewers (J.D.B.F., A.D.A., A.M., R.S., and F.G.). Stage-specific proportions were extracted and cancer registry data quality and risk of bias were assessed. National pooled estimates were calculated for subnational or annual data sets using a hierarchical rule of the most relevant and high-quality data to avoid duplicates. Main Outcomes and Measures: The proportion of women with breast cancer by (TNM Classification of Malignant Tumors or the Surveillance, Epidemiology, and End Results Program [SEER]) stage group. Results: Data were available for 2.4 million women with breast cancer from 81 countries. Globally, the proportion of cases with distant metastatic breast cancer at diagnosis was high in sub-Saharan Africa, ranging from 5.6% to 30.6% and low in North America ranging from 0.0% to 6.0%. The proportion of patients diagnosed with distant metastatic disease decreased over the past 2 decades from around 3.8% to 35.8% (early 2000s) to 3.2% to 11.6% (2015 onwards), yet stabilization or slight increases were also observed. Older age and lower socioeconomic status had the largest proportion of cases diagnosed with distant metastatic stage ranging from 2.0% to 15.7% among the younger to 4.1% to 33.9% among the oldest age group, and from 1.7% to 8.3% in the least disadvantaged groups to 2.8% to 11.4% in the most disadvantaged groups. Conclusions and Relevance: Effective policy and interventions have resulted in decreased proportions of women diagnosed with metastatic breast cancer at diagnosis in high-income countries, yet inequality persists, which needs to be addressed through increased awareness of breast cancer symptoms and early detection. Improving global coverage and quality of population-based cancer registries, including the collection of standardized stage data, is key to monitoring progress.