Cancer incidence and mortality trends in France over 1990-2018 for solid tumors: the sex gap is narrowing.

OBJECTIVE: To analyze trends in cancer incidence and mortality (France, 1990-2018), with a focus on men-women disparities. METHODS: Incidence data stemmed from cancer registries (FRANCIM) and mortality data from national statistics (CépiDc). Incidence and mortality rates were modelled using bidimensional penalized splines of age and year (at diagnosis and at death, respectively). Trends in age-standardized rates were summarized by the average annual percent changes (AAPC) for all-cancers combined, 19 solid tumors, and 8 subsites. Sex gaps were indicated using male-to-female rate ratios (relative difference) and male-to-female rate differences (absolute difference) in 1990 and 2018, for incidence and mortality, respectively. RESULTS: For all-cancers, the sex gap narrowed over 1990-2018 in incidence (1.6 to 1.2) and mortality (2.3 to 1.7). The largest decreases of the male-to-female incidence rate ratio were for cancers of the lung (9.5 to 2.2), lip - oral cavity - pharynx (10.9 to 3.1), esophagus (12.6 to 4.5) and larynx (17.1 to 7.1). Mixed trends emerged in lung and oesophageal cancers, probably explained by differing risk factors for the two main histological subtypes. Sex incidence gaps narrowed due to increasing trends in men and women for skin melanoma (0.7 to 1, due to initially higher rates in women), cancers of the liver (7.4 to 4.4) and pancreas (2.0 to 1.4). Sex incidence gaps narrowed for colon-rectum (1.7 to 1.4), urinary bladder (6.9 to 6.1) and stomach (2.7 to 2.4) driven by decreasing trends among men. Other cancers showed similar increasing incidence trends in both sexes leading to stable sex gaps: thyroid gland (0.3 to 0.3), kidney (2.2 to 2.4) and central nervous system (1.4 to 1.5). CONCLUSION: In France in 2018, while men still had higher risks of developing or dying from most cancers, the sex gap was narrowing. Efforts should focus on avoiding risk factors (e.g., smoking) and developing etiological studies to understand currently unexplained increasing trends.

Cancer incidence in France over the 1980-2012 period: Hematological malignancies.

BACKGROUND: The classification of hematological malignancies (HMs) has changed in recent decades. For the first time, the French network of cancer registries (Francim) provides estimates for incidence and trends of HM in France between 1980 and 2012 for major HM subtypes. METHODS: Incidence was directly estimated by modeling the incidence rates measured in the cancer registry area. For each HM subtype, a "usable incidence period" was defined a priori, corresponding to the years for which all the registries collected them in a homogeneous way. For both sexes and each HM subtype, age-period-cohort models were used to estimate national incidence trends. RESULTS: Overall in France, there were an estimated 35,000 new HMs in 2012 (19,400 in men and 15,600 in women). Lymphoid malignancies accounted for more than two-thirds of HM incident cases (n=25,136). The incidence sex ratio (M/F) varied from 1.1 for classical Hodgkin lymphoma to 4.0 for mantle-cell lymphoma. The median age at diagnosis ranged from 62 to 81 years according to the major HM subtypes. Overall in both sexes, the top five most frequent HMs in 2012 were plasma cell neoplasm (about 4900 estimated cases), chronic lymphocytic leukemia/small lymphocytic lymphoma (4500 cases), diffuse large B-cell lymphoma and myelodysplastic syndromes (4100 cases), and acute myeloid leukemia (2800 cases). The incidence rates increased for follicular lymphoma and plasma cell neoplasm during the study period in both sexes. Classical Hodgkin lymphoma was relatively stable in men between 1980 and 2012 and increased in both sexes during the most recent period. Chronic myeloproliferative neoplasms, other than chronic myelogenous leukemia, are the only subtype that showed a slightly downward trend in incidence between 2003 and 2012 in both sexes. CONCLUSION: The striking differences in the incidence patterns by histologic subtype strongly suggest a certain level of etiologic heterogeneity among hematological malignancies and support the pursuit of epidemiologic analysis by subtype for HMs in international studies. Age-standardized incidence rates are essential to analyze trends in risk, whereas the number of incident cases is necessary to make provisions for healthcare resources and to evaluate the overall burden of HM.

[Prostate cancer incidence and mortality trends in France from 1980 to 2011]. / Le cancer de la prostate, évolution de l'incidence et de la mortalité en France entre 1980 et 2011.

UNLABELLED: The prostate cancer became for two decades the most frequent cancer in men. We describe the evolution of its incidence and mortality from 1980 to 2011 for France. METHODS: Incidence data were collected from registries and national incidence estimates were based on the use of mortality as a correlate of incidence. RESULTS: After a very strong increase of incidence between 1980 (24.8/100,000) and 2005 (124.5/100,000), we observe a net decline since (97.7/100,000, in 2011). The reduction began earlier for the old patients. The evolution of mortality is very different. We observe a regular reduction since the end of 1990s (from 18.0/100,000 in 1990 to 10.5/100,000 in 2011). The reduction began earlier for the young patients. CONCLUSION: This pattern of evolution is observed in all the countries where the use of the PSA had caused an important increase of the diagnosis of prostate cancer. LEVEL OF EVIDENCE: 3.

Cancer incidence and mortality in France over the 1980-2012 period: solid tumors.

BACKGROUND: Cancer incidence and mortality estimates for 19 cancers (among solid tumors) are presented for France between 1980 and 2012. METHODS: Incidence data were collected from 21 local registries and correspond to invasive cancers diagnosed between 1975 and 2009. Mortality data for the same period were provided by the Institut national de la santé et de la recherche médicale. The national incidence estimates were based on the use of mortality as a correlate of incidence. The observed incidence and mortality data were modeled using an age-period-cohort model. The numbers of incident cases and deaths for 2010-2012 are the result of short-term projections. RESULTS: In 2012, the study estimated that 355,000 new cases of cancer (excluding non-melanoma skin cancer) and 148,000 deaths from cancer occurred in France. The incidence trend was not linear over the study period. After a constant increase from 1980 onwards, the incidence of cancer in men declined between 2005 and 2012. This recent decrease is largely related to the reduction in the incidence of prostate cancer. In women, the rates stabilized, mainly due to a change in breast cancer incidence. Mortality from most cancer types declined over the study period. A combined analysis of incidence and mortality by cancer site distinguished cancers with declining incidence and mortality (e.g., stomach) and cancers with increasing incidence and mortality (e.g., lung cancer in women). Some other cancers had rising incidence but declining mortality (e.g., thyroid). CONCLUSION: This study reveals recent changes in cancer incidence trends, particularly regarding breast and prostate cancers.

[Critical analysis of French DRG based information system (PMSI) databases for the epidemiology of cancer: a longitudinal approach becomes possible]. / Analyse critique des données du PMSI pour l'épidémiologie des cancers : une approche longitudinale devient possible.

BACKGROUND: Use of French Diagnosis Related Groups (DRGs) program databases, apart from financial purposes, has recently been improved since a unique anonymous patient identification number has been created for each inpatient in administrative case mix database. Based on the work of the group for cancer epidemiological observation in the Rhône-Alpes area, (ONC-EPI group), we review the remaining difficulties in the use of DRG data for epidemiological purposes and we consider a longitudinal approach based on analysis of database over several years. We also discuss limitations of this approach. DIFFICULTIES: The main problems are related to a lack of quality of administrative data, especially coding of diagnoses. These errors come from missing or inappropriate codes, or not being in accordance with prioritization rules (causing an over- or under-reporting or inconsistencies in coding over time). One difficulty, partly due to the hierarchy of coding and the type of cancer, is the choice of an extraction algorithm. In two studies designed to estimate the incidence of cancer cared in hospitals (breast, colon-rectum, kidney, ovaries), a first algorithm, including a code of cancer as principal diagnosis with a selection of surgical procedures less performed than the second one including a code of cancer as principal diagnosis only, for which the number of hospitalizations per patient ratio was stable across time and space. The chaining over several years allows, by tracing the trajectory of the patient, to detect and correct inaccuracies, errors and missing values, and for incidence studies, to correct incident cases by removing prevalent cases. DISCUSSION: However, linkage, complete only since 2007, does not correct data in all cases. Ways of future improvement certainly pass through improved algorithms for case identification and especially by linking DRG data with other databases.

Evolution of pleural cancers and malignant pleural mesothelioma incidence in France between 1980 and 2005.

The evolution of pleural cancers and malignant pleural mesothelioma incidence in France between 1980 and 2005 was analysed using data derived from the French network of cancer registries (FRANCIM) and the French National Mesothelioma Surveillance Program (PNSM). Mesothelioma proportions in pleural cancers were calculated by diagnosis year in the 1980-2000 period. Our results suggest that the incidences of pleural cancer and mesothelioma levelled off in French men since 2000 and continued to increase in French women. A decrease of the annual pleural cancer incidence average in men was noticed (-3.4% of annual rate of change) between 2000 and 2005. The proportion of pleural cancers that were mesothelioma was unchanged between 1980 and 2003 with an average of 86%. The age standardised incidence rate of pleural mesothelioma remained relatively stable between 1998 and 2005 with a slight falling trend. For women, the age standardised incidence rate of pleural cancers and mesothelioma increased during the period 1998-2005. Additionally, the proportion of pleural cancers that were mesothelioma increased during the same period of time. Finally, the increased trend observed in the incidence of pleural mesothelioma and cancers in women is credibly due to their under diagnosis in the 1980-1997 period. The comparison between the French incidence and the American and British ones shows that the decreasing trend in incidence of mesothelioma and pleural cancers in French men since 2000 is potentially associated with a lower amphibole consumption and by the implementation of safety regulations at work from 1977.

Analysis of the effect of age on the prognosis of breast cancer.

To explore the effect of age at diagnosis on relative survival from breast cancer at different cancer stages and grades, using appropriate statistical modeling of time-varying and non-linear effects of that prognostic covariate. Data on 4,791 female invasive breast cancers diagnosed between 1990 and 1997 were obtained from a French cancer registry. The effect of age on relative survival was studied using an approach based on excess rate modeling. Different models testing non-linear and non-proportional effects of age were explored for each grade and each stage. In the whole population, the effect of age was not linear and varied with the time elapsed since diagnosis. When analyzing the different sub-groups according to grade and stage, age did not have a significant effect on relative survival in grade 1 or stage 3 tumors. In grade 2 and stage 4 tumors, the excess mortality rate increased with age, in a linear way. In grade 3 tumors, age was a time-dependent factor: older women had higher excess rates than younger ones during the first year after diagnosis whereas the inverse phenomenon was observed 5 years after diagnosis. Our findings suggest that when taking into account grade and stage, the time-varying impact of young age at diagnosis is limited to grade 3 tumors, without evidence of worst prognosis at 5 years for the youngest women.

[Some interpretation of regional estimates of the incidence of cancer in France over the period 1980--2005]. / Eléments d'interprétation des estimations régionales de l'incidence du cancer en France sur la période 1980--2005.

Francim Network has already provided French national estimations of cancer incidence then regional estimations for Metropolitan France. The present technical note summarizes the underlying hypotheses and the limits of the method and suggests some aspects of interpretation of those regional results in terms of absolute numbers and of standardized rates. Results on "all cancers" illustrate those comments.

Cancer incidence and mortality in France over the period 1980-2005.

BACKGROUND: The objective of this study was to provide updated estimates of national trends in cancer incidence and mortality for France for 1980-2005. METHODS: Twenty-five cancer sites were analysed. Incidence data over the 1975-2003 period were collected from 17 registries working at the department level, covering 16% of the French population. Mortality data for 1975-2004 were provided by the Inserm. National incidence estimates were based on the use of mortality as a correlate of incidence, mortality being available at both department and national levels. Observed incidence and mortality data were modelled using an age-cohort approach, including an interaction term. Short-term predictions from that model gave estimates of new cancer cases and cancer deaths in 2005 for France. RESULTS: The number of new cancer cases in 2005 was approximately 320,000. This corresponds to an 89% increase since 1980. Demographic changes were responsible for almost half of that increase. The remainder was largely explained by increases in prostate cancer incidence in men and breast cancer incidence in women. The relative increase in the world age-standardised incidence rate was 39%. The number of deaths from cancer increased from 130,000 to 146,000. This 13% increase was much lower than anticipated on the basis of demographic changes (37%). The relative decrease in the age-standardised mortality rate was 22%. This decrease was steeper over the 2000-2005 period in both men and women. Alcohol-related cancer incidence and mortality continued to decrease in men. The increasing trend of lung cancer incidence and mortality among women continued; this cancer was the second cause of cancer death among women. Breast cancer incidence increased regularly, whereas mortality has decreased slowly since the end of the 1990s. CONCLUSION: This study confirmed the divergence of cancer incidence and mortality trends in France over the 1980-2005 period. This divergence can be explained by the combined effects of a decrease in the incidence of the most aggressive cancers and an increase in the incidence of less aggressive cancers, partly due to changes in medical practices leading to earlier diagnoses.

Survival of cancer patients in France: a population-based study from The Association of the French Cancer Registries (FRANCIM).

We present the main results of the first population-based cancers survival study gathering all French registry data. Survival data on 205,562 cancer cases diagnosed between 01/01/1989 and 31/12/1997 were analysed. Relative survival was estimated using an excess rate model. The evolution of the excess mortality rate over the follow-up period was graphed. The analysis emphasised the effect of age at diagnosis and its variation with time after diagnosis. For breast and prostate cancers, the age-standardised five-year relative survivals were 84% and 77%, respectively. The corresponding results in men and women were 56% versus 58% for colorectal cancer and 12% versus 16% for lung cancer. For some cancer sites, the excess mortality rate decreased to low values by five years after diagnosis. For most cancer sites, age at diagnosis was a negative prognostic factor but this effect was often limited to the first year after diagnosis.

Morphometric analysis of the distal femur in total knee arthroplasty and native knees.

AIMS: Analysis of the morphology of the distal femur, and by extension of the femoral components in total knee arthroplasty (TKA), has largely been related to the aspect ratio, which represents the width of the femur. Little is known about variations in trapezoidicity (i.e. whether the femur is more rectangular or more trapezoidal). This study aimed to quantify additional morphological characteristics of the distal femur and identify anatomical features associated with higher risks of over- or under-sizing of components in TKA. METHODS: We analysed the shape of 114 arthritic knees at the time of primary TKA using the pre-operative CT scans. The aspect ratio and trapezoidicity ratio were quantified, and the post-operative prosthetic overhang was calculated. We compared the morphological characteristics with those of 12 TKA models. RESULTS: There was significant variation in both the aspect ratio and trapezoidicity ratio between individuals. Femoral trapezoidicity was mostly due to an inward curve of the medial cortex. Overhang was correlated with the aspect ratio (with a greater chance of overhang in narrow femurs), trapezoidicity ratio (with a greater chance in trapezoidal femurs), and the tibio-femoral angle (with a greater chance in valgus knees). DISCUSSION: This study shows that rectangular/trapezoidal variability of the distal femur cannot be ignored. Most of the femoral components which were tested appeared to be excessively rectangular when compared with the bony contours of the distal femur. These findings suggest that the design of TKA should be more concerned with matching the trapezoidal/rectangular shape of the native femur. TAKE HOME MESSAGE: The distal femur is considerably more trapezoidal than most femoral components, and therefore, care must be taken to avoid anterior prosthetic overhang in TKA

Addition of oxaliplatin to continuous fluorouracil, l-folinic acid, and concomitant radiotherapy in rectal cancer: the Lyon R 97-03 phase I trial.

PURPOSE: Oxaliplatin could increase the efficacy of fluorouracil (5-FU)/folinic acid chemoradiotherapy in rectal cancer. We tested three dose levels to identify a feasible oxaliplatin dose for combination therapy. PATIENTS AND METHODS: Between February 1998 and April 2000, we included 17 rectal adenocarcinoma patients in a single-center phase I study. Patients had T4 rectal carcinoma, T1-T3 disease with colostomy refusal, or potentially operable T2/T3 M1 requiring local treatment. Pelvic radiotherapy was 45 Gy over 5 weeks, 1.8 Gy/fraction, with concomitant chemotherapy weeks 1 and 5. Chemotherapy was oxaliplatin 80, 100, or 130 mg/m2 2-hour infusion on day 1 followed by L-folinic acid 100 mg/m2/d intravenous bolus, and 5-FU 350 mg/m2/d continuous infusion on days 1 to 5 (FolfoR1). Six patients refusing surgery received additional contact radiotherapy +/- brachytherapy. Dose escalation proceeded if less than two of six patients had dose-limiting toxicity (DLT) at a given dose-level. RESULTS: All except two patients completed treatment; patients at level 1 (prolonged grade 1 thrombocytopenia) and level 3 (prolonged cold-related dysesthesia) had no second chemotherapy course. Median follow-up is 14 months (range, 2 to 28 months). One elderly patient at dose level 1 had DLT asthenia, severe diarrhea and vomiting, and more than 10% weight loss. There were no other DLTs and no severe rectitis or gastrointestinal toxicity. There were objective responses at all doses and no progressions. Eight patients underwent radical surgery after chemoradiotherapy. Two had complete pathologic responses. CONCLUSION: FolfoR1 seems feasible and effective. Dose escalation did not increase toxicity. Although the MTD was not reached in this study, we recommend oxaliplatin 130 mg/m2 for phase II studies because it is the dose determined from studies in metastatic patients with no toxicity when given concurrently with radiation.

Increased incidence of femoral fractures in small femurs and women undergoing uncemented total hip arthroplasty - why?

The aim of this study was to investigate the relationship between the geometry of the proximal femur and the incidence of intra-operative fracture during uncemented total hip arthroplasty (THA). We studied the pre-operative CT scans of 100 patients undergoing THA with an uncemented femoral component. We measured the anteroposterior and mediolateral dimensions at the level of division of the femoral neck to calculate the aspect ratio of the femur. Wide variations in the shape of the femur were observed, from round, to very narrow elliptic. The femurs of women were narrower than those of men (p < 0.0001) and small femurs were also narrower than large ones. Patients with an intra-operative fracture of the calcar had smaller and narrower femurs than those without a fracture (p < 0.05) and the implanted Corail stems were smaller in those with a fracture (mean size 9 vs 12, p < 0.0001). The variability of the shape of the femoral neck at the level of division contributes to the understanding of the causation of intra-operative fractures in uncemented THA.

The effect of nonhomogeneous clone length distribution on the progress of an STS mapping project.

We provide both theoretical and simulation results on the progress of an STS mapping project in the presence of clone length inhomogeneity. For an example in which the genome comprises alternating regions of clones with short and long average length, the main conclusion is that the efficiency of the project is clearly decreased in the presence of such inhomogeneity. The case of deterministic clone length gives the worst progress. The general simulation algorithm we propose shows that strategies that space the anchors as regularly as possible do best: fewer contigs of larger average length are expected. The simulation algorithm can be used to study many statistical properties of the progress of any anchoring project.

[Prognostic importance of ambulatory arterial pressure monitoring in France. Initial results of the OCTAVE II study. OCTAVE II Research Group]. / Intérêt pronostique de la mesure ambulatoire de pression artérielle en France. Premiers résultats de l'étude OCTAVE II. Groupe de Recherche OCTAVE II.

RATIONALE: Ambulatory blood pressure measurement (ABPM) is commonly used in clinical practice, whereas its added value to the management of hypertension is not definitely documented. OBJECTIVE: The OCTAVE II study was launched in 1991 to explore the prognostic value of ABPM, compared to that of the gold standard, the clinical blood pressure measurement. METHODS: Two hundred and six French cardiologists recruited 3569 participants over 18 years of age, provided they deemed ABPM was useful (mean age of 56 years, 52% of men, 65% already treated by antihypertensive drugs). The prognostic value of various blood pressure measurements, systolic or diastolic, clinical or ambulatory (diurnal, nocturnal or during 24 hours), has been assessed in multivariate models adjusted on the baseline characteristics associated with risk. The outcome was the occurrence of a major cardiovascular event, including stroke, myocardial infarction and cardiovascular death. RESULTS: After an average follow-up of five years, cardiovascular morbidity was known for 85% of the participants, and their vital status for 91%. On the whole population, the best prognostic indicators were systolic blood pressure compared with diastolic, ABPM compared with clinical blood pressure measurements, and nocturnal ABPM compared with diurnal ABPM. In the untreated participants at baseline, cardiovascular risk regularly increased among the four groups: normotensives, white-coat hypertensives, dippers, non-dippers. Between the extreme categories, the cardiovascular event rate was multiplied by 6.5. CONCLUSION: In this French population, ABPM and most of all its nocturnal component, was better correlated with cardiovascular prognosis. It remains to assess: 1) the general value of our findings, 2) the respective values of self blood pressure measurement versus ABPM, and 3) whether ABPM allows a better risk prevention.

[Oral contraception and genetic factors in breast cancer: characteristics and limits of case-only studies]. / Contraception orale et facteurs génétiques dans le cancer du sein : intérêts et limites des études cas versus cas n

The analysis of the interaction between environmental and genetic factors is a matter of increasing interest in cancerology. More particularly the discovery of the BRCAx family and the high cumulated incidence of familial breast cancers related to mutations of these proteins raised the issue of the differential effect of long term and/or early exposure to oral contraceptives in the presence of these mutations. The classical case-control design assumes the presence of a control group, which can be sometimes difficult to obtain from both the technical and ethical points of view. Case-only or case-case studies, which are based only on series of cases, making them apparently attractive, have been proposed to analyze more specifically the interaction term. The aim of the present paper is to review and discuss the methodological basis and main assumptions of the case-only design, and their applicability to breast cancer studies. The measure of the interaction between an environmental factor and a susceptibility genetic factor differs in an important aspect from the measure of the association between an environmental factor and a acquired tumoral genetic factor; this aspect is reminded.

[Risk factors in overweight: a survey among female hospital personnel]. / Facteurs de risque de surcharge pondérale: enquête auprès du personnel féminin hospitalier.

The purpose of this study was to explore the eventual relationship between the working conditions, and overweight women working in hospitals. The sample comprised 594 women working in hospitals in Lyon; 34% of them were overweight which is 10% above the theoretical weight. The rate of overweight hospital staff increased with the woman's age, the number of children and when the social level decreased. The analysis showed that being overweight was more frequent in women working in cleaning staff (56%) and in nursing auxiliaries (36%) than in nurses and administrative staff (24% and 27% respectively). After taking the above personal risk factors into account, this relationship remained the same. However, the night work and the length of service in hospitals are not found to be risk factors, after adjustment for the personal risk factors and type of work. Considering the women who were not overweight at the time of commencing employment, the relationship between being overweight and the type of working conditions in the hospitals disappeared.

[Hierarchies according to the level of evidence of source data, before their integration in the synthesis, in the matter of therapeutic efficacy]. / La hiérarchisation selon leur niveau de preuve des données sources, avant leur intégration dans une synthèse, en matière d'efficacité thérapeutique.

The discipline therapeutic information uses the concept of the level of evidence for source data concerning therapeutic efficacy, and its ordering before integration in syntheses. In this paper we will start by considering the problems raised by the definition of the level of evidence in terms of the dimensions it covers. We have differentiated three components: clinical pertinance of the question asked, the methods used to reply and the quality of the data collected. Second, we will examine the different criteria important for each of these three dimensions. There are many criteria possible which do not all have the same weight, and thus for any non-arbitrary tool developed to enable the level of evidence to be ordered, it is necessary to know the weight of the different criteria. Thirdly, we will present the techniques used for working with multicriteria situations in econometrics which represent a methodology we propose using to apply in our context. To do so we need to build a 'reference' base for the level of evidence using 'experts' opinions which will help us to examine the weights of the different criteria. This approach, in conjunction with some epistemological and sociological considerations, may contribute to a better understanding of the different dimensions of this concept.

Probabilities of dying from cancer and other causes in French cancer patients based on an unbiased estimator of net survival: a study of five common cancers.

BACKGROUND: Net survival is the survival that would be observed if cancer were the only possible cause of death. Although it is an important epidemiological tool allowing temporal or geographical comparisons, it cannot inform on the "crude" probability of death of cancer patients; i.e., when taking into account other possible causes of deaths. METHODS: In this work, we provide estimates of the crude probabilities of death from cancer and from other causes as well as the probability of being alive up to ten years after cancer diagnosis according to the age and year of diagnosis. Based on a flexible excess hazard model providing unbiased estimates of net survival, our methodology avoids the pitfalls associated with the use of the cause of death. We used data from FRANCIM, the French network of cancer registries, and studied five common cancer sites: head and neck, breast, prostate, lung, and colorectal cancers. RESULTS: For breast, prostate, and colorectal cancers, the impact of the other causes on the total probability of death increased with the age at diagnosis whereas it remained negligible for lung and head and neck cancers whatever the age. For breast, prostate, and colorectal cancer, the more recently was the cancer diagnosed, the less was the probability of death from cancer. CONCLUSION: The crude probability of death is an intuitive concept that may prove particularly useful in choosing an appropriate treatment, or refining the indication of a screening strategy by allowing the clinician to estimate the proportion of cancer patients who will die specifically from cancer.

National cancer incidence is estimated using the incidence/mortality ratio in countries with local incidence data: is this estimation correct?

BACKGROUND: In countries with local cancer registration, the national cancer incidence is usually estimated by multiplying the national mortality by the incidence/mortality (I/M) ratio from pooled registries. This study aims at validating this I/M estimation in France, by a comparison with estimation obtained using the ratio of incidence over hospital discharge (I/HD) or the ratio of incidence over health insurance data (long-duration diseases, I/LDD). METHODS: This comparison was performed for 22 cancer sites over the period 2004-2006. In France, a longitudinal I/M approach was developed relying on incidence and mortality trend analyses; here, the corresponding estimations of national incidence were extracted for 2004-2006. The I/HD and I/LDD estimations were performed using a common cross-sectional methodology. RESULTS: The three estimations were found similar for most cancers. The relative differences in incidence rates (vs. I/M) were below 5% for numerous cancers and below 10% for all cancers but three. The highest differences were observed for thyroid cancer (up to +21% in women and +8% in men), skin melanoma (up to +13% in women and +8% in men), and Hodgkin disease in men (up to +15%). Differences were also observed in women aged over 60 for cervical cancer. Except for thyroid cancer, differences were mainly due to the smoothing performed in the I/M approach. CONCLUSION: Our results support the validity of I/M approaches for national estimations, except for thyroid cancer. The longitudinal version of this approach has, furthermore, the advantage of providing smoothed estimations and trend analyses, including useful birth-cohort indicators, and should thus be preferred.