A new cure model that corrects for increased risk of non-cancer death: analysis of reliability and robustness, and application to real-life data.

BACKGROUND: Non-cancer mortality in cancer patients may be higher than overall mortality in the general population due to a combination of factors, such as long-term adverse effects of treatments, and genetic, environmental or lifestyle-related factors. If so, conventional indicators may underestimate net survival and cure fraction. Our aim was to propose and evaluate a mixture cure survival model that takes into account the increased risk of non-cancer death for cancer patients. METHODS: We assessed the performance of a corrected mixture cure survival model derived from a conventional mixture cure model to estimate the cure fraction, the survival of uncured patients, and the increased risk of non-cancer death in two settings of net survival estimation, grouped life-table data and individual patients' data. We measured the model's performance in terms of bias, standard deviation of the estimates and coverage rate, using an extensive simulation study. This study included reliability assessments through violation of some of the model's assumptions. We also applied the models to colon cancer data from the FRANCIM network. RESULTS: When the assumptions were satisfied, the corrected cure model provided unbiased estimates of parameters expressing the increased risk of non-cancer death, the cure fraction, and net survival in uncured patients. No major difference was found when the model was applied to individual or grouped data. The absolute bias was < 1% for all parameters, while coverage ranged from 89 to 97%. When some of the assumptions were violated, parameter estimates appeared more robust when obtained from grouped than from individual data. As expected, the uncorrected cure model performed poorly and underestimated net survival and cure fractions in the simulation study. When applied to colon cancer real-life data, cure fractions estimated using the proposed model were higher than those in the conventional model, e.g. 5% higher in males at age 60 (57% vs. 52%). CONCLUSIONS: The present analysis supports the use of the corrected mixture cure model, with the inclusion of increased risk of non-cancer death for cancer patients to provide better estimates of indicators based on cancer survival. These are important to public health decision-making; they improve patients' awareness and facilitate their return to normal life.

The Economic Cost of Thyroid Cancer in France and the Corresponding Share Associated With Treatment of Overdiagnosed Cases.

OBJECTIVES: Thyroid cancer incidence in France has increased rapidly in recent decades. Most of this increase has been attributed to overdiagnosis, the major consequence of which is overtreatment. We aimed to estimate the cost of thyroid cancer management in France and the corresponding cost proportion attributable to the treatment of overdiagnosed cases. METHODS: Multiple data sources were integrated: the mean cost per patient with thyroid cancer was estimated by using the Echantillon Généraliste des Bénéficiaires data set; thyroid cancer cases attributable to overdiagnosis were estimated for 21 departments using data from the French network of cancer registries and extrapolated to the whole country; medical records from 6 departments were used to refine the diagnosis and care pathway. RESULTS: Between 2011 and 2015, 33 911 women and 10 846 men in France were estimated to be diagnosed of thyroid cancer, with mean cost per capita of €6248. Among those treated, 8114 to 14 925 women and 1465 to 3626 men were due to overdiagnosis. The total cost of thyroid cancer patient management was €203.5 million (€154.3 million for women and €49.3 million for men), of which between €59.9 million (or 29.4% of the total cost, lower bound) and €115.9 million (or 56.9% of the total cost, upper bound) attributable to treatment of overdiagnosed cases. CONCLUSIONS: The management of thyroid cancer represents not only a relevant clinical and public health problem in France but also a potentially important economic burden. Overdiagnosis and corresponding associated treatments play an important role on the total costs of thyroid cancer management.

Health status of prevalent cancer cases as measured by mortality dynamics (cancer vs. noncancer): Application to five major cancers sites.

BACKGROUND: Cancer prevalence is heterogeneous because it includes individuals who are undergoing initial treatment and those who are in remission, experiencing relapse, or cured. The proposed statistical approach describes the health status of this group by estimating the probabilities of death among prevalent cases. The application concerns colorectal, lung, breast, and prostate cancers and melanoma in France in 2017. METHODS: Excess mortality was used to estimate the probabilities of death from cancer and other causes. RESULTS: For the studied cancers, most deaths from cancer occurred during the first 5 years after diagnosis. The probability of death from cancer decreased with increasing time since diagnosis except for breast cancer, for which it remained relatively stable. The time beyond which the probability of death from cancer became lower than that from other causes depended on age and cancer site: for colorectal cancer, it was 6 years after diagnosis for women (7 years for men) aged 75-84 and 20 years for women (18 years for men) aged 45-54 years, whereas cancer was the major cause of death for women younger than 75 years whatever the time since diagnosis for breast and for all patients younger than 75 years for lung cancer. In contrast, deaths from other causes were more frequent in all the patients older than 75 years. Apart from breast cancer in women younger than 55 years and lung cancer in women older than 55 years and men older than 65 years, the probability of death from cancer among prevalent cases fell below 1%, with varying times since diagnosis. CONCLUSIONS: The authors' approach can be used to better describe the burden of cancer by estimating outcomes in prevalent cases.

Temporal and geographical variations of thyroid cancer incidence and mortality in France during 1986-2015: The impact of overdiagnosis.

BACKGROUND: France is among the countries showing fastest growth of thyroid cancer (TC) incidence and highest incidence rates in Europe. This study aimed to clarify the temporal and geographical variations of TC in France and to quantify the impact of overdiagnosis. METHODS: We obtained TC incidence data in 1986-2015, and mortality data in 1976-2015, for eight French departments covering 8% of the national population, and calculated the age-standardised rates (ASR). We estimated the average annual percent changes (AAPC) of TC incidence, overall and by department and histological subtype. Numbers and proportions of TC cases attributable to overdiagnosis were estimated by department and period, based on the comparison between the shape of the age-specific curves with that observed prior to changes in diagnostic practice. RESULTS: During 1986-2015, there were 13,557 TC cases aged 15-84 years. Large variations of TC incidence were observed across departments, with the highest ASR and the fastest increase in Isère. Papillary subtype accounted for 82.8% of the cases, and presented an AAPC of 7.0% and 7.6% in women and men, respectively. Anaplastic TC incidence decreased annually 3.0% in women and 0.8% in men. Mortality rates declined consistently for all departments. The absolute number (and proportion) of TC cases attributable to overdiagnosis grew from 1074 (66%) in 1986-1995 to 3830 (72%) in 2006-2015 in women, and varied substantially across departments. CONCLUSIONS: Overdiagnosis plays an important role in the temporal and regional variations of TC incidence in France. Monitoring the time trends and regulating the regional healthcare practice are needed to reduce its impact.

Flexible Modeling of Net Survival and Cure by AML Subtype and Age: A French Population-Based Study from FRANCIM.

With improvements in acute myeloid leukemia (AML) diagnosis and treatment, more patients are surviving for longer periods. A French population of 9453 AML patients aged ≥15 years diagnosed from 1995 to 2015 was studied to quantify the proportion cured (P), time to cure (TTC) and median survival of patients who are not cured (MedS). Net survival (NS) was estimated using a flexible model adjusted for age and sex in sixteen AML subtypes. When cure assumption was acceptable, the flexible cure model was used to estimate P, TTC and MedS for the uncured patients. The 5-year NS varied from 68% to 9% in men and from 77% to 11% in women in acute promyelocytic leukemia (AML-APL) and in therapy-related AML (t-AML), respectively. Major age-differenced survival was observed for patients with a diagnosis of AML with recurrent cytogenetic abnormalities. A poorer survival in younger patients was found in t-AML and AML with minimal differentiation. An atypical survival profile was found for acute myelomonocytic leukemia and AML without maturation in both sexes and for AML not otherwise specified (only for men) according to age, with a better prognosis for middle-aged compared to younger patients. Sex disparity regarding survival was observed in younger patients with t-AML diagnosed at 25 years of age (+28% at 5 years in men compared to women) and in AML with minimal differentiation (+23% at 5 years in women compared to men). All AML subtypes included an age group for which the assumption of cure was acceptable, although P varied from 90% in younger women with AML-APL to 3% in older men with acute monoblastic and monocytic leukemia. Increased P was associated with shorter TTC. A sizeable proportion of AML patients do not achieve cure, and MedS for these did not exceed 23 months. We identify AML subsets where cure assumption is negative, thus pointing to priority areas for future research efforts.

What is the most appropriate period to define synchronous cancers?

BACKGROUND: Studies about second primary cancers (SPC) incidence exclude a period following the first cancer diagnosis given the high probability of diagnosing another primary cancer during this phase (synchronous cancers). However, definition of synchronicity period varies widely, from one to six months, without clear epidemiological justification. The objective of this study was to determine the most appropriate synchronicity period. METHODS: Data from 13 French population-based cancer registries were used to establish a cohort of all patients diagnosed with a first cancer between 1989 and 2010. The incidence rate of subsequent cancer was computed by day within 1 year of follow-up after the first diagnosis. Incidence was modelized by joinpoint regression models with an initial quadratic trend and a second constant part (plateau). The joinpoint was the point from which the plateau began and defining the synchronicity period. RESULTS: Our cohort included 696,775 patients with a first cancer, of which 12,623 presented a SPC. The median joinpoint for all sites combined was estimated at 120.5 days [112.0-129.0]. Analysis by gender reported a higher difference in 32 days for males (127.8 vs 96.1 days). Noteworthy differences were found depending on patient age and the site of first cancer, with joinpoint ranging from 84.7 (oesophagus cancer) to 250.1 days (bladder cancer). CONCLUSION: Although some heterogeneity was observed based on the characteristic of the patients, the appropriate synchronicity period appears to be 4 months after the diagnosis of first cancer.

Modeling excess hazard with time-to-cure as a parameter.

Cure models have been widely developed to estimate the cure fraction when some subjects never experience the event of interest. However, these models were rarely focused on the estimation of the time-to-cure, that is, the delay elapsed between the diagnosis and "the time from which cure is reached," an important indicator, for instance, to address the question of access to insurance or loans for subjects with personal history of cancer. We propose a new excess hazard regression model that includes the time-to-cure as a covariate-dependent parameter to be estimated. The model is written similarly to a Beta probability distribution function and is shown to be a particular case of the non-mixture cure models. Parameters are estimated through a maximum likelihood approach and simulation studies demonstrate good performance of the model. Illustrative applications to three cancer data sets are provided and some limitations as well as possible extensions of the model are discussed. The proposed model offers a simple and comprehensive way to estimate more accurately the time-to-cure.

How to produce sound predictions of incidence at a district level using either health care or mortality data in the absence of a national registry: the example of cancer in France.

BACKGROUND: In many countries, epidemiological surveillance of chronic diseases is monitored by local registries (LR) which do not necessarily cover the whole national territory. This gap has fostered interest in using non-registry databases (e.g., health care or mortality databases) available for the whole territory as proxies for incidence at the local level. However, direct counts from these databases do not provide reliable incidence measures. Accordingly, specific methods are needed to correct proxies and assess their epidemiological usefulness. METHODS: This study's objective was to implement a three-stage turnkey methodology using national non-registry data to predict incidence in geographical areas without an LR as follows: constructing a calibration model to make predictions including accurate prediction intervals; accuracy assessment of predictions and rationale for the criteria to assess which predictions were epidemiologically useful; mapping after spatial smoothing of the latter predictions. The methodology was applied to a real-world setting, whereby we aimed to predict cancer incidence, by gender, at the district level in France over the 2007-15 period for 24 different cancer sites, using several health care indicators and mortality. In the present paper, the spatial smoothing performed on predicted incidence of epidemiological interest is illustrated for two examples. RESULTS: Predicted incidence of epidemiological interest was possible for 27/34 solid site-gender combinations and for only 2/8 haematological malignancies-gender combinations. Mapping of smoothed predicted incidence provided a clear picture of the main contrasts in incidence between districts. CONCLUSIONS: The methodology implemented provides a comprehensive framework to produce valuable predictions of incidence at a district level, using proxy measures and existing LR.

Association of Mammography Screening With a Reduction in Breast Cancer Mortality: A Modeling Study Using Population-Based Data From 2 French Departments.

Meta-analyses of randomized controlled trials that started from 1963 to 1991 reported a decrease of breast cancer mortality, associated with mammography screening. However, the effectiveness of population-based screening programs conducted currently might have changed due to the higher effectiveness of treatments for late-stage cancers and the better diagnostic performance of mammography. The main objective of this study was to predict the reduction of breast cancer mortality associated with mammography screening in the current French setting. We compared breast cancer mortality in 2 simulated cohorts of women, which differed from each other solely in a 70% biennial participation in screening from 50 to 74 years old. The microsimulation model used for predictions was calibrated with incidence rates of breast cancer according to stage that were observed in Isère and Loire-Atlantique departments, France, in 2007-2013. The model predicted a decrease of breast cancer mortality associated with mammography screening of 18% (95% CI: 5, 31) and 17% (95% CI: 3, 29) for models calibrated with data from Isère and Loire-Atlantique departments, respectively. Our results highlight the interest in biennial mammography screening from ages 50 to 74 years old to decrease breast cancer mortality in the current setting, despite improvements in treatment effectiveness.

Progression of incidence and estimate of net survival from papillary thyroid cancers diagnosed between 2008 and 2016 in France.

BACKGROUND: After several decades of increasing incidence of papillary thyroid cancer (PTC), a change in this trend has been recently observed, particularly in the United States. This is attributed to the impact of new guidelines for the management of thyroid disease. The objective of this study was to describe the recent situation in France in terms of incidence and survival, taking account of tumor size. METHODS: Data from the FRANCIM network cancer registries, covering around 25% of the French metropolitan population, were analyzed. Distribution according to tumor size was determined in terms of frequency, trends in incidence and spatial distribution for the period 2008-2016. Analysis of net survival considered gender, age and tumor size. RESULTS: Cancers of size≤5mm were predominant in patients diagnosed between 55 and 74 years of age. Incidence of≤5mm tumors in women and of 5-10mm tumors in men began declining in the early 2010s. Incidence of 10-20mm and 20-40mm tumors in men increased significantly throughout the period 2008-2016. For both men and women, the incidence of the largest tumors (>40mm) also increased, but not significantly. The spatial distribution of incidence showed great heterogeneity. Net survival was generally high, although decreasing with age and tumor size. CONCLUSION: The recent epidemiological situation in France is consistent with the hypothesis of recent progress in medical management of thyroid pathologies. Variations in incidence should be monitored for both small (<10mm) and larger tumors, and notably>40mm tumors. Net survival is generally high, although decreasing with age and tumor size.

Cancer cure for 32 cancer types: results from the EUROCARE-5 study.

BACKGROUND: Few studies have estimated the probability of being cured for cancer patients. This study aims to estimate population-based indicators of cancer cure in Europe by type, sex, age and period. METHODS: 7.2 million cancer patients (42 population-based cancer registries in 17 European countries) diagnosed at ages 15-74 years in 1990-2007 with follow-up to 2008 were selected from the EUROCARE-5 dataset. Mixture-cure models were used to estimate: (i) life expectancy of fatal cases (LEF); (ii) cure fraction (CF) as proportion of patients with same death rates as the general population; (iii) time to cure (TTC) as time to reach 5-year conditional relative survival (CRS) >95%. RESULTS: LEF ranged from 10 years for chronic lymphocytic leukaemia patients to <6 months for those with liver, pancreas, brain, gallbladder and lung cancers. It was 7.7 years for patients with prostate cancer at age 65-74 years and >5 years for women with breast cancer. The CF was 94% for testis, 87% for thyroid cancer in women and 70% in men, 86% for skin melanoma in women and 76% in men, 66% for breast, 63% for prostate and <10% for liver, lung and pancreatic cancers. TTC was <5 years for testis and thyroid cancer patients diagnosed below age 55 years, and <10 years for stomach, colorectal, corpus uteri and melanoma patients of all ages. For breast and prostate cancers, a small excess (CRS < 95%) remained for at least 15 years. CONCLUSIONS: Estimates from this analysis should help to reduce unneeded medicalization and costs. They represent an opportunity to improve patients' quality of life.

Multidimensional penalized splines for incidence and mortality-trend analyses and validation of national cancer-incidence estimates.

BACKGROUND: Cancer-incidence and mortality-trend analyses require appropriate statistical modelling. In countries without a nationwide cancer registry, an additional issue is estimating national incidence from local-registry data. The objectives of this study were to (i) promote the use of multidimensional penalized splines (MPS) for trend analyses; (ii) estimate the national cancer-incidence trends, using MPS, from only local-registry data; and (iii) propose a validation process of these estimates. METHODS: We used an MPS model of age and year for trend analyses in France over 1990-2015 with a projection up to 2018. Validation was performed for 22 cancer sites and relied essentially on comparison with reference estimates that used the incidence/health-care ratio over the period 2011-2015. Alternative estimates that used the incidence/mortality ratio were also used to validate the trends. RESULTS: In the validation assessment, the relative differences of the incidence estimates (2011-2015) with the reference estimates were <5% except for testis cancer in men and < 7% except for larynx cancer in women. Trends could be correctly derived since 1990 despite incomplete histories in some registries. The proposed method was applied to estimate the incidence and mortality trends of female lung cancer and prostate cancer in France. CONCLUSIONS: The validation process confirmed the validity of the national French estimates; it may be applied in other countries to help in choosing the most appropriate national estimation method according to country-specific contexts. MPS form a powerful statistical tool for trend analyses; they allow trends to vary smoothly with age and are suitable for modelling simple as well as complex trends thanks to penalization. Detailed trend analyses of lung and prostate cancers illustrated the suitability of MPS and the epidemiological interest of such analyses.

[Breast cancer epidemiology]. / Épidémiologie des cancers du sein.

The breast is the leading cancer site in women throughout the world. That said, breast cancer incidence varies widely, ranging from 27/100,0002 (Central-East Asia and Africa) to 85-94/100,0002 (Australia, North America and Western Europe). Its frequency in France is among the highest in Europe. While in most countries, its incidence has been increasing for more than 40 years, in a few other countries (USA, Canada, Australia, France…), it has been decreasing since 2000-2005. Possibly due to a substantial reduction of hormone-based treatments at menopause, the decrease may be transient. It is also the leading cause of female cancer deaths in almost all countries, with the exception of the most economically developed, in which it is currently second to lung cancer. That much said, for thirty years in highly industrialized countries such as France, breast cancer mortality has been declining. Taken together, early diagnosis and improved treatment explain this success. In France, 5-year survival and 10-year survival approximate 88 % and 78 % respectively; these rates are among the most elevated in Western Europe. Excess mortality due to breast cancer is consequently low (<5 %) but variable according to age, and maximal during the first two years of follow-up. Several thousand epidemiological studies on risk factors for breast cancer have been carried out worldwide; it is difficult to draw up an overall assessment, especially insofar as the identified factors interact and vary according to whether the cancers occur before or after menopause and depending on their histological, biological (receptors) or molecular characteristics. Moreover, their prevalence varies in time and from one region to another. For the majority of these factors, the level of relative risk is≤2. Genetic particularities: presence of proliferative mastopathy, a first child after 35 years of age and thoracic irradiation are the sole factors entailing relative risk from 2 to 5 (comparatively speaking, the risk levels associated with tobacco consumption reach values from 10 to 20, and in some cases even higher). However, exposure to risk factors≤2 may be relatively frequent and consequently favorable to development of a substantial number of breast cancers. Estimation (based on degree of risk and frequency of exposure) of the proportion of risk attributable to a given factor facilitates decision-making aimed at determining the most effective primary prevention actions. Taking into consideration the identified factors pertaining to post-menopausal cancers, only 35 % [23 to 45 %] of the attributable proportions could be reduced by primary prevention. In view of achieving this level of reduction, it is possible to put forward the following recommendations: for the women themselves: have a first child before the age of 30, breastfeed for several months, engage in sufficiently intense and regular physical activity, avoid or reduce excess weight after turning thirty, avoid exposure to active or passive smoking, limit alcohol consumption; for their physicians: do not prescribe pointless thoracic irradiations (unnecessary mammography in particular) or unjustified hormonal treatments. *persons/years.

Time-to-cure and cure proportion in solid cancers in France. A population based study.

BACKGROUND: In cancer care, the cure proportion (P) and time-to-cure (TTC) are important indicators for practitioners, patients, and healthcare policy makers. The recent definition of TTC as the time at which the probability of belonging to the cured group reaches 95% was used for the first time. METHODS: The data stem from the common database of French cancer registries including 335,358 solid tumours diagnosed between 1995 and 2009 at 27 sites. P and TTC were estimated through a flexible parametric net survival cure model for each cancer site, sex, and age at diagnosis with acceptable assumption of cure (excess mortality rate ≤0.05). RESULTS: TTC was ≤5 years and P was >80% for skin melanoma and thyroid and testis cancers. It was 0 for testis cancer in men <55 and for thyroid cancer in men <45 and women <65. TTC was between 5 and 10 years for all digestive cancers except small intestine and all gynaecologic cancers except breast. It was ≥10 years in prostate, breast, and urinary tract. The range of P according to age and sex was 37-79% for urinary tract 72-88% for prostate and breast, 4-16% for pancreatic and 47-62% for colorectal cancer. CONCLUSION: Time-to-cure was estimated for the first time from a large national database and individual probabilities of cure. It was 0 in the younger patients with testis or thyroid cancer and <12 years in most cancer sites. These results should help improve access to credit and insurance for patients still alive past the estimated TTCs.

[Descriptive epidemiology of cancer in metropolitan France: Incidence, survival and prevalence]. / Épidémiologie descriptive des cancers en France métropolitaine : incidence, survie et prévalence.

INTRODUCTION: Incidence, mortality, survival and prevalence are key indicators to assess public health policies and estimate the needs of the population for cancer management. The aim of this article is to provide the more current estimates of these indicators, in line with the fifteenth operational objective of the 2014-2019 Cancer Plan "Collect data/Support Public Health". METHODS: Incidence and survival data came from cancer registries. Mortality data came from the French epidemiology center on medical causes of death. Prevalence was estimated by using incidence and survival estimates. RESULTS: In metropolitan France in 2017, the estimated number of new cancer cases and cancer deaths was respectively 399,500 and 150,000. The most frequent cancers (breast, prostate) had highest net survivals: 78 and 84% at 10 years. Several cancers (including lung, liver and pancreatic cancers) had worse prognosis (5-year survival≤33%). In 2017, 1,396,000 men and 1,359,000 women had cancer in the previous 15 years, representing respectively 5.4% and 4.8% of the population aged 15 and over. DISCUSSION: Despite the decrease of cancer mortality, the prognosis of some cancers remains poor and the cancer prevalence is high. These results highlight the need for intensifying the efforts already made in cancer prevention, diagnosis, and treatment and justify the interest in the post-cancer period.

For a sound use of health care data in epidemiology: evaluation of a calibration model for count data with application to prediction of cancer incidence in areas without cancer registry.

There is a growing interest in using health care (HC) data to produce epidemiological surveillance indicators such as incidence. Typically, in the field of cancer, incidence is provided by local cancer registries which, in many countries, do not cover the whole territory; using proxy measures from available nationwide HC databases would appear to be a suitable approach to fill this gap. However, in most cases, direct counts from these databases do not provide reliable measures of incidence. To obtain accurate incidence estimations and prediction intervals, these databases need to be calibrated using a registry-based gold standard measure of incidence. This article presents a calibration model for count data developed to predict cancer incidence from HC data in geographical areas without cancer registries. First, the ratio between the proxy measure and incidence is modeled in areas with registries using a Poisson mixed model that allows for heterogeneity between areas (calibration stage). This ratio is then inverted to predict incidence from the proxy measure in areas without registries. Prediction error admits closed-form expression which accounts for heterogeneity in the ratio between areas. A simulation study shows the accuracy of our method in terms of prediction and coverage probability. The method is further applied to predict the incidence of two cancers in France using hospital data as the proxy measure. We hope this approach will encourage sound use of the usually imperfect information extracted from HC data.

Impact of thyroid surgery volume and pathologic detection on risk of thyroid cancer: A geographical analysis in the Rhône-Alpes region of France.

OBJECTIVE: To investigate the impact of the volume of thyroid surgery and pathologic detection on the risk of thyroid cancer. METHODS: We investigated the influence of the volume of thyroid surgery in a first study that included 23 384 thyroid surgeries and 5302 thyroid cancers collected between 2008 and 2013. Standardized incidence ratios (SIRs) and thyroid intervention rates (STIRs) were used as indicators of cancer risk and surgery volume, respectively. The influence of pathologic detection, using the number of cuts per gram of tissue as the indicator, was studied in a second study that included 1257 thyroid specimens, collected in 2014. RESULTS: We found departmental variations in SIRs and a significant effect of the STIR on the SIR (men, P = 0.0008; women, P < 0.0001). A 1/100 000 increase in the STIR resulted in a 3% and 1.3% increase in the SIR in men and women, respectively. This effect was greatest for microcancers and absent for tumours >4 cm. The risk of cancer diagnosis was significantly associated with the number of cuts per gram of tissue (OR 6.1, P < 0.001), and was greater for total thyroidectomy than for lobectomy (P = 0.014) and when FNA cytology had been preoperatively performed (P < 0.001). The prevalence of incidental microcancers was highest in the centres performing the highest number of cuts per gram. CONCLUSIONS: The risk of thyroid cancer, particularly microcancer, is related to the volume of surgery and to the level of pathologist scrutiny. Both factors contribute to the increase in overdiagnosis. This further advocates for appropriate selection of patients for thyroid surgery.

Incidence of prostate cancer and net survival by grade in a geriatric population: A population-based study in a French administrative entity from 1991 to 2013.

BACKGROUND: Prostate cancer is the leading type of cancer among men in more developed countries. Incidence trends and survival rates could differ by age groups considering potential differences in the frequency of PSA testing, types of cancers and medical management. Our objective was to compare incidence trends and survival rates of prostate cancer between men aged ≥75 and 60-74 years. METHOD: We analyzed data from a population-based cancer registry in Isère, France. All men aged ≥60 years diagnosed with an incident prostate cancer during the 1991-2013 period were included. Incidence and mortality rates were computed as well as net survival rates. RESULTS: In 2013, observed incidence rates were 557.6 and 568.7 per 100,000 for men aged 60-74 and ≥75, respectively, with high grades cancers more frequent among elderly men. The incidence and mortality trends among men aged ≥75 included a period of stability followed by a decreasing trend from 2003, whereas a peak of incidence was observed in 2005 for men aged 60-74. For both age groups, net survival rates increased with period of diagnosis and 8-year net survival remained higher than 70% for cases diagnosed in the 2000-2004 period. Lower survival rate of 51% (95%CI: 42%; 60%) was observed for high grades cancers diagnosed among men aged 75-84 in 2000-2004. CONCLUSION: The epidemiology of prostate cancers among men aged ≥75 include a decrease of incidence and mortality rates from 2003, an important proportion of high grade cancers and a relatively good prognosis except for high grade cancers.