Impact of anatomical location of lower limb venous thrombus on the risk of subsequent cancer

After a proximal deep-vein thrombosis (P-DVT), the risk of diagnosis of a previously unsuspected cancer is high. Isolated distal DVT (iD-DVT; i.e. infra-popliteal DVT without pulmonary embolism [PE]) and isolated superficial-vein thrombosis (iSVT; i.e. without concomitant DVT and PE) are at least as frequent as P-DVT but their association with subsequent cancer is uncertain. We exploited data from the OPTIMEV prospective, observational, multicentre study to i) compare the risk of subsequent cancer three years after a first objectively confirmed iSVT, iD-DVT and iP-DVT in patients without a prior history of cancer or of venous thromboembolism, ii) assess predictors of subsequent cancer in cases of iD-DVT. The overall cumulative rates of cancer among the 304 patients with iSVT, 536 patients with iD-DVT, and 327 patients with iP-DVT were similar (3.4% 95% confidence interval [1.8-6.2], 3.9% [2.5-5.9] and 3.9% [2.3-6.8], respectively), regardless of whether the index venous thromboembolic event was unprovoked or associated with a major transient risk factor. Neither anatomical (muscular vs deep-calf DVT) nor ultrasound scan characteristics (number of thrombosed veins, clot diameter under compression) seemed strongly associated with the risk of cancer in cases of iD-DVT. In patients managed in routine practice, all the different clinical expressions of lower limb venous thromboembolism are associated with a similar risk of subsequent cancer. From a clinical practice point of view, this suggests that cancer screening, without discussing the necessity, or not, of such screening, should not differ between a deep-proximal, deep-distal or superficial location of thrombosis.

How to interpret and choose a Bayesian spatial model and a Poisson regression model in the context of describing small area cancer risks variations

BACKGROUND

The statistical Bayesian approach is widely used in disease mapping and Poisson regression. Results differ depending on the underlying hypothesis. Our objective is to give a comprehensive presentation of the tools that can be used to interpret results and choose between the different hypotheses. Data from the Isere cancer registry (France) illustrate this presentation.

METHOD

We consider, first, Bayesian models for disease mapping. Classic heterogeneity (Potthoff-Whithinghill statistic) and spatial autocorrelation tests (Moran statistic) of the SIRs, the DIC criteria of the different Bayesian models and finally the comparison of the empirical variance of the unstructured and structured heterogeneity components of the BYM model are considered. The last two criteria are considered for Bayesian Poisson regression including a covariate. Mapping the components of the BYM model with a covariate is also considered.

RESULTS

Four cancer sites (prostate, lung, colon-rectum and bladder) in men diagnosed during the 1998-2007 period are used to illustrate our presentation. We show that the different criteria used to interpret and to choose a model give coherent results.

CONCLUSION

A relevant interpretation of results is a necessary step in choosing the best-adapted Bayesian model. This choice is easy to make with criteria such as the DIC. The comparison of the empirical variance of the unstructured and structured heterogeneity components of the BYM model is also informative.

Cancer prevalence in United States, Nordic Countries, Italy, Australia, and France: an analysis of geographic variability

BACKGROUND

The objectives of this study were to quantitatively assess the geographic heterogeneity of cancer prevalence in selected Western Countries and to explore the associations between its determinants.

METHODS

For 20 cancer sites, 5-year cancer prevalence, incidence, and survival were observed and age standardised for the mid 2000s in the United States, Nordic European Countries, Italy, Australia, and France.

RESULTS

In Italy, 5-year crude prevalence for all cancers was 1.9% in men and 1.7% in women, while it was ∼1.5% in all other countries and sexes. After adjustment for the different age distribution of the populations, cancer prevalence in the United States was higher (20% in men and 10% in women) than elsewhere. For all cancers combined, the geographic heterogeneities were limited, though relevant for specific cancers (e.g., prostate, showing >30% higher prevalence in the United States, or lung, showing >50% higher prevalence in USA women than in other countries). For all countries, the correlations between differences of prevalence and differences of incidence were >0.9, while prevalence and survival were less consistently correlated.

CONCLUSION

Geographic differences and magnitude of crude cancer prevalence were more strongly associated with incidence rates, influenced by population ageing, than with survival rates. These estimates will be helpful in allocating appropriate resources.

Fluctuations and symmetry energy in nuclear fragmentation dynamics

Within a dynamical description of nuclear fragmentation, based on the liquid-gas phase transition scenario, we explore the relation between neutron-proton density fluctuations and nuclear symmetry energy. We show that, along the fragmentation path, isovector fluctuations follow the evolution of the local density and approach an equilibrium value connected to the local symmetry energy. Higher-density regions are characterized by smaller average asymmetry and narrower isotopic distributions. This dynamical analysis points out that fragment final state isospin fluctuations can probe the symmetry energy of the density domains from which fragments originate.

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.