Childhood leukemia and lymphoma: time trends and factors affecting survival in five Southern and Eastern European Cancer Registries

Purpose

Within Europe, incidence and mortality rates of childhood leukemia and lymphoma are rather heterogeneous. The present study comprising data from five Southern and Eastern European Cancer Registries aims to compare time trends and examine whether sociodemographic variables, clinical parameters, and proxies of efficient care affect survival.

Methods

Data spanning 1996–2010 were obtained for a total of 3,041 newly diagnosed childhood leukemia and 1,183 lymphoma cases reported by the Greek Nationwide Registry for Childhood Hematological Malignancies, Bulgarian National Cancer Registry, Moscow Region and Turkey (Antalya and Izmir) Cancer Registries. Poisson modeling for the evaluation of time trends and multivariate Cox regression analysis for the assessment of prognostic factors were performed.

Results

The incidence of leukemia was increasing in all cases, with Bulgaria and Greece presenting statistically significant annual changes (+3.5, and +1.7 %, respectively), followed by marginally increasing trends in Izmir and Moscow; by contrast, there was a remarkable, statistically significant, decreasing mortality trend for leukemia. Rates for lymphoma remained flat. Greece experienced almost twofold better survival rates for both leukemia and lymphoma, probably due to its higher socioeconomic status during the study period. Overall, patients with leukemia living in rural areas had a 28 % lower prognosis (RR: 1.28, 95 % CI 1.03–1.59), pointing to effects of remoteness, when the most privileged country (Greece) was excluded from the analysis.

Conclusions

The favorable mortality trends highlight the progress in Southern–Eastern European countries along their trajectory to converge with Northern–Western EU counterpart states. Socioeconomic status may act as a multipotent factor underlying the study findings.     

Circulating leptin levels and risk of colorectal cancer and adenoma: a case–control study and meta-analysis

Purpose

Equivocal results regarding the role of leptin in colorectal cancer (CRC) and adenoma (CRA) have been reported. A case–control study investigating the association of leptin with CRC risk and clinicopathological characteristics along with meta-analysis of published data on both CRC and CRA were conducted.

Methods

Pubmed and Embase were searched for the meta-analysis, comprising 28 case–control studies amounting 3,614 CRC and 1,215 CRA cases, along with 5,220 controls. Meticulous contact with the authors of individual studies was undertaken for the provision of additional data. Pooling of standardized mean differences (SMD), relative risks (RR) and 95 % CI (random effects models), subgroup, sensitivity, and meta-regression analyses were conducted.

Results

The meta-analysis suggested positive association of serum leptin with CRA (RR, 95 % CI 1.35, 1.03 to +1.76), but not CRC either at the pooled analysis on SMDs or RRs (SMD, 95 % CI 0.18, ?0.04 to +0.40; RR, 95 % CI 1.04, 0.65 to +1.65). Significant heterogeneity between studies on CRC as well as between studies on CRA providing SMD was noted. Subgroup, meta-regression and sensitivity analyses highlighted potential methodology-, design-, size- and quality-related effect modifiers.

Conclusions

Meta-analysis of current evidence suggests positive association of serum leptin with CRA but not with CRC risk. Given the case–control nature of available studies, the limited number of studies on serum leptin and CRA, and the heterogeneity of CRC studies, carefully designed, prospective studies preferably reporting RRs adjusted for a variety of confounders may be warranted.