Chronic diseases, medical history and familial cancer, and risk of leukemia and non-Hodgkin’s lymphoma in an adult population: a case–control study

Hematological Malignancies in Giant Cell Arteritis: a French population-based study

OBJECTIVES

An increased risk of hematological malignancies (HM) has been reported in giant cell arteritis (GCA) patients. Our study aimed to investigate the incidence and the type of HM occurring in GCA.

METHODS

All patients with GCA and HM living in Côte D'Or (France) were identified by crossing data from the RHEMCO (Registre des Hémopathies Malignes de Côte d'Or) and those having a positive temporal artery biopsy between 1st January 2001 and 31 December 2018.

RESULTS

Among 276 biopsy-proven GCA patients, 14 HM were identified in 12 patients (4.3%). In comparison with the general population aged over 50 years, the incidence of myeloid HM and myeloproliferative syndromes were increased in GCA patients (standardized incidence ratios = 2.71 and 5.16, respectively), with a specific increase in men with GCA (SIR = 4.82 and 9.04, respectively) but not in women. In addition, the study of standardized incidence ratios depending on the chronology between GCA and HM diagnoses suggests that there was an increased risk of developing GCA in men but not in women, after a diagnosis of myeloid HM (SIR = 9.56), especially if it was a MPS (SIR = 17.56).

CONCLUSIONS

Our study shows a particular epidemiology of HM in GCA patients, which is characterized by an increased incidence of myeloid HM, especially MPS, in male GCA patients. The chronology of the diagnoses of GCA and HM raises the hypothesis that clonal hematopoiesis may be implicated in some cases of GCA.

A clandestine culprit with critical consequences: Benzene and acute myeloid leukemia

While most clinicians recognize adult therapy-related leukemias following cytotoxic chemotherapy and radiation, environmental regulatory agencies evaluate exposure to "safe levels" of leukemogenic compounds. Benzene represents the most notorious leukemogenic chemical. Used in the production of ubiquitous items such as plastics, lubricants, rubbers, dyes, and pesticides, benzene may be responsible for the higher risk of acute myeloid leukemia (AML) among automobile, janitorial, construction, and agricultural workers. It is possible that ambient benzene may contribute to many cases of "de novo" AML not arising out of germline predispositions. In this appraisal of the available literature, we evaluate and discuss the association between chronic, low-dose and ambient exposure to environmental benzene and the development of adult AML.

Dental X-Rays and the Risk of Thyroid Cancer and Meningioma: A Systematic Review and Meta-Analysis of Current Epidemiological Evidence

Background: Exposure to moderate-to-high doses of ionizing radiation is the only established environmental risk factor for thyroid cancer and brain and central nervous system tumors. Considering the high lifetime prevalence and frequency of exposure to dental X-rays, the most common source of diagnostic radiation exposure in the general population, even a small associated increase in cancer risk would be of considerable public health importance. With the objective to inform clinical practice and guidelines, we synthesized the current epidemiological evidence on the association between dental X-rays and the risk of thyroid cancer, meningioma, and other cancers of the head and neck region. Methods: The Medline, Embase, and Web of Science databases were searched to identify eligible studies. Summary odds ratio/relative risk estimates and confidence intervals were extracted, and pooled risk ratios (RRs) for each cancer were calculated using random effects meta-analysis. Results: The literature search identified 5537 publications; of these, 26 studies including 10,868 cancer patients were included in the synthesis. The random effects meta-analyses, based on seven studies of thyroid cancer (six case/control, one cohort) and eight studies of meningioma (all case/control), showed that multiple (or repeated) exposures to dental X-rays were significantly associated with an increased risk of thyroid cancer (pooled RR = 1.87 [95% confidence interval, CI 1.11-3.15]) and meningioma (pooled RR = 1.53 [CI 1.26-1.85]). There was no association with glioma, and there were too few studies of other cancers of the head and neck region to conduct a meaningful meta-analysis. Conclusions: Based on a meta-analysis of retrospective case/control studies, these findings provide some support to the hypothesis that multiple (or repeated) exposures to dental X-rays may be associated with an increased risk of thyroid cancer and meningioma. These studies did not include individual organ doses and ages at exposure, and are subject to recall bias and other limitations. Furthermore, the thyroid exposure has decreased dramatically over time from the use of thyroid shields and improved technology/equipment. Prospective studies, based on dental X-ray records and patient follow-up, are needed to test the hypothesis further and clarify the possible cancer risk associated with dental radiography, as although the risk at the individual level, particularly with improved technology/equipment, is likely to be very low, the proportion of the population exposed is high. Considering that about one-third of the general population in developed countries is routinely exposed to one or more dental X-rays per year, these findings manifest the need to reduce diagnostic radiation exposure as much as possible.

[Influence of therapy on risk of cancer in rheumatoid arthritis. Pathophysiological principles]

The increased incidence of certain tumor entities in chronic inflammation and infections as well as the increased tumor risk under immunosuppression, illustrate the multiple and complex influences of the immune system on tumor pathogenesis. It is therefore conceivable that immunomodulatory therapy for rheumatoid arthritis (RA) could also influence the risk of malignancies, apart from treating the underlying disease. Basic scientific research studies have identified various signal transduction pathways that are relevant for tumorigenesis and tumor defense mechanisms. This review presents the current knowledge on the effects of the immune system on the occurrence of cancer and tries, where possible, to relate it to specific treatment options.