Epidemiology of myelodysplastic syndromes: Why characterizing the beast is a prerequisite to taming it

Physical Activity, Sitting Time, and Risk of Myelodysplastic Syndromes, Acute Myeloid Leukemia, and Other Myeloid Malignancies

INTRODUCTION

There is limited research on associations of moderate-to-vigorous physical activity (MVPA) and sitting with risk of myeloid neoplasms (MN) or MN subtypes. We examined these associations in the Cancer Prevention Study-II Nutrition Cohort.

METHODS

Among 109,030 cancer-free participants (mean age 69.2, SD 6.1 years) in 1999, 409 were identified as having been diagnosed with a MN [n = 155 acute myeloid leukemia (AML), n = 154 myelodysplastic syndromes (MDS), n = 100 other ML] through June 2013. Cox proportional hazards regression was used to calculate multivariable adjusted hazard ratios (HR) and 95% confidence intervals (CI) for associations of MVPA (MET-h/wk) and sitting (h/d) with risk of all MN, myeloid leukemia only, MDS, and AML.

RESULTS

Compared with insufficient MVPA [>0-<7.5 metabolic equivalent hours/week (MET)-h/wk], the HR (95% CI) for meeting physical activity guidelines (7.5-<15 MET-h/wk MVPA) and risk of MN was 0.74 (95% CI, 0.56-0.98) and for doubling guidelines (15-<22.5 MET-h/wk) was 0.75 (0.53-1.07); however, there was no statistically significant association for higher MVPA (22.5+ MET-h/wk, HR, 0.93; 95% CI, 0.73-1.20). Similarly, meeting/doubling guidelines was associated with lower risk of MDS (HR, 0.57; 95% CI, 0.35-0.92/HR, 0.51; 95% CI, 0.27-0.98), but there was no association for 22.5+ MET-h/wk (HR, 0.93; 95% CI, 0.63-1.37). MVPA was not associated with risk of myeloid leukemia or AML. Sitting time was not associated with risk of any outcome.

CONCLUSIONS

These results suggest that there may be a nonlinear association between MVPA and risk of MDS and possibly other MN.

IMPACT

Further studies are needed to better understand the dose-response relationships between MVPA and risk of MDS, a highly fatal and understudied cancer.

Epidemiology of acute myeloid leukemia: Recent progress and enduring challenges

Acute myeloid leukemia (AML) is a malignant disorder of the bone marrow which is characterized by the clonal expansion and differentiation arrest of myeloid progenitor cells. The age-adjusted incidence of AML is 4.3 per 100,000 annually in the United States (US). Incidence increases with age with a median age at diagnosis of 68 years in the US. The etiology of AML is heterogeneous. In some patients, prior exposure to therapeutic, occupational or environmental DNA-damaging agents is implicated, but most cases of AML remain without a clear etiology. AML is the most common form of acute leukemia in adults and has the shortest survival (5-year survival = 24%). Curative therapies, including intensive chemotherapy and allogeneic stem cell transplantation, are generally applicable to a minority of patients who are younger and fit, while most older individuals exhibit poor prognosis and survival. Differences in patient outcomes are influenced by disease characteristics, access to care including active therapies and supportive care, and other factors. After many years without therapeutic advances, several new therapies have been approved and are expected to impact patient outcomes, especially for older patients and those with refractory disease.

Getting personal with myelodysplastic syndromes: is now the right time?

INTRODUCTION

Commonly used scoring systems rely on blood counts, histological and cytological examination of bone marrow and peripheral blood as well as cytogenetic assessments to estimate prognosis of patients with myelodysplastic syndromes (MDS) and guide therapy decisions. Next-generation sequencing (NGS) has identified recurrent genetic abnormalities in up to 90% of patients with MDS and may provide important information regarding the pathogenesis of the disease, diagnostic and prognostic evaluation, and therapy selection. Areas covered: Herein, the authors review the role of NGS in diagnosis, treatment, and prognosis of MDS at various disease stages, and discuss advantages and caveats of incorporating molecular genetics in routine management of MDS. While a vast majority of patients harbor recurrent mutations implicated in MDS pathogenesis, similar mutations can be detected in otherwise healthy individuals with other hematologic malignancies. Besides establishing a diagnosis, NGS may be used to monitor minimal residual disease following treatment. Expert opinion: As more targeted therapies become available, assessment of genetic mutations will become central to individualized therapy selection and may improve diagnostic accuracy and further guide management for each patient. However, multiple challenges remain before NGS can be incorporated into routine clinical practice.

Clinicopathological aspects of therapy-related acute myeloid leukemia and myelodysplastic syndrome

Therapy-related myeloid neoplasm (t-MN) is a rare but devastating consequence of chemotherapy and/or radiotherapy used for the treatment of solid cancers and various hematologic malignancies. Our current understanding of the etiology is that hematopoietic clones that are contemporaneous with the primary cancer and resistant to the cytotoxic exposure have the potential to undergo selective expansion and transformation to t-MN. Consequently, a large proportion of cases are associated with adverse risk factors, resulting in limited effective treatment options. Despite the emergence of some therapies with promising activity in t-MN, most effects are short-lived and allogeneic stem cell transplantation remains the only curative option for eligible patients. This review summarizes the current literature on t-AML and t-MDS, with the aim of providing practical recommendations on the clinical evaluation and management of these conditions.

Myeloid disorders after autoimmune disease

Autoimmune diseases (ADs) are associated with an increased risk not only of lymphoproliferative disorders but also of myeloid malignancies. The excess risk of myelodysplastic syndromes and/or acute myeloid leukemia is observed across several AD types, including systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disorders, multiple sclerosis, among others. The risk of developing myeloid neoplasms (MNs) is dependent on several variables, including the specific AD type, chronicity and severity of the AD, type and duration of exposure of disease modifying anti-rheumatic drugs or cytotoxics/immunosuppressives, and genetic predisposition risk. Putative triggering factors linking AD to elevated MN risk include AD-directed medications, shared genetic susceptibilities between the two disease entities, and chronic immune stimulation or bone marrow infiltration by the AD. Molecular mechanisms underpinning leukemogenesis remain largely speculative and warrant further investigation. Leukemias arising in patients with AD are not always 'therapy-related' in that MNs may develop in certain AD subtypes even among patients with no prior therapy exposure. Only a few studies have attempted to determine factors associated with MN development in AD but failed to demonstrate consistent characteristic clinical or paraclinical features. These reports have failed to demonstrate a clear correlation between individual agent exposure and subsequent leukemia development due to the low rates of therapy exposure compounded by the rarity of MN occurrence. Notwithstanding, the leukemogenic potential is best documented with agents such as azathioprine, cyclophosphamide, and mitoxantrone; this risk of MN development does not appear to be shared by biologic approaches such as anti-tumor necrosis factors-alpha inhibitors. In this article, we discuss plausible biologic mechanisms underlying MN pathogenesis in AD and review the data available on the development of MNs in patients with AD.