Therapy-related myelodysplastic syndrome following primary breast cancer

Epidemiologic outlook of therapy-related myeloid neoplasms and selection of high-risk patients: A Korean nationwide study

BACKGROUND

Although a considerable proportion of patients with cancer receive chemotherapy (CT) or radiotherapy (RT), only a very few patients eventually develop therapy-related myeloid neoplasms (t-MNs).

METHODS

To identify subsets of cancer patients who have substantially elevated risk of developing t-MNs. Incidences and risks of t-MNs after contemporary CT or RT in patients newly diagnosed major cancers during 2009-2013 were analyzed. By merging two Korean nationwide health care big data sets, patients were selected and observed on follow-up to until t-MN development or December 2019.

RESULTS

Among 250,155 patients, 555 (0.22%) were diagnosed with t-MNs with a standard incidence ratio (SIR) of 3.40 (95% CI, 3.13-3.70). Patients had bone/joint cancers (SIR, 94.25; 95% CI, 50.71-137.80) and a remarkably high SIR for t-MN development. Patients receiving both CT and RT had the highest SIR (4.64; 95% CI, 4.08-5.20), followed by those receiving CT only (SIR, 3.30; 95% CI, 2.89-3.70). Contrarily, RT alone did not increase t-MN risk (SIR, 1.16; 95% CI, 0.76-1.56). More exposure to leukemogenic agents resulted in the higher t-MNs development.

CONCLUSIONS

The increased risk of developing acute myeloid leukemia or myelodysplastic syndrome after CT and/or RT was confirmed and subsets with substantially elevated risk for developing t-MNs were found. Such patients would be suitable for a prospective cohort for investigating t-MN pathogenesis by time series analyses.

Prognostic Factors, Survival Analyses and the Risk of Second Primary Cancer: A Population-Based Study on Burkitt Lymphoma/Leukemia

Burkitt lymphoma/leukemia (BL/L) is an aggressive oncohematological disease. This study evaluated the population-based prognosis and survival on BL/L as well as if BL/L behaved as a risk factor for the development of second primary cancers (SPCs) and if other first tumors behaved as risk factors for the occurrence of BL/L as an SPC. A retrospective cohort using the Surveillance, Epidemiology and End Results (SEER) Program (2008–2016) was performed. Kaplan–Meier, time-dependent covariate Cox regression and Poisson regression models were conducted. Overall, 3094 patients were included (median, 45 years; IQR, 22–62). The estimated overall survival was 65.4 months (95% CI, 63.6–67.3). Significantly more deaths occurred for older patients, black race, disease at an advanced stage, patients without chemotherapy/surgery and patients who underwent radiotherapy. Hodgkin lymphomas (nodal) (RR, 7.6 (3.9–15.0; p < 0.001)), Kaposi sarcomas (34.0 (16.8–68.9; p < 0.001)), liver tumors (3.4 (1.2–9.3; p = 0.020)) and trachea, mediastinum and other respiratory cancers (15.8 (2.2–113.9; p = 0.006)) behaved as risk factors for the occurrence of BL/L as an SPC. BL/L was a risk factor for the occurrence of SPCs as acute myeloid leukemias (4.6 (2.1–10.4; p < 0.001)), Hodgkin lymphomas (extranodal) (74.3 (10.0–549.8; p < 0.001)) and Kaposi sarcomas (35.1 (12.1–101.4; p < 0.001)). These results may assist the development of diagnostic and clinical recommendations for BL/L.

Representation of therapy-related myelodysplastic syndrome in clinical trials over the past 20 years

Therapy-related myelodysplastic syndrome (t-MDS), defined as MDS occurring after previous exposure to chemotherapy or radiotherapy, constitutes 10% to 20% of all MDS diagnoses. t-MDS patients tend to have higher-risk disease and worse outcomes than de novo MDS patients and are often excluded from therapeutic clinical trials. To explore this further, we extracted clinical trials across all status types registered on ClinicalTrials.gov from 1999 to 2018 studying untreated MDS patients. Using these specific search criteria, we analyzed 317 therapeutic MDS trials based on study status, therapeutic indication, eligibility criteria, and sponsor type to examine if these factors influenced t-MDS patient inclusion. Only 18 studies (5.7%) accrued 231 t-MDS patients in total, representing 3.2% of the total accrued MDS trial patient population. Fewer t-MDS patients were accrued in therapeutic trials sponsored by pharmaceutical sponsors vs nonpharmaceutical sponsors (2.8% vs 4.0%; P = .0073). This pattern of exclusion continues in actively enrolling trials; only 5 (10%) of 49 studies specifically mention the inclusion of t-MDS patients in their eligibility criteria. Our results indicate that therapeutic MDS trials seem to exclude t-MDS patients, rendering study results less applicable to this subset of MDS patients, who often have poor outcomes. Our study emphasizes the importance of the recent focus by National Cancer Institute cooperative groups and societies to broaden eligibility criteria for all patients.

Maximizing Breast Cancer Therapy with Awareness of Potential Treatment-Related Blood Disorders

In this review we summarize the impact of the various modalities of breast cancer therapy coupled with intrinsic patient factors on incidence of subsequent treatment-induced myelodysplasia and acute myelogenous leukemia (t-MDS/AML). It is clear that risk is increased for patients treated with radiation and chemotherapy at younger ages. Radiation is associated with modest risk, whereas chemotherapy, particularly the combination of an alkylating agent and an anthracycline, carries higher risk and radiation and chemotherapy combined increase the risk markedly. Recently, treatment with granulocyte colony-stimulating factor (G-CSF), but not pegylated G-CSF, has been identified as a factor associated with increased t-MDS/AML risk. Two newly identified associations may link homologous DNA repair gene deficiency and poly (ADP-ribose) polymerase inhibitor treatment to increased t-MDS/AML risk. When predisposing factors, such as young age, are combined with an increasing number of potentially leukemogenic treatments that may not confer large risk singly, the risk of t-MDS/AML appears to increase. Patient and treatment factors combine to form a biological cascade that can trigger a myelodysplastic event. Patients with breast cancer are often exposed to many of these risk factors in the course of their treatment, and triple-negative patients, who are often younger and/or BRCA positive, are often exposed to all of them. It is important going forward to identify effective therapies without these adverse associated effects and choose existing therapies that minimize the risk of t-MDS/AML without sacrificing therapeutic gain. IMPLICATIONS FOR PRACTICE: Breast cancer is far more curable than in the past but requires multimodality treatment. Great care must be taken to use the least leukemogenic treatment programs that do not sacrifice efficacy. Elimination of radiation and anthracycline/alkylating agent regimens will be helpful where possible, particularly in younger patients and possibly those with homologous repair deficiency (HRD). Use of colony-stimulating factors should be limited to those who truly require them for safe chemotherapy administration. Further study of a possible leukemogenic association with HRD and the various forms of colony-stimulating factors is badly needed.

Cui bono? Finding the value of allogeneic stem cell transplantation for lower-risk myelodysplastic syndromes

Introduction: The myelodysplastic syndromes (MDS) vary in their risk of disease progression; progression includes increasingly severe bone marrow failure, reclassification as acute myeloid leukemia (AML), and death. Prognostic tools guide recommendations for allogeneic stem cell transplantation (alloSCT), the only curative option. AlloSCT is typically reserved for patients with higher-risk MDS as defined by existing prognostic tools, although additional clinical and biological factors in lower-risk patients may influence this dogma.Areas covered: This review discusses the current understanding of MDS risk stratification as it pertains to the use of alloSCT in subpopulations of MDS patients with a particular focus on the use of alloSCT in patients with lower-risk disease.Expert commentary: Though high-quality data are lacking, some lower-risk MDS patients may benefit from alloSCT, which offers the only prospect of cure. Understanding the etiologic role and prognostic impact of recurring genetic events may improve existing risk stratification and become integral facets of prognostic schemata. The identification of additional factors influencing the prognoses of patients currently lumped together as 'lower-risk' will likewise improve the selection of MDS patients for early intervention or aggressive therapies such as alloSCT.

Clinical Effects of Hypomethylating Agents in Patients with Newly Diagnosed Myelodysplastic Syndrome Who Received DNA-Damaging Chemotherapy for Metastatic Breast Cancer

The cumulative risk of therapy-related myelodysplastic syndrome (t-MDS) in breast cancer patients exposed to chemotherapy and/or radiotherapy is significantly high compared to that in other cancer patients. This report reviews the use of hypomethylating agents (HMAs) to treat a 57-year-old woman newly diagnosed with MDS during palliative chemotherapy for metastatic breast cancer. Over a period of 6 years, the patient received several DNA-damaging chemotherapeutics including doxorubicin, cyclophosphamide, and paclitaxel. Repeated thrombocytopenia was the main reason for suspecting secondary hematologic malignancy. She was diagnosed with t-MDS based on bone marrow examination and her treatment history for breast cancer. While azacitidine was originally administered to stabilize MDS, it also stabilized the patient's lung and lymph node metastases without any major toxicity. Therefore, the current case highlights the promising effects of HMAs for treating t-MDS following heavily pretreated breast cancer.

Pharmacokinetic Effects and Safety of Olaparib Administered with Endocrine Therapy: A Phase I Study in Patients with Advanced Solid Tumours

INTRODUCTION

The PARP inhibitor olaparib is efficacious as monotherapy and has potential application in combination with endocrine therapy for the treatment of breast cancer. This phase I study assessed the safety and pharmacokinetic (PK) profiles of olaparib combined with tamoxifen, anastrozole or letrozole in patients with advanced solid tumours.

METHODS

During part A, PK profiles were assessed in three consecutive treatment periods: (1) olaparib (tablet) 300 mg bid, days 1-5 followed by a 4-day washout; (2) cohort 1, tamoxifen 60 mg loading dose qd days 10-13, 20 mg qd days 14-26; cohort 2, anastrozole 1 mg qd days 10-19; cohort 3, letrozole 2.5 mg qd days 10-38; (3) as for period 2, with concomitant olaparib 300 mg bid for 5 days. Patients could then enter part B and receive olaparib monotherapy (300 mg bid continuously). Safety was assessed in parts A and B until 12 months after the last patient entered part B.

RESULTS

Seventy-nine patients (20.3% with breast cancer) received treatment in part A; 72 completed part A and 69 entered part B. Anastrozole and letrozole had no effect on the PK profile of olaparib and vice versa. Co-administration with tamoxifen produced a modest decrease in exposure to olaparib [geometric least-squares mean (GLSmean) C_max,ss and AUC_0-τ decreased by 20% (90% CI 0.71-0.90) and 27% (0.63-0.84), respectively]. Exposure to tamoxifen was slightly increased when combined with olaparib [GLSmean C_max,ss and AUC_0-τ increased by 13% (1.06-1.22) and 16% (1.11-1.21), respectively]; however, the 90% CI fell within the 0.7-1.43 boundary and there were no changes in exposure to tamoxifen metabolites. The safety profile for olaparib alone and in combination with the antihormonal therapies was acceptable.

CONCLUSIONS

The combination of olaparib and either anastrozole, letrozole or tamoxifen was generally well tolerated, with no clinically relevant PK interactions identified.

FUNDING

AstraZeneca.

CLINICAL TRIAL REGISTRATION

NCT02093351.

Clonal haemopoiesis and therapy-related myeloid malignancies in elderly patients: a proof-of-concept, case-control study

BACKGROUND

Clonal haemopoiesis of indeterminate potential (CHIP) is an age-associated genetic event linked to increased risk of primary haematological malignancies and increased all-cause mortality, but the prevalence of CHIP in patients who develop therapy-related myeloid neoplasms is unknown. We did this study to investigate whether chemotherapy-treated patients with cancer who have CHIP are at increased risk of developing therapy-related myeloid neoplasms.

METHODS

We did a nested, case-control, proof-of-concept study to compare the prevalence of CHIP between patients with cancer who later developed therapy-related myeloid neoplasms (cases) and patients who did not develop these neoplasms (controls). We identified cases from our internal biorepository of 123 357 patients who consented to participate in the Total Cancer Care biobanking protocol at Moffitt Cancer Center (Tampa, FL, USA) between Jan 1, 2006, and June 1, 2016. We included all individuals who were diagnosed with a primary malignancy, were treated with chemotherapy, subsequently developed a therapy-related myeloid neoplasm, and were 70 years or older at either diagnosis. For inclusion in this study, individuals must have had a peripheral blood or mononuclear cell sample collected before the diagnosis of therapy-related myeloid neoplasm. Controls were individuals who were diagnosed with a primary malignancy at age 70 years or older and were treated with chemotherapy but did not develop therapy-related myeloid neoplasms. Controls were matched to cases in at least a 4:1 ratio on the basis of sex, primary tumour type, age at diagnosis, smoking status, chemotherapy drug class, and duration of follow-up. We used sequential targeted and whole-exome sequencing and described clonal evolution in cases for whom paired CHIP and therapy-related myeloid neoplasm samples were available. The primary endpoint of this study was the development of therapy-related myeloid neoplasm and the primary exposure was CHIP.

FINDINGS

We identified 13 cases and 56 case-matched controls. The prevalence of CHIP in all patients (23 [33%] of 69 patients) was higher than has previously been reported in elderly individuals without cancer (about 10%). Cases had a significantly higher prevalence of CHIP than did matched controls (eight [62%] of 13 cases vs 15 [27%] of 56 controls, p=0·024; odds ratio 5·75, 95% CI 1·52-25·09, p=0·013). The most commonly mutated genes in cases with CHIP were TET2 (three [38%] of eight patients) and TP53(three [38%] of eight patients), whereas controls most often had TET2 mutations (six [40%] of 15 patients). In most (four [67%] of six patients) cases for whom paired CHIP and therapy-related myeloid neoplasm samples were available, the mean allele frequency of CHIP mutations had expanded by the time of the therapy-related myeloid neoplasm diagnosis. However, a subset of paired samples (two [33%] of six patients) had CHIP mutations that decreased in allele frequency, giving way to expansion of a distinct mutant clone.

INTERPRETATION

Patients with cancer who have CHIP are at increased risk of developing therapy-related myeloid neoplasms. The distribution of CHIP-related gene mutations differs between individuals with therapy-related myeloid neoplasm and those without, suggesting that mutation-specific differences might exist in therapy-related myeloid neoplasm risk.

FUNDING

Moffitt Cancer Center.

Therapy-related myelodysplastic syndromes, or are they?

The incidence of therapy-related myelodysplastic syndromes (t-MDS) is increasing as the number of cancer survivors is increasing. While t-MDS is currently defined descriptively by prior receipt of chemotherapy and/or radiotherapy, some forms of MDS that occur post localized radiation monotherapy, biologically and clinically resemble de novo (d)-MDS more than t-MDS, and therefore may not be truly therapy-related. Although patients with t-MDS, as a group, fare worse than patients with d-MDS, a variation in individual outcomes of patients with t-MDS has increasingly been appreciated. As such, accurate risk stratification is important for counseling of patients and for clinical decision making. Most of the current clinical tools used for prognostication in t-MDS were developed for d-MDS and were not specifically validated in patients with t-MDS. The management of patients with t-MDS remains challenging, highlighting the importance of developing effective prevention strategies as well as newer, targeted, and rationally-designed therapeutic interventions.