F. Lennie Wong

PURPOSE: Older adults are vulnerable to chemotherapy toxicity; however, there are limited data to identify those at risk. The goals of this study are to identify risk factors for chemotherapy toxicity in older adults and develop a risk stratification schema for chemotherapy toxicity. PATIENTS AND METHODS: Patients age ≥ 65 years with cancer from seven institutions completed a prechemotherapy assessment that captured sociodemographics, tumor/treatment variables, laboratory test results, and geriatric assessment variables (function, comorbidity, cognition, psychological state, social activity/support, and nutritional status). Patients were followed through the chemotherapy course to capture grade 3 (severe), grade 4 (life-threatening or disabling), and grade 5 (death) as defined by the National Cancer Institute Common Terminology Criteria for Adverse Events. RESULTS: In total, 500 patients with a mean age of 73 years (range, 65 to 91 years) with stage I to IV lung (29%), GI (27%), gynecologic (17%), breast (11%), genitourinary (10%), or other (6%) cancer joined this prospective study. Grade 3 to 5 toxicity occurred in 53% of the patients (39% grade 3, 12% grade 4, 2% grade 5). A predictive model for grade 3 to 5 toxicity was developed that consisted of geriatric assessment variables, laboratory test values, and patient, tumor, and treatment characteristics. A scoring system in which the median risk score was 7 (range, 0 to 19) and risk stratification schema (risk score: percent incidence of grade 3 to 5 toxicity) identified older adults at low (0 to 5 points; 30%), intermediate (6 to 9 points; 52%), or high risk (10 to 19 points; 83%) of chemotherapy toxicity (P < .001). CONCLUSION: A risk stratification schema can establish the risk of chemotherapy toxicity in older adults. Geriatric assessment variables independently predicted the risk of toxicity.

PURPOSE: Mercaptopurine (MP) is the mainstay of curative therapy for acute lymphoblastic leukemia (ALL). We performed a genome-wide association study (GWAS) to identify comprehensively the genetic basis of MP intolerance in children with ALL. PATIENTS AND METHODS: The discovery GWAS and replication cohorts included 657 and 371 children from two prospective clinical trials. MP dose intensity was a marker for drug tolerance and toxicities and was defined as prescribed dose divided by the planned protocol dose during maintenance therapy; its association with genotype was evaluated using a linear mixed-effects model. RESULTS: MP dose intensity varied by race and ethnicity and was negatively correlated with East Asian genetic ancestry (P < .001). The GWAS revealed two genome-wide significant loci associated with dose intensity: rs1142345 in TPMT (Tyr240Cys, present in *3A and *3C variants; P = 8.6 × 10(-9)) and rs116855232 in NUDT15 (P = 8.8 × 10(-9)), with independent replication. Patients with TT genotype at rs116855232 were exquisitely sensitive to MP, with an average dose intensity of 8.3%, compared with those with TC and CC genotypes, who tolerated 63% and 83.5% of the planned dose, respectively. The NUDT15 variant was most common in East Asians and Hispanics, rare in Europeans, and not observed in Africans, contributing to ancestry-related differences in MP tolerance. Of children homozygous for either TPMT or NUDT15 variants or heterozygous for both, 100% required ≥ 50% MP dose reduction, compared with only 7.7% of others. CONCLUSION: We describe a germline variant in NUDT15 strongly associated with MP intolerance in childhood ALL, which may have implications for treatment individualization in this disease.

PURPOSE: Systemic exposure to mercaptopurine (MP) is critical for durable remissions in children with acute lymphoblastic leukemia (ALL). Nonadherence to oral MP could increase relapse risk and also contribute to inferior outcome in Hispanics. This study identified determinants of adherence and described impact of adherence on relapse, both overall and by ethnicity. PATIENTS AND METHODS: A total of 327 children with ALL (169 Hispanic; 158 non-Hispanic white) participated. Medication event-monitoring system caps recorded date and time of MP bottle openings. Adherence rate, calculated monthly, was defined as ratio of days of MP bottle opening to days when MP was prescribed. RESULTS: After 53,394 person-days of monitoring, adherence declined from 94.7% (month 1) to 90.2% (month 6; P < .001). Mean adherence over 6 months was significantly lower among Hispanics (88.4% v 94.8%; P < .001), patients age ≥ 12 years (85.8% v 93.1%; P < .001), and patients from single-mother households (80.6% v 93.1%; P = .001). A progressive increase in relapse was observed with decreasing adherence (reference: adherence ≥ 95%; 94.9% to 90%: hazard ratio [HR], 4.1; 95% CI,1.2 to 13.5; P = .02; 89.9% to 85%: HR, 4.0; 95% CI, 1.0 to 15.5; P = .04; < 85%: HR. 5.7; 95% CI, 1.9 to 16.8; P = .002). Cumulative incidence of relapse (± standard deviation) was higher among Hispanics (16.5% ± 4.0% v 6.3% ± 2.2%; P = .02). Association between Hispanic ethnicity and relapse (HR, 2.6; 95% CI, 1.1 to 6.1; P = .02) became nonsignificant (HR, 1.8; 95% CI, 0.6 to 5.2; P = .26) after adjusting for adherence and socioeconomic status. At adherence rates ≥ 90%, Hispanics continued to demonstrate higher relapse, whereas at rates < 90%, relapse risk was comparable to that of non-Hispanic whites. CONCLUSION: Lower adherence to oral MP increases relapse risk. Ethnic difference in relapse risk differs by level of adherence-an observation currently under investigation.

Hematopoietic cell transplantation (HCT) recipients may be at an increased risk of developing hypertension, diabetes, and dyslipidemia (referred to as cardiovascular risk factors [CVRFs]); and these factors can potentially increase the risk of cardiovascular disease (CVD). We examined the incidence and predictors of CVRFs and subsequent CVD in 1885 consecutive 1+year survivors of HCT performed at City of Hope between 1995 and 2004. Ten-year cumulative incidence of hypertension, diabetes, dyslipidemia, and multiple (≥ 2) CVRFs was 37.7%, 18.1%, 46.7%, and 31.4%, respectively. The prevalence of CVRFs was significantly higher among HCT recipients compared with the general population; contributed to largely by allogeneic HCT recipients. Older age and obesity at HCT were associated with increased risk of CVRFs. History of grade II-IV acute graft versus host disease was associated with an increased risk for hypertension (relative risk [RR] = 9.1, P < .01), diabetes (RR = 5.8, P < .01), and dyslipidemia (RR = 3.2, P < .01); conditioning with total body irradiation was associated with an increased risk of diabetes (RR = 1.5, P = .01) and dyslipidemia (RR = 1.4, P < .01). There was an incremental increase in 10-year incidence of CVD by number of CVRFs (4.7% [none], 7.0% [1 CVRF], 11.2% [≥ 2 CVRFs], P < .01); the risk was especially high (15.0%) in patients with multiple CVRFs and pre-HCT exposure to anthracyclines or chest radiation.

PURPOSE: To describe the epidemiology and risk factors for cardiovascular disease (CVD) in survivors of adolescent and young adult (AYA) cancer. METHODS: We identified a retrospective cohort of 2-year survivors of AYA cancer who were diagnosed between the ages of 15 to 39 years (1998 to 2009) at Kaiser Permanente Southern California. A comparison group without cancer was selected and matched 10:1 to cancer survivors on the basis of age, sex, Kaiser Permanente Southern California membership, and calendar year. Patients were followed through December 31, 2012, for coronary artery disease, heart failure, and stroke. Time-dependent Poisson regression was used to evaluate the effect that cancer survivorship had on the risk of developing CVD, adjusted for cardiovascular risk factors (CVRFs; ie, diabetes, hypertension, and dyslipidemia), ethnicity, smoking, and overweight/obesity. Among cancer survivors, mortality risk by CVD status was examined using Cox regression. RESULTS: A total of 5,673 2-year survivors of AYA cancer and 57,617 comparison patients were included, representing 24,839 and 239,073 person-years of follow-up, respectively. Overall, cancer survivors had more than two-fold risk of developing CVD (adjusted incidence rate ratio, 2.37; 95% CI, 1.93 to 2.93) when compared with patients without cancer; survivors of leukemia and breast cancer were at the highest risk (adjusted incidence rate ratio, 4.23; 95% CI, 1.73 to 10.31; and 3.63; 95% CI, 2.41 to 5.47, respectively) of developing CVD. Having any of the CVRFs increased the risk of CVD in cancer survivors. Cancer survivors who developed CVD had an 11-fold increased overall mortality risk (hazard ratio, 10.9; 95% CI, 8.1 to 14.8) when compared with survivors without CVD. CONCLUSION: Survivors of AYA cancer are at increased risk for developing CVD. Survival after CVD onset is compromised, and CVRFs are independent modifiers of CVD risk. These data form the basis for identifying high-risk individuals and proactive management of CVRFs.