Statistical analysis of mixed recurrent event data with application to cancer survivor study

Event history studies occur in many fields including economics, medical studies, and social science. In such studies concerning some recurrent events, two types of data have been extensively discussed in the literature. One is recurrent event data that arise if study subjects are monitored or observed continuously. In this case, the observed information provides the times of all occurrences of the recurrent events of interest. The other is panel count data, which occur if the subjects are monitored or observed only periodically. This can happen if the continuous observation is too expensive or not practical, and in this case, only the numbers of occurrences of the events between subsequent observation times are available. In this paper, we discuss a third type of data, which is a mixture of recurrent event and panel count data and for which there exists little literature. For regression analysis of such data, we present a marginal mean model and propose an estimating equation-based approach for estimation of regression parameters. We conduct a simulation study to assess the finite sample performance of the proposed methodology, and the results indicate that it works well for practical situations. Finally, we apply it to a motivating study on childhood cancer survivors.

Influenza viral RNA detection in blood as a marker to predict disease severity in hematopoietic cell transplant recipients

Influenza RNA in blood (viremia) was detected in 9 of 79 (11.4%) hematopoietic cell transplant recipients with influenza, and was less frequently observed in patients with upper respiratory tract disease only and more frequently in patients infected with 2009 pandemic influenza A/H1N1 strain (versus seasonal strains). Viremia increased the risk of progression to lower respiratory tract disease (LRD), hypoxemia, respiratory failure, and overall and influenza-related death. Among patients with LRD, viremia was associated with increased hazards of overall and influenza-associated death (hazard ratio 3.5, 1.1–12). Thus, influenza viremia may serve as marker for overall poor outcome.

Limitations in health care access and utilization among long-term survivors of adolescent and young adult cancer

BACKGROUND

Health care outcomes for long-term survivors of adolescent and young adult (AYA) cancer were compared with young adults without a cancer history, using the 2009 Behavioral Risk Factor Surveillance System data.

METHODS

Eligible participants were 20 to 39 years of age. There were N = 979 who self-reported a cancer diagnosis between the ages of 15 to 34 years and were at least 5 years from diagnosis (excluding nonmelanoma skin cancer). The remaining 67,216 participants with no cancer history were used as controls. Using multivariable regressions, relative risks and 95% confidence intervals were generated to examine the relationship of survivor status on indicators of poor health care (uninsured, no personal health care provider, no routine care, and avoiding seeing a doctor due to cost). Adjusted proportions were calculated by demographic groups. Results are weighted by Behavioral Risk Factor Surveillance System survey design.

RESULTS

Although the proportion uninsured did not differ (21% of survivors vs 23% of controls), AYA survivors reported forgoing care due to cost at higher levels than controls (relative risk = 1.67, 95% CI = 1.44-1.94). Cost barriers were particularly high for survivors aged 20 to 29 years (44% vs 16% of controls; P < .001) and female survivors (35% vs 18% of controls; P < .001). Survivors reporting poorer health had more cost barriers. Moreover, uninsured survivors tended to report lower use of health care than did controls.

CONCLUSIONS

AYA cancer survivors may forgo health care due to cost barriers, potentially inhibiting the early detection of late effects. Expanding health insurance coverage for young cancer survivors may be insufficient without adequate strategies to reduce their medical cost burdens.

Radiation-related risk of basal cell carcinoma: a report from the Childhood Cancer Survivor Study

BACKGROUND

Basal cell carcinoma (BCC) is the most common malignancy in the United States. Ionizing radiation is an established risk factor in certain populations, including cancer survivors. We quantified the association between ionizing radiation dose and the risk of BCC in childhood cancer survivors.

METHODS

Participants in the Childhood Cancer Survivor Study who reported a BCC (case subjects, n = 199) were matched on age and length of follow-up to three study participants who had not developed a BCC (control subjects, n = 597). The radiation-absorbed dose (in Gy) to the BCC location was calculated based on individual radiotherapy records using a custom-designed dosimetry program. Conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between demographic and treatment factors, therapeutic radiation dose, and surrogate markers of sun sensitivity (skin and hair color) and the risk of BCC. A linear dose-response model was fitted to evaluate the excess odds ratio per Gy of radiation dose.

RESULTS

Among case subjects, 83% developed BCC between the ages of 20 and 39 years. Radiation therapy, either alone or in combination with chemotherapy, was associated with an increased risk of BCC compared with no chemotherapy or radiation. The odds ratio for subjects who received 35 Gy or more to the skin site vs no radiation therapy was 39.8 (95% CI = 8.6 to 185). Results were consistent with a linear dose-response relationship, with an excess odds ratio per Gy of 1.09 (95% CI = 0.49 to 2.64). No other treatment variables were statistically significantly associated with an increased risk of BCC.

CONCLUSIONS

Radiation doses to the skin of more than 1 Gy are associated with an increased risk of BCC.

Prevalence and predictors of risky and heavy alcohol consumption among adult siblings of childhood cancer survivors

OBJECTIVE

To describe alcohol consumption patterns and risk factors for risky and heavy alcohol use among siblings of childhood cancer survivors compared with survivors and national controls.

METHODS

Secondary analysis of prospectively collected data from two national surveys was performed including a cohort of 3034 adult siblings of childhood cancer survivors (age 18-56 years) and 10,398 adult childhood cancer survivors, both from the Childhood Cancer Survivor Study, plus 5712 adult participants from the population-based National Alcohol Survey. Cancer-related experiences, self-reported current health, and mental health were examined in relation to alcohol consumption patterns including heavy and risky drinking.

RESULTS

Adult siblings of childhood cancer survivors were more likely to be heavy drinkers (OR adj = 1.3; 1.0-1.6) and risky drinkers (OR adj = 1.3; 1.1-1.6) compared with controls from a national sample. Siblings were also more likely to drink at these two levels compared with survivors. Factors associated with heavy drinking among siblings included being 18-21 years old (OR adj = 2.9; 2.0-4.4), male (OR adj = 2.3; 1.7-3.0), having a high school education or less (OR adj = 2.4; 1.7-3.5), and drinking initiation at a young age (OR adj = 5.1; 2.5-10.3). Symptoms of depression, (OR adj = 2.1; 1.3-3.2), anxiety (OR adj = 1.9; 1.1-3.3), and global psychiatric distress (OR adj = 2.5; 1.5-4.3) were significantly associated with heavy alcohol use.

CONCLUSIONS

Siblings of children with cancer are more likely to be risky and heavy drinkers as adults compared with childhood cancer survivors or national controls. Early initiation of drinking and symptoms of psychological distress should be identified during early adolescence and effective sibling-specific interventions should be developed and made available for siblings of children with cancer.

Nonadherence to oral mercaptopurine and risk of relapse in Hispanic and non-Hispanic white children with acute lymphoblastic leukemia: a report from the children's oncology group

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.

Secondary gastrointestinal cancer in childhood cancer survivors: a cohort study

BACKGROUND

Childhood cancer survivors develop gastrointestinal cancer more frequently and at a younger age than the general population, but the risk factors have not been well-characterized.

OBJECTIVE

To determine the risk and associated risk factors for gastrointestinal subsequent malignant neoplasms (SMNs) in childhood cancer survivors.

DESIGN

Retrospective cohort study.

SETTING

The Childhood Cancer Survivor Study, a multicenter study of childhood cancer survivors diagnosed between 1970 and 1986.

PATIENTS

14 358 survivors of cancer diagnosed when they were younger than 21 years of age who survived for 5 or more years after the initial diagnosis.

MEASUREMENTS

Standardized incidence ratios (SIRs) for gastrointestinal SMNs were calculated by using age-specific population data. Multivariate Cox regression models identified associations between risk factors and gastrointestinal SMN development.

RESULTS

At median follow-up of 22.8 years (range, 5.5 to 30.2 years), 45 cases of gastrointestinal cancer were identified. The risk for gastrointestinal SMNs was 4.6-fold higher in childhood cancer survivors than in the general population (95% CI, 3.4 to 6.1). The SIR for colorectal cancer was 4.2 (CI, 2.8 to 6.3). The highest risk for gastrointestinal SMNs was associated with abdominal radiation (SIR, 11.2 [CI, 7.6 to 16.4]). However, survivors not exposed to radiation had a significantly increased risk (SIR, 2.4 [CI, 1.4 to 3.9]). In addition to abdominal radiation, high-dose procarbazine (relative risk, 3.2 [CI, 1.1 to 9.4]) and platinum drugs (relative risk, 7.6 [CI, 2.3 to 25.5]) independently increased the risk for gastrointestinal SMNs.

LIMITATION

This cohort has not yet attained an age at which risk for gastrointestinal cancer is greatest.

CONCLUSION

Childhood cancer survivors, particularly those exposed to abdominal radiation, are at increased risk for gastrointestinal SMNs. These findings suggest that surveillance of at-risk childhood cancer survivors should begin at a younger age than that recommended for the general population.

PRIMARY FUNDING SOURCE

National Cancer Institute.

Secondary gastrointestinal cancer in childhood cancer survivors: a cohort study

BACKGROUND

Childhood cancer survivors develop gastrointestinal cancer more frequently and at a younger age than the general population, but the risk factors have not been well-characterized.

OBJECTIVE

To determine the risk and associated risk factors for gastrointestinal subsequent malignant neoplasms (SMNs) in childhood cancer survivors.

DESIGN

Retrospective cohort study.

SETTING

The Childhood Cancer Survivor Study, a multicenter study of childhood cancer survivors diagnosed between 1970 and 1986.

PATIENTS

14 358 survivors of cancer diagnosed when they were younger than 21 years of age who survived for 5 or more years after the initial diagnosis.

MEASUREMENTS

Standardized incidence ratios (SIRs) for gastrointestinal SMNs were calculated by using age-specific population data. Multivariate Cox regression models identified associations between risk factors and gastrointestinal SMN development.

RESULTS

At median follow-up of 22.8 years (range, 5.5 to 30.2 years), 45 cases of gastrointestinal cancer were identified. The risk for gastrointestinal SMNs was 4.6-fold higher in childhood cancer survivors than in the general population (95% CI, 3.4 to 6.1). The SIR for colorectal cancer was 4.2 (CI, 2.8 to 6.3). The highest risk for gastrointestinal SMNs was associated with abdominal radiation (SIR, 11.2 [CI, 7.6 to 16.4]). However, survivors not exposed to radiation had a significantly increased risk (SIR, 2.4 [CI, 1.4 to 3.9]). In addition to abdominal radiation, high-dose procarbazine (relative risk, 3.2 [CI, 1.1 to 9.4]) and platinum drugs (relative risk, 7.6 [CI, 2.3 to 25.5]) independently increased the risk for gastrointestinal SMNs.

LIMITATION

This cohort has not yet attained an age at which risk for gastrointestinal cancer is greatest.

CONCLUSION

Childhood cancer survivors, particularly those exposed to abdominal radiation, are at increased risk for gastrointestinal SMNs. These findings suggest that surveillance of at-risk childhood cancer survivors should begin at a younger age than that recommended for the general population.

PRIMARY FUNDING SOURCE

National Cancer Institute.

Scarring, disfigurement, and quality of life in long-term survivors of childhood cancer: a report from the Childhood Cancer Survivor study

PURPOSE

Childhood cancer survivors are at increased risk for adverse outcomes and chronic medical conditions. Treatment-related scarring, disfigurement, and persistent hair loss, in addition to their long-term impact on psychological distress or health-related quality of life (HRQOL), have received little attention.

PATIENTS AND METHODS

Self-reported scarring/disfigurement and persistent hair loss were examined in 14,358 survivors and 4,023 siblings from the Childhood Cancer Survivor Study. Multivariable models were used to examine associations with demographic and cancer treatment. The impact of disfigurement and hair loss on HRQOL (ie, Medical Outcomes Short Form-36) and emotional distress (ie, Brief Symptom Inventory-18) was examined.

RESULTS

Survivors reported a significantly higher rate of scarring/disfigurement compared with siblings for head/neck (25.1% v 8.4%), arms/legs (18.2% v 10.2%), and chest/abdomen (38.1% v 9.1%), as well as hair loss (14.0% v 6.3%). In age-, sex-, and race-adjusted models, cranial radiation exposure ≥ 36 Gy increased risk for head/neck disfigurement (relative risk [RR], 2.42; 95% CI, 2.22 to 2.65) and hair loss (RR, 4.24; 95% CI, 3.63 to 4.95). Adjusting for cranial radiation, age, sex, race, education, and marital status, survivor hair loss increased risk of anxiety (RR, 1.60; 95% CI, 1.23 to 2.07), whereas head/neck disfigurement increased risk of depression (RR, 1.19; 95% CI, 1.01 to 1.41). Limitations due to emotional symptoms were associated with head/neck disfigurement (RR, 1.24; 95% CI, 1.10 to 1.41), arm/leg disfigurement (RR, 1.19; 95% CI, 1.05 to 1.35), and hair loss (RR, 1.26; 95% CI, 1.09 to 1.47).

CONCLUSION

Survivors of childhood cancer are at increased risk for disfigurement and persistent hair loss, which is associated with future emotional distress and reduced quality of life. Future studies are needed to better identify and manage functional outcomes in these patients.

Cancer prevention and screening practices of siblings of childhood cancer survivors: a report from the Childhood Cancer Survivor Study

BACKGROUND

To compare the skin and breast/cervical cancer prevention/screening practices of adult siblings of childhood cancer survivors with controls and to identify modifying factors for these practices.

METHODS

Cross-sectional, self-report data from 2,588 adult siblings of 5+ year survivors of childhood cancer were analyzed to assess cancer prevention/screening practices. Two age, sex, and race/ethnicity-matched samples (N = 5,915 and N = 37,789) of the Behavioral Risk Factor Surveillance System participants served as the comparison populations. Sociodemographic and cancer-related data were explored as modifying factors for sibling cancer prevention/screening practices through multivariable logistic regression.

RESULTS

Compared with controls, siblings were more likely to practice skin cancer prevention behaviors: use of protective clothing [OR, 2.85; 95% confidence interval (CI), 2.39-3.39], use of shade (OR, 2.11; 95% CI, 1.88-2.36), use of sunscreen (OR, 1.27; 95% CI, 1.14-1.40), and wearing a hat (OR, 1.77; 95% CI, 1.58-1.98). No differences were noted for breast/cervical cancer screening including mammography and Pap testing. Having less than a high school education and lack of health insurance were associated with diminished cancer prevention/screening behaviors. Survivor diagnosis, treatment intensity, adverse health, chronic health conditions, and second cancers were not associated with sibling cancer prevention/screening behaviors.

CONCLUSIONS

Siblings of cancer survivors report greater skin cancer prevention practices when compared with controls; however, no differences were noted for breast/cervical cancer screening practices. Access to care and lack of education may be associated with decreased cancer prevention/screening behaviors. Interventions are needed to address these barriers.

IMPACT

Research should be directed at understanding the impact of the cancer experience on sibling health behaviors.

Modifiable risk factors associated with bone deficits in childhood cancer survivors

BACKGROUND

To determine the prevalence and severity of bone deficits in a cohort of childhood cancer survivors (CCS) compared to a healthy sibling control group, and the modifiable factors associated with bone deficits in CCS.

METHODS

Cross-sectional study of bone health in 319 CCS and 208 healthy sibling controls. Bone mineral density (BMD) was measured by dual-energy x-ray absorptiometry (DXA). Generalized estimating equations were used to compare measures between CCS and controls. Among CCS, multivariable logistic regression was used to evaluate odds ratios for BMD Z-score ≤ -1.

RESULTS

All subjects were younger than 18 years of age. Average time since treatment was 10.1 years (range 4.3 - 17.8 years). CCS were 3.3 times more likely to have whole body BMD Z-score ≤ -1 than controls (95% CI: 1.4-7.8; p = 0.007) and 1.7 times more likely to have lumbar spine BMD Z-score ≤ -1 than controls (95% CI: 1.0-2.7; p = 0.03). Among CCS, hypogonadism, lower lean body mass, higher daily television/computer screen time, lower physical activity, and higher inflammatory marker IL-6, increased the odds of having a BMD Z-score ≤ -1.

CONCLUSIONS

CCS, less than 18 years of age, have bone deficits compared to a healthy control group. Sedentary lifestyle and inflammation may play a role in bone deficits in CCS. Counseling CCS and their caretakers on decreasing television/computer screen time and increasing activity may improve bone health.

Risk factors for smoking among adolescent survivors of childhood cancer: a report from the Childhood Cancer Survivor Study

BACKGROUND

Few studies have examined risk factors for smoking among adolescent survivors of childhood cancer. The present study reports on the rate of smoking and identifies factors associated with smoking in a sample of adolescent survivors from the Childhood Cancer Survivor Study (CCSS).

PROCEDURE

Participants included 307 adolescent survivors and 97 healthy siblings (ages 14-20) who completed a self-report survey of health, quality of life, and health behaviors.

RESULTS

Smoking rates did not differ significantly between survivor and sibling groups (ever smokers: 28% vs. 33%, recent smokers: 10% vs. 9%, respectively). Ever smoking was significantly associated with peer smoking, smokers in the household, binging, suicidal behavior, and no history of CRT. There were significant interactions of peer smoking with gender and CRT for ever smoking and with binging for recent smoking. Recent smoking was more likely for survivors with other household smokers (RR=2.24, CI=1.21-4.16), past suicidality (RR=1.89, CI=1.00-3.56), and no CRT (RR=2.40, CI=1.12-5.17). Among survivors with few smoking friends, ever smoking was more likely for survivors with no CRT (RR=4.47, CI=1.43-13.9), and recent smoking was more likely among survivors who binged (RR=3.37, CI=1.17-9.71).

CONCLUSIONS

Despite the health risks associated with survivorship, nearly one in three adolescent survivors of childhood cancer has smoked. Exposure to other smokers, in particular, appears to increase the likelihood of smoking for some survivors. Providing smoking cessation programs targeted to family members, helping survivors choose non-smoking friends, and teaching ways to resist smoking influences from peers may be important pathways for smoking prevention with adolescent survivors.

Abstract 8: Radiation and modifiable Stroke Risk Factors in adult Survivors of Pediatric Cancer: Results from the Childhood Cancer Survivor Study

Background: Radiation therapy has vascular sequelae including moyamoya (brain radiation), and accelerated cervical atherosclerosis (neck radiation). However, the impact of cranial radiation therapy (CRT) and modifiable stroke risk factors such as hypertension (HTN) on stroke risk in adulthood remains poorly understood.

Objective: To assess long-term incidence rates and risk factors for stroke in survivors of childhood cancer followed by the Childhood Cancer Survivor Study (CCSS).

Methods: CCSS is a multi-institutional longitudinal cohort study of 14,358 survivors of childhood cancer diagnosed between 1970 and 1986, and 4,023 randomly selected sibling controls. The age-adjusted incidence rates of self-reported late-occurring first-stroke (≥ 5 years after cancer diagnosis) were calculated for survivors compared to siblings. Multivariable Cox Proportional Hazards models were used to identify independent stroke predictors.

Results: During a mean follow-up of 23.3 years, 292 survivors reported a late-occurring stroke of which 125 (42.8%) occurred in CNS tumor survivors who constituted only (13%) of the survivor population. The age-adjusted stroke rate per 100,000 person-years at age 23 was 77 (95% CI 62 - 96) for all pediatric cancer survivors and 292 (95% CI 208-409) for CNS tumor survivors compared to 9.3 (95% CI 4 - 23) for siblings. CRT increased stroke risk in a dose dependent manner and cumulative incidence continues to rise decades after diagnosis (see Figure ). Treatment with 30-49 Gy CRT had a relative stroke risk of 5.9 (95% CI 3.5-9.9) compared to 11.0 (95% CI 7.4-16.5) in the 50+ Gy CRT group. The cumulative incidence of stroke 20 years post diagnosis was 0.7% (95% CI 0.5 - 1.0) for no CRT, 2.9% (95% CI 1.4 - 4.4) for 30-49.9 Gy CRT, and 4.9% (95% CI 3.4-6.4) for ≥ 50 Gy CRT. HTN increased stroke risk by 4-fold. If diabetes was present together with HTN in CNS tumor survivors, the RR increased from 2.9 (95% C.I. 1.6-5.3) for HTN alone to 14.4 (95% CI 5.7 - 36.2).

Conclusion: Survivors of pediatric cancer treated with CRT have an increased stroke risk that is dose dependent and increases with age. Modifiable risk factors such as HTN and diabetes further increased this risk and should be monitored and treated aggressively in these survivors to reduce the risk of late-occurring stroke.

Chemotherapy and thyroid cancer risk: a report from the childhood cancer survivor study

BACKGROUND

Although ionizing radiation is an established environmental risk factor for thyroid cancer, the effect of chemotherapy drugs on thyroid cancer risk remains unclear. We evaluated the chemotherapy-related risk of thyroid cancer in childhood cancer survivors and the possible joint effects of chemotherapy and radiotherapy.

METHODS

The study included 12,547 five-year survivors of childhood cancer diagnosed during 1970 through 1986. Chemotherapy and radiotherapy information was obtained from medical records, and radiation dose was estimated to the thyroid gland. Cumulative incidence and relative risks were calculated with life-table methods and Poisson regression. Chemotherapy-related risks were evaluated separately by categories of radiation dose.

RESULTS

Histologically confirmed thyroid cancer occurred in 119 patients. Thirty years after the first childhood cancer treatment, the cumulative incidence of thyroid cancer was 1.3% (95% CI, 1.0-1.6) for females and 0.6% (0.4-0.8) for males. Among patients with thyroid radiation doses of 20 Gy or less, treatment with alkylating agents was associated with a significant 2.4-fold increased risk of thyroid cancer (95% CI, 1.3-4.5; P = 0.002). Chemotherapy risks decreased as radiation dose increased, with a significant decrease for patients treated with alkylating agents (P(trend) = 0.03). No chemotherapy-related risk was evident for thyroid radiation doses more than 20 Gy.

CONCLUSIONS

Treatments with alkylating agents increased thyroid cancer risk, but only in the radiation dose range less than 20 Gy, in which cell sparing likely predominates over cell killing.

IMPACT

Our study adds to the evidence for chemotherapy agent-specific increased risks of thyroid cancer, which to date, were mainly thought to be related to prior radiotherapy.

Anthracycline-related cardiomyopathy after childhood cancer: role of polymorphisms in carbonyl reductase genes--a report from the Children's Oncology Group

PURPOSE

Carbonyl reductases (CBRs) catalyze reduction of anthracyclines to cardiotoxic alcohol metabolites. Polymorphisms in CBR1 and CBR3 influence synthesis of these metabolites. We examined whether single nucleotide polymorphisms in CBR1 (CBR1 1096G>A) and/or CBR3 (CBR3 V244M) modified the dose-dependent risk of anthracycline-related cardiomyopathy in childhood cancer survivors.

PATIENTS AND METHODS

One hundred seventy survivors with cardiomyopathy (patient cases) were compared with 317 survivors with no cardiomyopathy (controls; matched on cancer diagnosis, year of diagnosis, length of follow-up, and race/ethnicity) using conditional logistic regression techniques.

RESULTS

A dose-dependent association was observed between cumulative anthracycline exposure and cardiomyopathy risk (0 mg/m(2): reference; 1 to 100 mg/m(2): odds ratio [OR], 1.65; 101 to 150 mg/m(2): OR, 3.85; 151 to 200 mg/m(2): OR, 3.69; 201 to 250 mg/m(2): OR, 7.23; 251 to 300 mg/m(2): OR, 23.47; > 300 mg/m(2): OR, 27.59; P(trend) < .001). Among individuals carrying the variant A allele (CBR1:GA/AA and/or CBR3:GA/AA), exposure to low- to moderate-dose anthracyclines (1 to 250 mg/m(2)) did not increase the risk of cardiomyopathy. Among individuals with CBR3 V244M homozygous G genotypes (CBR3:GG), exposure to low- to moderate-dose anthracyclines increased cardiomyopathy risk when compared with individuals with CBR3:GA/AA genotypes unexposed to anthracyclines (OR, 5.48; P = .003), as well as exposed to low- to moderate-dose anthracyclines (OR, 3.30; P = .006). High-dose anthracyclines (> 250 mg/m(2)) were associated with increased cardiomyopathy risk, irrespective of CBR genotype status.

CONCLUSION

This study demonstrates increased anthracycline-related cardiomyopathy risk at doses as low as 101 to 150 mg/m(2). Homozygosis for G allele in CBR3 contributes to increased cardiomyopathy risk associated with low- to moderate-dose anthracyclines, such that there seems to be no safe dose for patients homozygous for the CBR3 V244M G allele. These results suggest a need for targeted intervention for those at increased risk of cardiomyopathy.

Abstract B23: Health care access and utilization of adolescent and young adult cancer survivors

Introduction: More than 72,000 adolescent and young adults (AYA) ages 15–39 are diagnosed with cancer each year in the United States and the majority will transition to long-term survivorship. Little is known about barriers this population faces in accessing medical care. Using the 2009 Behavioral Risk Factor Surveillance System (BRFSS) data, we compared markers of health care access and utilization for long-term AYA cancer survivors to young adults without a cancer history and examined whether certain demographic groups of survivors are at increased risk for poor health care outcomes.

Methods: Eligible participants were 18–39 years of age at interview. Of these 71,982 respondents, there were N=1003 who self-reported being diagnosed with cancer between the ages of 15–34, were at least 5 years from diagnosis, and did not have non-melanoma skin cancer. Using multivariable generalized linear models we generated relative risks (RR) and 95% confidence intervals (95% CI) to examine the relationship of survivor status on binary indicators of access to and utilization of health care (having a personal health care provider, having at least one routine check-up in the past 12 months, and avoiding seeing a doctor in the past 12 months due to cost). Among survivors, we calculated adjusted proportions reporting the health care measures by age, race, and gender. All results are adjusted for age, race, gender, and as relevant, health insurance, and are reported weighted by BRFSS survey design and for non-response.

Results: For AYA survivors, mean time since diagnosis was 10.5 years (sd=4.3). Average age of AYA survivors was 33.0 years compared to 28.8 for the non-cancer sample (p&lt;0.001), and more AYA survivors were female (81% vs. 49%; p&lt;0.001). Among female survivors, the most common cancer was cervical (51%), while among male survivors, non-Hodgkin lymphoma (20%). More AYA survivors were white (74%) compared to those without cancer (61%; p&lt;0.001). Household income did not significantly differ between the two groups.

Health insurance coverage was similar (78% survivors vs. 77% non-cancer); however, in multivariable regressions, survivors were less likely to report being insured (RR 0.94, 95% CI 0.88–0.99). Report of having a personal medical provider was comparable between the survivors and non-cancer sample (RR 1.02, 95% CI 0.96–1.09). When adjusted proportions were examined, survivors ages 30–39 were more likely to have a provider than survivors ages 18–29 (87% vs. 74%, p=0.02), while gender and race did not differ. AYA survivors and the non-cancer sample reported having at least one routine medical visit in the past year at similar levels (RR 0.97, 95% CI 0.89–1.07). Among survivors, black (81%) compared to white (62%), Hispanic (43%), and other race (65%) survivors were more likely to have had a routine visit (p=0.009), but age and gender did not differ significantly. In our final model, survivors were 70% more likely to report avoiding seeing a doctor in the past 12 months due to cost (RR 1.70, 95% CI 1.48–1.97). Fewer survivors ages 30–39 reported that cost prohibited medical care compared to those ages 18–29 (29% vs. 45%, p=0.05), while there were no differences by race or gender.

Conclusions: Long-term AYA cancer survivors face barriers to accessing health care. Although there were no significant differences in routine medical utilization or having a regular physician, AYA survivors are 70% more likely to forego seeing a medical provider due to cost than those without a history of cancer. Younger survivors, in particular, may face barriers to care. Due to the long-term effects from cancer treatment, AYA cancer survivors require consistent medical surveillance, and our results suggest that improvements in post-treatment health care access should be prioritized for this population.

Citation Information: Cancer Prev Res 2011;4(10 Suppl):B23.

Pain in long-term adult survivors of childhood cancers and their siblings: a report from the Childhood Cancer Survivor Study

Little is known about pain among long-term adult survivors of childhood cancers. The study investigated pain prevalence in this population compared with sibling controls and examined pain-related risk factors. Three self-reported pain outcomes including pain conditions, prescription analgesics used, and pain attributed to cancer and treatment were assessed among 10,397 cancer survivors and 3034 sibling controls from the Childhood Cancer Survivor Study. Pain conditions (pain/abnormal sensation, migraines, and other headaches) were reported by 12.3%, 15.5%, and 20.5% of survivors, respectively; 16.7% of survivors reported use of prescription analgesics, and 21% attributed pain to cancer and treatment. Risks of reporting pain conditions and using prescription analgesics were higher among survivors than siblings, adjusting for sociodemographic factors. Younger age at diagnosis and a history of non-Hodgkin lymphoma, Wilms tumor, or neuroblastoma (compared to leukemia) were associated with greater risk of reporting pain conditions. A history of bone cancer or soft tissue sarcoma (compared to leukemia) was associated with greater risks of using prescription analgesics and cancer-related pain attribution. Non-brain-directed scatter irradiation was associated with elevated risk for migraines and cancer-related pain attribution. Female gender and lower educational attainment were associated with increased reports of all 3 pain outcomes; minority status, unemployment, and being single were associated with greater risks for reporting pain conditions. These findings contribute to the understanding of pain and associated risk factors among adult survivors of childhood cancer and suggest areas of focus for pain intervention.

Physical, mental, and neurocognitive status and employment outcomes in the childhood cancer survivor study cohort

INTRODUCTION

We examined the relationship of physical, mental, and neurocognitive function with employment and occupational status in the Childhood Cancer Survivor Study.

METHODS

We included survivors 25 years or older with available short form-36 (physical and mental health component scores), brief symptom inventory (depression, anxiety, and somatization), and neurocognitive questionnaire (task efficiency, emotional regulation, organization, and memory). We generated relative risks (RR) from generalized linear models for these measures on unemployment (n = 5,386) and occupation (n = 3,763) outcomes adjusted for demographic and cancer-related factors and generated sex-stratified models.

RESULTS

Poor physical health was associated with an almost eightfold higher risk of health-related unemployment (P < 0.001) compared to survivors with normal physical health. Male survivors with somatization and memory problems were approximately 50% (P < 0.05 for both) more likely to report this outcome, whereas task efficiency limitations were significant for both sexes (males: RR = 2.43, P < 0.001; females: RR = 2.28, P < 0.001). Employed female survivors with task efficiency, emotional regulation, and memory limitations were 13% to 20% (P < 0.05 for all) less likely to work in professional or managerial occupations than unaffected females.

CONCLUSIONS

Physical problems may cause much of the health-related unemployment among childhood cancer survivors. Whereas both male and female survivors with neurocognitive deficits--primarily in task efficiencies--are at risk for unemployment, employed female survivors with neurocognitive deficits may face poor occupational outcomes more often than males.

IMPACT

Childhood cancer survivors are at risk for poor employment outcomes. Screening and intervention for physical, mental, and neurocognitive limitations could improve employment outcomes for this population.

Auditory complications in childhood cancer survivors: a report from the childhood cancer survivor study

BACKGROUND

Studies have found associations between cancer therapies and auditory complications, but data are limited on long-term outcomes and risks associated with multiple exposures.

PROCEDURE

The Childhood Cancer Survivor Study is a retrospective cohort investigating health outcomes of long-term survivors (5+ years) diagnosed and treated between 1970 and 1986 compared to a randomly selected sibling cohort. Questionnaires were completed by 14,358 survivors of childhood cancer and 4,023 sibling controls. Analysis determined the first occurrence of four auditory conditions in two time periods: diagnosis to 5 years post-diagnosis, and ≥ 5 years post-diagnosis. Multivariable analyses determined the relative risks (RR) and 95% confidence interval (CI) of auditory conditions by treatment exposure.

RESULTS

Five or more years from cancer diagnosis, survivors were at increased risk of problems hearing sounds (RR = 2.3; 95% CI: 1.8-2.8), tinnitus (RR = 1.7; 95% CI: 1.4-2.1), hearing loss requiring an aid (RR = 4.4; 95% CI: 2.8-6.9), and hearing loss in 1 or both ears not corrected by a hearing aid (RR = 5.2; 95% CI: 2.8-9.5), when compared to siblings. Temporal lobe and posterior fossa radiation was associated with these outcomes in a dose-dependent fashion. Exposure to platinum compounds was associated with an increased risk of problems hearing sounds (RR = 2.1; 95% CI: 1.3-3.2), tinnitus (RR = 2.8; 95% CI: 1.9-4.2), and hearing loss requiring an aid (RR = 4.1; 95% CI: 2.5-6.7).

CONCLUSIONS

Childhood cancer survivors are at risk of developing auditory complications. Radiation and platinum compounds are determinants of this risk. Follow-up is needed to evaluate the impact of auditory conditions on quality of life.

Occurrence of multiple subsequent neoplasms in long-term survivors of childhood cancer: a report from the childhood cancer survivor study

PURPOSE

Childhood cancer survivors experience an increased incidence of subsequent neoplasms (SNs). Those surviving the first SN (SN1) remain at risk to develop multiple SNs. Because SNs are a common cause of late morbidity and mortality, characterization of rates of multiple SNs is needed.

PATIENTS AND METHODS

In a total of 14,358 5-year survivors of childhood cancer diagnosed between 1970 and 1986, analyses were carried out among 1,382 survivors with an SN1. Cumulative incidence of second subsequent neoplasm (SN2), either malignant or benign, was calculated.

RESULTS

A total of 1,382 survivors (9.6%) developed SN1, of whom 386 (27.9%) developed SN2. Of those with SN2, 153 (39.6%) developed more than two SNs. Cumulative incidence of SN2 was 46.9% (95% CI, 41.6% to 52.2%) at 20 years after SN1. The cumulative incidence of SN2 among radiation-exposed survivors was 41.3% (95% CI, 37.2% to 45.4%) at 15 years compared with 25.7% (95% CI, 16.5% to 34.9%) for those not treated with radiation. Radiation-exposed survivors who developed an SN1 of nonmelanoma skin cancer (NMSC) had a cumulative incidence of subsequent malignant neoplasm (SMN; ie, malignancies excluding NMSC) of 20.3% (95% CI, 13.0% to 27.6%) at 15 years compared with only 10.7% (95% CI, 7.2% to 14.2%) for those who were exposed to radiation and whose SN1 was an invasive SMN (excluding NMSC).

CONCLUSION

Multiple SNs are common among aging survivors of childhood cancer. SN1 of NMSC identifies a population at high risk for invasive SMN. Survivors not exposed to radiation who develop multiple SNs represent a population of interest for studying genetic susceptibility to neoplasia.