Comparing causes of death of Hodgkin lymphoma and breast cancer patients between medical records and cause-of-death statistics

Comparison of Vital Status, Cause of Death, and Follow-Up after Hematopoietic Cell Transplantation in Linked Center for International Blood and Marrow Transplant Research and California Cancer Registry Data, 1991 to 2018

Assessing outcomes following hematopoietic cell transplantation (HCT) poses challenges due to the necessity for systematic and often prolonged patient follow-up. Linking the HCT database of the Center for International Blood and Marrow Transplant Research (CIBMTR) with cancer registry data may improve long-term outcome ascertainment, but the reliability of mortality data in death certificates from cancer registries among HCT recipients remains unknown. We compared the classification of vital status and primary cause of death (COD), as well as the length of follow-up between the CIBMTR and California Cancer Registry (CCR) to assess the possibility of supplementing the CIBMTR with cancer registry data. This retrospective study leveraged a linked CIBMTR-CCR dataset. We included patients who were California residents at the time of HCT and received a first allogeneic (allo) or autologous (auto) HCT for a hematologic malignancy diagnosed during 1991-2016. Follow-up was through 2018. We analyzed 18,450 patients (alloHCT, n = 8232; autoHCT, n = 10,218). The Vital status agreement was 97.7% for alloHCT and 97.2% for autoHCT. Unknown COD was higher in CIBMTR (12.9%) than in CCR (1.6%). After excluding patients with unknown COD information, the overall agreement of primary COD (cancer versus noncancer) was 53.7% for alloHCT and 83.2% for autoHCT. This agreement was lower within the first 100 days post-HCT (alloHCT, 31.0%; autoHCT, 54.6%). Compared with CIBMTR, deaths due to cancer were higher in CCR (alloHCT, 90.0%; autoHCT, 90.1% versus alloHCT, 47.3%; autoHCT, 82.5% in CIBMTR). CIBMTR reports more frequently noncancer-related deaths, including graft-versus-host disease and infections. The cumulative incidence of cancer-specific mortality at 20 years differed, particularly for alloHCT (CCR, 53.7%; CIBMTR, 27.6%). The median follow-up among alive patients was longer in CCR (alloHCT, 6.0 years; autoHCT, 4.7 years) than in CIBMTR (alloHCT, 5.0 years; autoHCT, 3.8 years). Our findings highlight the completeness of vital status data in CIBMTR but reveal substantial disagreement in primary COD. Consequently, caution is required when interpreting HCT studies that use only death certificates to estimate cause-specific mortality outcomes. Improving the accuracy of COD registration and follow-up completeness by developing communication pathways between cancer registries and hospital-based cohorts may enhance our understanding of late effects and long-term outcomes among HCT survivors.

Development and Validation of Risk Prediction Models for Coronary Heart Disease and Heart Failure After Treatment for Hodgkin Lymphoma

PURPOSE

Previous efforts to predict absolute risk of treatment-related cardiovascular diseases (CVDs) have mostly focused on childhood cancer survivors. We aimed to develop prediction models for risk of coronary heart disease (CHD) and heart failure (HF) for survivors of adolescent/adult Hodgkin lymphoma (HL).

METHODS

For model development, we used a multicenter cohort including 1,433 5-year HL survivors treated between 1965 and 2000 and age 18-50 years at HL diagnosis, with complete data on administered chemotherapy regimens, radiotherapy volumes and doses, and cardiovascular follow-up. Using cause-specific hazard models, covariate-adjusted cumulative incidences for CHD and HF were estimated in the presence of competing risks of death because of other causes than CHD and HF. Age at HL diagnosis, sex, smoking status, radiotherapy, and anthracycline treatment were included as predictors. External validation for the CHD model was performed using a Canadian cohort of 708 HL survivors treated between 1988 and 2004 and age 18-50 years at HL diagnosis.

RESULTS

After a median follow-up of 24 years, 341 survivors had developed CHD and 102 had HF. We were able to predict CHD and HF risk at 20 and 30 years after treatment with moderate to good overall calibration and moderate discrimination (areas under the curve: 0.68-0.74), which was confirmed by external validation for the CHD model (areas under the curve: 0.73-0.74). On the basis of our model including prescribed mediastinal radiation dose, 30-year risks ranged from 4% to 78% for CHD and 3% to 46% for HF, depending on risk factors.

CONCLUSION

We developed and validated prediction models for CHD and HF with good overall calibration and moderate discrimination. These models can be used to identify HL survivors who might benefit from targeted screening for CVD and early treatment for CVD risk factors.

Late Mortality in Childhood Cancer Survivors according to Pediatric Cancer Diagnosis and Treatment Era in the Dutch LATER Cohort

This multi-center cohort-study examined late mortality among 6,165 Dutch five-year childhood cancer survivors diagnosed 1963-2001. Clinical details and cause of death were based on medical records. Mortality was 12-fold that of the general population, with 51.3 additional deaths per 10,000 person-years (21.9 yrs median follow-up). Cumulative mortality 15 yrs post-diagnosis was 6.9%, predominantly from late recurrences; thereafter the absolute contribution of other health outcomes increased. Cumulative all-cause and recurrence-related mortality were highest for Central Nervous System and bone tumor survivors. All-cause, but not subsequent tumor and circulatory disease-related cumulative mortality, was highest for patients diagnosed 1963-1979 vs. later (p-trend <0.001).

Cause-Specific Mortality Following Initial Chemotherapy in a Population-Based Cohort of Patients With Classical Hodgkin Lymphoma, 2000-2016

PURPOSE

Mortality for patients with classical Hodgkin lymphoma (cHL) treated during an era characterized in the United States by widespread use of doxorubicin, bleomycin, vinblastine, and dacarbazine and diminishing use of radiotherapy is not well understood.

PATIENTS AND METHODS

We identified 20,007 individuals diagnosed with stage I/II (early) or III/IV (advanced) cHL between age 20 and 74 years treated with initial chemotherapy in US population-based cancer registries during 2000-2015 (follow-up through 2016). We used standardized mortality ratios (SMRs) to compare cause-specific relative mortality risk following cHL to that expected in the general population and estimated excess absolute risks (EARs; per 10,000 patient-years) to quantify disease-specific death burden.

RESULTS

We identified 3,380 deaths in the cHL cohort, including 1,321 (39%) not attributed to lymphoma. Overall, noncancer SMRs were increased 2.4-fold (95% CI, 2.2 to 2.6; observed, 559; EAR, 61.6) and 1.6-fold (95% CI, 1.4 to 1.7; observed, 473; EAR, 18.2) for advanced- and early-stage cHL, respectively, compared with the general US population. SMRs and EARs differed substantially by cause of death and cHL stage. Among the highest EARs for noncancer causes of death were those for heart disease (EAR, 15.1; SMR, 2.1), infections (EAR, 10.6; SMR, 3.9), interstitial lung disease (ILD; EAR, 9.7; SMR, 22.1), and adverse events (AEs) related to medications/drugs (EAR, 7.4; SMR, 5.0) after advanced-stage cHL and heart disease (EAR, 6.6; SMR, 1.7), ILD (EAR, 3.7; SMR, 13.1), and infections (EAR, 3.1; SMR, 2.2) after early-stage cHL. Strikingly elevated SMRs for ILD, infections, and AEs were observed < 1 year after cHL. Individuals age 60-74 years with advanced-stage cHL experienced a disproportionate excess of deaths as a result of heart disease, ILD, infections, AEs, and solid tumors.

CONCLUSION

Despite evolving cHL treatment approaches, patients continue to face increased nonlymphoma mortality risks from multiple, potentially preventable causes. Surveillance, early interventions, and cHL treatment refinements may favorably affect patient longevity, particularly among high-risk subgroups.

Adjuvant chemotherapy in small node-negative triple-negative breast cancer

BACKGROUND

Recommendations on adjuvant chemotherapy in pT1N0M0 triple-negative breast cancer (TNBC) differ among international guidelines owing to lack of randomized trial data. We evaluated associations of adjuvant chemotherapy with a long-term outcome in a population-based cohort of pT1N0M0 TNBC.

METHODS

All patients diagnosed with pT1N0M0 TNBC in the Netherlands between 2005 and 2016 were identified from the Netherlands Cancer Registry. Patient, tumour and treatment characteristics were recorded. The date and cause of death were obtained from Statistics Netherlands. We used multivariable Cox regression models to evaluate associations of adjuvant chemotherapy with breast cancer-specific survival (BCSS) and overall survival (OS), adjusted for baseline characteristics and performed sensitivity analyses using propensity score (PS) weighting.

RESULTS

We identified 4366 patients: 284 with pT1a, 923 with pT1b and 3159 with pT1c tumours. Adjuvant chemotherapy was administered in 53% of patients. Patients receiving chemotherapy had more unfavourable baseline characteristics including younger age, larger tumours and higher tumour grade. At 8.2 years median follow-up (interquartile range = 5.8-10.9), 671 patients had died, of whom 311 because of breast cancer. After adjustment for baseline characteristics, chemotherapy was associated with improved BCSS (adjusted hazard ratio [aHR] = 0.65; 95% confidence interval [CI] = 0.48-0.89). The effect of chemotherapy differed by tumour size (pT1a: aHR = 4.28, 95% CI = 1.12-16.44; pT1b: aHR = 1.12, 95% CI = 0.51-2.49; pT1c: aHR = 0.60, 95% CI = 0.43-0.82; p_interaction = 0.02). Findings for OS were in line with BCSS results. PS-weighting analysis confirmed the results of the primary analysis.

CONCLUSIONS

Adjuvant chemotherapy is associated with better BCSS and OS in pT1N0M0 TNBC. Better outcome is most evident in pT1c tumours and may not outweigh harm in pT1a/pT1b tumours.