Tandem High-Dose Chemotherapy Increases the Risk of Secondary Malignant Neoplasm in Pediatric Solid Tumors

PURPOSE

This study aimed to investigate the incidence and risk factors for secondary malignant neoplasms (SMN) in pediatric solid tumors, focusing on the effects of tandem high-dose chemotherapy (HDCT).

MATERIALS AND METHODS

Patients (aged < 19 years) diagnosed with or treated for pediatric solid tumors between 1994 and 2014 were retrospectively analyzed. The cumulative incidence of SMN was estimated using competing risk methods by considering death as a competing risk.

RESULTS

A total of 1,435 patients (413 with brain tumors and 1,022 with extracranial solid tumors) were enrolled. Seventy-one patients developed 74 SMNs, with a 10-year and 20-year cumulative incidence of 2.680±0.002% and 10.193±0.024%, respectively. The types of SMN included carcinoma in 28 (37.8%), sarcoma in 24 (32.4%), and hematologic malignancy in 15 (20.3%) cases. Osteosarcoma and thyroid carcinoma were the most frequently diagnosed tumors. Multivariate analysis showed that radiotherapy (RT) > 2, 340 cGy, and tandem HDCT were significant risk factors for SMN development. The SMN types varied according to the primary tumor type; carcinoma was the most frequent SMN in brain tumors and neuroblastoma, whereas hematologic malignancy and sarcomas developed more frequently in patients with sarcoma and retinoblastoma, respectively.

CONCLUSION

The cumulative incidence of SMN in pediatric patients with solid tumors was considerably high, especially in patients who underwent tandem HDCT or in those who received RT > 2,340 cGy. Therefore, the treatment intensity should be optimized based on individual risk assessment and the long-term follow-up of pediatric cancer survivors.

Identification of risk factors and prediction models for secondary malignant neoplasms (SMNs)-free survival and SMNs-specific survival in testicular cancer survivors

OBJECTIVE

This research endeavored to determine the key demographic and pathological factors tied to secondary malignant neoplasms (SMNs) in survivors of testicular cancer and to develop a predictive model.

METHOD

A total of 53,309 testicular cancer patients from the SEER national database (1975-2016) were included in our analysis. The primary outcome measured was SMNs-free survival, defined as the duration from testicular cancer diagnosis to the detection of a non-testicular malignancy. The secondary outcome was SMN-specific survival, defined as the period from testicular cancer diagnosis until the patient's death due to SMNs.

FINDINGS

Of the patients in the SEER cohort, 2978 (5.6%) developed non-testicular cancer SMNs. Higher age, receipt of chemotherapy, and radiation treatment were all significantly associated with the development of SMNs in survivors of testicular cancer (all p < 0.001). Kaplan-Meier analysis revealed a worse SMNs-free survival and poor SMN-specific survival in patients who underwent radiation therapy (both p < 0.001). Multivariable Cox regression analysis found non-Hispanic Black ethnicity, higher age, chemotherapy, and radiation therapy to be significantly associated with worse SMNs-free survival (p = 0.002, p < 0.001, p < 0.001, and p < 0.001, respectively), while lymphoma histology was associated with better SMNs-free survival (p < 0.001). The most common SMN types in patients receiving radiation therapy were prostate, lung, and bladder cancers. Predictive nomograms for SMNs-free survival and SMNs-specific survival were developed, with a C-index of 0.776 and 0.824, respectively.

CONCLUSION

The age of diagnosis, non-Hispanic Black ethnicity, lymphoma histology, and treatment history with chemotherapy and radiation therapy were identified as prognostic factors for SMNs-free survival.