Monitoring for Late Effects
Recognition of both acute and late modality-specific toxicity has motivated investigations evaluating the pathophysiology and prognostic factors for cancer treatment-related effects. The results of these studies have played an important role in changing pediatric cancer therapeutic approaches and reducing treatment-related mortality among survivors treated in more recent eras.[13,14] These investigations have also informed the development of risk counseling and health screening recommendations of long-term survivors by identifying the clinical and treatment characteristics of those at highest risk for treatment complications. The common late effects of pediatric cancer encompass several broad domains including growth and development, organ function, reproductive capacity and health of offspring, and secondary carcinogenesis. In addition, survivors of childhood cancer may experience a variety of adverse psychosocial sequelae related to the primary cancer, its treatment, or maladjustment associated with the cancer experience.
Late sequelae of therapy for childhood cancer can be anticipated based on therapeutic exposures, but the magnitude of risk and the manifestations in an individual patient are influenced by numerous factors. Factors that should be considered in the risk assessment for a given late effect include the following:
- Tumor location.
- Direct tissue effects.
- Tumor-induced organ dysfunction.
- Mechanical effects.
- Radiation therapy: total dose, fraction size, organ or tissue volume, type of machine energy.
- Chemotherapy: agent type, dose-intensity, cumulative dose, schedule.
- Surgery: technique, site.
- Use of combined modality therapy.
- Blood product transfusion.
- Hematopoietic cell transplantation.
- Age at diagnosis.
- Time from diagnosis/therapy.
- Developmental status.
- Genetic predisposition.
- Inherent tissue sensitivities and capacity for normal tissue repair.
- Function of organs not affected by cancer treatment.
- Premorbid health state.
- Socioeconomic status.
- Health habits.
Resources to Support Survivor Care
The need for long-term follow-up for childhood cancer survivors is supported by the American Society of Pediatric Hematology/Oncology, the International Society of Pediatric Oncology, the American Academy of Pediatrics, the Children's Oncology Group (COG), and the Institute of Medicine. Specifically, a risk-based medical follow-up is recommended, which includes a systematic plan for lifelong screening, surveillance, and prevention that incorporates risk estimates based on the previous cancer, cancer therapy, genetic predisposition, lifestyle behaviors, and comorbid conditions.[15,16] Part of long-term follow-up should also be focused on appropriate screening of educational and vocational progress. Specific treatments for childhood cancer, especially those that directly impact nervous system structures, may result in sensory, motor, and neurocognitive deficits that may have adverse consequences on functional status, educational attainment, and future vocational opportunities. A Childhood Cancer Survivor Study (CCSS) investigation observed that treatment with cranial radiation doses of 25 Gy or higher was associated with higher odds of unemployment (health related: odds ratio [OR] = 3.47; 95% confidence interval [CI], 2.54-4.74; seeking work: OR = 1.77; 95% CI, 1.15-2.71). Unemployed survivors reported higher levels of poor physical functioning than employed survivors, had lower education and income, and were more likely to be publicly insured than unemployed siblings. These data emphasize the importance of facilitating survivor access to remedial services, which has been demonstrated to have a positive impact on education achievement, which may in turn enhance vocational opportunities.