Dosimetric Advantages of Silicone-Filled Vaginal Spacers in Pediatric Proton Therapy.

We introduce a custom-made silicone-filled vaginal spacer for use during treatment of female patients receiving pelvic proton radiation therapy. Commercially available vaginal dilators can be purchased as hollow objects; when filled with a media, they can act as a beam stopper and/or tissue spacer while pushing uninvolved vaginal wall away from a high-dose region. Dosimetric advantages of these specifically constructed silicone-filled vaginal spacers were investigated when compared to the unaltered commercially available product or no vaginal spacer in pediatric proton therapy.

Association between hippocampal dose and memory in survivors of childhood or adolescent low-grade glioma: a 10-year neurocognitive longitudinal study.

BACKGROUND: Hippocampal avoidance has been suggested as a strategy to reduce short-term memory decline in adults receiving whole-brain radiation therapy (RT). The purpose of this study was to determine whether the hippocampal dose in children and adolescents undergoing RT for low-grade glioma was associated with memory, as measured by verbal recall. METHODS: Eighty patients aged at least 6 years but less than 21 years with low-grade glioma were treated with RT to 54 Gy on a phase II protocol. Patients underwent age-appropriate cognitive testing at baseline, 6 months posttreatment, yearly through 5 years posttreatment, year 7 or 8, and year 10 posttreatment. Random coefficient models were used to estimate the longitudinal trends in cognitive assessment scores. RESULTS: Median neurocognitive follow-up was 9.8 years. There was a significant decline in short-delay recall (slope = -0.01 standard deviation [SD]/year, P < 0.001), total recall (slope = -0.09 SD/y, P = 0.005), and long-delay recall (slope = -0.01 SD/y, P = 0.002). On multivariate regression, after accounting for hydrocephalus, decline in short-delay recall was associated with the volume of right (slope = -0.001 SD/y, P = 0.019) or left hippocampus (slope = -0.001 SD/y, P = 0.025) receiving 40 Gy (V40 Gy). On univariate regression, decline in total recall was only associated with right hippocampal dosimetry (V40 Gy slope = -0.002, P = 0.025). In children <12 years, on univariate regression, decline in long-delay recall was only associated with right (V40 Gy slope = -0.002, P = 0.013) and left (V40 Gy slope = -0.002, P = 0.014) hippocampal dosimetry. CONCLUSION: In this 10-year longitudinal study, greater hippocampal dose was associated with a greater decline in delayed recall. Such findings might be informative for radiation therapy planning, warranting prospective evaluation.

Premature Ovarian Insufficiency in Childhood Cancer Survivors: A Report From the St. Jude Lifetime Cohort.

Context: Long-term follow-up data on premature ovarian insufficiency (POI) in childhood cancer survivors are limited. Objective: To describe the prevalence of POI, its risk factors, and associated long-term adverse health outcomes. Design: Cross-sectional. Setting: The St. Jude Lifetime Cohort Study, an established cohort in a tertiary care center. Patients: Nine hundred twenty-one participants (median age, 31.7 years) were evaluated at a median of 24.0 years after cancer diagnosis. Main Outcome Measure: POI was defined by persistent amenorrhea combined with a follicle-stimulating hormone level >30 IU/L before age 40. Multivariable Cox regression was used to study associations between demographic or treatment-related risk factors and POI. Multivariable logistic regression was used to study associations between POI and markers for cardiovascular disease, bone mineral density (BMD), and frailty. Exposure to alkylating agents was quantified using the validated cyclophosphamide equivalent dose (CED). Results: The prevalence of POI was 10.9%. Independent risk factors for POI included ovarian radiotherapy at any dose and CED ≥8000 mg/m2. Patients with a body mass index ≥30 kg/m2 at the time of the St. Jude Lifetime Cohort assessment were less likely to have a diagnosis of POI. Low BMD and frailty were independently associated with POI. Conclusion: High-dose alkylating agents and ovarian radiotherapy at any dose are associated with POI. Patients at the highest risk should be offered fertility preservation whenever feasible. POI contributes to poor general health outcomes in childhood cancer survivors; further studies are needed to investigate the role of sex hormone replacement in improving such outcomes.