Does kV Image Guidance for Bone Metastases Improve Pain Control?

PURPOSE/OBJECTIVES: Despite its widespread availability, the use of kilovoltage (kV) image guidance is often related to factors such as perceived adequacy of clinical patient setup and individual practice patterns. We sought to determine whether kV image guidance in the treatment of painful bone metastases would improve therapeutic efficacy. MATERIALS/METHODS: Under an Institutional Review Board approved protocol, hospital records of 164 patients having received radiation therapy to 257 individual painful osseous metastases were retrospectively reviewed. Marginal logistic regression analyses using the generalized estimating equation (GEE) approach were used to investigate potential associations between pain reduction and several patient, disease, and treatment related variables. Correlation of kV image guidance with pain reduction was analyzed by univariate and multivariate GEE logistic regression analysis. RESULTS: Median time to pain reduction was 3 days (range 0~109 days) from the start of radiation therapy. Pain reduction ≥ 50% was noted in 196 (77%) metastatic lesions with 136 (53%) demonstrating complete pain relief. Patients with metastatic lesions from non-small cell lung cancer experienced less pain relief (p = 0.007). Disease extension outside of bone was a negative predictor for pain reduction (p = 0.02). On univariate and multivariate logistic regression, kV image guidance demonstrated a statistically significant correlation with improved pain control in cases involving treatment of the lower extremities (p = 0.03) and those with fewer treatment fractions (p = 0.01), particularly in the setting of extra-osseous disease extension (p = 0.003). CONCLUSIONS: Kilovoltage image guidance in the treatment of painful bone metastases may offer greater pain control through improved patient setup, particularly for patients with tumors of the lower extremities, extraosseous disease extension, and fewer treatment fractions.

Lens Dose-Response Prediction Modeling and Cataract Incidence in Patients With Retinoblastoma After Lens-Sparing or Whole-Eye Radiation Therapy.

PURPOSE: We retrospectively assessed the incidence of cataracts in patients with retinoblastoma (Rb) treated with either lens-sparing radiation therapy (LSRT) or whole-eye radiation therapy (WERT). A secondary aim of this study was to model the dose-response risk of cataract. METHODS AND MATERIALS: We reviewed 65 patients with Rb treated with radiation therapy (RT) at Children's Hospital, Los Angeles from 1997 to 2015. Eyes that were enucleated before RT or lacked follow-up eye examinations were excluded. All patients underwent computed tomography simulation, and mean lens dose data were collected. Follow-up ophthalmologic examinations and intraocular lens implant history were reviewed for cataracts. The primary event-free survival (EFS) outcome was cataract development. Eyes without cataracts were censored on the last date of eye examination or post-RT enucleation, if applicable. Kaplan-Meier estimates were used to compare EFS outcomes, and dose response was projected with Cox regression and logistic regression models. RESULTS: Sixty-one patients (94 eyes) were analyzed with a median follow-up of 51.8 months. For eyes treated with WERT, cataracts developed in 71.7% versus 35.3% for LSRT. Median EFS for WERT and LSRT were 20.8 and 67.9 months, respectively. Compared with WERT, a significant EFS benefit was demonstrated for LSRT (P < .001). Mean lens dose had a significant effect on cataracts in both Cox regression and logistic regression models (P < .01). The mean lens dose of 7 Gy was projected to have a 5-year cataract incidence of 20% and 25% with the logistic and Cox regression models, respectively. CONCLUSIONS: We report the first clinical data demonstrating significantly improved EFS in patients with Rb treated with LSRT. Through lens dose-response modeling, we validate a mean lens dose threshold of 7 Gy to keep cataract risk below 25%. Although RT is used less often for Rb owing to advances in chemotherapy delivery options, these findings are relevant for refining lens dose constraints, particularly in children who have received radiation dose near the orbit.

A Dosimetric Comparison of Intensity-Modulated Proton Therapy, Volumetric-Modulated Arc Therapy, and 4π Non-Coplanar Intensity-Modulated Radiation Therapy for a Patient with Parameningeal Rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children and manifests as two major histological subtypes: embryonal and alveolar. The five-year local failure rate for RMS at parameningeal sites (middle ear, mastoid region, nasal cavity, etc.) is around 17% despite multiple Intergroup Rhabdomyosarcoma Study Group (IRS) trials conducted to determine the optimal radiation treatment regimen. This case report explores the use of intensity-modulated proton therapy (IMPT) for a 10-year-old child who presented with left eye irritation, facial pain, and headaches and was found to have an alveolar parameningeal rhabdomyosarcoma. He received systemic therapy as well as radiation therapy to 5,640 cGy and 4,320 cGy over 24 fractions, prescribed for gross tumor extension and adjacent high-risk involved sites, respectively, via simultaneous integrated boost. Approximately two years following treatment, the patient has had no recurrence of his RMS with no distant metastases. In addition, his presenting symptom of left eye irritation has improved. His only side effect from radiation at this point is short stature, possibly due to growth hormone deficiency. The patient's IMPT plan was compared with volumetric-modulated arc therapy (VMAT) and 4π non-coplanar intensity-modulated radiation therapy (IMRT) plans, and comparisons of isodose lines show decreased dose to the distal brain tissue with preserved target conformality by IMPT. IMPT also allowed for increased sparing of the patient's retina, lens, and lacrimal gland. All radiation plans achieved conformal dose coverage to the planning/scanning target volumes, while the IMPT plan is potentially better at sparing the patient from developing long-term optic apparatus side effects and neurocognitive defects. In this case, IMPT is comparable, if not favorable, when long-term side effects can be reduced while maintaining dose conformality and local control.

Palliative Care Options for a Young Adult Patient with a Diffuse Intrinsic Pontine Glioma.

Diffuse intrinsic pontine gliomas (DIPGs) are rare but devastating brain tumors that occur primarily in children. These gliomas have poor prognoses and present options focus on palliation of symptoms and prolongation of life. Here, we present a case of a 16-year-old female diagnosed with a DIPG whose age group has been mostly left out of discussions regarding psychosocial support options. This report is meant to start a conversation about the different support options available at our institution that have shown promising results in the literature for palliative care applications. These options can include camps for patients with brain tumors, psychological counseling, the Ronald McDonald House, and other psychosocial programs. Many of these programs can be tailored to meet the specific needs of adolescent and young adult (AYA) patients and will hopefully be integrated into a comprehensive palliative care regimen in future studies.