American Society of Clinical Oncology 2022 Annual Meeting Highlights for Radiation Oncologists.

The American Society of Clinical Oncology annual meeting is the largest multidisciplinary oncology-focused conference in the world. With almost 5000 total abstracts in 2022, it is difficult for individuals to evaluate all the results. Here we present a review of 28 selected abstracts, across all disease sites, focusing on those of greatest relevance to radiation oncologists.

Evaluation of 5 Fraction Stereotactic Body Radiation Therapy (SBRT) for Osseous Renal Cell Carcinoma Metastases.

OBJECTIVES: The best fractionation for stereotactic body radiotherapy (SBRT) in renal cell carcinoma (RCC) metastases has not been well defined. In addition, the literature on outcomes using 5-fraction SBRT in the setting of osseous metastases has not been well reported. MATERIALS AND METHODS: Thirty-nine patients with 69 RCC osseous metastases were treated using 5-fraction SBRT at a single institution using 2 dose-fractionation schemes. Overall survival and local-control (LC) outcomes of the 2 fractionation schemes were studied using Kaplan-Meier curves. RESULTS: Of the 69 lesions included in the study, 20 were treated with 30 grays (Gy) in 5 fractions and 49 were treated with 40 Gy in 5 fractions. The median age of patients at diagnosis was 58.4 years. The 1-year LC rate for all treated lesions was 85.5% (59/69) with an LC of 90% (18/20) for lesions receiving 30 Gy and 83.7% (41/49) in lesions receiving 40 Gy. There was no statistically significant difference in 1-year LC rate between the 2 fractionation schemes (P-value, 0.553). CONCLUSIONS: Patients with osseous RCC metastases undergoing 5 fractions of SBRT had favorable LC outcomes. There was no difference in survival or LC between the 40 Gy and 30 Gy treatment arms.

Academic patterns of practice regarding CT simulation scans and radiology review.

OBJECTIVE: Currently, there are no consensus guidelines about handling incidental radiological findings on radiotherapy planning CT simulation scans. Retrospective studies analyzing incidental findings on CT simulations show a small, but not insignificant, rate of both oncologic and non-oncologic findings. These findings may have medico-legal, financial, and clinical implications. Given a lack of guidelines, we obtained a formal survey of multiple academic institutions to evaluate how CT simulations are handled in regard to incidental findings. METHODS: A formal survey was developed consisting of 12 questions related to institutional practices regarding CT simulation scans. From 7/18/21 to 8/27/21 and 5/6/22 to 5/24/22, the survey was administered electronically by REDCap to key personnel at Academic Radiation Oncology Programs identified through the American Society for Radiation Oncology (ASTRO) with inclusion criteria including an active ACGME approved Radiation Oncology residency program. RESULTS: In total, 88 academic radiation oncology programs were surveyed with total of 45 responses (51%). 1 out of 45 departments who responded has formal guidelines regarding workup of incidental findings. There is variability about sending CT simulation scans for official radiology review if an incidental finding is identified. CONCLUSIONS: Based on a measurable rate of incidental findings on radiotherapy planning CT simulations and their possible implications, our survey illustrates a likely need for consensus recommendations for handling such findings to improve patient care and safety.

The Use of Low-Dose Radiation Therapy in Osteoarthritis: A Review.

Despite its clinical use and investigation in other countries, low dose radiation therapy (LDRT) in the treatment of osteoarthritis (OA) is minimally used in the United States (US). Numerous recent studies published outside the US have shown moderate to long-term pain relief and improvement of mobility after treatment with LDRT for joints affected by OA. Here, we review the most recent literature published on the use of LDRT in OA. We provide a brief outline on the epidemiology, pathophysiology, current treatments, and health care burden of OA within the US. We provide a brief history of the historic use of LDRT in the US as well as a history of LDRT within the modern era of radiation oncology, discuss criticisms of LDRT including recently published randomized trials questioning its benefit as well as the risk of secondary malignancy from LDRT, and provide an outline of treatment planning considerations and recommendations regarding dose and fractionation, energy, beam arrangements, and immobilization techniques. LDRT has been shown to be a cost-effective, noninvasive treatment with minimal side effects. Further investigation into the potential role in the treatment of OA with modern LDRT is recommended.

Location as Destiny: Identifying Geospatial Disparities in Radiation Treatment Interruption by Neighborhood, Race, and Insurance.

PURPOSE: Radiation therapy interruption (RTI) worsens cancer outcomes. Our purpose was to benchmark and map RTI across a region in the United States with known cancer outcome disparities. METHODS AND MATERIALS: All radiation therapy (RT) treatments at our academic center were cataloged. Major RTI was defined as ≥5 unplanned RT appointment cancellations. Univariate and multivariable logistic and linear regression analyses identified associated factors. Major RTI was mapped by patient residence. A 2-sided P value <.0001 was considered statistically significant. RESULTS: Between 2015 and 2017, a total of 3754 patients received RT, of whom 3744 were eligible for analysis: 962 patients (25.8%) had ≥2 RT interruptions and 337 patients (9%) had major RTI. Disparities in major RTI were seen across Medicaid versus commercial/Medicare insurance (22.5% vs 7.2%; P < .0001), low versus high predicted income (13.0% vs 5.9%; P < .0001), Black versus White race (12.0% vs 6.6%; P < .0001), and urban versus suburban treatment location (12.0% vs 6.3%; P < .0001). On multivariable analysis, increased odds of major RTI were seen for Medicaid patients (odds ratio [OR], 3.35; 95% confidence interval [CI], 2.25-5.00; P < .0001) versus those with commercial/Medicare insurance and for head and neck (OR, 3.74; 95% CI, 2.56-5.46; P < .0001), gynecologic (OR, 3.28; 95% CI, 2.09-5.15; P < .0001), and lung cancers (OR, 3.12; 95% CI, 1.96-4.97; P < .0001) compared with breast cancer. Major RTI was mapped to urban, majority Black, low-income neighborhoods and to rural, majority White, low-income regions. CONCLUSIONS: Radiation treatment interruption disproportionately affects financially and socially vulnerable patient populations and maps to high-poverty neighborhoods. Geospatial mapping affords an opportunity to correlate RT access on a neighborhood level to inform potential intervention strategies.

Is there a role for salvage re-irradiation in pediatric patients with locoregional recurrent rhabdomyosarcoma? Clinical outcomes from a multi-institutional cohort.

BACKGROUND AND PURPOSE: Limited data exist detailing the role of salvage reirradiation following local-regional recurrence (LR) in previously irradiated pediatric patients with rhabdomyosarcoma (RMS). MATERIALS AND METHODS: We evaluated outcomes and prognostic factors in a multi-institutional cohort of 23 patients with LR-only (N = 19) or LR with distant failure (N = 4) RMS managed with (N = 12) or without (N = 11) re-irradiation who were treated from 1996 to 2012. RESULTS: At a median follow-up of 4.6 years from LR, 7 (30%) patients were alive and 5 (22%) had no evidence of disease. Median OS and PFS from LR were 19.3 and 16.9 months, respectively. LFFS and DFFS at 3 years from relapse were 54% and 56%, respectively. Salvage re-irradiation occurred in 12 (52%) patients, with 9 (75%) receiving resection before re-irradiation. Patients classified as low-risk at diagnosis with favorable primary tumor location had improved 3-year PFS 80% (95% CI 51.6-100%) vs. 47.1% (95% CI 27.3-81.2%), p = 0.066], and OS 80% [(95% CI 22.4-100%) vs. 47.1% (95% CI 27.3-81.3%), p = 0.051] following LR. Median LFFS and OS in unirradiated vs. re-irradiated patients was 12.4 vs. 19.6 (p = 0.1) and 18.8 vs. 26.1 months (p = 0.46). No patients experienced ≥grade 4 acute toxicity from re-irradiation. LR failure was a component of cancer-related death in 60% vs. 40% of the unirradiated and re-irradiated group (p = 0.02). CONCLUSION: Salvage re-irradiation appears tolerable with acceptable morbidity and may reduce the risk of subsequent LR as a component of death in patients with LR RMS.