Stereotactic Radiosurgery for Vestibular Schwannoma With Radiographic Brainstem Compression.

OBJECTIVE: The safety of single-treatment stereotactic radiosurgery (SRS) for vestibular schwannoma (VS) with radiographic evidence of brainstem compression but without motor deficit is controversial. Data on linear accelerator (linac)-based SRS in this setting are scarce. We address this with an outcomes report from an unselected series of patients with VS with radiographic brainstem compression treated with linac SRS. METHODS: We included 139 patients with unilateral VS (any size) with radiographic brainstem compression (all without serious brainstem neurological deficits). The SRS prescription dose was 12.5 Gy (single fraction) using 6MV linac-produced photon beams, delivered with a multiple arc technique. Inclusion criteria required at least 1 year of radiographic follow-up with magnetic resonance imaging. The primary endpoint was freedom from serious brainstem toxicity (≥grade 3 Common Terminology Criteria for Adverse Events v5); the secondary was freedom from enlargement (tumor progression or any requiring intervention). We assessed serious cranial nerve complications, excluding hearing loss, defined as Common Terminology Criteria for Adverse Events v5 grade 3 toxicity. RESULTS: Median magnetic resonance imaging follow-up time was 5 years, and median tumor size was 2.5 cm in greatest axial dimension and 5 ml in volume. The median brainstem D0.03 ml=12.6 Gy and median brainstem V10 Gy=0.4 ml. At 5 years, the actuarial freedom from serious brainstem toxicity was 100%, and freedom from tumor enlargement (requiring surgery and/or due to progression) was 90%. Severe facial nerve damage in patients without tumor enlargement was 0.9%. CONCLUSION: Linac-based SRS, as delivered in our series for VS with radiographic brainstem compression, is safe and effective.

Impact of Maximum Point Dose Within the Planning Target Volume on Local Control of Nonsmall Cell Lung Cancer Treated With Stereotactic Body Radiotherapy.

BACKGROUND: No consensus exists on the maximum dose delivered to the planning target volume (PTV) in the delivery of stereotactic body radiotherapy (SBRT) for primary lung cancer. We investigated whether higher biologically effective doses (BED) within the PTV were associated with improved tumor control. METHODS: We reviewed patients with early-stage, node-negative nonsmall cell lung cancer who received curative-intent SBRT between 2005 and 2018. We calculated the maximum BED (maxBED) within the PTV for all patients, analyzing outcomes using the cumulative incidence method and Fine-Gray test statistics to assess prognostic impact. RESULTS: We analyzed 171 patients (median age, 70.2; range, 43 to 90 y) with 181 lung nodules. Median follow-up was 2.7 years (range, 0.1 to 12 y) for all patients and 4.2 years (range, 0.2 to 8.4 y) for living patients. Median maximum tumor diameter was 1.9 cm (range, 0.7 to 5.6 cm). Patients received a prescription of 48 or 50 Gy in 4 or 5 fractions, respectively, except for one who received 60 Gy in 5 fractions. Median maxBED was 120 Gy (range, 101 to 171 Gy). There was no difference in the 3-year local control (LC) rate among patients treated with a maxBED<120 Gy versus ≥120 Gy ( P =0.83). CONCLUSIONS: No significant differences in LC were observed between patients with early-stage nonsmall cell lung cancer treated with SBRT in 4 or 5 fractions with a maxBED≥120 Gy. However, a higher maxBED trended toward improved LC rates, suggesting a maxBED threshold greater than 120 Gy may be needed to improve LC rates.

Nationwide changes in radiation oncology travel and location of care before and during the COVID-19 pandemic.

PURPOSE: Patients with cancer are particularly vulnerable to coronavirus disease (COVID). Transportation barriers made travel to obtain medical care more difficult during the pandemic. Whether these factors led to changes in the distance traveled for radiotherapy and the coordinated location of radiation treatment is unknown. MATERIALS AND METHODS: We analyzed patients across 60 cancer sites in the National Cancer Database from 2018 to 2020. Demographic and clinical variables were analyzed for changes in distance traveled for radiotherapy. We designated the facilities in the 99th percentile or above in terms of the proportion of patients who traveled more than 200 miles as "destination facilities." We defined "coordinated care" as undergoing radiotherapy at the same facility where the cancer was diagnosed. RESULTS: We evaluated 1,151,954 patients. There was a greater than 1% decrease in the proportion of patients treated in the Mid-Atlantic States. Mean distance traveled from place of residence to radiation treatment decreased from 28.6 to 25.9 miles, and the proportion traveling greater than 50 miles decreased from 7.7% to 7.1%. At "destination facilities," the proportion traveling more than 200 miles decreased from 29.3% in 2018 to 24% in 2020. In comparison, at the other hospitals, the proportion traveling more than 200 miles decreased from 1.07% to 0.97%. In 2020, residing in a rural area resulted in a lower odds of having coordinated care (multivariable odds ratio = 0.89; 95% confidence interval, 0.83-0.95). CONCLUSION: The first year of the COVID pandemic measurably impacted the location of U.S. radiation therapy treatment.

Corrigendum to "Challenges in the transition to independent radiation oncology practice and targeted interventions for improvement" [Tech. Innov. Patient Support Radiat. Oncol. 24 (2022) 113-117].

[This corrects the article DOI: 10.1016/j.tipsro.2022.09.002.].

Challenges in the transition to independent radiation oncology practice and targeted interventions for improvement.

Numerous radiation oncology residents and junior attendings have identified common weaknesses in residency training that hinder the transition from training to independent practice. Recurrent themes include not only general autonomy but also proficiency in technical skills, such as treatment plan review and image verification, and nontechnical skills, such as leadership, mentorship, and education. While multiple strategies to address these deficiencies have been investigated, many are not widely available or may be difficult to implement. We aim to summarize the frequently cited challenges in the transition to independent radiation oncology practice as well as the pertinent interventions that have been explored.

Early-stage vocal cord cancer treated with hypofractionated radiotherapy to the larynx with or without concurrent chemotherapy.

BACKGROUND: We report outcomes among patients with T2 and select T3 glottic squamous cell carcinoma (SCC) treated with radiotherapy. METHODS: We reviewed T2 and T3 (only paraglottic space invasion) N0 M0 glottic SCC patients treated with curative-intent hypofractionated larynx radiotherapy, with or without concurrent systemic therapy. RESULTS: Of 71 patients, those who received concurrent chemotherapy (23/71; 32%) had worse prognostic factors, including impaired cord mobility (70% vs. 40%, p = 0.02) and larger median gross tumor volume (3.0 vs. 1.6 cm3 , p = 0.003). Over a median follow-up of 3.8 years, 2-year local control among patients with impaired cord mobility appeared higher for those who received chemotherapy (88% vs. 61%, p = 0.12), but the difference was not statistically significant. Acute and late toxicity rates were not higher among patients who received chemotherapy. CONCLUSIONS: The addition of concurrent platinum-based chemotherapy to hypofractionated larynx radiotherapy among patients with early-stage glottic SCC with impaired cord mobility appears safe and worthy of additional investigation.

The incidence of brainstem toxicity following high-dose conformal proton therapy for adult skull-base malignancies.

BACKGROUND: Dose escalation for skull-based malignancies often presents risks to critical adjacent neural structures, including the brainstem. We report the incidence of brainstem toxicity following fractionated high-dose conformal proton therapy and associated dosimetric parameters. MATERIAL AND METHODS: We performed a single-institution review of patients with skull-base chordoma or chondrosarcoma who were treated with proton therapy between February 2007 and January 2020 on a prospective outcomes-tracking protocol. The primary endpoint was grade ≥2 brainstem toxicity. No patients received concurrent chemotherapy, and brainstem toxicity was censored for analysis if it coincided with local disease progression. RESULTS: We analyzed 163 patients who received a minimum of 45 GyRBE to 0.03 cm3 of the brainstem. Patients were treated to a median total dose of 73.8 (range 64.5-74.4) GyRBE at 1.8 GyRBE per fraction with 17 patients undergoing twice-daily treatment at 1.2 GyRBE per fraction. With a median follow-up of 4 years, the 5-year cumulative incidence of grade ≥2 brainstem injury was 1.3% (95% CI 0.25-4.3%). There was one grade 2, one grade 3, and no grade 4 or 5 events, with all patients recovering function with medical management. CONCLUSION: In delivering curative-intent radiotherapy for skull-base chordoma and chondrosarcoma in adults, small volumes of the brainstem can safely receive at least 64 GyRBE with minimal risk of serious brainstem injury.

How 3 Academic Centers Prescribe Stereotactic Body Radiation Therapy for Primary Lung Cancer.

Stereotactic body radiation therapy (SBRT) is commonly used to treat early-stage, node-negative primary lung cancer, but society guidelines provide limited information regarding several technical aspects of SBRT, leading to potential variation in practice. In this report, we present the technical details used by 3 academic institutions when treating a solitary primary lung tumor up to 5 cm in dimension with curative-intent SBRT. We provide specifications outlined in major active or recently completed clinical trials. Among the participating institutions, we discovered multiple divergences in treatment parameters, including, but not limited to, prescription dose and desired degree of heterogeneity within the target volume. It is unclear to what extent these differences in parameters might affect tumor control or toxicity, but updated consensus guidelines addressing the relevant SBRT prescription details may help standardize practice patterns.

Clinical Outcomes Following Dose-Escalated Proton Therapy for Skull-Base Chordoma.

PURPOSE: To evaluate the effectiveness of external-beam proton therapy (PT) on local control and survival in patients with skull-base chordoma. MATERIALS AND METHODS: We reviewed the medical records of patients with skull-base chordoma treated with definitive or adjuvant high-dose PT and updated their follow-up when feasible. We assessed overall survival, disease-specific survival, local control, and freedom from distant metastasis. Radiotherapy toxicities were scored using the Common Terminology Criteria for Adverse Events, version 4.0. RESULTS: A total 112 patients were analyzed, of whom 105 (94%) received PT and 7 (6%) received combined proton-photon therapy between 2007 and 2019. Eighty-seven patients (78%) underwent a subtotal resection, 22 (20%) a gross total resection, and 3 (3%) a biopsy alone. The median radiotherapy dose was 73.8 Gy radiobiologic equivalent (GyRBE; range, 69.6-74.4). Ninety patients (80%) had gross disease at radiotherapy and 7 (6%) were treated for locally recurrent disease following surgery. Median follow-up was 4.4 years (range, 0.4-12.6); for living patients, it was 4.6 years (range, 0.4-12.6), and for deceased patients, 4.1 years (range, 1.2-11.2). At 5 years after radiotherapy, the actuarial overall survival, disease-specific survival, local control, and freedom from distant metastasis rates were 78% (n = 87), 83% (n = 93), 74% (n = 83), and 99% (n = 111), respectively. The median time to local progression was 2.4 years (range, 0.8-7). Local control and disease-specific survival by resection status was 95% versus 70% (P = 0.28) and 100% versus 80% (P = 0.06) for gross total, versus subtotal, resection or biopsy alone, respectively. There were no serious acute toxicities (grade ≥ 3) related to radiotherapy. CONCLUSION: High-dose PT alone or after surgical resection for skull-base chordoma reaffirms the favorable 5-year actuarial local control rate compared with conventional techniques with acceptable late-complication-free survival. Outcomes following gross total resection and adjuvant PT were excellent. Further follow-up of this cohort is necessary to better characterize long-term disease control and late toxicities.

Sparing the Larynx and Hypopharynx With Radiation Therapy for Squamous Cell Carcinoma of Unknown Primary Site and Predominant Adenopathy in Level IIA.

PURPOSE: There is controversy about the need to target the mucosa of the larynx and hypopharynx during radiation therapy (RT) for squamous cell carcinoma of an unknown primary site (SCCA-UP). By 1997, the policy in our department was to target only the oropharynx and nasopharynx in patients with SCCA-UP metastatic to the level II cervical nodes. The purpose of this study was to report the rate of cancer recurrence in the larynx or hypopharynx using an approach that excluded these areas from the RT target volumes. METHODS AND MATERIALS: The inclusion criteria for this study were RT in our department for SCCA-UP between January 1, 1997, and December 31, 2019; no history of surgery that could disrupt the cervical lymphatics; predominant adenopathy in level IIA; and neck stage N1-2c. We excluded N3 because the incidental dose to the larynx and hypopharynx is usually high in patients with a >6-cm nodal conglomerate. RESULTS: The study population was comprised of 50 patients with a median follow-up after RT of 7.1 years. No patient developed recurrent cancer in a mucosal site (0/50), 2% (1/50) developed a neck recurrence in a high-dose area with synchronous distant metastases, and 2% (1/50) developed distant metastases with no evidence of local or regional recurrence. CONCLUSIONS: When delivering RT for SCCA-UP metastatic predominantly to level IIA, it is not necessary to target the mucosa of the larynx or hypopharynx. The extent to which the incidental RT dose to these areas contributes to cancer control is not evaluated in this study.

Vision loss following high-dose proton-based radiotherapy for skull-base chordoma and chondrosarcoma.

BACKGROUND & PURPOSE: Dose escalation for skull-based chordoma and chondrosarcoma can put critical adjacent structures at risk, specifically the anterior optic pathway. We report the incidence of vision loss following high-dose conformal proton-based radiotherapy. MATERIALS AND METHODS: We reviewed patients with skull-base chordoma or chondrosarcoma treated with proton-based therapy between 2007 and 2018. We analyzed 148 patients and 283 individual eyes with functional vision at baseline who received a minimum 30GyRBE to 0.1 cm3 of the anterior optic pathway. Eyes were classified as "functionally blind" if visual acuity was 20/200 or worse. Kaplan-Meier and normal tissue complication probability modeling were used to establish the relationship between radiation dose and risk of functional vision loss. RESULTS: At last follow-up, 110 of 148 patients were alive with no evidence of disease progression. With a median follow-up of 4.1 years (range, 0.5-12.8), 5 eyes in 3 patients developed functional blindness, with 2 patients developing bilateral blindness. Median time to blindness was 15.2 months. The 5-year incidence of vision loss was 2.1% (95% CI: 0.9-4.9%). On univariate analysis, development of blindness was associated with presence of multiple medical comorbidities (p = 0.0040). While there were no events with a maximum dose < 60GyRBE delivered to the anterior optic pathway, the crude rate was 3.6% over 60GyRBE, with all events occurring between 60-65GyRBE. CONCLUSIONS: Despite the high radiotherapy dose delivered to patients with skull-base chordoma and chondrosarcoma, the rate of vision loss is low and no events occurred in those who received a maximum dose under 60GyRBE.

Radiotherapy in Early-stage Gastric MALT: Improved Survival Without Increased Cardiac Death.

PURPOSE: Radiotherapy (RT) is an effective treatment for localized gastric mucosa-associated lymphoid tissue (MALT) lymphomas unresponsive to antibiotic therapy; however, irradiating the stomach can result in significant radiation to the heart, a risk factor for cardiac disease. We analyzed the Surveillance, Epidemiology, and End Results database to evaluate outcomes related to cardiac disease among patients treated with RT for stage I gastric MALT. MATERIALS AND METHODS: We identified adult patients treated between 1993 and 2014. The relationship between treatment modality (RT, chemotherapy, combination, and no treatment) and overall survival (OS), mucosa-associated lymphoid tissue-specific survival (MSS), non-mucosa-associated lymphoid tissue-specific survival (non-MSS), and cardiac-specific survival (CSS) was assessed using the Kaplan-Meier estimator and Cox proportional hazards analyses. RESULTS: A total of 2996 patients (median follow-up, 5.6 y) were analyzed: 27.5% had received RT alone, 12.1% chemotherapy alone, 3.9% chemoradiotherapy, and 56.5% no/unknown treatment (including antibiotic therapy). Compared with RT alone, patients who received chemotherapy alone exhibited worse OS (hazard ratio [HR]: 1.67; 95% confidence interval [CI]: 1.32-2.10; P<0.001) and MSS (HR: 2.10; 95% CI: 1.36-3.23; P=0.001). Although CSS appeared worse in patients who received chemotherapy (HR: 1.56; 95% CI: 0.92-2.66; P=0.10), it was not statistically significant. When comparing orbital and gastric MALT patients, there was no significant difference in CSS (HR: 0.80; 95% CI: 0.49-1.31; P=0.38). CONCLUSIONS: RT improved survival among patients with stage I gastric MALT without increasing the risk of cardiac death. Those with gastric MALT exhibited similar CSS to those with orbital MALT. Although we cannot analyze nonfatal cardiac toxicity, these results suggest that, absent antibiotic therapy, RT should remain first-line treatment for early-stage gastric MALT.

Oligometastatic squamous cell carcinoma of the head and neck treated with stereotactic body ablative radiotherapy: Single-institution outcomes.

PURPOSE/OBJECTIVES: We analyzed outcomes after stereotactic ablative body radiotherapy for oligometastatic (1-5 metastatic foci) head-and-neck squamous cell carcinoma (OM-HNSCC). MATERIALS/METHODS: We reviewed patients treated between 2012 and 2016. Endpoints included overall survival (OS), distant progression, and treated-metastasis local control (TM-LC). RESULTS: We analyzed 27 patients with 60 primarily metachronous metastases (81.5%). Median follow-up was 1.6 years (0.2-5.2). Median time from diagnosis to treatment was 1.1 years (0.08-8.5). Overall, 44.4% had solitary, 44.4% had 2-3, and 11.1% had >3 metastases; most metastases were in the lung (44 of 60 metastases). Median OS was 1.9 years; at 1 and 2 years, 78% and 43% were alive (14% without disease progression). Median time to progression was 0.5 years. The 1-year and 2-year TM-LC rates were 75% and 57%. CONCLUSIONS: OS is encouraging and disease-free survival remains poor; nevertheless, patients with OM-HNSCC may represent a more favorable subset of patients with metastatic HNSCC.