Intensity-Modulated Reirradiation Therapy With Nivolumab in Recurrent or Second Primary Head and Neck Squamous Cell Carcinoma: A Nonrandomized Controlled Trial

Importance

Intensity-modulated radiation therapy (IMRT) reirradiation of nonmetastatic recurrent or second primary head and neck squamous cell carcinoma (HNSCC) results in poor progression-free survival (PFS) and overall survival (OS).

Objective

To investigate the tolerability, PFS, OS, and patient-reported outcomes with nivolumab (approved standard of care for patients with HNSCC) during and after IMRT reirradiation.

Design, Setting, and Participants

In this multicenter nonrandomized phase 2 single-arm trial, the treatment outcomes of patients with recurrent or second primary HNSCC who satisfied recursive partitioning analysis class 1 and 2 definitions were evaluated. Between July 11, 2018, and August 12, 2021, 62 patients were consented and screened. Data were evaluated between June and December 2023.

Intervention

Sixty- to 66-Gy IMRT in 30 to 33 daily fractions over 6 to 6.5 weeks with nivolumab, 240 mg, intravenously 2 weeks prior and every 2 weeks for 5 cycles during IMRT, then nivolumab, 480 mg, intravenously every 4 weeks for a total nivolumab duration of 52 weeks.

Main Outcomes and Measures

The primary end point was PFS. Secondary end points included OS, incidence, and types of toxic effects, including long-term treatment-related toxic effects, patient-reported outcomes, and correlatives of tissue and blood biomarkers.

Results

A total of 62 patients were screened, and 51 were evaluable (median [range] age was 62 [56-67] years; 42 [82%] were male; 6 [12%] had p16+ disease; 38 [75%] had salvage surgery; and 36 [71%.] had neck dissection). With a median follow-up of 24.5 months (95% CI, 19.0-25.0), the estimated 1-year PFS was 61.7% (95% CI, 49.2%-77.4%), rejecting the null hypothesis of 1-year PFS rate of less than 43.8% with 1-arm log-rank test P = .002 within a 1-year timeframe. The most common treatment-related grade 3 or higher adverse event (6 [12%]) was lymphopenia with 2 patients (4%) and 1 patient each (2%) exhibiting colitis, diarrhea, myositis, nausea, mucositis, and myasthenia gravis. Functional Assessment of Cancer Therapy-General and Functional Assessment of Cancer Therapy-Head and Neck Questionnaire quality of life scores remained stable and consistent across all time points. A hypothesis-generating trend favoring worsening PFS and OS in patients with an increase in blood PD1+, KI67+, and CD4+ T cells was observed.

Conclusions and Relevance

This multicenter nonrandomized phase 2 trial of IMRT reirradiation therapy and nivolumab suggested a promising improvement in PFS over historical controls. The treatment was well tolerated and deserves further evaluation.

Trial Registration

ClinicalTrials.gov Identifier: NCT03521570.

Using Nerve Blocks for Addressing Radiation-Induced Pain During Pelvic Cancer Treatment

This Viewpoint discusses the use of nerve blocks for pain during pelvic cancer treatment.

Patterns of Undertreatment and Overtreatment in Adjuvant Radiotherapy for Early-Stage Endometrial Cancer Based on Molecular Classification

The quality improvement study examines the use of risk-adaptive adjuvant radiotherapy in women with non–mismatch repair deficiency endometrial cancer.

Photon vs. Proton Radiotherapy in the Definitive Treatment of Nasopharyngeal Cancer: Single Institution Experience

PURPOSE/OBJECTIVE(S)

Definitive therapy for nasopharyngeal cancer includes chemotherapy and radiation (RT). Common toxicities such as xerostomia, mucositis, and hearing loss are correlated with the RT dose delivered to associated organs at risk. We hypothesized that compared to our historical experience with IMRT, the implementation of proton therapy (PT) would reduce radiation dose to organs at risks without compromising oncologic outcomes.

MATERIALS/METHODS

A retrospective review of all non-metastatic stage II-IV nasopharyngeal carcinoma (SCC, lymphoepithelioma, undifferentiated carcinomas) treated with definitive therapy at our institution from 2012-2022. Disease parameters and the mean dose to organs at risk were evaluated. Statistical comparison was made with the chi square test for categorical and Wilcoxon rank sum test for continuous variables. The Kaplan-Meier method was used to estimate overall survival (OS) and progression-free survival (PFS), using a log-rank test to compare IMRT and PT. PFS was defined as the time from the start of treatment to the first of either disease progression, relapse or death from any cause. PT was delivered with pencil-beam scanning in all patients. IMRT included multi-field treatment and volumetric-modulated arc therapy.

RESULTS

A total of 80 patients were included in analyses: 48 treated with IMRT and 32 with PT. Comparing IMRT to PT cohorts, there was no difference in the median age of patients (51 vs 55 years, p = 0.73), nor the distribution by T stage (p = 0.57) or N stage (p = 0.34) or in the percentage of patients with ECOG 2/3 performance status at presentation (p = 0.11). All but one patient received concurrent systemic therapy and there was no difference in the use of concurrent cisplatin between cohorts (83% vs 78%, p = 0.57). The most common non-cisplatin concurrent regimen was weekly carboplatin and paclitaxel. Induction chemotherapy was more commonly used in patients treated with PT (10.4% vs 25%, p = 0.04) while there was no difference in the use of adjuvant chemotherapy (10.4% vs 9.4%, p = 0.88). Among 42 cases initiating treatment since the opening of our proton center, 32 (76%) have received PT. Comparing IMRT and PT dosimetry, patients treated with PT received significantly lower mean dose to the better spared parotid gland (32.8 vs 25.7 Gy, p = 0.001), lesser spared parotid gland (35.5 vs 31.1 Gy, p = 0.047), better spared cochlea (31.5 vs 25.5 Gy, p = 0.004), lesser spared cochlea (41.8 vs 33.2 Gy, p = 0.004), larynx (44.5 vs 21.7 Gy, p<0.001), and oral cavity (42.6 vs 17.0 Gy, p<0.001). After a median follow-up time of 30 months (45 mos IMRT, 23 mos PT) the estimated 2-year PFS was 63.9% with IMRT and 90.3% with PT (p = 0.047). The estimate of 2-year overall survival was 86.8% with IMRT and 96.8% with PT (p = 0.17).

CONCLUSION

Comparing patients by radiation treatment modality, PT was associated with a statistically significant reduction in mean radiation dose to the parotid glands, cochlea, larynx, and oral cavity with excellent initial oncologic outcomes.

Risk Factors and Clinical Features of Fistula after Concurrent Chemoradiation and Brachytherapy for Locally Advanced Cervical Cancer

PURPOSE/OBJECTIVE(S)

The standard treatment for locally advanced cervical cancer (LACC) is concurrent chemoradiation and brachytherapy (CRT-B). Fistula formation is a serious complication of treatment; however, risk factors and clinical outcomes are not well described. We sought to identify the incidence, risk factors and prognosis of radiation-induced fistula in women who underwent CRT-B for LACC.

MATERIALS/METHODS

A single institution retrospective review of patients treated with CRT-B for LACC from July 2013 to August 2022 across 3 centers was performed. Inclusion criteria were Stage IB-IVB cervical cancer treated with definitive intent. Patients with upfront or adjuvant surgery were excluded. Cox-proportional hazards model was performed to assess factors associated with fistula. Local control and fistula-free survival were estimated using the Kaplan-Meyer method. Clinical significance was defined as p < 0.05.

RESULTS

A total of 105 patients met the inclusion criteria and were included in this analysis. Patients consisted of FIGO Stage I (n = 20, 19%), Stage II (n = 22, 21%), Stage III (n = 46, 43.8%) or Stage IV disease (n = 17, 16.2%). 12 (11.4%) patients developed fistula following CRT-B; 1/12 patients (8.3%) had fistula present at time of diagnosis. Median time to fistula development was 12 months. Fistula was characterized as vesicovaginal/urethrovaginal in 58.3% (n = 7) and rectovaginal/intestinovaginal in 83.3% (n = 10), including 8 patients (66.7%) who had more than one type of fistula. 4/12 (33.3%) of patients with fistula had concurrent local recurrence. Patients were treated with conservative management (41.7%), hyperbaric oxygen (16.7%) and/or surgery (83.3%). Complications included infection (50.0%), urinary/bowel diversion (83.3%), hospitalization (50.0%) and death (8.3%). Fistula was resolved in 7/12 patients (58.3%) at time of last follow up. Higher BMI (p = 0.04) and use of hybrid applicators (p = 0.02) were associated with decreased likelihood of fistula development. Disease extension into bladder was associated with increased likelihood of fistula development (p = 0.03). Compared to former and never smoking, current smoking was associated with a higher risk of developing fistula (p = 0.04, OR 4.42, CI:1.07-18.34). Compared to intracavitary and hybrid applicators, the use of a Syed applicator was associated with increased likelihood of fistula development (p = 0.02, OR 8.00, CI: 1.37-46.55). Two-year local control was 82.5% (CI: 64.5-91.9) for Stage I-II, 80.7% (CI: 62.8-90.6) for Stage III, and 62.2% (CI: 30.1-82.9) for Stage IV. Two-year fistula free survival was 89.9% (CI: 80.6 - 94.9).

CONCLUSION

Women who undergo definitive chemoradiation for treatment of LACC have a 11.4% risk of fistula formation overall. The risk is higher amongst patients with current smoking, disease extension into bladder and Syed applicators. Overall two-year local control was 78.7% and fistula free survival was 89.9%.

Single Institution Experience of the Effect of Adjuvant Radiation on Outcomes for Patients with Uterine Carcinosarcoma

PURPOSE/OBJECTIVE(S)

Uterine carcinosarcoma (UCS) is a rare but aggressive malignancy with poor outcomes. Due to its low incidence, there is no well-established optimal treatment. Standard treatment involves surgery and chemotherapy (CT) +/- adjuvant radiation therapy (RT). Our primary aim was to determine if patients who underwent adjuvant RT had improved distant metastasis free survival (DMFS) and locoregional recurrence free survival (LRRFS). Our secondary aim was to determine the effect of adjuvant RT on overall survival (OS).

MATERIALS/METHODS

We performed a single institutional retrospective review of all patients with UCS who underwent primary surgical resection +/- CT and +/- RT between 2007 to 2021. Patients without at least 3 months of documented follow-up were excluded. We assessed DMFS, LRRFS, and OS between patients who did and did not receive adjuvant RT, consisting of vaginal brachytherapy (VBT), external beam radiation therapy (EBRT), or EBRT + VBT. Statistical analysis was performed with spreadsheet and statistical software.

RESULTS

Sixty-four patients underwent primary surgical resection for FIGO stage I-IV UCS. Sixty six percent (n = 42) had early stage, FIGO I-II disease and 34% (n = 22) had late stage, FIGO III-IV disease. Eleven percent (n = 7) underwent surgery alone, 28% (n = 18) underwent surgery + CT, 6% (n = 4) underwent surgery + adjuvant RT, and 55% (n = 35) underwent surgery + CT + RT. Most patients who underwent surgery + CT + EBRT + VBT (n = 9) had worse clinicopathologic features including late stage (56%), lymphovascular invasion positive (78%) disease with 50% or greater myometrial invasion (56%). EBRT doses ranged from 45-50.4 Gray (Gy) in 1.8 Gy per fraction. VBT doses ranged from 21-25 Gy in 3-5 fractions when delivered alone and 10-15 Gy in 2-3 fractions when delivered as a boost. Median DMFS was 20.3 months, median LRRFS was 22.6 months, median DFS was 19.4 months, and median OS was 24.7 months. Rate of distant metastasis appeared to drive rate of disease-free survival (Table 1). Patients who underwent adjuvant RT had improved median DMFS (71.5 vs. 11.3 months, p = .002), median LRRFS (71.5 vs 22.5 months, p = .002), and median OS (60.7 vs. 22.5 months, p = .002) compared to those who did not receive RT.

CONCLUSION

Prognosis of patients with UCS remains poor; however, adjuvant RT delivered after CT may offer potential benefit in survival outcomes despite worse clinicopathologic features in these patients.

Effect of COVID-19 on Gynecologic Oncology Care: A Survey of Practicing Gynecologic Radiation Oncologists in the United States

Purpose

The COVID-19 pandemic has placed demands and limitations on the delivery of health care. We sought to assess the effect of COVID-19 on the delivery of gynecologic oncologic care from the perspective of practicing radiation oncologists in the United States.

Methods and Materials

An anonymous online survey was created and distributed to preidentified radiation oncologists in the United States with clinical expertise in the management of gynecologic patients. The survey consisted of demographic questions followed by directed questions to assess specific patterns of care related to the COVID-19 pandemic.

Results

A total of 47 of 96 invited radiation oncologists responded to the survey for a response rate of 49%. Fifty-six percent of respondents reported an increase in locally advanced cervical cancer with no similar increase for endometrial, vulvar, or vaginal patients. Most respondents (66%) reported a pause in surgical management, with a duration of 1 to 3 months being most common (61%). There was a reported increased use of shorter brachytherapy regimens during the pandemic. Most providers (61%) reported caring for at least 1 patient with a positive COVID-19 test. A pause or delay in treatment due to COVID-19 positivity was reported by 45% of respondents, with 55% reporting that patients chose to delay their own care because of COVID-19-related concerns. Total treatment times >8 weeks for patients with cervical cancer were observed by 33% of respondents, but occurred in >25% of patients.

Conclusions

Data from this prospectively collected anonymous survey of practice patterns among radiation oncologists reveal that the COVID-19 pandemic resulted in delays initiating care, truncated brachytherapy treatment courses, and a reported increase in locally advanced cervical cancer cases at presentation. These data can be used as a means of self-assessment to ensure appropriate decision making for gynecologic patients during the endemic phase of COVID-19.

Insurance Authorization and Access to Proton Therapy for Patients With Head and Neck Cancers

PURPOSE

We evaluated our institutional experience to assess potential racial inequities in insurance coverage for proton therapy in patients with head and neck (HN) cancer.

METHODS AND MATERIALS

We examined the demographics of 1519 patients with HN cancer seen in consultation at our HN multidisciplinary clinic (HN MDC) and 805 patients for whom a proton insurance authorization was sought (PAS) from January 2020 to June 2022. The prospects for proton therapy insurance authorization were prospectively noted based on each patient's ICD-10 (International Classification of Diseases, 10th Revision) diagnosis code and their specific insurance plan. Proton-unfavorable (PU) insurance were those plans whose policy describes proton beam therapy as "experimental" or "not medically necessary" for the given diagnosis.

RESULTS

For patients seen in our HN MDC, Black, Indigenous, and people of color (BIPOC) were significantly more likely to have PU insurance than non-Hispanic White (NHW) patients (24.9% vs 18.4%, P = .005). In multivariable analysis including race, average income of residence ZIP code, and Medicare eligibility age, BIPOC patients had an odds ratio of 1.25 for PU insurance (P = .041). In the PAS cohort, while there was no difference in the percentage of patients receiving insurance approval for proton therapy between NHW and BIPOC populations (88% vs 88.2%, P = .80), for patients with PU insurance, the median time to determination was significantly longer (median, 15.5 days), and the median time to start any radiation of any modality was longer (46 vs 35 days, P = .08). Compared with NHW patients, the median time from consultation to start of radiation therapy was longer for BIPOC patients (37 vs 43 days, P = .01).

CONCLUSIONS

BIPOC patients were significantly more likely to have insurance plans unfavorable to proton therapy coverage. These PU insurance plans were associated with a longer median time to determination, a lower approval rate for proton therapy, and a longer time to start radiation of any modality.

Ninety-day mortality following transoral robotic surgery or radiation at Commission on Cancer-accredited facilities

BACKGROUND

Postoperative mortality for oropharynx squamous cell carcinoma (OPSCC) with transoral robotic surgery (TORS) varies from 0.2% to 6.5% on trials; the real-world rate is unknown.

METHODS

NCDB study from 2010 to 2017 for patients with cT1-2N0-2M0 OPSCC with Charleson-Deyo score 0-1. Ninety-day mortality assessed from start and end of treatment at Commission on Cancer-accredited facilities.

RESULTS

3639 patients were treated with TORS and 1937 with radiotherapy. TORS cohort had more women and higher income, was younger, more often treated at academic centers, and more likely to have private insurance (all p < 0.05). Ninety-day mortality was 1.3% with TORS and 0.7% or 1.4% from start or end of radiotherapy, respectively. From end of therapy, there was no significant difference on MVA between treatment modality.

CONCLUSIONS

There is minimal difference between 90-day mortality in patients treated with TORS or radiotherapy for early-stage OPSCC. While overall rates are low, for patients with expectation of cure, work is needed to identify optimal treatment.

Incidence and predictors of toxicity in the management of vulvar squamous cell carcinoma treated with radiation therapy

Purpose/Objective

Given the rarity of vulvar cancer, data on the incidence of acute and late severe toxicity and patients' symptom burden from radiotherapy (RT) are lacking.

Materials/Methods

This multi-center, single-institution study included patients with vulvar squamous cell carcinoma treated with curative intent RT between 2009 and 2020. Treatment-related acute and late grade ≥ 3 toxicities and late patient subjective symptoms (PSS) were recorded.

Results

Forty-two patients with predominantly stage III/IV disease (n = 25, 59.5 %) were treated with either definitive (n = 25, 59.5 %) or adjuvant (n = 17, 40.5 %) external beam RT to a median dose of 64 Gy and 59.4 Gy, respectively. Five patients received a brachytherapy boost with a median total dose of 84.3 Gy in 2 Gy-equivalent dose (EQD2). Intensity-modulated RT was used in 37 (88.1 %) of patients, and 25 patients (59.5 %) received concurrent chemotherapy. Median follow-up was 27 months. Acute grade ≥ 3 toxicity occurred in 17 patients (40.5 %), including 13 (31.0 %) acute grade 3 skin events. No factors, including total RT dose (p = 0.951), were associated with acute skin toxicity. Eleven (27.5 %) patients developed late grade ≥ 3 toxicity events, including 10 (23.8 %) late grade ≥ 3 skin toxicity events. Patients with late grade ≥ 3 skin toxicity had a higher mean body-mass index (33.0 vs 28.2 kg/m²; p = 0.009). Common late PSS included vaginal pain (n = 15, 35.7 %), skin fibrosis (n = 10, 23.8 %), and requirement of long-term opiates (n = 12, 28.6 %).

Conclusion

RT for vulvar cancer is associated with considerable rates of severe acute and late toxicity and PSS burden. Larger studies are needed to identify risk factors, explore toxicity mitigation strategies, and assess patient-reported outcomes.

Spatially Fractionated Radiotherapy (GRID) Prior to Standard Neoadjuvant Conventionally Fractionated Radiotherapy for Bulky, High-Risk Soft Tissue and Osteosarcomas: Feasibility, Safety, and Promising Pathologic Response Rates

Spatially fractionated radiotherapy (GRID) has been utilized primarily in the palliative and definitive treatment of bulky tumors. Delivered in the modern era primarily with megavoltage photon therapy, this technique offers the promise of safe dose escalation with potential immunogenic, bystander and microvasculature effects that can augment a conventionally fractionated course of radiotherapy. At the University of Maryland, an institutional standard has arisen to incorporate a single fraction of GRID radiation in large (>8 cm), high-risk soft tissue and osteosarcomas prior to a standard fractionated course. Herein, we report on the excellent pathologic responses and apparent safety of this regimen in 26 consecutive patients.

Simulation of an HDR "Boost" with Stereotactic Proton versus Photon Therapy in Prostate Cancer: A Dosimetric Feasibility Study

Purpose/Objectives

To compare the dose escalation potential of stereotactic body proton therapy (SBPT) versus stereotactic body photon therapy (SBXT) using high-dose rate prostate brachytherapy (HDR-B) dose-prescription metrics.

Patients and Methods

Twenty-five patients previously treated with radiation for prostate cancer were identified and stratified by prostate size (≤ 50cc; n = 13, > 50cc; n = 12). Initial CT simulation scans were re-planned using SBXT and SBPT modalities using a prescription dose of 19Gy in 2 fractions. Target coverage goals were designed to mimic the dose distributions of HDR-B and maximized to the upper limit constraint for the rectum and urethra. Dosimetric parameters between SBPT and SBXT were compared using the signed-rank test and again after stratification for prostate size (≤ 50cm³ and >50cm³) using the Wilcoxon rank test.

Results

Prostate volume receiving 100% of the dose (V100) was significantly greater for SBXT (99%) versus SBPT (96%) (P ≤ 0.01), whereas the median V125 (82% vs. 73%, P < 0.01) and V200 (12% vs. 2%, P < 0.01) was significantly greater for SBPT compared to SBXT. Median V150 was 49% for both cohorts (P = 0.92). V125 and V200 were significantly correlated with prostate size. For prostates > 50cm³, V200 was significantly greater with SBPT compared to SBXT (14.5% vs. 1%, P = 0.005), but not for prostates 50cm³ (9% vs 4%, P = 0.11). Median dose to 2cm³ of the bladder neck was significantly lower with SBPT versus SBXT (9.6 Gy vs. 14 Gy, P < 0.01).

Conclusion

SBPT and SBXT can be used to simulate an HDR-B boost for locally advanced prostate cancer. SBPT demonstrated greater dose escalation potential than SBXT. These results are relevant for future trial design, particularly in patients with high risk prostate cancer who are not amenable to brachytherapy.

Immune checkpoint inhibition in patients treated with stereotactic radiation for brain metastases

Purpose

Stereotactic radiation therapy (SRT) and immune checkpoint inhibitors (ICI) may act synergistically to improve treatment outcomes but may also increase the risk of symptomatic radiation necrosis (RN). The objective of this study was to compare outcomes for patients undergoing SRT with and without concurrent ICI.

Methods and materials

Patients treated for BMs with single or multi-fraction SRT were retrospectively reviewed. Concurrent ICI with SRT (SRT-ICI) was defined as administration within 3 months of SRT. Local control (LC), radiation necrosis (RN) risk and distant brain failure (DBF) were estimated by the Kaplan-Meier method and compared between groups using the log-rank test. Wilcoxon rank sum and Chi-square tests were used to compare covariates. Multivariate cox regression analysis (MVA) was performed.

Results

One hundred seventy-nine patients treated with SRT for 385 brain lesions were included; 36 patients with 99 lesions received SRT-ICI. Median follow up was 10.3 months (SRT alone) and 7.7 months (SRT- ICI) (p = 0.08). Lesions treated with SRT-ICI were more commonly squamous histology (17% vs 8%) melanoma (20% vs 2%) or renal cell carcinoma (8% vs 6%), (p < 0.001). Non-small cell lung cancer (NSCLC) compromised 60% of patients receiving ICI (n = 59). Lesions treated with SRT-ICI had significantly improved 1-year local control compared to SRT alone (98 and 89.5%, respectively (p = 0.0078). On subset analysis of NSCLC patients alone, ICI was also associated with improved 1 year local control (100% vs. 90.1%) (p = 0.018). On MVA, only tumor size ≤2 cm was significantly associated with LC (HR 0.38, p = 0.02), whereas the HR for concurrent ICI with SRS was 0.26 (p = 0.08). One year DBF (41% vs. 53%; p = 0.21), OS (58% vs. 56%; p = 0.79) and RN incidence (7% vs. 4%; p = 0.25) were similar for SRT alone versus SRT-ICI, for the population as a whole and those patients with NSCLC.

Conclusion

These results suggest SRT-ICI may improve local control of brain metastases and is not associated with an increased risk of symptomatic radiation necrosis in a cohort of predominantly NSCLC patients. Larger, prospective studies are necessary to validate these findings and better elucidate the impact of SRT-ICI on other disease outcomes.

A multi-center analysis of single-fraction versus hypofractionated stereotactic radiosurgery for the treatment of brain metastasis

Background

Hypofractionated-SRS (HF-SRS) may allow for improved local control and a reduced risk of radiation necrosis compared to single-fraction-SRS (SF-SRS). However, data comparing these two treatment approaches are limited. The purpose of this study was to compare clinical outcomes between SF-SRS versus HF-SRS across our multi-center academic network.

Methods

Patients treated with SF-SRS or HF-SRS for brain metastasis from 2013 to 2018 across 5 radiation oncology centers were retrospectively reviewed. SF-SRS dosing was standardized, whereas HF-SRS dosing regimens were variable. The co-primary endpoints of local control and radiation necrosis were estimated using the Kaplan Meier method. Multivariate analysis using Cox proportional hazards modeling was performed to evaluate the impact of select independent variables on the outcomes of interest. Propensity score adjustments were used to reduce the effects confounding variables. To assess dose response for HF-SRS, Biologic Effective Dose (BED) assuming an α/β of 10 (BED₁₀) was used as a surrogate for total dose.

Results

One-hundred and fifty six patients with 335 brain metastasis treated with SF-SRS (n = 222 lesions) or HF-SRS (n = 113 lesions) were included. Prior whole brain radiation was given in 33% (n = 74) and 34% (n = 38) of lesions treated with SF-SRS and HF-SRS, respectively (p = 0.30). After a median follow up time of 12 months in each cohort, the adjusted 1-year rate of local control and incidence of radiation necrosis was 91% (95% CI 86–96%) and 85% (95% CI 75–95%) (p = 0.26) and 10% (95% CI 5–15%) and 7% (95% CI 0.1–14%) (p = 0.73) for SF-SRS and HF-SRS, respectively. For lesions > 2 cm, the adjusted 1 year local control was 97% (95% CI 84–100%) for SF-SRS and 64% (95% CI 43–85%) for HF-SRS (p = 0.06). On multivariate analysis, SRS fractionation was not associated with local control and only size ≤2 cm was associated with a decreased risk of developing radiation necrosis (HR 0.21; 95% CI 0.07–0.58, p < 0.01). For HF-SRS, 1 year local control was 100% for lesions treated with a BED₁₀ ≥ 50 compared to 77% (95% CI 65–88%) for lesions that received a BED₁₀ < 50 (p = 0.09).

Conclusions

In this comparison study of dose fractionation for the treatment of brain metastases, there was no difference in local control or radiation necrosis between HF-SRS and SF-SRS. For HF-SRS, a BED₁₀ ≥ 50 may improve local control.

Downstream Effect of a Proton Treatment Center on an Academic Medical Center

PURPOSE

To quantify the effects of opening a proton center (PC) on an academic medical center (AMC)/radiation oncology department.

METHODS AND MATERIALS

Radiation treatment volume and relative value units from fiscal year 2015 (FY15) to FY17 were retrospectively analyzed at the AMC and 2 community-based centers. To quantify new patient referrals to the AMC, we reviewed the electronic medical record for all patients seen at the PC since consults were initiated in November 2015 (n = 1173). Patients were excluded if the date of entry into the AMC electronic medical record predated their PC consultation. Hospital resource use and professional and technical charges were obtained for these patients. Academic growth, philanthropy, and resident education were evaluated based on grant submissions, clinical trial enrollment, philanthropy, and pediatric case exposure, respectively, from PC opening through FY17.

RESULTS

From FY15 to FY17, radiation fractions at the AMC and the 2 community sites decreased by 14% (95% confidence interval [CI], 12%-16%, P < .001) and increased by 19% (95% CI, 16%-23%, P < .001) and 2% (95% CI, -1.1 to 4.3%, P = NS), respectively; the number of new starts decreased by 3% (95% CI, -13% to 7%, P = NS) and 2% (95% CI, -20% to 16%, P = NS) and increased by 13% (95% CI -2% to 27%, P = NS), respectively. At the AMC, technical and professional relative value units decreased by 5% and 14%, respectively. The PC made 561 external referrals to the AMC, which resulted in $2.38 million technical and $2.13 million professional charges at the AMC. Fifteen grant submissions ($12.83 million) resulted in 6 awards ($3.26 million). Twenty-two clinical trials involving proton therapy were opened, on which a total of 5% (n = 54) of patients enrolled during calendar years 2017 and 2018. The PC was involved in gift donations of $1.6 million. There was a nonsignificant 37% increase in number of pediatric cases.

CONCLUSIONS

Despite a slight decline in AMC photon patient volumes and relative value units, a positive downstream effect was associated with the addition of a PC, which benefited the AMC.