Patterns of utilization and clinical adoption of 0.35 Tesla MR-guided radiation therapy in the United States - Understanding the transition to adaptive, ultra-hypofractionated treatments.

Purpose/Objective: Magnetic resonance-guided radiation therapy (MRgRT) utilization is rapidly expanding worldwide, driven by advanced capabilities including continuous intrafraction visualization, automatic triggered beam delivery, and on-table adaptive replanning (oART). Our objective was to describe patterns of 0.35Tesla(T)-MRgRT (MRIdian) utilization in the United States (US) among early adopters of this novel technology. Materials/Methods: Anonymized administrative data from all US MRIdian treatment systems were extracted for patients completing treatment from 2014 to 2020. Detailed treatment information was available for all MRIdian linear accelerator (linac) systems and some cobalt systems. Results: Seventeen systems at 16 centers delivered 5736 courses and 36,389 fractions (fraction details unavailable for 1223 cobalt courses), of which 21.1% were adapted. Ultra-hypofractionation (UHfx) (1-5 fractions) was used in 70.3% of all courses. At least one adaptive fraction was used for 38.5% of courses (average 1.7 adapted fractions/course), with higher oART use in UHfx dose schedules (47.7% of courses, average 1.9 adapted fractions per course). The most commonly treated organ sites were pancreas (20.7%), liver (16.5%), prostate (12.5%), breast (11.5%), and lung (9.4%). Temporal trends show a compounded annual growth rate (CAGR) of 59.6% in treatment courses delivered, with a dramatic increase in use of UHfx to 84.9% of courses in 2020 and similar increase in use of oART to 51.0% of courses. Conclusions: This is the first comprehensive study reporting patterns of utilization among early adopters of MRIdian in the US. Intrafraction MR image-guidance, advanced motion management, and increasing adoption of adaptive radiation therapy has led to a substantial transition to ultra-hypofractionated regimens. 0.35 T-MRgRT has been predominantly used to treat abdominal and pelvic tumors with increasing use of on-table adaptive replanning, which represents a paradigm shift in radiation therapy.

Transoral robotic surgery and neck dissection for HPV-positive oropharyngeal carcinoma: Importance of nodal count in survival.

BACKGROUND: In this study we determine the survival in patients with HPV-positive oropharyngeal carcinoma treated with transoral robotic surgery (TORS), neck dissection and risk-adapted adjuvant therapy. METHODS: We retrospectively identified 122 patients with HPV-positive oropharyngeal carcinoma treated with TORS and neck dissection between 2011 and 2018. Survival probability was calculated. We determined the effect of the type of neck dissection performed (modified radical neck dissection-MRND vs. selective neck dissection - SND), extranodal extension (ENE), margin status, and presence of ≥ 5 metastatic nodes on survival. RESULTS: Our patient population had a five-year overall survival of 91.0% (95% C.I. 85-97%). The five-year probability of recurrence or cancer-associated death was 0.0977 (95% C.I. 0.0927-0.1027). The five-year probability of cancer-associated death was 0.0528 (95% C.I. 0.048-0.0570). All patients who died of their disease had distant metastasis. Our PEG dependence rate was 0%. Patients with ENE and positive margins who underwent adjuvant chemoradiation did not have worse survival. Presence of ≥ 5 metastatic nodes portended worse survival after controlling for age, positive ENE and margins. Low yield (<18 nodes) on neck dissection worsened DFS on multivariable analysis. Furthermore, patients who underwent SND did not have worse OS than those who underwent MRND. CONCLUSION: Our study demonstrates that surgery could be simplified by performing TORS with SND rather than MRND. The one true poor prognostic factor in HPV-positive oropharyngeal carcinoma patients who undergo surgery is high nodal burden. Patients with high nodal burden are much more likely to die from their disease.

Randomized phase II study of stereotactic body radiotherapy and interleukin-2 versus interleukin-2 in patients with metastatic melanoma.

BACKGROUND: A pilot study of stereotactic body radiation therapy (SBRT) followed by high-dose interleukin-2 (IL-2) showed a higher than anticipated objective response rate (ORR) among patients with metastatic melanoma (MM). We performed a prospective randomized study to determine if the ORR of SBRT + IL-2 was greater than IL-2 monotherapy in patients with advanced melanoma. METHODS: Patients with MM who had adequate physiological reserve for IL-2 and at least one site suitable for SBRT were eligible. There was a 1:1 randomization to SBRT + IL-2 or IL-2 monotherapy. Patients received one or two doses of SBRT (20 Gy per fraction) with the last dose administered 3 days before starting the first cycle of IL-2. IL-2 (600,000 IU per kg via intravenous bolus infusion) was given every 8 hours for a maximum of 14 doses with a second cycle after a 2-week rest. Responding patients received up to six IL-2 cycles. Patients assigned to IL-2 monotherapy who exhibited progression of melanoma after cycle 2 were allowed to crossover and receive SBRT and additional IL-2. Response Evaluation Criteria in Solid Tumors 1.1 criteria were applied to non-irradiated lesions for response assessment. RESULTS: 44 patients were included in the analysis. The ORR in the SBRT + IL-2 group was 54%: 21% complete response (CR), 33% partial response (PR), 21% stable disease (SD) and 25% progressive disease (PD). The ORR in patients receiving IL-2 monotherapy was 35%: 15% CR, 20% PR, 25% SD and 40% PD. Seven patients assigned to IL-2 subsequently received SBRT + IL-2. One CR and two PRs were observed in the crossover group. There was no difference in progression-free or overall survival (OS). At 5 years the OS was 26% in the SBRT + IL-2 group and 25% in the IL-2 monotherapy group. The disease control rate (DCR) was higher in the SBRT + IL-2 group (75% vs 60%, p=0.34). CONCLUSIONS: SBRT + IL-2 induced more objective responses with a higher DCR compared to IL-2 monotherapy in MM. IL-2 monotherapy resulted in a significantly higher ORR than anticipated. Some patients in the crossover group also achieved objective responses. TRIAL REGISTRATION NUMBER: NCT01416831.

Cytoreductive surgery for head and neck squamous cell carcinoma in the new age of immunotherapy.

Cytoreductive surgery is an approach to cancer treatment that aims to reduce the number of cancer cells via resection of primary tumor or metastatic deposits, in an effort to minimize a potentially immunosuppressive tumor burden, palliate symptoms, and prevent complications. Furthermore, it provides a platform for investigation of biomarkers with the goal of optimizing immunotherapy to reverse the immunosuppressive tumor microenvironment and enhance adaptive immune responses. Ultimately, our group aims to exploit the concept that successful cancer therapy is dependent upon an effective immune response. Surgery will remain an integral part of head and neck squamous cell carcinoma (HNSCC) treatment in the future, even as checkpoint inhibitors, co-stimulatory molecules, vaccines, adoptive T cell therapy and other novel agents enter clinical routine. Cytoreductive resection may provide an effective platform for immunotherapy and biomarker directed interventions to improve outcomes for patients with HNSCC.

American College of Radiology (ACR) and American Society for Radiation Oncology (ASTRO) Practice Guideline for the Performance of Stereotactic Radiosurgery (SRS).

American College of Radiology and American Society for Radiation Oncology Practice Guideline for the Performance of Stereotactic Radiosurgery (SRS). SRS is a safe and efficacious treatment option of a variety of benign and malignant disorders involving intracranial structures and selected extracranial lesions. SRS involves a high dose of ionizing radiation with a high degree of precision and spatial accuracy. A quality SRS program requires a multidisciplinary team involved in the patient management. Organization, appropriate staffing, and careful adherence to detail and to established SRS standards is important to ensure operational efficiency and to improve the likelihood of procedural success. A collaborative effort of the American College of Radiology and American Society for Therapeutic Radiation Oncology has produced a practice guideline for SRS. The guideline defines the qualifications and responsibilities of all the involved personnel, including the radiation oncologist, neurosurgeon, and qualified medical physicist. Quality assurance is essential for safe and accurate delivery of treatment with SRS. Quality assurance issues for the treatment unit, stereotactic accessories, medical imaging, and treatment-planning system are presented and discussed. Adherence to these practice guidelines can be part of ensuring quality and patient safety in a successful SRS program.

Radiation and immunotherapy: Renewed allies in the war on cancer.

Anticancer immunotherapy holds great promises, as long-term responses to interleukin-2 have been observed in metastatic melanoma and renal cell carcinoma patients. However, improving the relative low rates of such responses has constituted a great challenge. In our experience, high-dose radiation combined with interleukin-2 provided encouraging results that are worth exploring further.

Phase 1 study of stereotactic body radiotherapy and interleukin-2--tumor and immunological responses.

Preclinical models suggest that focal high-dose radiation can make tumors more immunogenic. We performed a pilot study of stereotactic body radiation therapy (SBRT) followed by high-dose interleukin-2 (IL-2) to assess safety and tumor response rate and perform exploratory immune monitoring studies. Patients with metastatic melanoma or renal cell carcinoma (RCC) who had received no previous medical therapy for metastatic disease were eligible. Patients received one, two, or three doses of SBRT (20 Gy per fraction) with the last dose administered 3 days before starting IL-2. IL-2 (600,000 IU per kilogram by means of intravenous bolus infusion) was given every 8 hours for a maximum of 14 doses with a second cycle after a 2-week rest. Patients with regressing disease received up to six IL-2 cycles. Twelve patients were included in the intent-to-treat analysis, and 11 completed treatment per the study design. Response Evaluation Criteria in Solid Tumors criteria were used to assess overall response in nonirradiated target lesions. Eight of 12 patients (66.6%) achieved a complete (CR) or partial response (PR) (1 CR and 7 PR). Six of the patients with PR on computed tomography had a CR by positron emission tomography imaging. Five of seven (71.4%) patients with melanoma had a PR or CR, and three of five (60%) with RCC had a PR. Immune monitoring showed a statistically significantly greater frequency of proliferating CD4(+) T cells with an early activated effector memory phenotype (CD3(+)CD4(+)Ki67(+)CD25(+)FoxP3(-)CCR7(-)CD45RA(-)CD27(+)CD28(+/-)) in the peripheral blood of responding patients. SBRT and IL-2 can be administered safely. Because the response rate in patients with melanoma was significantly higher than expected on the basis of historical data, we believe that the combination and investigation of CD4(+) effector memory T cells as a predictor of response warrant further study.

Adjuvant therapy with agonistic antibodies to CD134 (OX40) increases local control after surgical or radiation therapy of cancer in mice.

The tumor recurrence from residual local or micrometastatic disease remains a problem in cancer therapy. In patients with soft tissue sarcoma and the patients with inoperable nonsmall cell lung cancer, local recurrence is common and significant mortality is caused by the subsequent emergence of metastatic disease. Thus, although the aim of the primary therapy is curative, the outcome may be improved by additional targeting of residual microscopic disease. We display in a murine model that surgical removal of a large primary sarcoma results in local recurrence in approximately 50% of animals. Depletion of CD8 T cells results in local recurrence in 100% of animals, indicating that these cells are involved in the control of residual disease. We further show that systemic adjuvant administration of αOX40 at surgery eliminates local recurrences. In this model, αOX40 acts to directly enhance tumor antigen-specific CD8 T-cell proliferation in the lymph node draining the surgical site, and results in increased tumor antigen-specific cytotoxicity in vivo. These results are also corroborated in a murine model of hypofractionated radiation therapy of lung cancer. Administration of αOX40 in combination with radiation significantly extended the survival compared with either agent alone, and resulted in a significant proportion of long-term tumor-free survivors. We conclude that αOX40 increases tumor antigen-specific CD8 T-cell cytotoxic activity resulting in improved endogenous immune control of residual microscopic disease, and we propose that adjuvant αOX40 administration may be a valuable addition to surgical and radiation therapy for cancer.

Phase II trial of combined modality therapy with concurrent topotecan plus radiotherapy followed by consolidation chemotherapy for unresectable stage III and selected stage IV non-small-lung cancer.

PURPOSE: The optimal combination of chemotherapy and radiotherapy (RT) and the role of consolidation chemotherapy in patients with locally advanced non-small-cell lung cancer (NSCLC) are unknown. Topotecan is active against NSCLC, can safely be combined with RT at effective systemic doses, and can be given by continuous infusion, making it an attractive study agent against locally advanced NSCLC. METHODS AND MATERIALS: In this pilot study, 20 patients were treated with infusion topotecan 0.4 mg/m(2)/d with three-dimensional conformal RT to 63 Gy both delivered Monday through Friday for 7 weeks. Patients without progression underwent consolidation chemotherapy with etoposide and a platinum agent for one cycle followed by two cycles of docetaxel. The study endpoints were treatment response, time to progression, survival, and toxicity. RESULTS: Of the 20 patients, 19 completed induction chemoradiotherapy and 13 completed consolidation. Of the 20 patients, 18 had a partial response and 1 had stable disease after induction chemoradiotherapy. The 3-year overall survival rate was 32% (median, 18 months). The local and distant progression-free survival rate was 30% (median, 21 months) and 58% (median, not reached), respectively. Three patients developed central nervous system metastases, 1 within 228 days, 1 within 252 days, and 1 within 588 days. Three patients had pulmonary emboli. Therapy was well tolerated with 1 of 20 developing Grade 4 lymphopenia. Grade 3 hematologic toxicity was seen in 17 of 20 patients but was not clinically significant. Other Grade 3 toxicities included esophagitis in 3, esophageal stricture in 2, fatigue in 8, and weight loss in 1. Grade 3 pneumonitis occurred in 6 of 20 patients. CONCLUSION: Continuous infusion topotecan with RT was well tolerated and active in the treatment of poor-risk patients with unresectable Stage III NSCLC.

Intensity-modulated radiotherapy for head-and-neck cancer in the community setting.

PURPOSE: To review outcomes with intensity-modulated radiation therapy (IMRT) in the community setting for the treatment of nasopharyngeal and oropharyngeal cancer. METHODS AND MATERIALS: Between April 2003 and April 2007, 69 patients with histologically confirmed cancer of the nasopharynx and oropharynx underwent IMRT in our practice. The primary sites included nasopharynx (11), base of tongue (18), and tonsil (40). The disease stage distribution was as follows: 2 Stage I, 11 Stage II, 16 Stage III, and 40 Stage IV. All were treated with a simultaneous integrated boost IMRT technique. The median prescribed doses were 70 Gy to the planning target volume, 59.4 Gy to the high-risk subclinical volume, and 54 Gy to the low-risk subclinical volume. Forty-five patients (65%) received concurrent chemotherapy. Toxicity was graded according to the Radiation Therapy Oncology Group toxicity criteria. Progression-free and overall survival rates were estimated with the Kaplan-Meier product-limit method. RESULTS: Median duration of follow-up was 18 months. The estimated 2-year local control, regional control, distant control, and overall survival rates were 98%, 100%, 98%, and 90%, respectively. The most common acute toxicities were dermatitis (32 Grade 1, 32 Grade 2, 5 Grade 3), mucositis (8 Grade 1, 33 Grade 2, 28 Grade 3), and xerostomia (0 Grade 1, 29 Grade 2, 40 Grade 3). CONCLUSIONS: Intensity-modulated radiotherapy in the community setting can be accomplished safely and effectively. Systematic internal review systems are recommended for quality control until sufficient experience develops.

Selective dose escalation of chemoradiotherapy for esophageal cancer: role of treatment intensification.

This ongoing phase II study is designed to assess the outcomes (survival and failure patterns) of therapy for localized esophageal cancer with conventional dose radiation (50.4 Gy) with concurrent continuous infusion 5-fluorouracil (5-FU) and weekly carboplatin/paclitaxel. Patients with less than complete response or partial response received dose escalation of radiation to 59.4 Gy with the same chemotherapy. This report details the results of the first 18 patients treated. From July 2000 to June 2003, we prospectively enrolled 18 patients with T1-4, N0-1, M0-1a esophageal carcinoma to receive paclitaxel 45 mg/m 2 intravenously over 1 hour and carboplatin AUC 2 intravenously over 30 minutes on days 1, 8, 15, 22, 29, and 36. 5-Fluorouracil 225 mg/m2 was delivered as a continuous infusion on days 1 through 38. Radiation therapy was given 1.8 Gy x 5 days/week x 5.5 weeks (50.4 Gy in 28 fractions). After 6 to 8 weeks, patients underwent repeat staging with computed tomography scan, endoscopic ultrasound, and biopsy. Patients with a positive biopsy, or less than partial response by computed tomography and endoscopic ultrasound, received a boost of 9 Gy with the same concurrent chemotherapy. Patients were followed every 4 months with computed tomography/endoscopic ultrasound the first year and every 6 months thereafter. Median follow-up was 19 months. Eleven of 18 patients (61.1%) attained a complete response/partial response; six of 18 (33.3%) received a boost. Overall survival was 30% at 3 years, with a median of 25 months. Patients with less than 10% pretreatment weight loss had an overall survival of 36% with a median of 26 months. In patients with more than 10% pretreatment weight loss, median survival was 14 months with 0% surviving at 2 years. Local/regional control was 67% (no-boost patients [78%]; boost patients [40%]). Progression-free survival was 31% at 3 years, with a median of 14 months. Distant metastasis-free survival was 40% at 3 years, with a median of 27 months. Seventy-nine percent of patients required at least one dose reduction in chemotherapy because of toxicities. Radiation delays ranged from 0 to 62 days, with a median of 7 days. Grade 2/3 acute esophagitis was experienced by 89% and 39% of patients, respectively; 28% of patients developed esophageal strictures requiring dilatations. The combination of continuous-infusion 5-FU and weekly carboplatin/paclitaxel with selective radiation dose escalation yields promising results without surgery and adjuvant chemotherapy. The toxicities of therapy, while manageable, were significant.