[INTRAOPERATIVE RADIOTHERAPY FOR EARLY BREAST CANCER - THE SHEBA EXPERIENCE AND EARLY OUTCOMES].

AIMS: This study presents our experience with Intra-Operative Electron Radio-Therapy (IOeRT) using a mobile linear accelerator at the Sheba Medical Center. BACKGROUND: Intraoperative radiotherapy is an alternative approach of partial breast irradiation for patients with early breast cancer and low risk for local recurrence who are undergoing breast conservation surgery. METHODS: Patients were selected by a multidisciplinary team according to ASTRO\GEC-ESTRO guidelines for partial breast irradiation. IOeRT was administered using SIT LIAC HWL®. RESULTS: A total of 28 patients were referred for breast conservation surgery and IOeRT between 8/2019 and 10/2020; 27/28 received IOeRT. In one patient, radiation was aborted due to anaphylactic shock in response to patent blue dye injected for sentinel node identification. Larger than usual seroma were reported on the first post-operative visit in all patients, and regressed spontaneously in 3-6 months. Infected seroma developed post-operatively in 5 patients, requiring surgical drainage in 2 patients. Final pathology matched the preoperative biopsy. There were no cases of pathology upstaging requiring additional adjuvant irradiation or chemotherapy. The patient who did not receive IOeRT was treated with adjuvant external radiotherapy. CONCLUSIONS: IOeRT is a safe alternative to partial breast irradiation, with a slight increase of postoperative infection rate.

A Phase I clinical trial of dose-escalated metabolic therapy combined with concomitant radiation therapy in high-grade glioma.

BACKGROUND: Animal brain-tumor models have demonstrated a synergistic interaction between radiation therapy and a ketogenic diet (KD). Metformin has in-vitro anti-cancer activity, through AMPK activation and mTOR inhibition. We hypothesized that the metabolic stress induced by a KD combined with metformin would enhance radiation's efficacy. We sought to assess the tolerability and feasibility of this approach. METHODS: A single-institution phase I clinical trial. Radiotherapy was either 60 or 35 Gy over 6 or 2 weeks, for newly diagnosed and recurrent gliomas, respectively. The dietary intervention consisted of a Modified Atkins Diet (ModAD) supplemented with medium chain triglycerides (MCT). There were three cohorts: Dietary intervention alone, and dietary intervention combined with low-dose or high-dose metformin; all patients received radiotherapy. Factors associated with blood ketone levels were investigated using a mixed-model analysis. RESULTS: A total of 13 patients were accrued, median age 61 years, of whom six had newly diagnosed and seven with recurrent disease. All completed radiation therapy; five patients stopped the metabolic intervention early. Metformin 850 mg three-times daily was poorly tolerated. There were no serious adverse events. Ketone levels were associated with dietary factors (ketogenic ratio, p < 0.001), use of metformin (p = 0. 02) and low insulin levels (p = 0.002). Median progression free survival was ten and four months for newly diagnosed and recurrent disease, respectively. CONCLUSIONS: The intervention was well tolerated. Higher serum ketone levels were associated with both dietary intake and metformin use. The recommended phase II dose is eight weeks of a ModAD combined with 850 mg metformin twice daily.

COVID-RO study: the radiation oncology practice at times of COVID-19 outbreak - international survey.

BACKGROUND: Radiation therapy (RT), an essential treatment of cancer, involves multiple hospital visits. We hypothesized that radiation departments would adjust their work patterns and RT protocols in response to the SARS-CoV-2 pandemic. MATERIALS AND METHODS: An electronic survey was sent during April 2020 to an international sample of radiation oncologists. The survey explored various aspects of departmental preparedness, and changes to their institutional RT protocols. RESULTS: A total of 68 radiation oncologists from 13 countries answered the survey. Healthcare systems were at least moderately affected in 76%. Most institutes appeared well prepared for the outbreak: regarding the availability of personal protective equipment, tests, and telemedicine/videoconference facilities. Screening for SARS-CoV-2 was applied in 59% of responders. Modification of RT protocols were minor in 66%, significant in 19% and no changes made in 15%. The extent to which protocols were modified correlated with overall healthcare disruption (p = 0.028). Normal fractionation was recommended to continue in 83% and 85% of head & neck, and cervical cancers vs. 64% of lung cancers (p = 0.001).In case the pandemic worsens, there was strong agreement to prioritize RT for aggressive cancers (80%), delay RT for slow-growing tumors (78%) and change to evidance-based hypofractionations protocols (79.4%). The option of delayed/omitted adjuvant RT (not site specific) was selected in 47%. CONCLUSION: This international survey concludes that, by making significant organizational adjustments and minor protocol modifications, RT may be safely continued during this pandemic. If the crisis worsens, there was strong agreement to continue the treatment of aggressive tumors and utilize evidence-based hypofractionated protocols.

PSMA PET/CT to evaluate response to SBRT for prostate cancer bone metastases.

BACKGROUND: In the current study we evaluated 68Ga PSMA PET/ CT to measure local control of bone metastasis in oligometastatic prostate cancer patients treated with SBRT. MATERIALS AND METHODS: After the institutional review board approval, a retrospective review of medical records of consecutive prostate cancer patients treated between 2014 and 2018 was conducted. Only medical records of patients that were treated with SBRT for bone metastasis and had pre-and post-SBRT 68Ga PSMA PET/CT scans were included in our study. Data extracted from the medical files included patient-related (age), disease-related (Gleason score, site of metastasis), and treatment-related factors and outcomes. RESULTS: During the study period, a total of 12 patients (15 lesions) were included, with a median age of 73 years. The median follow-up was 26.5 months (range 13-45 months). Median time of 68Ga PSMA PET/ CT follow up was 17.0 months (range 3-39 months). The median pre-treatment PSA was 2 ng/mL (range 0.56-44 ng/mL) vs. post treatment PSA nadir of 0.01 ng/mL (0.01-4.32) with a median time to nadir of 7 months (range, 2-12). Local control was 93% during the follow up period and there was correlation with PS MA avidity on PE T. None patients developed recurrences in the treated bone. None of the patients had grade 3 or more toxicities during follow-up. CONCLUSIONS: SBRT is a highly effective and safe method for treatment of prostate cancer bone metastases. More studies are required to determine if SBRT provides greater clinical benefit than standard fractionation for oligometastatic prostate cancer patients. 68Ga PSMA PET/CT should be further investigated for delineation and follow-up.

Local recurrence of breast cancer: Salvage lumpectomy as an option for local treatment.

INTRODUCTION: The best local management for breast cancer recurrence following conservative treatment for breast cancer (BC) continues to be an open question. In this study, we compared patients' outcome after salvage lumpectomy (SL) vs mastectomy for ipsilateral breast tumor recurrence (IBTR). MATERIALS AND METHODS: Between 1987 and 2014 we identified 121 patients with pT0-2, N0-3, M0 BC who had BCT as their primary treatment, and subsequently had IBTR (unifocal). 47 patients underwent SL and 74 salvage mastectomy (SM) as the local treatment for their 1st recurrence. RESULTS: Median follow-up was 14 years (1-30) from first BC diagnosis. For the SL and SM cohorts, 8 and 10 patients (17%, 13.5%, P = 0.22), respectively, developed subsequent local recurrence as a 3rd event. Although in MVA, woman who underwent SL had higher chances of having a 2nd recurrence (3rd event), P = 0.020, at a median follow-up of 14 years, 95.8% of SL patients are alive, NED, 85% are mastectomy free. 87% of patients who opted for SM are alive, NED. Having re-irradiation following SL did not protect against 2nd breast cancer recurrence (3rd event, P = 0.42). CONCLUSION: Salvage lumpectomy following IBTR, while associated with higher second LR rate than SM is not associated with inferior outcome. With survival >95% at 14 years in the SL cohort, salvage lumpectomy with or without re-radiation, in a selected population (unifocal T), represents an acceptable treatment option for patients in order to delay time to mastectomy without reducing BC survival. Both options should be discussed prior to any surgical decision.

RPM Inspiration Gating: Improving Radiotherapy for Left Breast Cancer Patients with Anterior Heart Position.

BACKGROUND: Adjuvant radiotherapy for breast cancer reduces local recurrence and improves survival. In patients with left sided breast cancer, anterior heart position or medial tumor location may cause inadequate breast coverage due to heart shielding. Respiration gating using the Real-time Position Management (RPM) system enables pushing the heart away from the tangential fields during inspiration, thus optimizing the treatment plan. OBJECTIVES: To compare breathing inspiration gating (IG) techniques with free breathing (FB), focusing on breast coverage. METHODS: The study comprised 49 consecutive patients with left sided breast cancer who underwent lumpectomy and adjuvant radiation. RPM was chosen due to insufficient breast coverage caused by an anterior heart position or medial lumpectomy cavity. FB and IG computed tomography simulations were generated for each patient. Breast (PTVbreast) and lumpectomy cavity (CTVlump) were defined as the target areas. Optimized treatment plans were created for each scan. A dosimetric comparison was made for breast coverage and heart and lungs doses. RESULTS: PTVbreast V95% and mean dose (Dmean) were higher with IG vs. FB (82.36% vs. 78.88%, P = 0.002; 95.73% vs. 93.63%, P < 0.001, respectively). CTVlump V95% and Dmean were higher with IG (98.87% vs. 88.92%, P = 0.001; 99.14% vs. 96.73%, P = 0.003, respectively). The cardiac dose was lower with IG. The IG left lung Dmean was higher. No statistical difference was found for left lung V20. CONCLUSIONS: In patients with suboptimal treatment plans due to anterior heart position or medial lumpectomy cavity, RPM IG enabled better breast/tumor bed coverage and reduced cardiac doses.

Salvage Radiation Therapy for Biochemical Failure Following Radical Prostatectomy.

BACKGROUND: Radiotherapy to the prostate bed is used to eradicate residual microscopic disease following radical prostatectomy for prostate cancer. Recommendations are based on historical series. OBJECTIVES: To determine outcomes and toxicity of contemporary salvage radiation therapy (SRT) to the prostate bed. METHODS: We reviewed a prospective ethics committee-approved database of 229 patients referred for SRT. Median pre-radiation prostate-specific antigen (PSA) was 0.5 ng/ml and median follow-up was 50.4 months (range 13.7-128). Treatment was planned and delivered using modern three-dimensional radiation techniques. Mean bioequivalent dose was 71 Gy (range 64-83 Gy). Progression was defined as two consecutive increases in PSA level > 0.2 ng/ml, metastases on follow-up imaging, commencement of anti-androgen treatment for any reason, or death from prostate cancer. Kaplan-Meier survival estimates and multivariate analysis was performed using STATA. RESULTS: Five year progression-free survival was 68% (95%CI 59.8-74.8%), and stratified by PSA was 87%, 70% and 47% for PSA < 0.3, 0.3-0.7, and > 0.7 ng/ml (P < 0.001). Metastasis-free survival was 92.5%, prostate cancer-specific survival 96.4%, and overall survival 94.9%. Low pre-radiation PSA value was the most important predictor of progression-free survival (HR 2.76, P < 0.001). Daily image guidance was associated with reduced risk of gastrointestinal and genitourinary toxicity (P < 0.005). CONCLUSIONS: Contemporary SRT is associated with favorable outcomes. Early initiation of SRT at PSA < 0.3 ng/ml improves progression-free survival. Daily image guidance with online correction is associated with a decreased incidence of late toxicity.

Stereotactic Ablative Body Radiation for Stage I Lung Cancer in Israel: A Retrospective Single-Center Report.

BACKGROUND: Stereotactic ablative radiation therapy (SABR) is the application of a very high radiation dose to a small treatment volume. It is the new standard of care in medically inoperable early-stage lung cancer. OBJECTIVES: To report the outcomes of SABR in stage I lung cancer at Sheba Medical Center since its introduction in 2009. METHODS: We conducted a retrospective chart review of patients with stage I lung cancer treated during the period 2009-2015. Survival status was retrieved from the electronic medical records and confirmed with the national registry. Local failure was defined as increased FDG uptake on PETCT scan within a 2 cm radius of the treated region. Toxicity was estimated from medical records and graded according to common toxicity criteria for adverse events (CTCAE) version 4.03. Overall survival and local control were estimated by the Kaplan-Meier method. RESULTS: During the study period 114 patients were treated for 122 stage I lung cancer lesions. Median follow-up time was 27 months (range 8.2-69.5 months), median age was 76 years. Eighty-two percent of the tumors were stage IA (size ≤ 3 cm). Median survival was 46 months; estimated 3 year overall survival was 59% (95%CI 47-69%) and local control was 88% (95%CI 78-94%). Toxicity included chest wall pain in 8.4% of patients, rib fracture in 0.9%, grade 1-2 pneumonitis in 12%, grade 3 in 12% and grade 5 (death) in 0.9%. CONCLUSIONS: SABR has been successfully implemented at Sheba Medical Center for the treatment of stage I lung cancer in inoperable patients. It is associated with excellent local control, minor toxicity and an acceptable overall survival.

Neo-adjuvant Chemo-Radiation to 60 Gray Followed by Surgery for Locally Advanced Non-Small Cell Lung Cancer Patients: Evaluation of Trimodality Strategy.

BACKGROUND: Neoadjuvant chemo-radiation therapy (CRT) dosages in locally advanced non-small cell lung cancer (NSCLC) were traditionally limited to 45 Gray (Gy). OBJECTIVES: To retrospectively analyze outcomes of patients treated with 60 Gy CRT followed by surgery. METHODS: A retrospective chart review identified patients selected for CRT to 60 Gy followed by surgery between August 2012 and April 2016. Selection for surgery was based on the extent of disease, cardiopulmonary function, and response to treatment. Pathological response after neoadjuvant CRT was scored using the modified tumor regression grading. Local control (LC), disease free survival (DFS), and overall survival (OS) were estimated by the Kaplan-Meier method. RESULTS: Our cohort included 52 patients: 75% (39/52) were stage IIIA. A radiation dose of 60 Gy (range 50-62Gy) was delivered in 82.7%. Surgeries performed included: lobectomy, chest-wall resection, and pneumonectomy in 67.3%, 13.4%, and 19.2%, respectively. At median follow-up of 22.4 months, the 3 year OS was 74% (95% confidence interval [CI] 52-87%), LC was 84% (95%CI 65-93), and DFS 35% (95%CI 14-59). Grade 4-5 postoperative complications were observed in 17.3% of cases and included chest wall necrosis (5.7%), bronco-pleural fistula (7.7%), and death (3.8%). A major pathologic regression with < 10% residual tumor occurred in 68.7% of patients (36/52) and showed a trend to improved OS (P = 0.1). Pneumonectomy cases had statistically worse OS (P = 0.01). CONCLUSIONS: Major pathologic regression was observed 68.7% with 60 Gy neoadjuvant CRT with a trend to improved survival. Pneumonectomy correlated with worse survival.

Impact of Androgen Deprivation Therapy on Sexual and Hormonal Function in Patients Receiving Radiation Therapy for Prostate Cancer.

BACKGROUND: Androgen deprivation therapy (ADT) added to radiation therapy (RT) in intermediate to high risk prostate cancer negatively impacts quality of life. OBJECTIVES: To compare health-related quality of life (HR-QOL) in patients receiving combined RT with and without ADT METHODS: The study population comprised patients treated with definitive RT for prostate cancer who completed the Expanded Prostate Cancer Index Composite-26 form between 3 and 24 months after completing RT. Covariance and a stepwise backward logistic regression model was used. RESULTS: Data were available for 143 patients who received RT+ADT and 70 who received RT alone. The sexual function and hormonal vitality scores of patients receiving RT+ADT were significantly lower than those receiving RT alone (P < 0.0001). Patients with only compulsory school education had significantly lower sexual function scores than patients with university level education (P ≤ 0.005). Patients with depression had significantly lower hormonal vitality scores than those without depression (P ≤ 0.0001). CONCLUSIONS: The addition of ADT to RT is responsible for decrements in quality of life in the sexual and hormonal vitality domains, which is further compounded by depression and lack of education. This underlines the need to improve education, identify and treat depression, and develop strategies to improve the quality of life of patients receiving combination therapy.

[STEREOTACTIC ABLATIVE BODY RADIATION -SABR: A NEW THERAPEUTIC OPTION FOR TREATMENT OF STAGE I LUNG CANCER].

INTRODUCTION: Stereotactic ablative radiotherapy (SABR) also known as stereotactic body radiation therapy (SBRT) offers a new therapeutic option for stage 1 lung cancer that cannot undergo surgery due to co-morbidities or patient refusal. This treatment evolved in the last decade thanks to technologic advancement of radiation therapy planning and delivery that allow real time imaging of the tumor and real time position correction before every treatment. Ultra high doses of radiation cause ablation of the target with very low collateral scatter dose to surrounding tissue. Numerous phase I/II trials and institutional series have demonstrated efficacy of this treatment with over 90% control of tumors of 3 cm or less and 80-85% for larger tumors, very similar to surgical results. Data from trials have driven guidelines for safe administration, thus, when properly administered, toxicity is minimal. SABR treatment is administered routinely at the Chaim Sheba Medical Center and in other radiation centers in Israel.

Association between variants of 5-hydroxytryptamine receptor 3C (HTR3C) and chemotherapy-induced symptoms in women receiving adjuvant treatment for breast cancer.

Administration of chemotherapy is associated with a wide array of symptoms affecting quality of life. Genetic risk factors for severity of chemotherapy-induced symptoms have not been determined. The present study aimed to explore the associations between polymorphisms in candidate genes and chemotherapy-induced symptoms. Women treated with at least two cycles of adjuvant doxorubicin and cyclophosphamide, with or without paclitaxel for early breast cancer (n = 105) completed the memorial symptom assessment scale and provided blood for genotyping. DNA was extracted from peripheral blood leukocytes and assayed for single nucleotide polymorphisms (SNPs) in GTP cyclohydrolase 1 (GCH1, rs10483639, rs3783641, and rs8007267), catecholamine-o-methyltransferase (COMT, rs4818), and 5-hydroxytryptamine (serotonin) receptor 3C (HTR3C, rs6766410, and rs6807362). Genotyping of HTR3C revealed a significant association between the presence of rs6766410 and rs6807362 SNPs (K163 and G405 variants) and increased severity of symptoms (p = 0.0001 and p = 0.007, respectively). Multiple regressions revealed that rs6766410 and rs6807362, but not age or stage at diagnosis, predicted severity of symptoms (p = 0.001 and p = 0.006, respectively) and explained 12 % of the variance in each regression model. No association was found between the genetic variants of CGH1 or COMT and symptom score. Our study indicates, for the first time, an association between variants of HTR3C and severity of chemotherapy-induced symptoms. Analyzing these genetic variants may identify patients at increased risk for the development of chemotherapy-induced symptoms and targeting the serotonin pathway may serve as a novel treatment strategy for these patients.

Total dose, fraction dose and respiratory motion management impact adrenal SBRT outcome.

Purpose/Objectives: Stereotactic body radiotherapy (SBRT) is an effective treatment for oligometastatic disease in multiple sites. However, the optimal radiation dose for long-term local control of adrenal metastases has yet to be determined. The aim of this study is to evaluate outcomes of adrenal SBRT and to evaluate factors that correlate with local control. Materials/Methods: After IRB approval, a retrospective data review of patients treated with SBRT for adrenal metastases at a medical center in Israel between 2015 and 2021 was conducted. A biological effective dose was calculated using an alpha beta ratio of 10. Kaplan Meier and Cox regression were calculated using SPSS software to describe the hazard ratio for local control and survival. Results: 83 cases of adrenal SBRT were identified. The average age was 67 (range 42-92 years old). Non-small cell lung cancer was the primary site in 44 % of patients. A total of 70 % of the patients had oligometastatic disease (less than five lesions), and the rest were polymetastatic, responding to systemic therapy with oligo progression in the adrenal. The average gross tumor volume (GTV) was 42 ml. Respiratory control was applied in 88 % of cases; 49.3 % used 4-D/ITV, and 38.5 % used breath-hold or continuous positive airway pressure (CPAP) with free breathing. On multivariable analysis, Dose above 75 Gy (biological effective Dose) (HR = 0.41, p = 0.031), Dose above 8 Gy per fraction (HR = 0.53p = 0.038), and breath-holds or CPAP (HR = 0.65, p = 0.047) were significant for local control. From multivariable analysis, we computed a predicted nomogram curve using seven clinical parameters to evaluate local control odds. Conclusion: In this single institution series reported to date, we found unilateral adrenal SBRT safe, yet bilateral treatment harbors a risk of adrenal insufficiency. Biological effective Dose > 75 Gy (BED), motion management with breath-hold or CPAP, and Dose per fraction > 8 Gy were the enhanced local controls. We propose a nomogram to help in decision-making regarding total Dose and Dose per fraction when treating adrenal SBRT.

Urethra-Sparing Prostate Cancer Stereotactic Body Radiation Therapy: Sexual Function and Radiation Dose to the Penile Bulb, the Crura, and the Internal Pudendal Arteries From a Randomized Phase 2 Trial.

PURPOSE: Erectile dysfunction (ED) is a common side effect after prostate cancer stereotactic body radiation therapy (SBRT). We aimed to assess the correlation between the dose to the penile bulb (PB), internal pudendal arteries (IPA), and crura with the development of ED after ultrahypofractionation as part of a phase 2 clinical trial of urethra-sparing prostate SBRT. METHODS AND MATERIALS: Among the 170 patients with localized prostate cancer from 9 centers included in the trial, 90 men with Common Terminology Criteria for Adverse Events version 4.03 grade 0 to 1 ED (ED-) at baseline treated with 36.25 Gy in 5 fractions were selected for the present analysis. Doses delivered to the PB, crura, and IPA were analyzed and correlated with grade 2 to 3 ED (ED+) development. The effect on quality of life, assessed by the European Organisation for Research and Treatment of Cancer (EORTC QLQ-PR25) questionnaire, was reported. RESULTS: After a median follow-up of 6.5 years, 43% (n = 39) of the patients developed ED+, and 57% (n = 51) remained ED-. The dose delivered to the crura was significantly higher in ED+ patients than in ED- patients (7.7 vs 3.6 Gy [P = .014] for the Dmean and 18.5 vs 7.2 Gy [P = .015] for the D2%, respectively). No statistically significant difference between ED+ and ED- patients was observed for the dose delivered to the PB and IPA. The median ED+-free survival was worse in patients receiving a crura Dmean ≥ 4.7 versus < 4.7 Gy (51.5% vs 71.7%, P = .005) and a crura D2% > 12 versus ≤ 12 Gy (54.9% vs 68.9%, P = .015). No ED+-free survival differences were observed for doses delivered to the PB and IPA. Decline in EORTC QLQ-PR25 sexual functioning was significantly more pronounced in patients with higher doses to the crura. CONCLUSIONS: By keeping a Dmean and D2% to crura below 4.7 and 12 Gy, respectively, the risk of developing ED+ after prostate SBRT may be significantly reduced.

CX3CR1-Expressing Immune Cells Infiltrate the Tumor Microenvironment and Promote Radiation Resistance in a Mouse Model of Lung Cancer.

INTRODUCTION: Chemokine (C-X3-C Motif) Receptor 1 (CX3CR1) is present in a subset of the immune cells in the tumor microenvironment (TME) and plays an essential and diverse role in cancer progression. However, its potential function in the irradiated TME remains unknown. MATERIALS AND METHODS: A mouse lung cancer model was performed by subcutaneously inoculating Lewis Lung Carcinoma (LLC) cells expressing luciferase (Luc-2) and mCherry cells in CX3CR1GFP/GFP, CX3CR1DTR/+, and wild-type (WT) mice. Bioluminescence imaging, clonogenic assay, and flow cytometry were used to assess tumor progression, proliferation, and cell composition after radiation. RESULTS: Radiation provoked a significant influx of CX3CR1-expressing immune cells, notably monocytes and macrophages, into the TME. Co-culturing irradiated LLC cells with CX3CR1-deficient monocytes, and macrophages resulted in reduced clonogenic survival and increased apoptosis of the cancer cells. Interestingly, deficiency of CX3CR1 in macrophages led to a redistribution of the irradiated LLC cells in the S-phase, parallel to increased expression of cyclin E1, required for cell cycle G1/S transition. In addition, the deficiency of CX3CR1 expression in macrophages altered the cytokine secretion with a decrease in interleukin 6, a crucial mediator of cancer cell survival and proliferation. Next, LLC cells were injected subcutaneously into CX3CR1DTR/+ mice, sensitive to diphtheria toxin (DT), and WT mice. After injection, tumors were irradiated with 8 Gy, and mice were treated with DT, leading to conditional ablation of CX3CR1-expressing cells. After three weeks, CX3CR1-depleted mice displayed reduced tumor progression. Furthermore, combining the S-phase-specific chemotherapeutic gemcitabine with CX3CR1 cell ablation resulted in additional attenuation of tumor progression. CONCLUSIONS: CX3CR1-expressing mononuclear cells invade the TME after radiation therapy in a mouse lung cancer model. CX3CR1 cell depletion attenuates tumor progression following radiation and sensitizes the tumor to S-phase-specific chemotherapy. Thus, we propose a novel strategy to improve radiation sensitivity by targeting the CX3CR1-expressing immune cells.

Deep inspiratory breath hold assisted by continuous positive airway pressure ventilation for lung stereotactic body radiotherapy.

PURPOSE: Continuous positive airway pressure (CPAP) ventilation hyperinflates the lungs and reduces diaphragmatic motion. We hypothesized that CPAP could be safely combined with deep inspiratory breath hold (CPAP-DIBH) during lung stereotactic radiotherapy (SBRT). MATERIAL AND METHODS: Patients with stage-1 lung cancer or lung metastasis treated with CPAP-DIBH SBRT between 3/2017-5/2021 were analyzed retrospectively. Patient characteristics, treatment parameters, duration of breath holds in all sessions and tolerance to CPAP-DIBH were recorded. Local control (LC) was assessed from CT or PET-CT imaging. The distances between the tumor and mediastinal organs at risk (OAR) in centrally located tumors using either free breathing (FB) or CPAP-DIBH were compared. Toxicity was graded retrospectively. RESULTS: Forty-five patients with 71 lesions were treated with CPAP-DIBH SBRT. Indications for CPAP-DIBH were prior radiation (35/71, 65%), lower lobe location (34/71, 48%), multiple lesions (26/71, 36.6%) and proximity to mediastinal OAR (7/71, 10%). Patient characteristics were: F:M 43%: 57%; mean gross tumor volume 4.5cm3 (SD 7.9), mean planning target volume 20cm3 (SD 27), primary: metastatic lesions (7%:93%). Mean radiation dose was 52.5 Gray (SD3.5). Mean lung volume was 5292cm3 (SD 1106). Mean duration of CPAP-DIBH was 41.3s (IQR 31-46.8). LC at 2 years was 89.5% (95% CI 76-95.5). In patients with central lesions, the distance between the tumor and mediastinal OAR increased from 0.84cm (SD 0.65) with FB to 1.23cm (SD 0.8) with CPAP-DIBH (p=0.002). Most patients tolerated CPAP well and completed all treatments after starting therapy. Three patients did not receive treatment: 2 were unable to tolerate CPAP and 1 had syncope (pre-existing). Toxicity was grade 2 in 4/65 (6%) and grade 3 in 1/65 (1.5%). There was no grade 2 or higher esophageal or tracheal toxicities. CONCLUSION: CPAP-DIBH assisted lung SBRT was tolerated well and was associated with minimal toxicity and favorable LC. This technique may be considered when treating multiple lung lesions, lesions located in the lower lobes or adjacent to mediastinal OAR.

Every-Other-Day Versus Once-a-Week Urethra-Sparing Prostate Stereotactic Body Radiation Therapy: 5-Year Results of a Randomized Phase 2 Trial.

PURPOSE: The objective of this study was to present the 5-year results from a prospective, multicenter, phase 2 randomized trial of every-other-day (EOD) versus once-a-week (QW) urethra-sparing stereotactic body radiation therapy for localized prostate cancer. METHODS AND MATERIALS: Between 2012 and 2015, 170 patients with cT1c-3aN0M0 prostate cancer from 9 European institutions were randomized to 36.25 Gy in 5 fractions (6.5 Gy/fraction to the urethra) delivered either EOD (arm A, n = 84) or QW (arm B, n = 86). The median follow-up was 78 months (interquartile range, 66-89 months) and 77 months (interquartile range, 66-82 months) for arms A and B, respectively. RESULTS: Among the 165 patients treated and retained for the final analysis (arm A, n = 82; arm B, n = 83), acute toxicity (National Cancer Institute Common Terminology Criteria for Adverse Events version 4.03 scale) was mild or absent, with no differences between arms. The 5-year grade 2 or greater genitourinary toxicity-free survival was 75.9% and 76.1% for arms A and B, respectively (P = .945), whereas the 5-year grade 2 or greater gastrointestinal toxicity-free survival was 89% and 92% for arms A and B, respectively (P = .596). No changes in European Organisation for Research and Treatment of Cancer QLQ-PR25 scores were observed in both arms for genitourinary, gastrointestinal, and sexual domains at 5-year follow-up compared with baseline. At the last follow-up, biochemical failure was observed in 14 patients in the EOD arm and in 7 patients in the QW arm, with a 5-year biochemical relapse-free survival rate of 92.2% and 93% for arms A and B, respectively (P = .13). CONCLUSIONS: Stereotactic body radiation therapy for prostate cancer with a 10% dose reduction to urethra was associated with a minimal effect on urinary function and quality of life regardless of an EOD or QW fractionation schedule. Biochemical control so far has been encouraging and much alike in both study arms, although longer follow-up is probably needed to assess the true value of overall treatment time on disease outcome.

IOeRT in retroperitoneal sarcoma: Towards more organ preservation with comparable oncological outcomes.

BACKGROUND: Retroperitoneal sarcomas (RPS) present a surgical challenge with high rates of local recurrence (LR). We investigated the role of intraoperative electron radiotherapy (IOeRT) in reducing LR after surgical resection of RPS. METHODS: A retrospective analysis of all patients who underwent surgical resection for RPS between 2014 and 2021 at a tertiary academic referral center (n = 172). Patients included underwent surgical resection of their RPS and received IOeRT (n = 36) and were compared by case control matching to patients with similar tumor characteristics (recurrence status and tumor grade) that did not receive IOeRT (n = 36). RESULTS: The median length of hospitalization was 8 days (range, 4-34) in the IOeRT group and 10 days (range, 2-42) in the non-IOeRT group (p = 0.25). The mean operating room (OR) time was 4h (±1.3) and 4h (±1.9) in the IOeRT and non-IOeRT groups respectively, (p = 0.37). Complete resection with R0 margins was achieved in 30 patients (83.3%) and 24 patients (66.6%) in the IOeRT and non-IOeRT groups, respectively (p = 0.1). R1 resection was achieved in 6 patients (16.6%) and 12 patients (33.3%) respectively, (p = 0.1). The resected organ weighted score was significantly different between the groups; score 0 observed in 19 (52.7%) patients in the IOeRT group and 3 (8.3%) in the non-IOeRT group (p < 0.001), score 1 observed in 7 (19.4%) in the IOeRT group and 17 (47.2%) in the non-IOeRT group (p = 0.012). The rate of severe complications (CD score>3) did not differ between the groups, 5 (13.8%) patients in the IOeRT group and 9 (25%) patients in the non-IOeRT group (p = 0.23). No radiation associated complications were noted. The 2-year local recurrence free survival (LRFS) was 75.9% in the IOeRT group and 60.3% in the non-IOeRT group (p = 0.4). The 2-year IOeRT field recurrent free survival (IRFS) was 88.4% in the IOeRT group and 60.3% in the non-IOeRT group (p = 0.04). CONCLUSIONS: The use of IOeRT did not increase the rate of surgical complications and was associated with superior local control in the radiation field, improved organ preservation without an impact on overall survival.

Effects of EGFR driver mutations on pathologic regression in resectable locally advanced non-small cell lung cancer treated with neoadjuvant chemoradiation and completion surgery.

OBJECTIVE: We hypothesized that driver mutations in epidermal growth factor receptor (EGFR) are associated with decreased pathologic response to neoadjuvant chemoradiation (NA-ChRT) in locally advanced non-small cell lung cancer (LA-NSCLC). METHODS: Patients with Stage IIB-IIIA NSCLC treated with NA-ChRT, completion surgery, and underwent molecular profile testing were identified in a lung cancer database. Pathologic response was quantified using: (i) major pathologic response (MPR), (ii) complete pathologic response (pCR), and (iii) mean residual viable tumor cells (MRTC). Two groups were formed based on the presence or absence of driver mutations. Clinical and pathological correlations between the groups were studied. RESULTS: Forty-seven patients underwent tumor molecular profile testing, NA-ChRT, and completion surgery. Compared to the no-driver mutation group, the driver mutation group had lower MPR (23% vs 71%, p = 0.003), pCR (0% vs 26%, p = 0.02), and higher MRTC (43.4% vs 15.8%, p = 0.009). Univariate analysis showed an increased MPR rate for smokers, squamous cell histology, ChRT-surgery interval >65 days, and no-driver mutations. Multivariate analysis showed that only no-driver mutations (OR 0.39, p = 0.02) remained significant for MPR. PD-L1 status did not affect MPR. At 2 years, the driver mutation group had lower rates of local control (Hazard ration [HR] 0.67, p = 0.17) and disease-free survival (HR 0.5, p = 0.001). Overall survival was similar for both groups (HR = 1.04, p = 0.86). CONCLUSION: Following 60 Gray NA-ChRT, tumors with a driver mutation had lower MPR and pCR rates than tumors without a driver mutation. PD-L1 was not associated with tumor regression. ADVANCES IN KNOWLEDGE: Patients with resectable LA-NSCLC and an EGFR driver mutation treated with neoadjuvant-ChRT and completion surgery have reduced pathologic regression, lower local control rates, and shorter disease-free survival than patients without a driver mutation. Evaluation of molecular testing should be introduced in LA-NSCLC intended for prognostication and treatment decisions.