Median Radiation Dose Research Articles

Association Between Time From Surgery to Radiation Therapy and Multimodality Treatment Outcomes in HPV+ Head and Neck Cancer: A Multi-Institutional Cohort Experience

Oropharyngeal squamous cell cancers (OPSCCs) are traditionally managed with surgery and, if indicated, adjuvant radiation therapy (RT) with or without chemotherapy. NCCN recommends keeping the time from surgery to the start of RT (TSRT) within 6 weeks to avoid possibly compromising patient outcomes. HPV+ OPSCCs behave more favorably than HPV- OPSCCs. We hypothesized that TSRT beyond 6 weeks may not portend poorer outcomes for the former. We identified nonmetastatic, high-risk HPV+ OPSCCs treated with multimodal therapy at 2 institutions. Prolonged TSRT was defined as >6 weeks and was evaluated for association with recurrence-free survival (RFS). Radiation treatment time (RTT; time from the first to the last day of RT), total treatment package time (TTPT; time from surgery to the end of adjuvant treatments), de-escalated RT (dose ≤56 Gy), concurrent chemotherapy, smoking history, and treatment institution were evaluated as possible confounders. In total, 96 patients were included. The median follow-up time was 62 months (4-123 months); 69 patients underwent transoral robotic surgeries, and 27 received open surgeries. The median postoperative RT dose was 60 Gy (50-70.8 Gy). The median TSRT, RTT, and TTPT were 38 days (11-208), 43 days (26-56 days), and 81 days (40-255 days), respectively. Ten patients failed treatment at a median of 8 months (4-64 months). Two locoregional and 4 distant failures occurred in the group without prolonged TSRT, whereas 2 locoregional and 2 distant failures were recorded in the prolonged TSRT group. Prolonged TTPT, de-escalated RT, chemotherapy, smoking history, and treatment institution were not associated with treatment failure. RTT was dropped from our analyses as no events appeared in the prolonged RTT group, and no reliable hazard ratio could be computed. TSRT > 6 weeks was not significantly associated with inferior outcomes in the postoperative management of HPV+ OPSCCs. Longer TSRT may facilitate better recovery from surgical toxicity, as needed, without compromising oncologic outcomes. The TSRT goal for these cancers should be investigated in future studies.

Predictive and Prognostic Factors Related to Chemoradioresistance in Neoadjuvant Treatment of Locally Advanced Rectal Cancer at Panama

<i>Background:</i> In Panama, and the rest of Latin America, there are few publications on chemoradioresistance, it leads to poor prognosis and represents the main reason for failure of therapy, ultimately it can lead to tumor recurrence and metastasis. <i>Objective:</i> Identify factors associated with chemoradioresistance in the neoadjuvant treatment of locally advanced rectal cancer at the Instituto Oncológico Nacional de Panamá, period 2016-2020. Methodology: This retrospective study included 71 patients with LARC who received neoadjuvant chemoradiotherapy and surgery. Chemoradioresistant patients were those who did not reach a higher pathological stage of ypT2NO and the results were compared. <i>Results:</i> Of the 71 patients, pathological complete response (pCR) was achieved in 34 patients (48%). 49% of patients met chemoradioresistance criteria. In this group, the median CEA was 136 ng/ml, the median hemoglobin was 12 g/dl, and the median BMI was 26 kg/m2. The median radiation dose was 5000Gy. The time between completion of chemoradiotherapy and surgery was 110 days (16 weeks). Depending on the type of surgery, 65% who underwent low anterior resection were chemoradioresistant. The variables with statistical significance were the CEA value >5 ng/mL (OR=1.81, p=0.026) prior to the start of neoadjuvant treatment, with a lower pCR rate. Likewise, the ECOG scale (OR=2.51, p=0.015) was a risk factor related to chemoradioresistance, the lower the ECOG, the lower the risk of chemoradioresistance. The median overall survival and median recurrence-free survival was not reached in both groups and there was no statistically significant difference. <i>Conclusions:</i> Significant interactions were identified between CEA levels prior to the start of neoadjuvant treatment with the pathological complete response rate and the ECOG score with chemoradioresistance. Therefore, these factors can be used to predict patient outcomes, will help optimize personalized treatment strategies and improve patient outcomes.

Proton beam reirradiation for locally recurrent rectal cancer patients with prior pelvic irradiation.

The aim of the present study was to report the feasibility of proton beam reirradiation for patients with locally recurrent rectal cancer (LRRC) with prior pelvic irradiation. The study population included patients who were treated with proton beam therapy (PBT) for LRRC between 2008 and December 2019 in our institution. Those who had a history of distant metastases of LRRC, with or without treatment, before reirradiation, were excluded. Overall survival (OS), progression-free survival (PFS) and local control (LC) were estimated using the Kaplan-Meier method. Ten patients were included in the present study. The median follow-up period was 28.7months, and the median total dose of prior radiotherapy (RT) was 50Gy (range, 30Gy-74.8Gy). The median time from prior RT to reirradiation was 31.5months (range, 8.1-96.6months), and the median reirradiation dose was 72Gy (relative biological effectiveness) (range, 56-77Gy). The 1-year/2-year OS, PFS and LC rates were 100%/60.0%, 20.0%/10.0% and 70.0%/58.3%, respectively, with a median survival time of 26.0months. Seven patients developed a Grade 1 acute radiation dermatitis, and no Grade≥2 acute toxicity was recorded. Grade≥3 late toxicity was recorded in only one patient, who had developed a colostomy due to radiation-related intestinal bleeding. Reirradiation using PBT for LRRC patients who had previously undergone pelvic irradiation was feasible. However, the indications for PBT reirradiation for LRRC patients need to be considered carefully due to the risk of severe late GI toxicity.

Comprehensive radiotherapy for pediatric Ewing Sarcoma: Outcomes of a prospective proton study

Background and purposePatients with Ewing Sarcoma (EWS) are treated with multimodality therapy which includes radiation therapy (RT) as an option for local control. We report on the efficacy after proton radiation therapy (PRT) to the primary site for localized and metastatic EWS. Materials and methodsForty-two children with EWS (33 localized, 9 metastatic) treated between 2007 and 2020 were enrolled on 2 prospective registry protocols for pediatric patients undergoing PRT. PRT was delivered by passive scatter (74 %), pencil-beam scanning (12 %) or mixed technique (14 %). Treated sites included the spine (45 %), pelvis/sacrum (26 %), skull/cranium (14 %), extraosseous (10 %), and chest wall (5 %). Median radiation dose was 54 Gy-RBE (range 39.6–55.8 Gy-RBE). Patients with metastatic disease received consolidative RT to metastatic sites (4 at the time of PRT to the primary site, 5 after completion of chemotherapy). Median follow-up time was 47 months after PRT. ResultsThe 4-year local control (LC), progression-free survival (PFS), and overall survival (OS) rates were 83 %, 71 %, and 86 %, respectively. All local failures (n = 6) were in-field failures. Tumor size ≥ 8 cm predicted for inferior 4-year LC (69 % vs 95 %, p = 0.04). 4-year PFS and OS rates were not statistically different in patients with localized versus metastatic disease (72 % vs 67 %, p = 0.70; 89 % vs 78 %, p = 0.38, respectively). ConclusionIn conclusion, LC for pediatric patients with EWS treated with PRT was comparable to that of historical patients who received photon-RT. Tumor size ≥ 8 cm predicted increased risk of local failure. Patients with metastatic disease, including non-pulmonary only metastases, received radiation therapy to all metastatic sites and had favorable survival outcomes.

Quality of Life and Depression Symptoms After Therapy De-Escalation in HPV+ Oropharyngeal Squamous Cell Carcinoma

Despite interest in therapy de-escalation for survivors of human papillomavirus-mediated oropharyngeal squamous cell carcinoma (HPV-positive OPSCC), the association of de-escalated therapy with patient-reported quality of life (QoL) outcomes and burden of depressive symptoms remains unclear. To identify associations between clinicopathologic and therapeutic variables with patient-reported QoL outcomes and depression symptom burden in patients with HPV-positive OPSCC, who were enrolled in a therapy de-escalation trial. In this nonrandomized controlled, open-label, curative-intent therapy de-escalation clinical trial in adults with stage I, II, and III HPV-positive OPSCC, patients were recruited from a high-volume head and neck oncology practice. The main outcomes of this study included quantitative, patient-reported QoL and depression symptoms per well-validated inventories. Patient-reported QoL was based on Functional Assessment of Cancer Therapy-Head & Neck (FACT-HN) scores (range, 0-148; lower score indicates inferior QoL). Patient-reported depression-related symptom burden was based on Quick Inventory of Depressive Symptomatology-Self-Report (QIDS-SR) scores (range, 0-27; a higher score indicates a higher burden of depression symptoms). Baseline clinicopathologic and treatment variables were paired with FACT-HN and QIDS-SR scores at baseline, 3, 6, 12, 24, and 36 months. Linear mixed-effect models with a random intercept were used for each participant and fixed effects for other measures. Regression coefficients are reported with 95% CIs. A total of 95 patients were followed up for a median (IQR) of 2.2 (1.6-3.2) years. Of these, 93 patients (98%) were male with a mean (SD) age of 60.5 (8.2) years. Overall, 54 participants (57%) had a history of current or former smoking, 47 (50%) underwent curative-intent surgery (with or without adjuvant therapy), and 48 (50%) underwent primary radiotherapy (with or without chemotherapy). The median (IQR) radiotherapy dose was 60 (60-70) Gy. Five deaths and 2 recurrence events were observed (mean [SD] recurrence interval, 1.4 [1.5] years). A higher radiotherapy dose was the only modifiable factor associated with inferior patient-reported QoL (lower FACT-HN) (coefficient, -0.66 [95% CI, -1.09 to -0.23]) and greater burden of depression-related symptoms (higher QIDS-SR) (coefficient, 0.11 [95% CI, 0.04-0.19]). With the 70-Gy dose as reference, improvements in FACT-HN and QIDS-SR scores were identified when patients received 51 to 60 Gy (coefficient, 12.75 [95% CI, 4.58-20.92] and -2.17 [-3.49 to -0.85], respectively) and 50 Gy or lower (coefficient, 15.03 [4.36-25.69] and -2.80 [-4.55 to -1.04]). In this nonrandomized controlled, open-label, curative-intent therapy de-escalation trial, a higher radiotherapy dose was associated with inferior patient-reported QoL and a greater burden of depression-related symptoms. This suggests opportunities for improved QoL outcomes and reduced depression symptom burden with a reduction in radiotherapy dose. ClinicalTrials.gov Identifier: NCT04638465.

Role of external radiation in benign tumors: A clinical outcome and safety audit of 7 years from a tertiary care center in India.

Radiotherapy (RT) is a well-established modality for treating malignancies, but its role in treatment of benign lesions has not been well explored. Herein, we present a retrospective analysis of a 7-year data regarding the benefit and the safety profile of RT for treating benign tumors in our institute. Data of 23 patients who received RT for benign tumors from January 2015 to April 2022 were retrieved, and a retrospective analysis was conducted. All the pertinent demographic data, treatment and follow-up data were retrieved. The most common presentations were nasopharyngeal angiofibroma, vertebral hemangioma, paraganglioma, and others. The most common sites of occurrence were head and neck (43%) and paravertebral region (22%). Volumetric modulated arc therapy was the most commonly employed RT technique (39%), followed by three-dimensional conformal RT (34%) and two-dimensional conventional radiotherapy (26%). The median RT dose delivered was 36 Gy (range: 20-54 Gy). The median follow-up duration was 53 months (range: 3-120 months). Nine (39%) patients had progressive disease with a median time to progression of 8 months (range: 1-30 months). The median disease-free survival (DFS) was 70 months, while the 1-, 3-, and 5-year DFS rates were 97%, 88%, and 62%, respectively. Four patients (17%) died, all due to disease progression. The 1-, 3-, and 5-year overall survival rates was 97%, 85%, and 50%, respectively. The rate of radiation-induced cancer (RIC) was 0% as none of the patients had developed RIC secondary to radiation. RT is a safe and an effective option to manage benign tumors either in an adjuvant setting or in inoperable patients requiring definitive treatment, as well as in a setting to alleviate symptoms, providing excellent survival benefits. However, further prospective studies with much higher sample size are required to establish the absolute benefit and to estimate the risk of RIC, which will further direct for a better utilization of RT in treating benign tumors.

Radiotherapy in younger patients with advanced aggressive B-cell lymphoma—long-term results from the phase 3 R-MegaCHOEP trial

The role of consolidative radiotherapy (RT) for patients with aggressive B-cell lymphoma has not been fully elucidated. The R-MegaCHOEP trial investigated the use of high-dose chemotherapy and rituximab with subsequent autologous stem cell transplantations compared to conventional immunochemotherapy (R-CHOEP) for high-risk patients up to 60 years. The study protocol included RT for patients with bulky (maximum diameter ≥7.5 cm) or extranodal disease. Two-hundred sixty-one patients were analyzed, 120 of whom underwent RT. The most frequently irradiated regions were mediastinum (n = 50) and paraaortic (n = 27). Median RT dose was 36 Gray in median fractions of 1.8 Gray. Acute toxicities were mostly mild to moderate, with only 24 and 8 grade 3 and 4 toxicities reported during RT. Patients with bulky disease who received RT showed significantly better 10-year EFS, PFS and OS (EFS: 64% vs. 35%; p < 0.001; PFS 68% vs. 47%; p = 0.003; OS: 72% vs. 59%; p = 0.011). There was no significant increase in secondary malignancies with the use of RT. RT administered for consolidation of bulky disease after immunochemotherapy improved the prognosis of young high-risk patients with aggressive B-cell lymphoma and should be considered part of first-line therapy. The trial was registered with ClinicalTrials.gov, number NCT00129090.

Intrarectal formalin treatment for haemorrhagic radiation-induced proctopathy: efficacy and safety.

Pelvic radiotherapy is limited by dose-dependent toxicity to surrounding organs. The aim of this prospective study was to evaluate the efficacy and safety of intrarectal formalin treatment for radiotherapy-induced haemorrhagic proctopathy (RHP) at the Royal Marsden Hospital. Adult patients were enrolled. Haemoglobin was evaluated before and after formalin treatment. Antiplatelet and/or anticoagulation treatment and administration of transfusion were recorded. The interval between completion of radiotherapy and the first intrarectal 5% formalin treatment was assessed and the dose of radiotherapy was evaluated. Clinical assessment of the frequency and amount of rectal bleeding (rectal bleeding score 1-6) and endoscopic appearance (grade 0-3) were classified. Complications were recorded. Nineteen patients were enrolled, comprising 13 men (68%) and 6 women. The mean age was 75 ± 9 years. The median time between completion of radiotherapy and the first treatment was 20 months [interquartile range (IQR) 15 months] and the median dose of radiotherapy was 68 Gy (IQR 14 Gy). Thirty-two procedures were performed (average 1.7 per patient). In total, 9/19 (47%) patients were receiving anticoagulation and/or antiplatelet medication and 5/19 (26%) received transfusion prior to treatment. The mean value of serum haemoglobin before the first treatment was 110 ± 18 g/L and afterwards it was 123 ± 16 g/L (p = 0.022). The median rectal bleeding score before the first treatment was 6 (IQR 0) and afterwards 2 (IQR 1-4; p < 0.001), while the median endoscopy score on the day of first treatment was 3 (IQR 0) compared with 1 (IQR 1-2) on the day of the last treatment 1 (p < 0.001). One female patient with a persistent rectal ulcer that eventually healed (18 months of healing) subsequently developed rectovaginal fistula (complication rate 1/19, 5%). Treatment with intrarectal formalin in RHP is effective and safe.

Adjuvant proton beam therapy in patients with grade 2 meningiomas.

The World Health Organization (WHO) grade 2 meningiomas behave aggressively with a high proclivity toward recurrence despite maximal surgical resection. Our institution, a pioneer of proton therapy, uses exclusively proton beam radiation, and thus, we present a retrospective cohort analysis of patients with WHO grade 2 meningiomas treated with adjuvant proton beam therapy (PBT) at our institution between 2007 and 2019. The effects of adjuvant PBT were evaluated. Data collected include diagnosis, gender, histological subtype, WHO grade, the extent of surgical resection, adjuvant PBT radiation, details of the PBT radiation, recurrence, any additional PBT radiation, systemic medical therapy, and disease-specific survival. Among the WHO grade 2 meningiomas (n = 50) recommended PBT, 80% and 78% of patients with gross-total resection (GTR) and subtotal resection (STR), respectively, followed through with PBT. The median radiation dose of PBT was 59.5 Gy and 59.92 Gy for patients with GTR and STR, respectively, with a median of 33 fractions delivered in 1.8 Gy doses for both groups. Combined 3-year progression-free survival (PFS) was 96%, and 5-year PFS was 92%. Combined overall survival was 95% at five years. Minimal radiation side effects were reported with no grade 3 or higher toxicities. Our results suggest that adjuvant PBT is well tolerated with minimal radiation toxicity. Alternative to photon radiation, PBT may be considered at least as safe and effective for adjuvant treatment of WHO grade 2 meningiomas when it is available.

Hybrid operating room with ceiling mounted imaging system assisted pre-operative and intra-operative lung nodule localization for thoracoscopic resections: a 5-year case series

BackgroundVideo-assisted thoracoscopic (VATS) lung resections are increasingly popular and localization techniques are necessary to aid resection. We describe our experience with hybrid operating room (OR) cone-beam computed tomography (CT) assisted pre-operative and intra-operative lesion localization of lung nodules for VATS wedge resections, including our novel workflow using the hybrid OR cone-beam CT to re-evaluate patients who have undergone pre-operative localization for those who are unsuitable for intra-operative localization.MethodsRetrospective analysis of all consecutive patients with small (≤ 20 mm), deep (≥ 10 mm distance from pleura) and/or predominantly ground-glass nodules selected for lesion localization in the Interventional Radiology suite followed by re-evaluation with cone-beam CT in the hybrid OR (pre-operative), or in the hybrid OR alone (intra-operative), prior to intentional VATS wedge performed by a single surgeon at our centre from January 2017 to December 2021.Results30 patients with 36 nodules underwent localization. All nodules were successfully resected with a VATS wedge resection, although 10% of localizations had hookwire or coil dislodgement. The median effective radiation dose in the pre-operative group was 10.4 mSV including a median additional radiation exposure of 0.9 mSV in the hybrid OR for reconfirmation of hookwire or coil position prior to surgery (p = 0.87). The median effective radiation dose in the intra-operative group was 3.2 mSV with a higher mean rank than the intra-operative group, suggesting a higher radiation dose (p = 0.01).ConclusionsWe demonstrate that our multidisciplinary approach utilizing the hybrid OR is safe and effective. Intra-operative localization is associated with lower radiation doses. Routine use of cone-beam CT to confirm the position of the physical marker prior to surgery in the hybrid OR helps mitigate consequences of localization failure with only a modest increase in radiation exposure.

Predictive Factors Associated With Radiation Myelopathy in Pediatric Patients With Cancer: A PENTEC Comprehensive Review

Radiation myelitis (RM) is a rare complication of radiation therapy (RT). The Pediatric Normal Tissue Effects in the Clinic spinal cord task force aimed to identify RT dose effects and assess risk factors for RM in children. Through systematic review, we analyzed RT dose, fraction size, latency between completion of RT and toxicity, chemotherapy use, age when irradiated, and sex. We conducted literature searches of peer-reviewed manuscripts published from 1964 to June 2017 evaluating RM among children. Normality of variables was assessed with Kolmogorov-Smirnov or Shapiro-Wilk tests. Spearman's rank correlation coefficients were used to test correlations between RT dose/fraction size and latency between RT and development of toxicity. Of 1329 identified and screened reports, 144 reports were fully reviewed and determined to have adequate data for analysis; 16 of these reports had a total of 33 cases of RM with a median age of 13 years (range, 0.2-18) at the time of RT. The most common primary tumor histologies were rhabdomyosarcoma (n = 9), medulloblastoma (n = 5), and Hodgkin lymphoma (n = 2); the most common chemotherapy agents given were vincristine (n = 15), intrathecal methotrexate (n = 12), and intrathecal cytarabine (n = 10). The median RT dose and fraction size were 40 Gy (range, 24-57.4 Gy) and 1.8 Gy (range, 1.3-2.6 Gy), respectively. RT dose resulting in RM in patients who also received chemotherapy was lower than in those not receiving chemotherapy (mean 39.6 vs 49.7 Gy; P = .04). There was no association of age with RT dose. The median latency period was 7 months (range, 1-29). Higher RT dose was correlated with longer latency periods (P = .03) to RM whereas sex, age, fraction size, and chemotherapy use were not. Two of 17 patients with adequate follow-up recovered from RM; unfortunately, it was fatal in 6 of 15 evaluable patients. Complication probability modeling was not possible because of the rarity of events. This report demonstrates a relatively short latency from RT (with or without chemotherapy) to RM and a wide range of doses (including fraction sizes) associated with RM. No apparent association with age at the time of RT could be discerned. Chemotherapy appears to reduce spinal cord tolerance. Recovery from RM is rare, and it is often fatal.

Abstract TP229: Stroke Rate and Associated Factors in Individuals With Primary Brain Gliomas and Brain Radiation Therapy: A Retrospective Cohort Study

Background/Objectives: The risk of stroke in individuals with brain gliomas may be increased due to several possible factors including chemotherapy, radiation-induced toxicity, and concomitant vascular risks. We report on the stroke rate and associated factors following brain tumor diagnosis and radiation therapy. Design: This is a retrospective cohort study, from a single tertiary academic brain tumor center, of patients with brain gliomas diagnosed between 2004-2021 who received brain radiation therapy during their treatment. Chi-square test was used to calculate the odds ratios. Results: Among a total of 912 patients with primary gliomas who received radiation therapy, stroke subsequently occurred in 93 patients (10.2%). Strokes were ischemic in 72.0% (N=67), intracerebral hemorrhage (ICH) in 25.8% (N=24), and subarachnoid hemorrhage in 2.2% (N=2). Individuals who sustained a stroke were 44.1% female and had a mean age of 54.2 years (range 21-84) at the time of stroke diagnosis. Of those who had a stroke, 64.5% (N=60) were also taking bevacizumab at the time of stroke. Median time from initiation of radiation therapy to stroke was 653 days (range 0-3788). Median radiation dose was 5940 cGy (range 1800-6000). The following factors were associated with a higher odd of having a stroke: radiation necrosis (OR 4.51; 95% CI 1.98-10.29, P=0.0003); hypertension (OR 1.82; 95% CI 1.17-2.82, P=0.008); hyperlipidemia (OR 5.50; 95% CI 3.45-8.78, P&lt;0.0001); and diabetes (OR 2.19; 95% CI 1.25-3.84, P=0.007). Among stroke patients, 80.6% had strokes on the same side as radiation therapy. Those who were taking bevacizumab were more likely to have an ICH (31.7% vs. 15.1%, OR 2.60, 95% CI 0.87-7.77, P=0.09) as compared to other stroke types. Conclusions: Individuals with primary brain gliomas undergoing radiation therapy who were subsequently diagnosed with a stroke had higher rates of comorbid vascular risk factors and radiation necrosis.

Radiation therapy dose escalation achieves high rates of local control with tolerable toxicity profile in pediatric and young adult patients with Ewing sarcoma.

Local control for patients with Ewing sarcoma (EWS) who present with large tumors are suboptimal when treated with standard radiation therapy (RT) doses of 54-55.8Gy. The purpose of this study is to determine local control and toxicity of dose-escalated RT for tumors ≥8cm (greatest diameter at diagnosis) in pediatric and young adult patients with EWS. Eligible patients ≤30years old with newly diagnosed EWS ≥8cm treated with definitive conformal or intensity modulated photon, or proton radiation therapy techniques were included. All patients in the study received dose-escalated RT doses. Outcomes included overall survival (OS), event-free survival (EFS), local failure rates, and toxicity. Thirty-two patients were included, 20 patients presented with metastatic disease and 12 patients with localized disease. The median RT dose was 64.8Gy (range, 59.4-69.4Gy) with variability of doses to protect normal surrounding tissues. All patients received systemic chemotherapy. The 5-year OS and EFS for the cohort was 64.2% and 42%, respectively. The 5-year cumulative incidence of local failure was 6.6%. There were two combined local and distant failures with no isolated local failures. Twenty-nine patients experienced short term toxicity, 90% of those being radiation dermatitis. Twenty-seven patients experienced long-term toxicity, with only one experiencing grade 4 toxicity, a secondary malignancy after therapy. This study demonstrates that definitive RT for pediatric and young adult patients with EWS ≥8cm provides high rates of local control, while maintaining a tolerable toxicity profile.

Evaluation of the efficacy of adjuvant radiotherapy versus chemoradiotherapy in patients with salivary gland tumors.

The aim of this study was to compare the efficacy of adjuvant radiotherapy (RT) versus adjuvant chemoradiotherapy (CRT) in patients with salivary gland tumors (SGTs). Data from patients who underwent adjuvant RT for a diagnosis of SG cancer at Ankara Atatürk Education and Research Hospital, Ankara Numune Education and Research Hospital and Ankara Bilkent City Hospital between September 01, 2009 and September 01, 2022 were analysed retrospectively. We evaluated the efficacy of RT alone versus CRT in these patients in terms of acute response, treatment tolerance, overall survival (OS), and disease-free survival (DFS). Fifty-five patients who underwent RT between September 14, 2009 and August 04, 2022 at Ankara Atatürk Education and Research Hospital, Ankara Numune Education and Research Hospital and Ankara Bilkent City Hospital were included in this study. Eight patients who did not meet the study criteria were excluded; thus, the analysis was performed for 47 patients. The median follow-up period was 60 months (range: 6-160 months). The median patient age was 53 years (range: 18-86 years). Thirty-nine patients (83%) had parotid tumors and eight patients (17%) had submandibular cancer. The time from surgery to RT was 48 days (range: 20-126 days). Intensity-modulated radiotherapy was administered to all patients and the median RT dose was 66 Gy (range: 52-70 Gy). Concomitant chemotherapy (CCT) (40 mg/m 2 of cisplatin weekly) was administered to 13 patients (27.7%). Acute adverse events were observed in 17 patients (36.2%). Interruption of RT was noted for only six patients (12.8%), and this proportion did not differ significantly between the CRT and RT-only arms ( P = 0.538). Acute side effects were observed in 17 patients (36.2%), and there were no significant relationships between acute side effects and the administration of CCT ( P = 0.112). Recurrence was observed in 10 patients (21.3%). All recurrences were locoregional and no distant metastases were observed during the follow-up period. The median DFS of the patients was 48 months (range: 4-160 months), 1-year DFS was 86%, 2-year DFS was 83.5%, and 5-year DFS was 77.9%. There was no statistically significant difference in DFS between the adjuvant CRT and RT-alone arms ( P = 0.114). At the date of last follow-up, 14 patients (29.8%) had died. The median OS of the patients was 58.5 months (range: 6-160 months), 1-year OS was 91.4%, 2-year OS was 86.8%, and 5-year OS was 78%. There was no statistically significant difference in OS between the adjuvant CRT and RT-only arms ( P = 0.453). Stage was identified as the most important prognostic factor for DFS and OS. No significant differences in OS, DFS, or acute side effects were observed between the CRT and RT-only arms. Additional studies are needed to identify the subgroup of SGT patients for which CRT is most warranted.

Evaluating the safety and efficacy of the addition of liver radiation (RT) to atezolizumab and bevacizumab (A/B) in advanced hepatocellular carcinoma (HCC): A retrospective cohort analysis.

481 Background: Recently, the addition of stereotactic body RT to sorafenib in patients (pts) with advanced HCC demonstrated improved overall survival. However, A/B is the current standard of care for pts with advanced HCC based on IMBrave150. For these pts, RT may potentiate the antitumor immune response of A/B but carries the risk of bowel toxicity and impaired liver function. To date, there are limited data regarding safety and outcomes with the addition of liver RT to A/B in pts with advanced HCC. Here, we describe our single-center experience of adding RT to A/B for pts with advanced HCC. Methods: This single-center retrospective cohort study was conducted at the University of Pennsylvania. We identified all pts with HCC naïve to systemic therapy who received infusions of A/B and those who received RT to the liver within 30 days of starting A/B until discontinuation from 1/1/2020 until 2/2/2023. We assessed the real-world response rate (rwRR) determined from clinician impression after initiating A/B, safety outcomes, overall survival (OS), and time-to-progression (TTP) from initiation of A/B. Time-to-event outcomes were analyzed by the Kaplan-Meier method with log-rank test and Cox proportional hazards modeling. Results: We identified 49 pts (n=34 control, n=15 RT) with advanced HCC receiving first-line A/B. Those who received RT were more likely to have alcoholic liver disease (p=0.013) and were less likely to have ascites (p=0.04) but were otherwise balanced regarding demographics, prior locoregional therapies, presence of macrovascular invasion and extrahepatic spread, and baseline laboratories. The median RT dose was 63 Gy. The rwRR in the RT group was 73.3% (11/15) compared to 17.6% (6/34) in the control group (Risk Ratio (RR) 3.9, 95% CI 1.7-8.6, p&lt;0.001). Two pts in the control group (5.8%) and one patient in the RT group (6.7%) experienced clinically significant bleeding (RR=1.1 95% CI 0.1-11.6). In the RT group, three pts (20%) developed worsening liver dysfunction after completing RT, concerning for possible radiation-induced liver disease. Six pts in the control group and one patient in the RT group developed immune-related adverse events leading to discontinuation of A/B. The median OS in the RT group was 14.4 mos and 10.8 mos in the control group (Hazard Ratio (HR) death 0.49 (95% CI 0.20-1.22, p=0.12)). Median TTP was 6.4 months (mos) with RT compared to 5.8 mos in the control group (HR progression 0.72 (95%CI 0.35-1.46, p=0.36. Conclusions: In our retrospective cohort, the addition of liver RT to standard A/B resulted in increased responses and a non-significant improvement in outcomes without an increased risk of bleeding. An assessment of changes in liver dysfunction by Child-Pugh and ALBI score is ongoing. Overall, these data support prospective trials to evaluate the addition of RT to A/B.

Radiation dose to multidisciplinary staff members during complex interventional procedures

IntroductionComplex interventional radiology procedures involve extensive fluoroscopy and image acquisition while staff are in-room. Monitoring occupational radiation dose is crucial in optimization. The purpose was to determine radiation doses received by staff involved in complex interventional procedures performed in a dedicated vascular or neuro intervention room. MethodsIndividual real-time radiation dose for all staff involved in vascular and neuro-interventional procedures in adult patients was recorded over a one-year period using wireless electronic dosimeters attached to the apron thyroid shield. A reference dosimeter was attached to the C-arm near the tube housing to measure scattered, unshielded radiation. Radiology staff carried shoulder thermo-luminescent dosimeters with monthly read-out to monitor dose over time. ResultsOccupational radiation dose was measured in 99 interventional procedures. In many cases prostate artery embolization procedures exposed radiologists to high radiation doses with a median of 15.0 μSv and a very large spread, i.e. 0.2–152.5 μSv. In all procedures except uterine fibroid embolization radiographers were exposed to lower doses than those of radiologists, with endovascular aortic repair being the procedure with highest median exposure to assisting radiographers, i.e. 2.2 μSv ranging from 0.1 to 36.1 μSv. Median radiation dose for the reference dosimeter was 670 μGy while median staff dose for all procedures combined was 3.2 μGy. ConclusionRadiation doses for multiple staff were determined and the ratio between staff dose and reference dosimeter indicated proper use of shielding in general. Some high-dose procedures may need further optimization for certain staff members, especially those not primarily employed in radiology. Implications for practiceThe study provides benchmark doses that may be used widely in audits and in the ongoing effort to optimize radiation protection for staff in interventional radiology.

Abstract A071: Definitive radiation therapy for treatment of non-metastatic pancreatic ductal adenocarcinoma: Practice patterns and outcomes

Abstract Background: Advances in radiation therapy (RT) have allowed for increased biologically effective doses, or ablative RT, to be safely administered to pancreatic tumors. Pancreatic ductal adenocarcinoma (PDA) is diagnosed as local disease without metastasis in roughly 45% of patients (pts) however only 20-25% of pts are candidates for upfront surgical resection, and many are medically unfit to undergo surgery. In such patients, ablative RT can be given with curative intent, termed definitive RT (dRT). Defining practice patterns and outcomes of dRT is needed. Methods: A retrospective chart review was performed on pts with non-metastatic PDA who underwent dRT, defined as &amp;gt; = 100Gy BED over a protracted hypofractionation course, for treatment at our institution. Data collected included: age, gender, primary tumor location, resectability status, surveillance scan frequency and modality, chemotherapy (chemo) used, site of recurrence, cancer antigen (CA) 19-9 levels pre and post dRT, adverse events, and vital status. Neoadjuvant (NA) and adjuvant chemo was defined as chemo received within 6 weeks prior to dRT and 6 weeks after dRT, respectively. Time from diagnosis and dRT until death (OS and dRT-OS, respectively) and time from diagnosis and dRT until progression (PFS and dRT-PFS, respectively) was calculated. Time from diagnosis and dRT until metastasis (MFS and dRT-MFS, respectively) was also calculated. Results: A total of 25 pts who received dRT were identified. Median dose of RT given was 6750 cGY (range 3750-6750) in 15 fractions. Median age at receipt of dRT was 71.5 years (range 50-91), 50% were female. 76% of pts had pancreatic head mass and 24% of pts were considered resectable at time of diagnosis. 2 patients received dRT after isolated local recurrence after surgical resection. 80% of pts received chemo of any kind prior to dRT and 65% of those patients as NA chemo. 35% of patients received 2 chemo regimens prior to dRT; 55% and 65% of patients received mFOLFIRINOX and gemcitabine-based therapy, respectively. 12% of pts received adjuvant chemo. 43% of patients had at least 1 surveillance PET scan. 80% of patients had progression of any kind; of which 85% and 40% experienced distant and local recurrence, respectively. The median OS and dRT-OS was 17.3 months (95% CI 12.2-NA) and 10.1 months (95% CI 6.5-NA), respectively. The median PFS and dRT-PFS was 14.7 months (95% CI 10.3-17.9) and 5.1 months (95% CI 3.6-9.3), respectively. The median MFS and dRT-MFS was 14.7 months (95% CI 10.3-18.0) and 5.6 months (95% CI 3.6-11.3), respectively. Median CA 19-9 pre dRT was 85 (range 4.3-1790) and post-dRT was 42 (range 1.2-1673). 56% of pts had RT-associated toxicity of any kind. Conclusions: Of a single-institutional cohort of 25 patients with non-metastatic PDA who received dRT, more than half of patients received NA chemo; adjuvant chemo was rarely given. dRT provided high rates of local control while MFS was nearly identical to PFS, emphasizing the importance of systemic therapy to reduce distant recurrence in pancreatic cancer treated with dRT. Citation Format: Michael M. Caplan, Brian W. Labadie, Hope Choy, Albert Lee, Weijia Fan, David P. Horowitz. Definitive radiation therapy for treatment of non-metastatic pancreatic ductal adenocarcinoma: Practice patterns and outcomes [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A071.

Efficacy and safety of adjuvant radiation therapy in localized adrenocortical carcinoma.

Adrenocortical carcinoma (ACC) is rare and have high rates of recurrence and mortality. The role of adjuvant radiation therapy (RT) in localized ACC was controversial. We conducted a retrospective study in our center between 2015 and 2021 to evaluate the efficacy and safety of adjuvant RT in localized ACC. Overall survival (OS) and disease-free survival (DFS) were estimated using the Kaplan-Meier method. Cox proportional hazards regression models were used to estimate the independent risk factors. Adverse events associated with RT were documented according to the toxicity criteria of the radiation therapy oncology group (RTOG) and the common terminology criteria for adverse events (CTCAE v5.0). Of 105 patients with localized ACC, 46 (43.8%) received adjuvant RT after surgery. The median radiation dose was 45.0Gy (range:30.0-50.4) and median follow up time was 36.5 (IQR: 19.7-51.8) months. In comparison to the no adjuvant RT group, patients with adjuvant RT had better 3-year OS (87.9% vs 79.5%, P=0.039), especially for patients with ENSAT I/II stage (P=0.004). Adjuvant RT also improved the median DFS time from 16.5months (95%CI, 12.0-20.9) to 34.6months (95%CI, 16.1-53.0). Toxicity of RT was generally mild and moderate with six grade 3 events. Postoperative adjuvant RT significantly improved OS and DFS compared with the use of surgery alone in resected ACC patients. Although this retrospective study on RT in localized ACC indicates that RT is effective in ACC, its findings need to be prospectively confirmed.

Keratin-based topical cream for radiation dermatitis during head and neck radiotherapy: a randomised, open-label pilot study.

Radiation dermatitis (RD) is a frequent toxicity during radiotherapy (RT) for head and neck cancer (HNC). We report the first use of KeraStat® Cream (KC), a topical, keratin-based wound dressing, in patients with HNC receiving RT. This pilot study randomized HNC patients treated with definitive or postoperative RT (≥60 Gy) to KC or standard of care (SOC), applied at least twice daily during and for 1-month after RT. Outcomes of interest included adherence to the assigned regimen (at least 10 applications per week of treatment), clinician- and patient-reported RD, and skin-related quality of life. 24 patients were randomized and completed the study. Most patients had stage III-IV disease and oropharynx cancer. Median RT dose was 68 Gy; the bilateral neck was treated in 19 patients, and 18 patients received concurrent chemotherapy. Complete adherence was observed in 7/12 (SOC) vs. 10/12 (KC, p = 0.65). Adherence by patient-week was 61/68 versus 64/67, respectively (p = 0.20). No differences in RD were observed between groups. A randomized trial of KC versus SOC in HNC patients treated with RT is feasible with good adherence to study agent. An adequately powered randomized study is warranted to test the efficacy of KC in reducing RD.

A retrospective cohort study of stereotactic radiosurgery for vestibular schwannomas: Comparison of two age groups (75 years or older vs. 65-74 years).

Treatment outcome data of stereotactic radiosurgery (SRS) for vestibular schwannomas (VS) in patients ≥75 years (late elderly) are lacking. Approximately 39% of patients ≥75 years with VS were reported to experience severe facial palsy after surgical removal. This study compared the treatment outcomes post-SRS for VS between patients ≥75 and 65-74 years (early elderly). Of 453 patients who underwent gamma knife SRS for VS, 156 were ≥65 years old. The late and early elderly groups comprised 35 and 121 patients, respectively. The median tumor volume was 4.4 cc, and the median radiation dose was 12.0 Gy. The median follow-up periods were 37 and 56 months in the late and early elderly groups, respectively. Tumor volume control was observed in 27 (88%) and 95 (83%) patients (P = 0.78), while additional procedures were required in 2 (6%) and 6 (6%) patients (P = 1.00) in the late and early elderly groups, respectively. At the 60th and 120th months post-SRS, the cumulative tumor control rates were 87%, 75%, 85%, and 73% (P = 0.81), while the cumulative clinical control rates were 93% and 87%, 95%, and 89% (P = 0.80), in the late and early elderly groups, respectively. In the early elderly group, two patients experienced facial pain, and one experienced facial palsy post-SRS; there were no adverse effects in the late elderly group (both P = 1.00). SRS is effective for VS and beneficial in patients ≥75 years old as it preserves the facial nerve.