Predicting factors of symptomatic radiation pneumonitis induced by durvalumab following concurrent chemoradiotherapy in locally advanced non-small cell lung cancer

Background Concurrent chemoradiotherapy (CCRT) followed by durvalumab is the standard of care for unresectable locally-advanced non-small cell carcinoma (LA-NSCLC). However, a major concern about administration of durvalumab after CCRT is whether the incidence of symptomatic radiation pneumonitis (RP) may increase or not. In the present analysis, we report the initial results of CCRT followed by durvalumab in patients with LA-NSCLC in a real-world setting with focus on predicting factors for symptomatic RP. Methods Patients who were pathologically diagnosed as NSCLC and initiated treatment with CCRT followed by durvalumab between July 2018 to December 2019 were eligible for this study. Patients were included if they completed the planned CRT course and administered at least one course of durvalumab. We retrospectively investigated the preliminary survival outcome and incidence and predicting factors for symptomatic RP. Results Of the 67 patients who planned CCRT, 63 patients completed the entire CCRT course. Of these, 56 patients proceeded to consolidation with durvalumab. The median time to eternal discontinuation of durvalumab was 9.7 months. The cumulative proportion of the patients who exhibited symptomatic RP was 30, 40 and 44% at 3, 6 and 12 months, respectively. In multivariate analyses, pulmonary fibrosis score and lung V40 were significant predictive factors for symptomatic RP (p < 0.001, HR: 7.83, 95% CI: 3.38–18.13, and p = 0.034, HR: 3.17, 95% CI: 1.09–9.19, respectively). Conclusions Pulmonary fibrosis sore and lung V40 were significant predictive factors for symptomatic RP. We should be cautious about the administration of durvalumab for patients having subclinical pulmonary fibrosis. To our best knowledge, this is one of the first report showing the predictive value of high dose volumes to the lung in patients with LA-NSCLC who received CCRT followed by durvalumab.

Impact of Advanced Radiotherapy on Second Primary Cancer Risk in Prostate Cancer Survivors: A Nationwide Cohort Study

PurposeExternal Beam Radiotherapy (EBRT) techniques dramatically changed over the years. This may have affected the risk of radiation-induced second primary cancers (SPC), due to increased irradiated low dose volumes and scatter radiation. We investigated whether patterns of SPC after EBRT have changed over the years in prostate cancer (PCa) survivors.Materials and MethodsPCa survivors diagnosed between 1990-2014 were selected from the Netherlands Cancer Registry. Patients treated with EBRT were divided in three time periods, representing 2-dimensional Radiotherapy (RT), 3-dimensional conformal RT (3D-CRT), and the advanced RT (AdvRT) era. Standardized incidence ratios (SIR) and absolute excess risks (AER) were calculated to estimate relative and excess absolute SPC risks. Sub-hazard ratios (sHRs) were calculated to compare SPC rates between the EBRT and prostatectomy cohort. SPCs were categorized by subsite and anatomic region.ResultsPCa survivors who received EBRT had an increased risk of developing a solid SPC (SIR=1.08; 1.05-1.11), especially in patients aged &lt;70 years (SIR=1.13; 1.09-1.16). Pelvic SPC risks were increased (SIR=1.28; 1.23-1.34), with no obvious differences between the three EBRT eras. Non-pelvic SPC were only significantly increased in the AdvRT era (SIR=1.08; 1.02-1.14), in particular for the 1-5 year follow-up period. Comparing the EBRT cohort to the prostatectomy cohort, again an increased pelvic SPC risk was found for all EBRT periods (sHRs= 1.61, 1.47-1.76). Increased non-pelvic SPC risks were present for all RT eras and highest for the AdvRT period (sHRs=1.17, 1.06-1.29).ConclusionSPC risk in patients with EBRT is increased and remained throughout the different EBRT eras. The risk of developing a SPC outside the pelvic area changed unfavorably in the AdvRT era. Prolonged follow-up is needed to confirm this observation. Whether this is associated with increased irradiated low-dose volumes and scatter, or other changes in clinical EBRT practice, is the subject of further research.

CTNI-28. VOLUMETRIC AND DOSIMETRIC PATTERNS OF FAILURE ANALYSIS OF A PHASE II CLINICAL TRIAL OF 18F-DOPA-PET DIRECTED DOSE ESCALATED RADIOTHERAPY FOR GLIOBLASTOMA

While dose escalation of radiotherapy (DERT) has failed to improve overall survival (OS) or progression-free survival (PFS) for glioblastoma in previous studies, a recent phase II clinical trial utilizing 18F-DOPA-PET-directed DERT demonstrated improved PFS in MGMT-unmethylated patients and OS in MGMT-methylated patients compared to historical controls. This planned secondary analysis sought to determine 1) how 18F-DOPA-PET changes RT volumes beyond standard MRI-planning, 2) which patients benefit most and least from this protocol, 3) which are mostly likely to experience clinically significant radionecrosis after DERT, and 4) patterns of failure after DERT. For 69 evaluable patients, median MRI-defined, PET-defined, and combined low-dose gross tumor volumes (GTV51) were 54 cc (range 9-248), 23 cc (0.4-179), and 62 cc (10-260), respectively. Median MRI-defined, PET-defined, and combined high-dose GTVs (GTV76) were 32 cc (range 4-136), 6 cc (0.1-138), and 34 cc (4-162), respectively. 18F-DOPA-PET resulted in a median volumetric expansion of 13% (0-243%) and 5% (0-217%) from MRI-defined low-dose and high-dose GTV’s, respectively. Central failures ( &gt;95% of recurrence tumor volume) occurred within the 76 Gy, 60 Gy, and 51 Gy isodose lines in 32 (46%), 60 (87%), and 64 (93%) patients, respectively. Recursive partitioning analysis stratified patients by OS and PFS. Patients with 18F-DOPA-PET-defined GTV76 &gt; 7.8cc, MRI-defined GTV76 &gt; 42.7cc, and MGMT promotor-unmethylated tumors had the shortest OS, while patients with smaller PET and MRI-defined tumors had the longest OS (median 10.4 vs. 64.6 months, p&lt; 0.001). Similarly, PFS was worst in patients with 18F-DOPA-PET-defined GTV76 &gt; 2.17 cc who had biopsy only (median PFS 3.2 months, p&lt; 0.001). Patients with 18F-DOPA-PET-defined GTV51 &gt; 50 cc had the highest risk of grade 3+ radionecrosis (p&lt; 0.001). In conclusion, larger 18F-DOPA-PET and MRI-defined tumor volumes were associated with worse outcomes, and 18F-DOPA-PET-directed DERT appears to reduce risk of central recurrence in high-dose volumes.

CTIM-28. MDNA55, AN INTERLEUKIN-4 RECEPTOR TARGETED IMMUNOTHERAPY, FOR RECURRENT GBM DELIVERED BY CONVECTION ENHANCED DELIVERY (CED)

BACKGROUND MDNA55 is an IL4R-targeted toxin in development for treatment of recurrent glioblastoma (rGBM). MDNA55 binds to IL4R expressed by tumor cells and non-malignant cells of the tumor microenvironment. METHOD MDNA55-05 was an open-label, single-arm study of MDNA55 delivered by CED as a single treatment in patients with 1st or 2nd recurrence following de novo GBM, IDH wild type status and not indicated for resection at relapse. Dose volumes (up to 60mL) and concentration of MDNA55 (1.5 to 9.0 μg/mL) were studied. RESULTS MDNA55 showed an acceptable safety profile at all doses tested. Median OS (mOS) amongst all subjects was 11.9 months, OS-24 was 20%, and PFS-12 was 27%. Among subjects expressing high levels of IL4R (irrespective of MDNA55 dose) and low levels of IL4R expression administered high dose (≥ 180μg) of MDNA55 (IL4Rhi + IL4Rlo/hd), mOS further improved to 14.0 months with OS-24 of 20%. Unmethylated MGMT promoter status did not affect MDNA55 treatment outcomes. In the IL4Rhi + IL4Rlo/hd population (N=17), mOS was 14.9 months with OS-24 of 22%. Following treatment with high concentrations of MDNA55 (6.0 or 9.0 μg/mL), transient (median of 3 cycles) low dose Avastin (5mg/kg q2w or 7.5mg/kg q3w) was used for symptom control and steroid sparring. Among these subjects, mOS amongst all comers (N=9) and the IL4Rhi + IL4Rlo/hd group (N=8) increased to 21.8 and 18.6 months with OS-24 of 44% and 38%, respectively. CONCLUSIONS MDNA55 shows potential to benefit all rGBM patients treated at high dose irrespective of IL4R expression. In the 1:1 randomized Phase 3 trial, the study will enrol two-thirds of subjects in the SOC arm from a matched external control arm. Unlike conventional RCTs, the hybrid design sets a new precedent for GBM trials, allowing robust OS analysis while significantly reducing the number of subjects randomized to SOC arm.

RADT-08. A VOLUMETRIC ANALYSIS OF STEREOTACTIC RADIOSURGERY LOW DOSE VOLUMES IN PREVENTING FUTURE BRAIN METASTASES

PURPOSE/OBJECTIVE(S) Stereotactic radiosurgery (SRS), compared to whole brain radiotherapy is limited in its ability to prevent development of brain metastases in untreated areas. The purpose of this study is to assess whether low-dose volumes delivered to uninvolved regions of the brain during SRS can reduce the risk of developing brain metastases in those regions. MATERIALS AND METHODS Data were collected for 69 patients with brain metastases who were treated with SRS at least two occasions. The regions of uninvolved brain receiving a high, intermediate, and low dose of incidental radiotherapy were defined as the volume receiving at least 10, 5, and 2.5 Gy if the prescribed dose was &lt; 25 Gy (1-3 fraction plans) or the volume receiving at least 15, 7.5, and 5 Gy if the prescribed dose was ≥ 25 Gy (5 fraction plans). A second round metastasis was considered to occur within a given dose level if 20% or more of the tumor was found within that dose level. Probabilities were calculated based on the volume of each dose level as a percentage of total brain volume and were used to estimate the expected number of cases with at least one metastasis occurring in each dose level. RESULTS The average number of metastases treated in both rounds of SRS was two. The expected and observed number of cases with at least one second round metastasis were 0 and 2 for the high dose level (p=0.151), 7 and 3 for the intermediate dose level (p=0.018), and 17 and 11 for the low dose level (p=0.094). CONCLUSION We observed fewer than expected new metastases within prior SRS low dose levels based on volumetric probabilities, though this difference was only significant for the intermediate dose level. This suggests that low dose volumes from SRS may provide benefit in preventing future regional metastases.

Predictive factors of symptomatic radiation pneumonitis induced by durvalumab following concurrent chemoradiotherapy in locally advanced non-small cell lung cancer

BackgroundConcurrent chemoradiotherapy (CCRT) followed by durvalumab is the standard of care for unresectable locally advanced non-small cell cancer (LA-NSCLC). However, a major concern about the administration of durvalumab after CCRT is whether the incidence of symptomatic radiation pneumonitis (RP) increases. In the present analysis, we report the initial results of CCRT followed by durvalumab in patients with LA-NSCLC in a real-world setting with a focus on predictive factors for symptomatic RP. MethodsPatients who were pathologically diagnosed with NSCLC and initiated treatment with CCRT followed by durvalumab between July 2018 and December 2019 were eligible for this study. Patients were included if they completed the planned CRT course and were administered at least one course of durvalumab. We retrospectively investigated the preliminary survival outcome and incidence and predictive factors for symptomatic RP. ResultsOf the 67 patients who were scheduled to receive CCRT, 63 completed the entire CCRT course. Of these patients, 56 proceeded to consolidation with durvalumab. The median time to eternal discontinuation of durvalumab was 9.7 months. The cumulative proportions of patients who exhibited symptomatic RP were 30, 40 and 44% at 3, 6 and 12 months, respectively. In multivariate analyses, the pulmonary fibrosis score and lung V40 were significant predictive factors for symptomatic RP (p < 0.001, HR: 7.83, 95% CI: 3.38-18.13, and p = 0.034, HR: 3.17, 95% CI: 1.09-9.19, respectively). ConclusionsThe pulmonary fibrosis sore and lung V40 are significant predictive factors for symptomatic RP. We should be cautious about the administration of durvalumab for patients with subclinical pulmonary fibrosis. To the best of our knowledge, this is one of the first reports showing the predictive value of high dose volumes to the lung in patients with LA-NSCLC who receive CCRT followed by durvalumab.

Dosimetric comparison and biological evaluation of fixed-jaw intensity-modulated radiation therapy for T-shaped esophageal cancer

Background To evaluate the dosimetric and biological benefits of the fixed-jaw (FJ) intensity-modulated radiation therapy (IMRT) technique for patients with T-shaped esophageal cancer. Methods FJ IMRT plans were generated for thirty-five patients and compared with jaw tracking (JT) IMRT, static jaw (SJ) IMRT and JT volumetric modulated arc therapy (VMAT). Dosimetric parameters, tumor control probability (TCP) and normal tissue complication probability (NTCP), monitor units (MUs), delivery time and gamma passing rate, as a measure of dosimetric verification, were compared. The correlation between the length of PTV-C below the upper boundary of lung tissue (PTV-Cinferior) and dosimetric parameters and NTCP of the lung tissue were analyzed. Results The homogeneity and conformity of the target in the four plans were basically equivalent. When compared to the JT IMRT and SJ IMRT plans, FJ IMRT plan led to a statistically significant improvement in the NTCP and low-middle dosimetric parameters of the lung, and the improvement had a moderately positive correlation with the length of PTV-Cinferior, with a correlation coefficient ranging from 0.523 to 0.797; the FJ IMRT plan exhibited better lung sparing in low-dose volumes than the JT VMAT plan. The FJ IMRT plan had similar MUs (888 ± 99) and delivery times (516.1 ± 54.7 s) as the JT IMRT plan (937 ± 194, 522 ± 5.6 s) but higher than SJ IMRT (713 ± 137, 488.8 ± 45.2 s) and JT VMAT plan (517 ± 59, 263.7 ± 43.3 s). Conclusions The FJ IMRT technique is superior in reducing the low-dose volumes of lung tissues for patients with T-shaped esophageal cancer.

LID Study: Plasma lidocaine levels following airway topicalisation for paediatric microlaryngobronchoscopy (MLB)

Background A dose of 5mg/kg lidocaine is considered appropriate for paediatric airway topicalisation. Existing literature suggests younger children are susceptible to toxic lidocaine plasma levels and achieve this at a faster rate. Aims The primary outcome of this study was to ascertain peak plasma lidocaine levels after topicalisation for airway endoscopy. Secondary endpoints included: time to peak lidocaine plasma levels, signs of lidocaine toxicity (restricted to ECG changes or seizures when under anaesthesia) and clinical adverse events of laryngospasm, coughing or desaturation during the procedure. Methods Data was collected prospectively over 18 months at Royal Manchester Children’s Hospital. Children aged 0-8 years undergoing elective diagnostic or therapeutic airway endoscopy were included within the study. Standardised 2% lidocaine was used for airway topicalisation. Dose varied depending upon practitioner usual practice. Venous blood sampling occurred at 5, 10, 15 and 20 minutes post administration and plasma lidocaine levels (ng/ml) analysed. Results A significant relationship exists between higher peak plasma levels and ages <18 months (p=0.00973). Strong linear correlation exists between weight and age for our cohort (r=0.88). Higher peak plasma lidocaine levels occur with total dose volumes between 2 and 3mls of 2% lidocaine local anaesthetic (p=0.03) compared with <2ml total dose volumes. Data suggests a potential relationship of lower weights achieving higher peak plasma levels (p=0.0516). Reduced IQR variation of peak plasma lidocaine levels exists when lidocaine dosing is <5mg/kg. Conclusions Age and total dose volume of topicalised lidocaine have a significant relationship with plasma lidocaine levels. A dose of 5mg/kg topicalised lidocaine for paediatric airway endoscopy is safe and provides good operating conditions. Lower patient weights trend toward higher peak lidocaine plasma concentrations and require further investigation.