Faculty Bibliography

Tumors of the paranasal sinus and nasal cavity (PNS/NC) are rare and exhibit diverse histology, anatomic subsite, and malignant potential. Early-stage disease is typically managed with surgery, and locally advanced disease is treated with a combination of surgery, radiotherapy, and chemotherapy. Clinical decision-making is commonly guided by limited retrospective evidence. To address this limitation, we performed a systematic review to inform evidence-based consensus for the management of common clinical scenarios, including the potential roles of radiation and systemic therapy to promote structural preservation, elective neck management, and radiation technique considerations. A librarian-mediated literature search identified 39 studies of adult patients with PNS/NC tumors treated with curative intent that met the study inclusion criteria. Search results were reported using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) methodology. A modified-Delphi process was used to guide consensus for the appropriate use of various management strategies. Strong consensus existed for the appropriateness of primary surgery for early-stage disease, approaches to locally advanced disease with minimal periorbital fat invasion, and the use of induction chemotherapy with response-directed local therapy. Consensus regarding nodal treatment and the use of proton therapy in the adjuvant setting was less robust. The rarity and diversity of PNS/NC tumors limit randomized phase III trials to guide management. As such, this systematic review and appropriate-use consensus statements provide clinical guidance for the management of this challenging disease spectrum.

PURPOSE/UNASSIGNED:Screening colonoscopies (CS) performed before prostate stereotactic body radiation therapy (SBRT) allow for identifying synchronous malignancies and comorbid gastrointestinal (GI) conditions. Performing these procedures prior to radiation precludes the necessity of post-SBRT pelvic instrumentation, which may lead to severe toxicity and fistulization. We review compliance of CSs, incidence of GI pathology, and the impact of pretreatment CS findings on subsequent physician-reported toxicity and patient-reported quality of life (QoL). METHODS AND MATERIALS/UNASSIGNED:We reviewed an institutional database of patients treated for prostate cancer with SBRT including toxicity and QoL outcomes. A detailed review of pretreatment CS findings was reviewed including identification of diverticulosis, location of polyp resection, and presence of hemorrhoids. Pretreatment CS findings were then correlated with outcomes following SBRT. RESULTS/UNASSIGNED:Identification of comorbid GI conditions was a common event, with the presence of diverticulosis in 49.5% (n = 100), hemorrhoids in 67% (n = 136), and polyps in 48% (n = 98). More than half of patients with polyps removed had at least 1 removed from the rectosigmoid. Pretreatment CS did not introduce a delay in SBRT start date. Grade 1 toxicity was significantly lower in patients who underwent CS closer to the initiation of SBRT. There was no increased risk of physician-graded toxicity in the presence of diverticulosis, hemorrhoids, or polyps. Patient-reported GI QoL pattern in our screening cohort mimicked that seen in the previously published nonscreened population. There was no overt QoL detriment observed in patients who had GI pathology identified before SBRT. CONCLUSIONS/UNASSIGNED:GI pathology identified in our elderly patient population was commonly identified on pretreatment CS. Screening CS may optimize bowel health for patients heading into radiation therapy. Toxicity and QoL for patients with GI pathologies identified on pretreatment CS do not preclude the delivery of prostate SBRT. We advocate for pretreatment CS in patients eligible prior to SBRT.

PURPOSE/OBJECTIVE:Immune checkpoint inhibition (ICI) has revolutionized the treatment of melanoma care. Stereotactic radiosurgery combined with ICI has shown promise to improve clinical outcomes in prior studies in patients who have metastatic melanoma with brain metastases. However, others have suggested that concurrent ICI with stereotactic radiosurgery can increase the risk of complications. METHODS:We present a retrospective, single-institution analysis of 98 patients with a median follow up of 17.1 months managed with immune checkpoint inhibition and stereotactic radiosurgery concurrently and non-concurrently. A total of 55 patients were included in the concurrent group and 43 patients in the non-concurrent treatment group. Cox proportional hazards models were used to assess the relation between concurrent or non-concurrent treatment and overall survival or local progression-free survival. The Wald test was used to assess significance. Significant differences between patients in both groups experiencing adverse events including adverse radiation effects, perilesional edema, and neurological deficits were tested for using the Chi-square or Fisher's exact test. RESULTS:Patients receiving concurrent versus non-concurrent ICI showed a significant increase in overall survival (median 37.1 months, 95% CI: 18.9 months - NA versus median 11.4 months, 95% CI: 6.4-33.2 months, p = 0.0056) but not local progression-free survival. There were no significant differences between groups with regards to adverse radiation effects (2% versus 3%), perilesional edema (20% versus 9%), neurological deficits (3% versus 20%). CONCLUSION/CONCLUSIONS:These results suggest that the timing of ICI does not increase risk of neurological complications when delivered within 4 weeks of SRS.

BACKGROUND:Glioblastoma (GBM) is an aggressive form of brain cancer in which treatment is associated with toxicities that can result in therapy discontinuation or death. This analysis investigated clinical and genetic markers of vascular toxicities in GBM patients during active treatment. METHODS:591 Non-Hispanic White GBM patients with clinical data were included in the analysis from NRG RTOG-0825. Genome-wide association studies (GWAS) were performed from genotyped blood samples (N=367) by occurrence of thrombosis or hypertension (grade ≥2). A clinical prediction model was produced for each vascular toxicity. Significant GWAS variants were then added to the clinical model as a single nucleotide polymorphism (SNP) -dose effect variable to produce the final genetic models. RESULTS:Thrombosis and hypertension were experienced by 62 (11%) and 59 (10%) patients, respectively. Patients who experienced hypertension displayed improved survival over those without hypertension (median overall survival: 25.72 vs 15.47 months, p=0.002). The genetic model of thrombosis included corticosteroid use (OR: 7.13, p=0.02), absolute neutrophil count (OR: 1.008, p=0.19), body surface area (OR: 18.87, p=0.0008), and the SNP-dose effect (3 variants; OR: 3.79, p<.0001). The genetic model of hypertension included bevacizumab use (OR: 0.97, p=0.95) and the SNP-dose effect (6 variants; OR: 4.44, p<.0001). CONCLUSION/CONCLUSIONS:In this study, germline variants were superior in predicting hypertension than clinical variables alone. Additionally, corticosteroid use was a considerable risk factor for thrombosis. Future investigations should confirm the hazard of corticosteroid use on thrombosis and the impact of bevacizumab in other malignancies after accounting for the genetic risk of hypertension.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Hydrocephalus after Gamma Knife® stereotactic radiosurgery (SRS) for vestibular schwannomas is a rare but manageable occurrence. Most series report post-SRS communicating hydrocephalus in about 1% of patients, thought to be related to a release of proteinaceous substances into the cerebrospinal fluid. While larger tumor size and older patient age have been associated with post-SRS hydrocephalus, the influence of baseline ventricular anatomy on hydrocephalus risk remains poorly defined. METHODS:A single-institution retrospective cohort study examining patients who developed symptomatic communicating hydrocephalus after undergoing Gamma Knife® SRS for unilateral vestibular schwannomas from 2011 to 2021 was performed. Patients with prior hydrocephalus and cerebrospinal fluid diversion or prior surgical resection were excluded. Baseline tumor volume, third ventricle width, and Evans Index (EI)-maximum width of the frontal horns of the lateral ventricles/maximum internal diameter of the skull-were measured on axial postcontrast T1-weighted magnetic resonance imaging. RESULTS:A total of 378 patients met the inclusion criteria; 14 patients (3.7%) developed symptomatic communicating hydrocephalus and 10 patients (2.6%) underwent shunt placement and 4 patients (1.1%) were observed with milder symptoms. The median age of patients who developed hydrocephalus was 69 years (IQR, 67-72) and for patients younger than age 65 years, the risk was 1%. For tumor volumes <1 cm3, the risk of requiring shunting was 1.2%. The odds of developing symptomatic hydrocephalus were 5.0 and 7.7 times higher in association with a baseline EI > 0.28 (P = .024) and tumor volume >3 cm3 (P = .007), respectively, in multivariate analysis. Fourth ventricle distortion on pre-SRS imaging was significantly associated with hydrocephalus incidence (P < .001). CONCLUSION/CONCLUSIONS:Patients with vestibular schwannoma with higher baseline EI, larger tumor volumes, and fourth ventricle deformation are at increased odds of developing post-SRS hydrocephalus. These patients should be counseled regarding risk of hydrocephalus and carefully monitored after SRS.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Stereotactic radiosurgery (SRS) is effective for patients with medically refractory trigeminal neuralgia with a 75%-90% response rate. Consideration of the integral dose (ID) to the target nerve within the 50% isodose line was reported to help select prescription doses to maximize effectiveness and minimize bothersome numbness. The objective of this study was to externally validate the ID as a predictor of outcomes after SRS. METHODS:We reviewed the outcomes and parameters of 94 consecutive patients of type 1 trigeminal neuralgia who had SRS for the first time where nerve ID was calculated. 70% of the prescription doses were 80 Gy, with 28% at 85 Gy, and 2% at 70 Gy. RESULTS:The median follow-up time was 14.4 months. A total of 85 (90%) patients reported significant pain relief (Barrow Neurological Institute I-III) after initial SRS. The median pain recurrence-free survival was 82 months (95% CI 41.1-NA), and estimates at 1, 3, and 5 years were 80.5%, 65.5%, and 55.9%, respectively. The ID was not significantly associated with initial pain relief, or affect the risk of pain recurrence or sensory dysfunction after SRS using the Cox proportional hazards model. A nerve mean dose ≥65 Gy was associated with a reduced risk of pain recurrence on multivariate analysis (hazard ratio 0.408, P = .039). Twenty (21%) patients experienced sensory dysfunction after SRS with 3 (3%) requiring further medications, which was not correlated with the prescription dose or brainstem maximum dose. CONCLUSION/CONCLUSIONS:The ID did not predict recurrence-free survival or sensory dysfunction. Our observations suggest improved nerve coverage by the most powerful area of the isocenter, for instance, by targeting a narrower segment if feasible, could result in more durable pain relief. Further studies to validate these findings are needed.

The pancreas tumor microbiota may influence tumor microenvironment and influence survival in early-stage pancreatic ductal adenocarcinoma (PDAC); however, current studies are limited and small. We investigated the relationship of tumor microbiota to survival in 201 surgically resected patients with localized PDAC (Stages I-II), from The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) cohorts. We characterized the tumor microbiome using RNA-sequencing data. We examined the association of the tumor microbiome with overall survival (OS), via meta-analysis with the Cox PH model. A microbial risk score (MRS) was calculated from the OS-associated microbiota. We further explored whether the OS-associated microbiota is related to host tumor immune infiltration. PDAC tumor microbiome α- and β-diversities were not associated with OS; however, 11 bacterial species, including species of Gammaproteobacteria, confirmed by extensive resampling, were significantly associated with OS (all Q < 0.05). The MRS summarizing these bacteria was related to a threefold change in OS (hazard ratio = 2.96 per standard deviation change in the MRS, 95% confidence interval = 2.26-3.86). This result was consistent across the two cohorts and in stratified analyses by adjuvant therapy (chemotherapy/radiation). Identified microbiota and the MRS also exhibited association with memory B cells and naïve CD4⁺ T cells, which may be related to the immune landscape through BCR and TCR signaling pathways. Our study shows that a unique tumor microbiome structure, potentially affecting the tumor immune microenvironment, is associated with poorer survival in resected early-stage PDAC. These findings suggest that microbial mechanisms may be involved in PDAC survival, potentially informing PDAC prognosis and guiding personalized treatment strategies.IMPORTANCEMuch of the available data on the PDAC tumor microbiome and survival are derived from relatively small and heterogeneous studies, including those involving patients with advanced stages of pancreatic cancer. There is a critical knowledge gap in terms of the tumor microbiome and survival in early-stage patients treated by surgical resection; we expect that advancements in survival may initially be best achieved in these patients who are treated with curative intent.

PURPOSE/OBJECTIVE:In patients with breast cancer, prone radiation therapy (RT) has been shown to reduce heart and lung dose. Though prone positioning is routinely used for whole breast RT, its use when treating the regional lymph nodes is not widespread. METHODS AND MATERIALS/METHODS:In this phase 1/2 trial for stage IB-IIA breast cancer treated with lumpectomy or mastectomy, patients received 40.5 Gy in 15 fractions to the breast or chest wall and regional lymph nodes with an integrated tumor bed boost for lumpectomy patients. Primary endpoints were grade >2 acute toxicity and dosimetric feasibility. Secondary endpoints were the incidence of resimulation to improve dosimetry and late toxicity. Exploratory endpoints were local recurrence, disease-free survival, distant recurrence-free survival, and overall survival. RESULTS:From 2009 to 2016, 97 patients were enrolled (68% lumpectomy and 32% mastectomy), among which 92 were treated in the prone position. Five patients were resimulated and treated supine. Among the prone-treated patients, there were no acute toxicities greater than grade 2. A total of 92%, 98%, and 89% met a planning target volume tumor V48 Gy ≥98%, breast V40.5 Gy ≥95%, and nodal V38.5 Gy ≥95%, respectively. All met the heart V5 Gy <5%, contralateral lung V5 Gy <15%, spinal cord dose maximum (Dmax) ≤37.5 Gy, esophagus V30 Gy <50%, and Dmax ≤40.5 Gy. Ninety-eight percent met the ipsilateral lung V10 Gy. Brachial plexus Dmax <42 Gy was met in 74% with a mean increase of 1.61 Gy (SD, 1.96 Gy) over the target. At a median follow-up of 8 years, grade 2 to 3 late toxicity was 23% for prone patients. There were 2 local recurrences (2%) and no chest wall or nodal recurrences. The 8-year distant recurrence-free survival, disease-free survival, and overall survival were 88% (95% CI, 81%-95%), 86% (95% CI, 78%-95%), and 91% (95% CI, 84%-98%), respectively. CONCLUSIONS:Toxicity was low, and outcomes were excellent in this prospective trial of prone hypofractionated nodal RT.