CT predictors of sub-centimeter occult lymph node metastases in oral cavity squamous cell carcinoma: A case-control study.

BACKGROUND: For patients with oral cavity squamous cell carcinoma (OCSCC) without evidence of nodal metastasis (cN0) on pre-operative evaluation, there are no clear guidelines who should undergo elective neck dissection (END) versus clinical surveillance. OBJECTIVE: To identify CT imaging characteristics of sub-centimeter lymph nodes that would help predict the likelihood of nodal metastases on pathology. METHODS: Retrospective review of cN0 OCSCC patients at a tertiary academic medical center was performed. Inclusion criteria included elective neck dissection, pre-operative CT imaging and presence of metastatic disease within lymph nodes. Control group consisted of patients without nodal metastases on pathology. CT features that were evaluated included asymmetric size, disrupted fatty hilum, asymmetric number, presence of cortical nodule, cortical nodule size, and round/oval shape. We evaluated the associations between CT LN features and the presence of metastases using multi-level mixed-effects logistic regression models. Model evaluation was performed using 5-fold cross-validation. The positive predictive value (PPV) and negative predictive value (NPV) were calculated. RESULTS: 26 patients in each study and control groups were included. Three-level mixed-effects logistic regression models indicated round/oval shape (OR = 1.39, p = .01), asymmetric number (OR = 7.20, p = .005), and disrupted fatty hilum (OR = 3.31, p = .04) to be independently predictive in a 3-variable model with sensitivity = 38.0%, specificity = 92.0%, and PPV = 93.8%. CONCLUSIONS: In cN0 OCSCC patients undergoing END, round/oval shape, asymmetric number, and disrupted fatty hilum of lymph nodes on pre-operative CT imaging are novel and highly predictive of occult nodal disease.

Reducing Surgical Risks for Otoplasty.

Prominauris is a common auricular deformity most often due to underdevelopment of the antihelical fold or overdevelopment of the conchal bowl. Significant psychosocial distress may result from prominent ears, leading to the development of a variety of surgical techniques over the years. A thorough understanding of the anatomy of both the normal and prominent ear is crucial for accurate analysis and surgical correction of the deformity. The procedure is well-tolerated and careful preoperative evaluation and adherence to meticulous cartilage-sparing techniques will lead to good results and low complication rates.

Predictors of Health Care Utilization Following Major Head and Neck Oncologic Surgery in Older Patients.

OBJECTIVE: To identify patient factors in older patients associated with making posttreatment visits in the first year after major head and neck oncologic surgery. STUDY DESIGN: Retrospective cohort study. SETTING: Academic institution. METHODS: Patients aged ≥60 years who underwent a neck dissection with or without a free flap reconstruction were retrospectively analyzed. Data collected included patient demographics, comorbidities, social variables, perioperative course, and clinical visits. RESULTS: Within a 1-year postoperative period, the 181 patients in our cohort had a mean ± SD 6.37 ± 3.6 postoperative clinic visits; 70% attended at least 4 visits. Multivariable regression analysis showed a significant association with distance closer to the hospital (P = .013): for every 10-mile increase in distance, the number of visits decreased by 0.15 (SE = 0.06). Additionally, receiving adjuvant radiation therapy (P = .0096) demonstrated significant associations: when compared with no adjuvant therapy, radiation therapy had on average 1.5 (SE = 0.56) more visits, and chemoradiation had 0.04 (SE = 0.73) more visits. CONCLUSION: Older patients who undergo major head and neck oncology surgery are more likely to attend posttreatment visits in the 1 year following surgery if they are discharged home rather than to a skilled nursing facility, live closer to the hospital, and undergo adjuvant radiation therapy.

Pediatric Mandible Fractures: Mechanism, Pattern of Injury, Fracture Characteristics, and Management by Age.

Background: Development of the craniofacial skeleton and different mechanisms of injury warrant different treatment paradigms for younger children versus those at skeletal maturity. Objective: To characterize the mechanism, fracture patterns, and management of mandible fractures across the pediatric age spectrum. Methods: A 10-year retrospective review of <18-year-old children with mandible fractures at a level 1 trauma center. Characteristics were compared by age subgroup analysis. Results: Of 220 patients meeting inclusion criteria, motor vehicle collision (n = 53, 40.8%), falls (n = 48, 36.9%), and assault (n = 19, 14.6%) were the most common mechanisms with more falls in younger children and more injury by assault in teenagers. Condylar fractures were most common in the 0- to <9-year-old children (n = 27, 38.4%); angle/ramus fractures (56, 62.6%) were most common in 15- to <18-year-old children (p < 0.001). Nonsurgical management was associated with younger age (p < 0.001). Fourteen of 125 patients (8.0%) undergoing surgical intervention experienced complications. Being uninsured was associated with shorter median (interquartile range) follow-up of 5.6 (1.4-10.7) weeks, compared with private [11.9 (4.3-49.0) weeks] and public insurance [11.7 (3.7-218.0) weeks] (p < 0.001). Conclusion: The mechanism, fracture sites, and treatment differed by age with the youngest frequently managed nonoperatively and teenagers treated with adult algorithms. Complications were rare overall within 6-12 weeks after injury, with or without surgical management.

Beauty Is in the Eye of the Beholder: Factors Influencing Disparity in Perceptions of Breast Reconstruction Aesthetic Outcomes.

BACKGROUND: Patient-reported outcomes are the primary measurement of breast reconstruction success, but results may be affected by nontechnical factors such as socioemotional determinants. Third-party observers provide an independent assessment of aesthetic outcomes. Factors associated with disparity between patient and observer perceptions of outcomes are not well understood. METHODS: One hundred forty-seven patients underwent breast reconstruction at the authors' institution between 2009 and 2011, completed the BREAST-Q, and had photographs graded by a diverse panel using the Validated Breast Aesthetic Scale. Patient satisfaction with breasts scores that aligned with observer scores were categorized as group 2; patient satisfaction that exceeded observer scores were group 1; and those lower than observer scores were group 3. Statistical analysis was performed using SPSS, with values of p < 0.05 considered statistically significant. RESULTS: Twenty-eight patients (19 percent) were categorized as group 1, 93 (63 percent) in group 2, and 26 (18 percent) in group 3. Median overall appearance was highest in group 3 (median, 4.0; interquartile range, 4 to 4) and lowest in group 1 (median, 3.0; interquartile range, 2 to 3) ( p < 0.001). Psychosocial, sexual, and physical well-being were significantly associated with disparity (group 1 or 3 status) ( p < 0.01). Satisfaction with outcomes, nipples, abdomen, and breasts were significantly associated with disparity. Factors not significantly associated with disparity include age, body mass index, autologous or implant-based, adjuvant therapies, and timing of reconstruction. CONCLUSIONS: Incongruously high patient satisfaction with breast reconstruction aesthetics relative to third-party perception of aesthetic outcomes is associated with high quality-of-life scores. Incongruously low patient satisfaction with breast cosmesis compared with higher third-party perceptions was associated with low quality-of-life scores. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.

Pre-styloid parapharyngeal space masses-Tumor margins as a predictor of benign versus malignant histology on pre-operative CT or MRI.

PURPOSE: Evaluate the frequency of benign versus malignant masses within the prestyloid parapharyngeal space (PPS) and determine if tumor margins on preoperative cross-sectional imaging can predict malignancy status. MATERIALS AND METHODS: The electronic health record at UC Davis Medical Center was searched for PPS masses surgically resected between 2015 and 2021. Cases located centrally within the prestyloid PPS with confirmed histologic diagnosis were included and separated into either benign or malignant groups. Margins of the tumors were categorized as "well defined" or "infiltrative" on preoperative cross-sectional imaging. Statistical analysis was performed to evaluate relationships between malignancy status and tumor margins. RESULTS: A total of 31 cases met the inclusion criteria. Fourteen separate histologic diagnoses were observed. Benign cases comprised 77% (24/31) and the remaining 23% (7/31) were malignant. Pleomorphic adenoma was the most common overall diagnosis at 48% (15/31). Adenoid cystic carcinoma 6% (2/31) was the most common malignant diagnosis. Well-defined tumor margins were seen in 81% (25/31) of cases. A benign diagnosis was found in 96% (24/25) of the cases with well-defined margins. Infiltrative tumor margins were displayed in 19% (6/31) of cases, all were malignant. The sensitivity and specificity of infiltrative tumor margins for malignancy were 85.7% and 100%, respectively. The negative predictive value of infiltrative margins for malignancy was 96%. CONCLUSION: Infiltrative tumor margins on preoperative imaging demonstrate high specificity and negative predictive value for malignant histology in prestyloid PPS masses. Margins should therefore be considered when determining clinical management for newly diagnosed PPS tumors.

A Novel Validated Breast Aesthetic Scale.

BACKGROUND: Breast aesthetics impacts patients' quality of life after breast reconstruction, but patients and surgeons frequently disagree on the final aesthetic evaluation. The need for a comprehensive, validated tool to evaluate breast aesthetics independently from the patient motivated this study. METHODS: The 13-item Validated Breast Aesthetic Scale was developed after several internal meetings, and worded to be understood by a nonspecialist. Three items are common for both breasts, with the remaining being side-specific. To test the internal consistency of the scale subitems, postoperative photographs after different breast reconstruction techniques were graded by a six-member panel. To test interrater and intrarater correlation across time, four physicians evaluated the results of abdominally based breast reconstructions following nipple-sparing mastectomies. RESULTS: Graded aesthetic outcomes of 53 patients showed that the Cronbach alpha of the subitems of the scale was 0.926, with no single item that, if excluded, would increase it. Twenty-two patients underwent aesthetic outcomes grading at four different time points. The mean overall appearance was 3.71 ± 0.62. The mean grade for overall nipple appearance was 4.0 ± 0.57. The coefficient alpha of the panel overall aesthetic grade across different time points was 0.957; whereas intragrader reliability for graders 1 through 4 individually showed alpha coefficients of 0.894, 0.9, 0.898, and 0.688, respectively. Similar results were found for the other items of the scale. CONCLUSIONS: The proposed aesthetic scale evaluates different aspects of the breast reconstruction aesthetic result with excellent internal consistency among its subitems. Grading by a gender-balanced, diverse four-member panel using postoperative photographs showed higher reliability and reproducibility compared to single graders.

Traumatic Optic Neuropathy Management: A Survey Assessment of Current Practice Patterns.

INTRODUCTION: The treatment of traumatic optic neuropathy (TON) is highly controversial with a lack of substantiated evidence to support the use of corticosteroids or surgical decompression of the optic nerve. The aim of the study was to determine if there was a general consensus in the management of TON despite controversy in the literature. METHODS: An anonymous survey of members of the American Society of Ophthalmic Plastic and Reconstructive Surgery and the North American Neuro-Ophthalmology Society regarding their practice patterns in the management of patients with TON was performed. RESULTS: The majority of 165 respondents indicated that they treated TON with corticosteroids (60%) while a significant minority (23%) performed surgical interventions (P < 0.0001). Subgroup analysis comparing rates of treatment with steroids among oculoplastic surgeons and neuro-ophthalmologists (67% vs. 47%) was not significant (Fisher's Exact test [FET], P =0.11) while results did suggest that a higher proportion of oculoplastic surgeons (33%) than neuro-ophthalmologists (11%) recommended surgical intervention (FET, P =0.004). In cases where visual acuity exhibited a downward trend treatment with steroids was the most commonly employed management. In general, neuro-ophthalmologists trended toward observation over treatment in TON patients with stable visual acuity while oculoplastic surgeons favored treatment with corticosteroids. CONCLUSIONS: In spite of the lack of class I evidence supporting intervention of TON, the majority of respondents were inclined to offer corticosteroid treatment to patients whose visual acuity showed progressive decline following injury.

The digital doctor: telemedicine in facial plastic surgery.

PURPOSE OF REVIEW: In the setting of the COVID-19 global pandemic, the demand for and use of telemedicine has surged in facial plastic and reconstructive surgery. This review aims to objectively review and summarize the existing evidence for the use of telemedicine within facial plastic surgery. RECENT FINDINGS: Telemedicine has been successfully implemented among subsets of facial plastic surgery patients, with high patient and provider satisfaction. Although the technology to facilitate telemedicine exists and preliminary studies demonstrate promise, multiple technological, financial, and medical barriers may persist in the postpandemic era. SUMMARY: Telemedicine will likely continue to grow and expand within facial plastic surgery moving forward, and we should continue to critically evaluate patient selection, access to care, and strategies for effective implementation to enhance current clinical practices.

A controlled cost and outcomes analysis of acellular dermal matrix and implant-based reconstruction.

INTRODUCTION: The use of acellular dermal matrix (ADM) for breast reconstruction continues to change in both single- and two-stage reconstruction. Determining optimal outcomes clinically, aesthetically, financially as well as for the patient's quality of life has become a priority. METHODS: A retrospective review of implant-based reconstructions was performed at a single center from 2010 to 2016, with patients blindly matched 1:1:1 into three cohorts based on reconstruction type: 1) single stage direct to implant with ADM, 2) two-stage tissue expander to implant (TE/I) without ADM, and 3) two-stage TE/I with ADM. Relative cost between groups, esthetic outcomes, and quality of life within each group was analyzed. RESULTS: Group 1 was more likely to be older and use intraoperative angiography, but with fewer overall surgeries and postoperative visits (p<0.001). There was no statistically significant difference in reconstructive success among all three groups (p = 0.85). Cost was significantly higher for group 3 relative to groups 1 and 2. Overall appearance was higher in groups 1 and 3 relative to group 2, with radiation therapy the only independent factor. Group 1 had higher scores using Breast-Q for the physical well-being domain (p = 0.01). CONCLUSION: This is the first study to incorporate clinical outcomes, esthetic visual grading, and patient-reported quality within the same cohort of individuals, considering both use of ADM and staging. Despite the added ADM cost, it is proven safe, eliminates time and cost associated with tissue expanders, decreases post-operative visits and can lead to equally as functional and aesthetically pleasing outcomes in single- and two-stage breast reconstructions.

Telemedicine, Patient Satisfaction, and Chronic Rhinosinusitis Care in the Era of COVID-19.

BACKGROUND: Telemedicine has become increasingly popular in the care of rhinologic patients during the COVID-19 pandemic. This change in practice patterns may place patients at risk of a perceived lower-quality exchange with their healthcare provider, which may in turn impact satisfaction. OBJECTIVE: This study compares patient satisfaction scores between in-person clinic visits and telemedicine video visits in patients with chronic rhinosinusitis (CRS). METHODS: Sixty-nine patients with CRS presenting to an academic rhinology clinic between March to April 2020 were retrospectively divided into video visits (VV) and clinic visits (CV) groups based on mandated state quarantine orders on March 19. Patient demographics, disease severity measures, and Patient Satisfaction Questionnaire-18 (PSQ-18) scores were collected and analyzed. Chi square test and Fisher's exact test were performed. RESULTS: There were no significant differences in age (p = 0.81), gender (p = 0.55), CRS phenotype (p = 0.16), and disease severity measures (Sinonasal Outcomes Test-22 (SNOT-22) (p = 0.92); Lund-Mackay score (p = 0.96)) between the video and clinic visit groups. There were no significant differences in PSQ-18 total scores (VV PSQ-18 mean score = 78.1, CV PSQ-18 mean score = 78.4; p = 0.67) or the following subdomain scores between the two groups: general satisfaction (p = 0.73), technical quality (p = 0.62), interpersonal manner (p = 0.41), communication (p = 0.31), financial aspects (p = 0.89), time spent with doctor (p = 0.88), and accessibility and convenience (p = 0.47). CONCLUSION: Patient satisfaction with telemedicine in the COVID-19 pandemic parallels that of traditional in-person visits. Video visits can serve as a viable alternative to clinic visits, while still maintaining high satisfaction.

Factors Influencing the Aesthetic Outcome and Quality of Life After Breast Reconstruction: A Cross-sectional Study.

BACKGROUND: The most important purpose of reconstruction is to increase or restore the patient's quality of life (QOL). The purpose of our study was to evaluate the QOL and aesthetic outcomes of patients after autologous versus implant-based breast reconstruction. METHODS: Patients who underwent breast reconstruction between 2009 and 2011 were included. The Breast-Q, a validated breast reconstruction QOL questionnaire, was used along with postoperative photographs panel analyses using a multiparameter breast-specific aesthetic outcome scale and retrospective evaluation of demographic and treatment data. RESULTS: Of 820 patients, 261 complete questionnaires were evaluated. On the multivariable linear regression, the "satisfaction with breasts" was positively influenced by autologous and bilateral reconstructions, whereas radiation therapy (RTx), the time between the reconstruction and the questionnaire, and the number of surgeries due to complications were negative factors (adjusted R = 0.183; P < 0.001). The same factors influenced the "satisfaction with the outcomes." The mean "overall breast appearance" was also positively influenced by autologous and bilateral reconstructions, and RTx and the total number of surgeries were negative predictive factors (adjusted R = 0.311, P < 0.001). CONCLUSIONS: The aesthetic result and QOL after breast reconstruction for breast cancer treatment are positively influenced by the use of autologous tissue and bilaterality. Factors that negatively influenced the aesthetic result and the QOL include use of RTx, a higher number of surgeries needed for the reconstruction, reoperations due to complications, higher body mass index, and a longer time elapsed between reconstruction and the questionnaire.

Neoadjuvant PD-1 Immune Checkpoint Blockade Reverses Functional Immunodominance among Tumor Antigen-Specific T Cells.

PURPOSE: Surgical resection of primary tumor with regional lymphadenectomy remains the treatment of choice for patients with advanced human papillomavirus-negative head and neck squamous cell carcinoma. However, even when pathologic disease-free margins can be achieved, locoregional and/or distant disease relapse remains high. Perioperative immunotherapy may improve outcomes, but mechanistic data supporting the use of neoadjuvant or adjuvant treatment clinically are sparse. EXPERIMENTAL DESIGN: Two syngeneic models of oral cavity carcinoma with defined T-cell antigens were treated with programmed death receptor 1 (PD-1) mAb before or after surgical resection of primary tumors, and antigen-specific T-cell responses were explored with functional and in vivo challenge assays. RESULTS: We demonstrated that functional immunodominance developed among T cells targeting multiple independent tumor antigens. T cells specific for subdominant antigens expressed greater levels of PD-1. Neoadjuvant, but not adjuvant, PD-1 immune checkpoint blockade broke immunodominance and induced T-cell responses to dominant and subdominant antigens. Using tumors lacking the immunodominant antigen as a model of antigen escape, neoadjuvant PD-1 immune checkpoint blockade induced effector T-cell immunity against tumor cells lacking immunodominant but retaining subdominant antigen. When combined with complete surgical excision, neoadjuvant PD-1 immune checkpoint blockade led to formation of immunologic memory capable of preventing engraftment of tumors lacking the immunodominant but retaining subdominant antigen. CONCLUSIONS: Together, these results implicate PD-1 expression by T cells in the mechanism of functional immunodominance among independent T-cell clones within a progressing tumor and support the use of neoadjuvant PD-1 immune checkpoint blockade in patients with surgically resectable carcinomas.

Contemporary management of frontal sinus fractures.

PURPOSE OF REVIEW: Frontal sinus fracture management is evolving. This article will highlight recent literature and provide an evidence-based algorithm in the contemporary management of frontal sinus fractures. RECENT FINDINGS: The role of transnasal endoscopic treatment of frontal sinus fractures has expanded to include fracture reduction and posterior table reconstruction. Evidence continues to support the safety of nonoperative management in select frontal sinus outflow tract fractures. SUMMARY: The management of frontal sinus fractures with frontal sinus outflow tract injury continues to evolve with a trend toward observation and minimally invasive approaches. Restoration of the frontal sinus outflow tracts with transnasal endoscopic techniques is being used increasingly in the acute and delayed setting. For severe fractures, the role of conservative treatment paradigms requires further research.

Early Otorrhea Rates: A Randomized Trial of Ciprofloxacin versus Saline Drops after Tympanostomy Tubes.

OBJECTIVE: The objectives of this study are to evaluate incidence, duration, and quality of life (QOL) impact of early tympanostomy tube otorrhea and tube patency when comparing topical ciprofloxacin versus normal saline use in the perioperative period. METHODS: Overall, 200 patients undergoing tube placement between November 19, 2015, and September 12, 2016, were randomized to intraoperative plus 5 days of either topical ciprofloxacin or normal saline. Parents or caregivers reported the incidence, duration, and QOL impact of early otorrhea via 4 weekly surveys. In addition, the patient's otorrhea history and tube patency were evaluated at a 4- to 6-week postoperative visit. RESULTS: Survey and in-office follow-ups were completed on 128 patients. The overall otorrhea incidence was 23.9% for normal saline and 16.7% for ciprofloxacin (P = .32). The week-by-week otorrhea incidence was not statistically different. The percentage of days otorrhea was present, likewise, was not statistically different (normal saline 4.5%, ciprofloxacin 2.8%; P = .74). The QOL impact was not statistically different (normal saline 1.2, ciprofloxacin 1.5; P = .71). Tube patency was not statistically different, with only 1 of 280 ears occluded at follow-up. CONCLUSION: We find no difference in the incidence, duration, and QOL impact of early tympanostomy tube otorrhea or tube patency between ciprofloxacin and normal saline. This supports the option to substitute normal saline for ciprofloxacin in ears without an active ear infection at the time of tube placement, which would reduce both cost and unnecessary antibiotic use. LEVEL OF EVIDENCE: 1b.

Inhibition of WEE1 kinase and cell cycle checkpoint activation sensitizes head and neck cancers to natural killer cell therapies.

BACKGROUND: Natural killer (NK) cells recognize and lyse target tumor cells in an MHC-unrestricted fashion and complement antigen- and MHC-restricted killing by T-lymphocytes. NK cells and T-lymphocytes mediate early killing of targets through a common granzyme B-dependent mechanism. Tumor cell resistance to granzyme B and how this alters NK cell killing is not clearly defined. METHODS: Tumor cell sensitivity to cultured murine KIL and human high affinity NK (haNK) cells in the presence or absence of AZD1775, a small molecule inhibitor of WEE1 kinase, was assessed via real time impedance analysis. Mechanisms of enhanced sensitivity to NK lysis were determined and in vivo validation via adoptive transfer of KIL cells into syngeneic mice was performed. RESULTS: Cultured murine KIL cells lyse murine oral cancer 2 (MOC2) cell targets more efficiently than freshly isolated peripheral murine NK cells. MOC2 sensitivity to granzyme B-dependent KIL cell lysis was enhanced by inhibition of WEE1 kinase, reversing G2/M cell cycle checkpoint activation and resulting in enhanced DNA damage and apoptosis. Treatment of MOC2 tumor-bearing wild-type C57BL/6 mice with AZD1775 and adoptively transferred KIL cells resulted in enhanced tumor growth control and survival over controls or either treatment alone. Validating these findings in human models, WEE1 kinase inhibition sensitized two human head and neck cancer cell lines to direct lysis by haNK cells. Further, WEE1 kinase inhibition sensitized these cell lines to antibody-dependent cell-mediated cytotoxicity when combined with the anti-PD-L1 IgG1 mAb Avelumab. CONCLUSIONS: Tumor cell resistance to granzyme B-induced cell death can be reversed through inhibition of WEE1 kinase as AZD1775 sensitized both murine and human head and neck cancer cells to NK lysis. These data provide the pre-clinical rationale for the combination of small molecules that reverse cell cycle checkpoint activation and NK cellular therapies.

Exploring the rationale for combining ionizing radiation and immune checkpoint blockade in head and neck cancer.

BACKGROUND: The ability of radiation to enhance antitumor immunity under specific experimental conditions is well established. Here, we explore preclinical data and the rationale for combining different radiation doses and fractions with immune checkpoint blockade immunotherapy. METHODS: We conducted a review of the literature. RESULTS: The ability of high-dose or hypofractionated radiation to enhance antitumor immunity resulting in additive or synergistic tumor control when combined with checkpoint blockade is well studied. Whether low-dose daily fractionated radiation does the same is less well studied and available data suggests it may be immunosuppressive. CONCLUSION: Although daily fractionated radiation is well established as the standard of care for the treatment of patients with head and neck cancer, how this radiation schema alters antitumor immunity needs further study. If the radiation doses and fractions alter antitumor immunity differently can have profound implications in the rational design of clinical trials investigating whether radiation can enhance response rates to immune checkpoint blockade.

PD-1 blockade reverses adaptive immune resistance induced by high-dose hypofractionated but not low-dose daily fractionated radiation.

Preclinical evidence suggests that high-dose hypofractionated ionizing radiation (IR) can enhance anti-tumor immunity and result in significant tumor control when combined with immune checkpoint blockade (ICB). However, low-dose daily fractioned IR used for many tumor types including head and neck squamous cell carcinoma results in lymphopenia and may be immunosuppressive. We compared immune correlates, primary tumor and abscopal tumor control rates following the addition of PD-1 mAb to either high-dose hypofractioned (8Gyx2) or low-dose daily fractionated (2Gyx10) IR in syngeneic models of cancer. When compared to 2Gyx10 IR, 8Gyx2 IR preserved peripheral and tumor-infiltrating CD8+ T-lymphocyte accumulation and activation and reduced peripheral and tumor gMDSC accumulation. Regulatory T-lymphocytes were largely unaltered. Type I and I IFN levels and expression of IFN-responsive MHC class I and PD-L1 was enhanced in tumors treated with 8Gyx2 compared to 2Gyx10 IR. Functionally, tumor-specific CD8+ T-lymphocyte IFN responses within tumor draining lymph nodes were enhanced following 8Gyx2 IR but suppressed following 2Gyx10 IR. When combined with PD-1 mAb, reversal of adaptive immune resistance and subsequent enhancement of CD8+ cell dependent primary and abscopal tumor control was observed following 8Gyx2 but not 2Gyx10 IR. These data strongly support that compared to daily fractionated low-dose IR, high-dose hypofractionated IR preserves or enhances anti-tumor immunity and, when combined with PD-1 mAb to reverse adaptive immune resistance, promotes anti-tumor immunity to control primary and distant tumors. These data critically inform the rational design of trials combining IR and ICB.

Dose-dependent enhancement of T-lymphocyte priming and CTL lysis following ionizing radiation in an engineered model of oral cancer.

OBJECTIVES: Determine if direct tumor cell cytotoxicity, antigen release, and susceptibility to T-lymphocyte killing following radiation treatment is dose-dependent. MATERIALS AND METHODS: Mouse oral cancer cells were engineered to express full-length ovalbumin as a model antigen. Tumor antigen release with uptake and cross presentation of antigen by antigen presenting cells with subsequent priming and expansion of antigen-specific T-lymphocytes following radiation was modeled in vitro and in vivo. T-lymphocyte mediated killing was measured following radiation treatment using a novel impedance-based cytotoxicity assay. RESULTS: Radiation treatment induced dose-dependent induction of executioner caspase activity and apoptosis in MOC1 cells. In vitro modeling of antigen release and T-lymphocyte priming demonstrated enhanced proliferation of OT-1 T-lymphocytes with 8Gy treatment of MOC1ova cells compared to 2Gy. This was validated in vivo following treatment of established MOC1ova tumors and adoptive transfer of antigen-specific T-lymphocytes. Using a novel impedance-based cytotoxicity assay, 8Gy enhanced tumor cell susceptibility to T-lymphocyte killing to a greater degree than 2Gy. CONCLUSION: In the context of using clinically-relevant doses of radiation treatment as an adjuvant for immunotherapy, 8Gy is superior to 2Gy for induction of antigen-specific immune responses and enhancing tumor cell susceptibility to T-lymphocyte killing. These findings have significant implications for the design of trials combining radiation and immunotherapy.