Losartan May Not Prevent Vestibular Schwannoma Growth or Related Hearing Loss During Observation.

OBJECTIVE: To evaluate the impact of losartan on vestibular schwannoma (VS) growth and related hearing loss during observation. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary referral center. PATIENTS: Sporadic VS patients undergoing initial observation with at least two magnetic resonance imaging and audiologic examinations. INTERVENTION: Losartan. MAIN OUTCOME MEASURES: Endpoints included VS growth, quantitative audiologic changes, survival free of tumor growth, and survival free of nonserviceable hearing. Patient characteristics and endpoints were compared by losartan use. RESULTS: Seventy-nine patients were included, of which 33% were taking losartan. Tumor growth was observed in 50% of patients in the losartan group and 36% in the non-losartan group (p = 0.329). Survival analysis failed to show a significant difference in the hazard rate of VS growth between groups (hazard ratio, 1.38; 95% confidence interval, 0.70-2.70; p = 0.346). Throughout observation, mean decreases in normalized pure-tone average were 5.5 and 9.3 dB in the losartan and non-losartan groups, respectively (p = 0.908). Mean decreases in normalized word recognition score were 11.0 and 16.6% in the losartan and non-losartan groups, respectively (p = 0.757). Nonserviceable hearing developed in 19% of patients in the losartan group and 28% in the non-losartan group (p = 0.734). Survival analysis did not demonstrate a significant difference in the hazard rate of developing nonserviceable hearing between groups (hazard ratio, 1.71; 95% confidence interval, 0.56-5.21; p = 0.337). CONCLUSIONS: Losartan use may not reduce the risk of VS growth or hearing loss during observation. A randomized trial would be ideal to further identify the true effect on growth and hearing.

Survival Outcomes of Temporal Bone Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis.

OBJECTIVE: Temporal bone squamous cell carcinoma (TBSCC) is a rare malignancy with poor prognosis, and optimal treatment for advanced cases is uncertain. Our systematic literature review aimed to assess 5-year survival outcomes for advanced TBSCC across different treatment modalities. DATA SOURCES: EMBASE, Medline, PubMed, and Web of Science. REVIEW METHODS: A systematic literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for articles published between January 1989 and June 2023. RESULTS: The review yielded 1229 citations of which 31 provided 5-year survival data for TBSCC. The final analysis included 1289 patients. T classification data was available for 1269 patients and overall stage for 1033 patients. Data for 5-year overall survival (OS) was 59.6%. Five-year OS was 81.9% for T1/2 and 47.5% for T3/4 (P < .0001). OS for T1/T2 cancers did not significantly differ between surgery and radiation (100% vs 81.3%, P = .103). For advanced-stage disease (T3/T4), there was no statistical difference in OS when comparing surgery with postoperative chemoradiotherapy (CRT) (OS 50.0%) versus surgery with postoperative radiotherapy (XRT) (OS 53.3%) versus definitive CRT (OS 58.1%, P = .767-1.000). There was not enough data to assess the role of neoadjuvant CRT. CONCLUSION: Most patients will present with advanced-stage disease, and nodal metastasis is seen in nearly 22% of patients. This study confirms the prognostic correlation of the current T classification system. Our results suggest that OS did not differ significantly between surgery and XRT for early stage disease, and combined treatment modalities yield similar 5-year OS for advanced cancers.

Cochlear Implantation After Head and Neck Radiation: A Case Series, Systematic Review, and Meta-analysis.

OBJECTIVE: To determine if cochlear implant (CI) is safe and effective in patients with radiation therapy (XRT)-induced sensorineural hearing loss and to discuss considerations in this population through a retrospective cohort review, systematic review, and meta-analysis. DATABASES REVIEWED: PubMed, Cochrane Library, and Embase. METHODS: We retrospectively reviewed all CI cases after head and neck (HN) XRT at our institution, noting intraoperative findings, postoperative complications, and hearing outcomes. Change in speech discrimination scores (SDSs) was the primary outcome measure. Systematic review was performed to identify all cases of CI after HNXRT. A meta-analysis was performed to assess SDS change. RESULTS: The retrospective cohort review identified 12 patients who underwent CI after HNXRT. One patient with HN cancer (HNC) and one with central nervous system pathology (CNSP) received bilateral implants. Six had HNC, three had CNSP, and one had Langerhans cell histiocytosis. Eleven had abnormal findings during CI. There were no postoperative complications. Twenty articles with an additional 97 patients were suitable for systematic review inclusion. Of the 109 patients, 67 (61.5%) had HNC and 18 (16.5%) had CNSP. Abnormal intraoperative findings were common (30.3%), most frequently in the mastoid (66.7%). Postoperative complications, including wound dehiscence and infection with some requiring explantation, occurred in 10.1% of patients. Sixty-six patients were included in the meta-analysis. All demonstrated SDS improvement (mean increase, 56.2%). CONCLUSION: Patients with prior HNXRT benefit from CI. Paying careful attention to surgical planning and technique, postoperative care, and patient expectations is imperative, as complications are not uncommon.

A case of sudden hearing loss in a patient with chronic myelomonocytic leukemia.

Chronic myelomonocytic leukemia is a myeloid stem cell disease characterized by an abnormal production and accumulation of monocytic cells in association with other signs of myeloproliferation. Extramedullary manifestations of CMML are common and can affect the spleen, liver skin, and lymph nodes. However, otologic manifestations are extremely rare and could have occurred from either direct leukemic infiltration, hemorrhage of the cochlea, labyrinth, leukostasis, or infection. There is no standard treatment protocol for sensorineural hearing loss in CMML patients. More research is needed to improve the understanding of the pathogenesis of this condition, in order to provide better treatment options.

Current status of sinonasal cancer survivorship care.

Sinonasal cancer is a heterogeneous orphan disease of diverse histologies, each with distinct clinical, oncologic, and toxicity profiles. Because of the comparative rarity of these cancers, sinonasal cancers are treated as a grouped diagnosis despite their clinical and biological heterogeneity. Multimodality treatment with a combination of surgery, chemotherapy, and/or radiotherapy is the standard-of-care for advanced-stage patients but there are few surveillance or follow-up practice guidelines or formalized survivorship care pathways. A scoping literature review was conducted via PubMed, EMBASE, and Google Scholar. A total of 112 studies were included, which were grouped along the following topics: surveillance, second primary tumors, quality of life, and symptom burden. Sinonasal cancer tends to exhibit a higher rate of local failure and occur in a delayed fashion compared to mucosal malignancies of the head and neck. Moreover, the site of failure and time-varying risk of recurrence is histology-specific. Following multimodality treatment of the skull base, patients may experience endocrine, visual, auditory, sinonasal, olfactory, and neurocognitive deficits, as well as psychosocial impairments that impact multiple physical and neuropsychological domains, resulting in diminished quality of life. Sinonasal cancer patients would benefit from tailored, histology-specific survivorship programs to address the recurrence, second primary, and functional impairments resulting from disease and treatment toxicity.

Predictors of postoperative performance status after surgical management of infratemporal fossa malignancies.

Infratemporal fossa (ITF) tumors are difficult to access surgically due to anatomical constraints. Moreover, aggressive ITF carcinomas and sarcomas necessitate aggressive treatment strategies that, along with tumor-related symptoms, contribute to decreases in patient performance status. To assess factors that predict postoperative performance in patients undergoing surgery for ITF tumors. We reviewed medical records for all patients surgically treated for an ITF malignancy between January 1, 1999, and December 31, 2017, at our institution. We collected patient demographics, preoperative performance, tumor stage, tumor characteristics, treatment modalities, pathological data, and postoperative performance data. The 5-year survival rate was 62.2%. Higher preoperative Karnofsky Performance Status (KPS) score (n = 64; p < 0.001), short length of stay (p = 0.002), prior surgery at site (n = 61; p = 0.0164), and diagnosis of sarcoma (n = 62; p = 0.0398) were predictors of higher postoperative KPS scores. Percutaneous endoscopic gastrostomy (PEG) (n = 9; p = 0.0327), and tracheostomy tube placement (n = 20; p = 0.0436) were predictors of lower postoperative KPS scores, whereas age at presentation (p = 0.72), intracranial tumor spread (p = 0.8197), and perineural invasion (n = 40; p = 0.2195) were not. Male patients and patients with carcinomas showed the greatest decreases in KPS scores between pretreatment and posttreatment. Higher preoperative KPS score and short length of stay were the best predictors of higher postoperative KPS scores. This work provides treatment teams and patients with better information on outcomes for shared decision-making.

The Effect of Metformin on Vestibular Schwannoma Growth: A Systematic Review and Meta-analysis.

OBJECTIVES: To systematically review and evaluate metformin's potential impact on vestibular schwannoma (VS) growth. DATA SOURCES: PubMed, Cochrane Library, and Embase. REVIEW METHODS: A retrospective cohort study was performed on sporadic VS patients undergoing initial observation who had at least two magnetic resonance imaging studies. Patients were stratified by metformin use during the observation period. Primary endpoint was VS growth, defined as at least a 2 mm increase in diameter. Survival free of tumor growth was evaluated between groups. Systematic review and meta-analysis were performed to produce a pooled odds ratio [OR]. Study heterogeneity was assessed and post-hoc power analysis was performed. RESULTS: A total of 123 patients were included, of which 17% were taking metformin. Median patient age was 56.6 years (range, 25.1-84.5). There were no statistically significant differences between the groups. Survival analysis did not demonstrate a statistically significant difference in time to VS growth between groups (hazard ratio = 0.61, 95% confidence interval [CI] = 0.29-1.29). Furthermore, logistic regression analysis did not demonstrate a statistically significant difference between groups in the odds of VS growth (OR = 0.46, 95% CI = 0.17-1.27). Systematic review identified 3 studies. Meta-analysis suggested that metformin reduces the odds of developing VS growth (pooled OR = 0.45, 95% CI = 0.29-0.71). Studies demonstrated low between-study heterogeneity. Power analysis demonstrated a sample size of 220 patients with equal randomization would be required to prospectively identify a true difference with 80% power. CONCLUSIONS: Metformin use may reduce the odds of VS growth. A randomized trial would be ideal to identify an unbiased estimate of metformin's effect on VS growth. Laryngoscope, 133:2066-2072, 2023.

Association of hearing loss and tinnitus symptoms with health-related quality of life among long-term oropharyngeal cancer survivors.

BACKGROUND: This study investigated the association of hearing loss and tinnitus with overall health-related quality of life (HRQoL) among long-term oropharyngeal cancer (OPC) survivors. METHODS: This study included OPC survivors treated between 2000 and 2013 and surveyed from September 2015 to July 2016. Hearing loss and tinnitus were measured by asking survivors to rate their "difficulty with hearing loss and/or ringing in the ears" from 0 (not present) to 10 (as bad as you can imagine). Hearing loss and tinnitus scores were categorized as follows: 0 for none, 1-4 for mild, and 5-10 for moderate to severe. The primary outcome was the mean score of MD nderson Symptom Inventory Head & Neck module interference component as a HRQoL surrogate dichotomized as follows: 0 to 4 for none to mild and 5 to 10 for moderate to severe interference. RESULTS: Among 880 OPC survivors, 35.6% (314), reported none, 39.3% (347) reported mild, and 25.1% (221) reported moderate to severe hearing loss and tinnitus. On multivariable analysis, mild (OR, 5.83; 95% CI; 1.48-22.88; p = 0.012) and moderate (OR, 30.01; 95% CI; 7.96-113.10; p < 0.001) hearing loss and tinnitus were associated with higher odds of reporting moderate to severe symptom interference scores in comparison to no hearing loss and tinnitus. This association of hearing dysfunction was consistent with all domains of HRQoL. CONCLUSIONS: Our findings provide preliminary evidence to support the need for continued audiological evaluations and surveillance to detect hearing dysfunction, to allow for early management and to alleviate the long-term impact on QoL.

Patient, Disease, and Treatment-Related Factors Affecting Progression-Free and Disease-Specific Survival in Recurrent Chondrosarcomas of the Skull Base.

BACKGROUND: Recurrent skull base chondrosarcomas (CSA) are difficult to treat, and limited data are available to help guide subsequent therapy. OBJECTIVE: To further characterize the natural history of CSA and identify treatment modalities that were most effective in prolonging progression-free (PFS) and disease-specific survival (DSS). METHODS: We conducted a single-institution retrospective review of patients with recurrent skull base CSA from 1993 to 2021. Kaplan-Meier survival analyses for PFS and DSS were completed. Univariable and multivariable Cox proportional hazards regression models were used to identify patient-related, treatment-related, and disease-related factors that predicted PFS and DSS. RESULTS: A total of 28 patients and 84 episodes of recurrence were included. One-year PFS was 70.6%, 5-year PFS was 28.9%, and 10-year DSS was 78.5%. The median time to first progression was 23.9 months (range, 2.8-282 months). In univariable Cox proportional hazards regression, male sex, higher grade histology, fourth or greater progression episode status, distal pattern of recurrence, and treatment of recurrence without surgery or with chemotherapy alone predicted worse PFS. Multivariable regression predicted shortened DSS in male patients (hazard ratio [HR] 0.16; P = .021) and higher-grade tumors (HR 0.22; P = .039). Treatment of recurrence with surgery was associated with, but did not significantly predict, improved DSS (HR 1.78; P = .11). CONCLUSION: Several patient and disease-specific factors were associated with shorter PFS and DSS in recurrent skull base chondrosarcoma. For recurrences amenable to resection, surgery is recommended for treatment of recurrent CSA. Local recurrence management without surgery results in shorter PFS and DSS.

Survival Outcomes of Patients with Mycosis Fungoides Involving the External Ear and Ear Canal.

OBJECTIVES/HYPOTHESIS: Mycosis Fungoides (MF) is the most common subtype of cutaneous T-cell lymphoma. Disease involvement of specific locations may be more significant than simply the symptoms associated with that site; it is possible that involvement of certain sites could be associated with poor prognosis. We aimed to evaluate the outcomes of patients with MF with documented involvement of the EAC and external ear. STUDY DESIGN: Retrospective analysis. METHODS: We retrospectively reviewed 40 patients with MF that were treated by otologists between 2012 and 2021. RESULTS: We report the largest series of patients with MF involving the external ear and EAC. Of the 40 patients included in this study, 17 presented with Mycosis Fungoides in the otologic region (MFO). Of these 17 MFO patients, 2/17 had involvement of the external ear only, 3/17 of the EAC only, 11/17 of both the external ear and EAC, and 1/17 of the periauricular skin. Of note, 11/14 (79%) patients presenting with EAC disease died compared to11/26 (42%) of patients without involvement. In addition, eight of the 13 (62%) patients with external ear involvement died compared to 14/27 (52%) of patients without involvement. Ear canal involvement was associated with a statistically significant shorter overall survival duration in patients with MF (p = 0.03). Furthermore, disease in the EAC was found to have a hazard ratio value of 2.565 (CI 1.102-5.970). CONCLUSIONS: Involvement of the EAC by MF portends a poor prognosis. This finding highlights the need for a more in-depth otologic evaluation of patients with MF. LEVEL OF EVIDENCE: 4 Laryngoscope, 133:1486-1491, 2023.

Distinct immune signature predicts progression of vestibular schwannoma and unveils a possible viral etiology.

BACKGROUND: The management of sub-totally resected sporadic vestibular schwannoma (VS) may include observation, re-resection or irradiation. Identifying the optimal choice can be difficult due to the disease's variable progression rate. We aimed to define an immune signature and associated transcriptomic fingerprint characteristic of rapidly-progressing VS to elucidate the underpinnings of rapidly progressing VS and identify a prognostic model for determining rate of progression. METHODS: We used multiplex immunofluorescence to characterize the immune microenvironment in 17 patients with sporadic VS treated with subtotal surgical resection alone. Transcriptomic analysis revealed differentially-expressed genes and dysregulated pathways when comparing rapidly-progressing VS to slowly or non-progressing VS. RESULTS: Rapidly progressing VS was distinctly enriched in CD4+, CD8+, CD20+, and CD68+ immune cells. RNA data indicated the upregulation of anti-viral innate immune response and T-cell senescence. K - Top Scoring Pair analysis identified 6 pairs of immunosenescence-related genes (CD38-KDR, CD22-STAT5A, APCS-CXCR6, MADCAM1-MPL, IL6-NFATC3, and CXCL2-TLR6) that had high sensitivity (100%) and specificity (78%) for identifying rapid VS progression. CONCLUSION: Rapid progression of residual vestibular schwannoma following subtotal surgical resection has an underlying immune etiology that may be virally originating; and despite an abundant adaptive immune response, T-cell immunosenescence may be associated with rapid progression of VS. These findings provide a rationale for clinical trials evaluating immunotherapy in patients with rapidly progressing VS.

Audiovestibular Toxicity Secondary to Immunotherapy: Case Series and Literature Review.

Introduction: Audiovestibular toxicity secondary to immunotherapy has only rarely been reported in the literature. Herein, we examine our experience diagnosing and managing audiovestibular immune-related adverse events (irAEs) in patients undergoing immunotherapy. Methods: Four patients who experienced irAEs were included. Demographics, immunotherapy regimen, diagnostic tests, treatment, and outcomes were recorded in a retrospective chart review. Results: The cases of three patients with metastatic melanoma and one patient with metastatic renal cell carcinoma are presented. Hearing loss and tinnitus were the most common presenting symptoms. Immune checkpoint inhibitors (ICIs) were implicated in three cases and T-cell therapy in one case. Two of three patients (67%) treated with steroids had substantial improvements in hearing. Conclusions: Audiovestibular irAEs are a rare complication of immunotherapy. Suspicion for symptoms including hearing loss, tinnitus, and/or vertigo should prompt an expedient referral to the otolaryngologist for evaluation, as symptoms may improve with corticosteroid use. Hearing and/or vestibular deficits can have a substantial impact on the quality of life for affected patients, but rehabilitation options do exist.

Ultrasound-Guided Placement of Percutaneous Abutments for Bone Conduction Hearing Devices.

OBJECTIVE: To introduce a minimally invasive and image-guided technique for staged placement of a percutaneous abutment after osseointegrated implantation. PATIENTS: Adults undergoing temporal bone resection at two academic medical centers. INTERVENTIONS: Ultrasound-guided percutaneous installation of a bone conduction hearing device abutment. All patients had lateral temporal bone resection with osseointegrated implantation. Abutment placement followed as a planned staged procedure 3 to 6 months later depending on the use of radiotherapy. MAIN OUTCOME MEASURES: Ability to use a bone conduction hearing device and occurrence of skin reactions or wound complications. RESULTS: Twelve patients successfully underwent abutment installation through a 5 mm skin biopsy punch incision, nine of which had minimal to no skin reaction surrounding the abutment. Two patients developed Holgers grade 1 skin reaction (redness with slight swelling). One patient experienced an osseointegration failure 152 days after abutment placement. CONCLUSIONS: Ultrasound is a widely available imaging modality that can be used to precisely localize subcutaneous osseointegrated implants, allowing for minimally invasive percutaneous placement of an abutment under local or general anesthesia.

Perineural Invasion of the Intratemporal Facial Nerve: How Far Proximally Do We Chase the Positive Margin?

OBJECTIVE: To determine recurrence patterns in patients with head and neck cancers requiring facial nerve sacrifice and to determine the optimal management of the positive proximal facial nerve margin. STUDY DESIGN: Case series with chart review. SETTING: Tertiary care center. PATIENTS: One hundred fifty-five patients with head and neck malignancies who underwent sacrifice of the facial nerve between March 1, 1999 and October 31, 2020. Demographics, preoperative facial nerve function, prior oncologic treatment, histologic type, operative details, adjuvant treatment, recurrence patterns, and overall survival were reviewed. MAIN OUTCOME MEASURES: Recurrence rates and recurrence location. RESULTS: Thirteen patients (8%) had positive proximal margins on final pathologic evaluation. Six of 13 (46%) experienced disease recurrence. No disease recurred proximally along the facial nerve. The recurrence rate was 26% for negative proximal facial nerve margins. Segments of the facial nerve biopsied included: extratemporally (n = 78), at the stylomastoid foramen (36), mastoid segment (22), second genu (7), tympanic (6), geniculate (3), labyrinthine (1), and IAC (2). Median patient follow-up was 30.3 months. CONCLUSIONS: Our data suggest that a conservative approach to a positive proximal facial nerve margin is optimal with respect to operative planning, patient morbidity, and disease recurrence patterns. Recurrence proximally along the facial nerve is an exceedingly rare event and the necessity of biopsy proximal to the geniculate ganglion, and in some cases even to the second genu, is called into question.

Temporal Bone Osteoradionecrosis: An 18-year, Single-Institution Experience.

OBJECTIVES/HYPOTHESIS: To report the largest single-institution review of temporal bone osteoradionecrosis (TBORN), and characterize the disease's natural history, prognostic factors, management, and outcomes. STUDY DESIGN: Retrospective chart review. METHODS: Retrospective review was conducted to identify patients with TBORN. Pertinent data were extracted. Descriptive statistics were used to summarize patient, tumor, and treatment characteristics. Multivariable analyses were conducted to explore associations between these characteristics and time to TBORN diagnosis and risk of developing diffuse disease. RESULTS: TBORN was identified in 145 temporal bones from 128 patients. Mean age at diagnosis was 62 years, and mean time to diagnosis after radiotherapy was 10 years. Age greater than 50 years was associated with earlier diagnosis. According to the Ramsden criteria, 76% of TBs had localized and 24% had diffuse disease at initial diagnosis; 37% had diffuse disease at last follow-up. On multivariable analysis, diabetes, three-dimensional conformal radiotherapy (3D-CRT), and periauricular skin malignancy were significant risk factors for developing diffuse disease. Localized disease was successfully managed with conservative measures, whereas surgery was often necessary for diffuse disease. When TBORN spread outside the mastoid or infratemporal fossa, conservative measures were always unsuccessful. CONCLUSIONS: TBORN occurs earlier in older patients. While diffuse disease is less common than localized disease, it occurs more frequently in patients with diabetes, history of 3D-CRT, and periauricular skin malignancies. Conservative management is appropriate for localized disease, while surgery is often necessary for diffuse disease. The prognostic factors identified helped propose a TBORN staging system and treatment guidelines which may improve patient risk stratification and disease management. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:2578-2585, 2021.

Melanoma of the External Auditory Canal: A Review of Seven Cases at a Tertiary Care Referral Center.

OBJECTIVES/HYPOTHESIS: Examine the presentation and management characteristics of seven patients with melanoma of the external auditory canal (EAC). STUDY DESIGN: Retrospective case series and review of the relevant literature. METHODS: Records of seven patients from 2003 to 2017 with melanoma of the EAC were reviewed for characteristics of presentation, subsequent management, and outcomes. A thorough review of relevant literature is presented. RESULTS: The median age is 52 years, with four females. The average Breslow depth was 3.6 mm, with five patients having a Clark level IV or greater on presentation. Six patients underwent lateral temporal bone resection, and one patient underwent wide local excision of the cartilaginous canal. Sentinel lymph node biopsy (SLNB) was performed in three patients. Three patients experienced distant recurrence an average of 20 months following primary therapy. Median follow-up was 21 months. At last follow-up, four were free of disease, one had active disease, and two were deceased from melanoma. CONCLUSIONS: This is the largest series and the first to report the use of SLNB for patients with EAC melanoma in the peer-reviewed literature. Patients with external auditory canal melanoma present with higher Breslow thickness and stage relative to all external ear melanomas. Management should include wide local excision, which entails lateral temporal bone resection when the bony ear canal is involved. SLNB has a critical role in identifying patients with early metastatic disease. Postoperative radiation therapy should be considered for patients with high-risk features to reduce the risk of locoregional relapse. Chemotherapy, and especially immunotherapy, has an emerging role for this disease. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:165-172, 2021.

Immune-Related Oral, Otologic, and Ocular Adverse Events.

Emerging immunotherapeutic agents, including immune checkpoint inhibitors targeting cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4), programmed cell death protein 1 (PD-1), and programmed cell death protein ligand 1 (PD-L1), have revolutionized cancer treatment. The first immune checkpoint inhibitor (ICI) ipilimumab, an anti-CTLA-4, was approved in 2011. Since then, the US Food and Drug Administration (FDA) has approved more than half a dozen immune checkpoint inhibitors to treat various malignancies. These agents are part of a broader class of chemotherapy agents termed immunotherapy, which selectively target different steps in the immune response cascade to upregulate the body's normal response to cancer. While the effects of traditional chemotherapy are well known, the toxicity profile of emerging immune therapies is not fully elucidated. They have been associated with atypical side effects labeled collectively as immune-related adverse events (irAEs).