Modern internet search analytics and thyroidectomy: What are patients asking?

Objectives

Thyroidectomy is among the most commonly performed head and neck surgeries, however, limited existing information is available on topics of interest and concern to patients.

Study Design

Observational.

Setting

Online.

Methods

A search engine optimization tool was utilized to extract metadata on Google-suggested questions that "People Also Ask" (PAA) pertaining to "thyroidectomy" and "thyroid surgery." These questions were categorized by Rothwell criteria and topics of interest. The Journal of the American Medical Association (JAMA) benchmark criteria enabled quality assessment.

Results

A total of 250 PAA questions were analyzed. Future-oriented PAA questions describing what to expect during and after the surgery on topics such as postoperative management, risks or complications of surgery, and technical details were significantly less popular among the "thyroid surgery" group (P < 0.001, P = 0.005, and P < 0.001, respectively). PAA questions about scarring and hypocalcemia were nearly threefold more popular than those related to pain (335 and 319 vs. 113 combined search engine response page count, respectively). The overall JAMA quality score remained low (2.50 ± 1.07), despite an increasing number of patients searching for "thyroidectomy" (r(77) = 0.30, P = 0.007).

Conclusions

Patients searching for the nonspecific term "thyroid surgery" received a curated collection of PAA questions that were significantly less likely to educate them on what to expect during and after surgery, as compared to patients with higher health literacy who search with the term "thyroidectomy." This suggests that the content of PAA questions differs based on the presumed health literacy of the internet user.

Clinical practice guidelines in the management of pediatric foreign body aspiration and ingestion: a systematic evaluation using the AGREE II instrument

PURPOSE

Several clinical practice guidelines (CPGs) have been produced to optimize the diagnosis and management of pediatric foreign body aspiration and ingestion. However, to date there have been no critical evaluations of their methodological rigor or quality. Herein, we address this need via the Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument.

METHODS

A literature search of Embase, MEDLINE via PubMed, and Scopus was performed up until February 25, 2021. Identified CPGs were then assessed by four independent reviewers trained in AGREE II. A scaled domain score of >60% was indicated as satisfactory quality. Intraclass correlation coefficients (ICC) were calculated to assess inter-reviewer agreement.

RESULTS

11 guidelines were assessed with only one being classified as high quality and others being either average (two) or low quality (eight). Domain 4 (clarity of presentation) achieved the highest mean score (66.41 ± 13.33%), while domain 5 (applicability) achieved the lowest score (10.80 ± 10.37%). ICC analysis revealed generally strong agreement between reviewers with a range of 0.60-0.98.

CONCLUSION

Quality appraisal using the AGREE II instrument suggests that the methodologic rigor and quality of current guidelines for the diagnosis and management of pediatric foreign body aspiration and ingestion need significant improvement.

Meningitis Risk and Role of Prophylactic Antibiotics in Spontaneous Lateral Skull Base CSF Leaks

OBJECTIVE

To review the literature and our institutional experience regarding the risk of meningitis in patients with spontaneous lateral skull base cerebrospinal fluid (sCSF) leaks awaiting surgical repair, and the roles of antibiotic prophylaxis and pneumococcal vaccination, if known.

METHODS

A retrospective chart review and systematic review of the literature was undertaken to identify the incidence of meningitis in patients with sCSF leaks awaiting surgical repair. Adults managed surgically for sCSF leaks at an academic tertiary care center over a 10-year period were included. Data was collected on receipt of prophylactic antibiotics and/or pneumococcal vaccines during the timeframe between diagnosis and surgical repair.

RESULTS

Institutional review identified 87 patients who underwent surgical repair of spontaneous leaks, with a 0% incidence of meningitis over a median duration of 2 months while awaiting surgery (mean 5.5 months, range 0.5-118 months). Eighty-eight percent of patients did not receive prophylactic antibiotics. No studies in the published literature demonstrated the impact of prophylactic antibiotics or pneumococcal vaccine on meningitis risk.

CONCLUSIONS

There appears to be a low risk of meningitis among patients with lateral skull base sCSF leaks awaiting surgery for short durations (≤2 months), even in the absence of prophylactic antibiotics. There is a substantial gap in the published literature assessing the risk of meningitis and roles of antibiotics and vaccination in this patient population, indicating the need for large-scale study to conclusively elucidate the nature of this risk.

Epidemiology and Management of Adult Laryngeal Trauma: An Analysis of the National Trauma Data Bank

INTRODUCTION

Laryngeal injuries are rare but life-threatening airway emergencies. Increased understanding of the epidemiology of these injuries can inform treatment and improve outcomes. We aimed to characterize the demographics and management of adult laryngeal trauma.

METHODS

The National Trauma Data Bank (NTDB) was queried from 2007 to 2015 for patients ≥18 years old with laryngeal trauma. Patient demographics, injury characteristics, and treatment course were collected. Outcomes were assessed via multivariate logistic regression.

RESULTS

From 7.3 million patients, 6,890 (0.1%) patients with laryngeal trauma were identified. Eighty-five percent of patients were male, and the median age was 40. Of these patients, 343 (5.0%) were dead on arrival and of the remaining patients, 510 (7.8%) of patients were deceased at discharge. Common concomitant injuries included facial fractures (27%), intracranial injuries (21%), and rib and sternum fractures (19%). The most common cause of injury was motor vehicle accident (26%), followed by assault with firearms/explosives (12%) and assault with cutting instruments (8%). Forty-three percent of patients received mechanical ventilation and 15% received surgical repair. After correcting for gender, age, and injury severity, firearm injuries (odds ratio [OR] 3.46, 95% CI: [2.88-4.15]) and cutting/piercing injuries (OR 2.23, 95% CI: [1.89-2.64]) were positively associated with the need for mechanical ventilation. Motor vehicle trauma (OR 0.63, 95% CI: [0.46-0.84]) was negatively associated with surgical repair while striking injuries (OR 1.61, 95% CI: [1.25-2.06]) were positively associated. Lastly, shorter time to tracheostomy was significantly associated with shorter ICU stays (p < 0.0001).

CONCLUSION

This study is the largest epidemiologic study of laryngeal trauma to date and identifies the risk of surgical intervention with firearm and cutting injuries as well as the importance of earlier time to tracheostomy for ICU management.

Gender Differences Among Head and Neck Microvascular Reconstructive Surgeons

OBJECTIVE

To determine whether gender differences exist in the training history, practice patterns, and home lives of surgeons who perform microvascular reconstruction of the head and neck.

STUDY DESIGN

Cross-sectional survey.

SETTING

Medical facilities that employ surgeons who practice head and neck microvascular reconstruction in the United States.

METHODS

A survey was created using the Research Electronic Data Capture Framework and was distributed via email to microvascular reconstructive surgeons. Descriptive statistics were performed using Stata software.

RESULTS

No significant differences were found in training or current practice patterns between microvascular surgeons who identify as men versus those who identify as women. Women had fewer children (p = .020) and were more likely to be childless (p = .002). Whereas men were more likely to report a spouse/partner as primary caretaker, women were more likely to hire a professional caretaker or cite themselves as a primary caretaker (p < .001). Women were more likely to have finished residency (p = .015) and fellowship (p = .014) more recently and to practice in the Southeast (p = .006). Of the microvascular surgeons who reported practice setting switches, men more commonly changed positions for career advancement, whereas women were more likely to switch due to burnout (p = .002).

CONCLUSION

This study found no gender-based differences in training or practice patterns. However, significant differences were identified in childbearing, family structure, geographic practice location, and motives for switching practice.

Exploring Olfactory Dysfunction as a Marker of Frailty and Postoperative Outcomes in Head and Neck Cancer

Importance

Olfactory dysfunction (OD) is increasingly recognized as a robust marker of frailty and mortality. Despite broad recognition of frailty as a critical component of head and neck cancer (HNC) care, there is no standardized frailty assessment.

Objective

To assess the prevalence of OD and its association with frailty and postoperative outcomes in HNC.

Design, Setting, and Participants

In this prospective cohort study with enrollment between February 17, 2021, to September 29, 2021, at a tertiary academic medical center, 85 eligible adult patients with primary, treatment-naive HNC of mucosal or cutaneous origin were included. Patients with a history of COVID-19, neurocognitive, or primary smell/taste disorders were excluded.

Exposures

Prospective olfactory assessments (self-reported, visual analog scale [VAS] and psychophysical, University of Pennsylvania Smell Identification Test [UPSIT]) with concurrent frailty assessment (Risk Analysis Index [RAI]) were used. Olfactory-specific quality of life (QOL) was examined with brief Questionnaire of Olfactory Disorders-Negative Statements (QOD-NS).

Main Outcome(s) and Measure(s)

The primary outcome was the prevalence of OD as assessed by VAS (0-10, no to normal smell) and UPSIT (0-40, higher scores reflect better olfaction) and its association with frailty (RAI, 0-81, higher scores indicate greater frailty). For surgical patients, secondary outcomes were associations between OD and postoperative length of stay (LOS), 30-day postoperative outcomes, and QOD-NS (0-21, higher scores indicate worse QOL).

Results

Among 51 patients with HNC (mean [SD] age, 63 [10] years; 39 [77%] male participants; 41 [80%] White participants), 24 (47%) were frail, and 4 (8%) were very frail. Despite median (IQR) self-reported olfaction by VAS of 9 (8-10), 30 (59%) patients demonstrated measured OD with psychophysical testing. No meaningful association was found between self-reported and psychophysical testing (Hodges-Lehmann, <0.001; 95% CI, -2 to 1); a total of 46 (90%) patients did not report decreased olfaction-specific QOL. Median UPSIT scores were lower in frail patients (Hodges-Lehmann, 6; 95% CI, 2-12). Multivariate modeling demonstrated severe microsmia/anosmia was associated with 1.75 (95% CI, 1.09-2.80) times odds of being frail/very frail and approximately 3 days increased LOS (β, 2.96; 95% CI, 0.29-5.62).

Conclusions and Relevance

Although patients with HNC are unaware of olfactory changes, OD is common and may serve as a bellwether of frailty. In this prospective cohort study, a dose-dependent association was demonstrated between increasing degrees of OD and frailty, and the potential utility of olfaction was highlighted as a touchstone in the assessment of HNC frailty.

Changes in otolaryngology application requirements and match outcomes: Are we doing any better?

Objectives

Otolaryngology-specific requirements were piloted to minimize applicant and program burdens. We investigated the impact of introducing and then removing these requirements on Match outcomes.

Methods

2014-2021 National Resident Matching Program® data were examined. The primary outcome was the impact of Otolaryngology Resident Talent Assessment (ORTA; prematch 2017, postmatch 2019) and Program-Specific Paragraph (PSP; implemented 2016, optional 2018) on applicant numbers and match rates. Secondary survey analysis assessed candidate perceptions of PSP/ORTA.

Results

Applicant numbers declined significantly during PSP/ORTA (18.9%; p = 0.001). With the optional PSP and postmatch ORTA, applicant numbers increased significantly (39.0%; p = 0.002). Examined individually, mandatory PSP was associated with a significant decline in applicants (p = 0.007), whereas postmatch ORTA was associated with significant increases in applicants (p = 0.010). ORTA and PSP negatively impacted the decision to apply to otolaryngology in 59.8% and 51.3% of applicants, respectively. Conversely, match rate success improved significantly from 74.8% to 91.2% during PSP/ORTA (p = 0.014), followed by a significant decline to 73.1% after PSP was made optional and ORTA moved to postmatch (p = 0.002).

Conclusions

ORTA and PSP correlated with decreased applicant numbers and increased match rate success. As programs seek ways to remove barriers to applying to otolaryngology, the potential consequences of an increasing pool of unmatched candidates must also be considered.

Rhytidectomy-Information Patients Seek and Where They Find Answers

Patients considering rhytidectomy often search for information online prior to in-office consultation. This study identifies the most searched queries regarding rhytidectomy and evaluates sources to which patients are directed. The search engine optimization tool Ahrefs was utilized to extract Google metadata on searches performed in the United States. Frequently asked questions were categorized by topic; websites were categorized by type. Journal of the American Medical Association (JAMA) benchmark criteria enabled information quality assessment. A total of 565 questions for three search phrases were extracted (265 "facelift," 265 "face lift," and 35 "rhytidectomy"). The majority of monthly searches in the facelift and face lift groups pertained to procedural cost, which was significantly higher than in the rhytidectomy group (52.9% and 50.7 vs. 0.0%, ANOVA p <0.001). The mean JAMA score for private practice sources (1.2 ± 0.42) was significantly lower than that of academic pages of (2.3 ± 1.9, p = 0.026) and commercial sources (3.0 ± 0.82, p = 0.008). The most popular destinations for rhytidectomy were California and Mexico (630 and 440 searches/month). Online searches for facelifts often revolve around the topic of cost and frequently direct patients to websites that provide inadequate information on authorship, attribution, disclosure, and currency.

Post-operative Monitoring for Head and Neck Microvascular Reconstruction in the Era of Resident Duty Hour Restrictions: A Retrospective Cohort Study Comparing 2 Monitoring Protocols

OBJECTIVES

To determine whether 2 different methods of post-operative head and neck free flap monitoring affect flap failure and complication rates.

METHODS

A retrospective chart review of 803 free flaps performed for head and neck reconstruction by the same microvascular surgeon between July 2013 and July 2020 at 2 separate hospitals within the same healthcare system. Four-hundred ten free flaps (51%) were performed at Hospital A, a medical center where flap checks were performed at frequent, scheduled intervals by in-house resident physicians and nurses; 393 free flaps (49%) were performed at Hospital B, a medical center where flap checks were performed regularly by nursing staff with resident physician evaluation as needed. Total free flap failure, partial free flap failure, and complications (consisting of wound infection, fistula, and reoperation within 1 month) were assessed.

RESULTS

There were no significant differences between Hospitals A and B when comparing rates of total free flap failure, partial free flap failure, complication, or re-operation (P = .27, P = .66, P = .65, P = .29, respectively). There were no significant differences in urgent re-operation rates for flap compromise secondary to thrombosis and hematoma (P = .54).

CONCLUSIONS

In our series, free flap outcomes did not vary based on the degree of flap monitoring by resident physicians. This data supports the ability of a high-volume, well-trained, nursing-led flap monitoring program to detect flap compromise in an efficient fashion while limiting resident physician obligations in the age of resident duty hour restrictions.

Feasibility and Cost of Telehealth Head and Neck Cancer Survivorship Care: A Systematic Review

OBJECTIVE

Evaluate the feasibility and cost-effectiveness of telehealth head and neck cancer (HNC) survivorship care.

DATA SOURCES

Ovid MEDLINE, Embase, Scopus, CINAHL.

REVIEW METHODS

A systematic search for peer-reviewed feasibility studies on telehealth models for HNC survivorship care published between 2005 and 2021 was conducted using the terms "head and neck cancer" and "telehealth" and their synonyms. Inclusion criteria were studies on telehealth survivorship program interventions for HNC patients with quantitative feasibility outcome measures (eg, enrollment, retention, attrition/dropout rate, adherence/task completion rate, patient satisfaction, cost).

RESULTS

Thirty-eight studies out of 1557 identified met inclusion criteria and were included for analysis. Feasibility outcomes evaluated were enrollment and attrition rates, adherence/task completion rates, patient satisfaction, and user feedback surveys in different survivorship domains. Patient enrollment ranged from 20.8% to 85.7%, while attrition ranged from 7% to 47.7%. Overall, adherence was 30.2% higher in the intervention group than in the control group (46.8% vs 16.6%). Studies with cost analysis found telehealth models of care to be statistically significantly less expensive and more cost-efficient than the standard model of care, with a $642.30 saving per patient (n = 3). Telehealth models also substantially reduced work time saving per visit (on average, 7 days per visit).

CONCLUSION

While telehealth survivorship programs are feasible and cost-effective and are associated with improved patient outcomes, they might not be ideal for every patient. Further investigations are needed to understand the role of telehealth in survivorship care, given the variability in study design, reporting, measures, and methodological quality.

Association of Head and Neck Anatomic Zones with Microvascular Reconstruction Outcomes

Background: Head and neck free flap survival relies on adequate tissue perfusion from the external carotid artery (ECA), and vessel length is inversely proportional to blood flow rate. Objective: Investigate whether distance from the ECA (as a proxy for pedicle vessel length) predicts flap survival or complications. Methods: Retrospective review of free flaps performed at three academic centers from 9/2006 to 8/2021. Flaps were categorized by distance from the ECA: orbit and above (zone 1), maxilla to parotid (zone 2), and mandible and below (zone 3). Secondary analysis assessed flap outcomes stratified by average historical pedicle length. Results: A total of 2,369 flaps were identified in zones 1 (n = 109), 2 (n = 1878), and 3 (n = 382). Rates of flap failure (4.9%) and perioperative complications (36.3%) did not differ by zone or pedicle length. Zone 3 flaps, most commonly located in the larynx and hypopharynx, had significantly higher rates of fistula and infection. Conversely, 30-day readmission rates were significantly lower in patients with zone 2 flaps (p < 0.001). Rates of all other complications did not differ significantly between zones. Conclusions: Proximity to mucosal anatomic sites was a more powerful predictor of free flap viability than pedicle length or ECA proximity.

Effect of ibuprofen on severity of surgically-managed pediatric post-tonsillectomy hemorrhage

OBJECTIVES

The association between ibuprofen use and severity of post-tonsillectomy hemorrhage (PTH) remains unclear. We aimed to compare PTH severity in patients who did or did not receive ibuprofen.

METHODS

A retrospective cohort study of pediatric patients requiring operative control of PTH at a tertiary children's hospital between 2015 and 2019 was performed. PTH severity was assessed using pre-tonsillectomy and post-hemorrhage hemoglobin and hematocrit values, estimated intraoperative blood loss, estimated hemorrhage flow rate, and need for transfusion. Differences in hemorrhage severity markers between the two cohorts were compared.

RESULTS

A total of 168 consecutive patients were included in this study. The mean age was 8.8 years, and 55.4% of patients were male. Sixty-five patients (38.7%) received ibuprofen postoperatively. There was no statistically significant difference in the mean change in hemoglobin (1.1 vs. 1.1, P = 0.85) or hematocrit (3.1 vs. 3.2, P = 0.97) between patients who received ibuprofen compared to those who did not. Similarly, there were no significant differences in need for transfusion (3.1% vs. 3.9%, P = 1.00) or occurrence of high-flow (arterial) blood loss (33.8% vs. 40.8%, P = 0.42) between the two groups.

CONCLUSION

Postoperative ibuprofen use does not appear to significantly increase PTH severity, as measured by change in hemoglobin and hematocrit values, need for transfusion, or presence of high-flow blood loss. This study introduces previously unexplored markers to assess PTH severity and supports further prospective studies to determine the effect of ibuprofen on PTH severity.

Medical malpractice in robotic surgery: a Westlaw database analysis

Malpractice claims involving robot-assisted surgical procedures have increased more than 250% in the past 7 years compared to the seven years prior. We examined robotic surgery malpractice claims to identify trends in claimed liabilities, describe legal outcomes, and determine strategies to minimize future litigation. The Westlaw legal database was queried retrospectively for U.S. state and federal trials regarding robot-assisted surgical procedures from 2006 to 2013 and 2014 to 2021. Data abstracted from verdict reports included year, state, court type, defendant specialty, procedure performed, claimed injuries and liabilities, verdict, and damage amount awarded. Sixty-one cases across 25 states were identified, 16 cases between 2006 and 2013, and 45 from 2014 to 2021. Among those 45 cases, defendant verdicts predominated (n = 35, 77.8%), with only four plaintiff verdicts (8.9%) and six settlements (13.3%). Overall, 169 liabilities were claimed, most commonly negligent surgery (82.2%), misdiagnosis/failure to diagnose (46.7%), delayed treatment (35.6%), and lack of informed consent (31.1%). Thirteen cases resulted in indemnity payments (mean = $1,251,274), with damages ranging from $10,087 (infection and retained foreign body) to $5,008,922 (patient death). Hysterectomy (n = 19, 42.2%) was the most commonly litigated surgery, followed by prostatectomy (n = 5) and hernia repair (n = 4). The most litigated specialties were obstetrics/gynecology (48.9%), general surgery (28.9%), and urology (15.6%). Malpractice litigation in robot-assisted surgery is infrequent. As robotic procedures become more commonplace, surgeons must keep common liabilities in mind, as there are valuable and actionable lessons to be learned from these cases. Malpractice reform, continuing medical education activities, and improved informed consent protocols may help minimize future litigation.

Clinical practice guidelines on management of infantile hemangioma: a systematic quality appraisal using the AGREE II instrument

Infantile hemangiomas (IH) are the most common benign tumors of childhood. Timely diagnosis and management of higher-risk IH is key in avoiding permanent disfigurement, visual impairment, and life-threatening airway compromise. Here, we identify and critically appraise existing clinical practice guidelines (CPGs) for IH diagnosis and management. A systematic search of MEDLINE, SCOPUS, and EMBASE was conducted until August 2021. Four independent reviewers assessed each CPG utilizing the Appraisal of Guidelines for Research and Evaluation, 2nd edition (AGREE II). An scaled domain score of ≥60% demonstrated adequacy in a given domain. Intraclass correlation coefficients (ICC) assessed agreement and scoring consistency between the reviewers. Eight CPGs were eligible and included for critical appraisal. Only one CPG was classified as 'high quality', with the remaining seven guidelines being 'average' (n = 3) or 'low' (n = 4) quality. Six guidelines (75.0%) were conducted via nonsystematic literature searches. The 'Applicability' (40.4%±14.0) and 'Rigor of development' (46.9%±17.3) domains achieved the lowest scores, while the highest average scores were in 'Scope and purpose' (76.7%±11.3) and 'Editorial independence' (90.8%±13.0). We found high consistency between the four independent reviewers, with 'very good' (n = 5) or 'good' (n = 1) interrater reliability in all six AGREE II domains. Based on the AGREE II instrument, there is only one available high-quality consensus statement on the diagnosis and management of IH. Low scores in 'Rigor of development' and 'Applicability' suggest notable weaknesses in the development process and reporting quality of existing IH CPGs. Future guidelines should be backed by systematic literature searches and focus on guideline clinical translation.

Clinical Practice Guidelines on Sentinel Lymph Node Biopsy for Melanoma: A Systematic Review and Quality Appraisal Using the AGREE II Instrument

Sentinel lymph node biopsy (SLNB) is a minimally invasive surgical procedure that is standard of care for the evaluation of clinically negative regional lymph nodes in patients with cutaneous melanoma. As the presence of metastases dictates patient prognosis and determines the need for further regional disease control or adjuvant therapy, SLNB is invaluable to clinical decision-making in patients presenting with melanoma. However, the indications for SLNB, specifically among patients with thin (<1 mm) or thick (>4 mm) melanomas, remain unclear. A number of clinical practice guidelines (CPGs) have been developed outlining recommendations for the role of lymph node biopsy in the management of melanoma. However, to date, their quality has not been critically appraised. Our objective was to systematically evaluate all available CPGs on this topic using the validated Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument. Four total guidelines met the inclusion criteria and underwent appraisal. Only one CPG achieved a "high" quality rating, indicating scores of >60% in at least five of the six AGREE II domains. Across all CPGs, the lowest scoring domains were "Applicability" and "Stakeholder involvement," which had average scores of 41.2% and 48.3%, respectively. Based on the AGREE II instrument, the quality of existing CPGs for the indications of SLNB for melanoma is low. Future guidelines should be pilot tested to evaluate barriers to application and should utilize multidisciplinary guideline development teams that include patients and key stakeholders in addition to clinical experts from all relevant disciplines.

Clinical practice guidelines for management of medullary thyroid carcinoma: An AGREE II appraisal

PURPOSE

Medullary thyroid carcinoma (MTC) is a rare and aggressive form of thyroid neoplasia that requires multidisciplinary collaboration for effective management. We systematically appraise the quality of clinical practice guidelines (CPG) for the diagnosis and treatment of MTC using the Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument.

MATERIALS AND METHODS

A systematic literature search was performed to identify CPGs pertaining to the diagnosis and treatment of MTC. Data were abstracted from guidelines meeting inclusion criteria and appraised by four independent reviewers in the six domains of quality defined by the AGREE II. Intraclass correlation coefficients (ICC) were calculated across domains to qualify interrater reliability.

RESULTS

Fourteen guidelines met inclusion criteria. No guideline achieved a score of >60 % in five or more AGREE II quality domains, which is required to gain designation as 'high' quality. One "average quality" guideline authored by the British Thyroid Association achieved a score of >60 % in three quality domains. The remaining thirteen (92.9 %) CPGs demonstrated low quality content, with deficits most pronounced in domains 3, 5, and 6, suggesting a lack of rigorously developed, clinically applicable, and transparent information.

CONCLUSIONS

As the diagnosis and treatment of MTC continues to evolve, the development of high-quality guidelines becomes increasingly important; few existing meet appropriate standards.

Parotid Mass in an 81-Year-Old Woman

An 81-year-old woman presented with a 3-month history of a slow-growing mass in her left cheek and denied having any symptoms, tenderness, numbness, or facial nerve weakness. What is your diagnosis?

Indocyanine green fluorescence-guided surgery in head and neck cancer: A systematic review

OBJECTIVE

To assess the feasibility and effectiveness of indocyanine green (ICG) for image-guided resection of head and neck cancer (HNC).

DATA SOURCES

PubMed, Embase, and Scopus databases.

REVIEW METHODS

Searches were conducted from database inception to February 2022. Patient and study characteristics, imaging parameters, and imaging efficacy data were extracted from each study.

RESULTS

Nine studies met inclusion criteria, representing 103 head and neck tumors. Weighted mean ICG dose and imaging time were 1.27 mg/kg and 11.77 h, respectively. Among the five studies that provided quantitative metrics of imaging efficacy, average ICG tumor-to-background ratio (TBR) was 1.56 and weighted mean ONM-100 TBR was 3.64. Pooled sensitivity and specificity across the five studies were 91.7 % and 71.9 %, respectively.

CONCLUSION

FGS with ICG may facilitate real-time tumor-margin delineation to improve margin clearance rates and progression-free survival. Future studies with validated, quantitative metrics of imaging success are necessary to further evaluate the prognostic benefit of these techniques.

Quality appraisal of clinical practice guidelines for the use of radiofrequency ablation in the treatment of thyroid nodules and cancer

INTRODUCTION

Radiofrequency ablation (RFA) has gained significant recent global interest in the treatment of benign thyroid nodules and thyroid cancer. It is a relatively new, minimally invasive, thermal ablation technique that is an alternative to surgery. Several clinical practice guidelines (CPGs), consensus statements, and recommendations currently exist for the use of RFA in the treatment of benign thyroid nodules and thyroid cancers. These documents have considerable variability amongst them, and to date, their quality and methodologic rigor have not been appraised.

OBJECTIVE

To identify and perform a quality appraisal of clinical practice guidelines for RFA in the treatment of benign thyroid nodules and thyroid cancer using the Appraisal of Guidelines for Research and Evaluation (AGREE II) tool.

METHODS

A comprehensive literature search was performed in MEDLINE (via PubMed), EMBASE, and SCOPUS databases from inception to November 1, 2021. Four reviewers independently evaluated each guideline using the AGREE II instrument. Scaled domain scores were generated and the threshold used for satisfactory quality was >60%. Additionally, intraclass correlation coefficients (ICCs) were calculated to determine level of agreement between reviewers.

RESULTS

Seven guidelines were selected for final evaluation based on inclusion/exclusion criteria. Two guidelines were classified "high" quality, one "average" quality, and the rest "low" quality. The "Clarity and Presentation" (65.68 ± 26.1) and "Editorial Independence" (61.32 ± 25.8) domains received the highest mean scores, while the "Applicability" (32.14 ± 22.8) and "Rigor of Development" (45.02 ± 29.8) domains received the lowest mean scores. ICC statistical analysis showed high magnitude of agreement between reviewers with a range of (0.722-0.944).

CONCLUSION

Reflecting upon our quality appraisal, it is evident that the quality and methodologic rigor of RFA guidelines can be improved upon in the future. Our findings also elucidate the existing variability/discrepancies amongst guidelines in the indications and use of RFA.

Clinical practice guidelines for pain management after tonsillectomy: Systematic quality appraisal using the AGREE II instrument

PURPOSE

We identified and appraised clinical practice guidelines (CPGs) for the management of post-tonsillectomy pain using the Appraisal of Guidelines for Research and Evaluation (AGREE II) guideline research tool.

MATERIALS AND METHODS

We conducted a literature search to identify CPGs addressing pain management after tonsillectomy. CPGs meeting inclusion criteria were then appraised by four independent reviewers in six areas of quality, as defined by AGREE II. Scaled domain scores were calculated for each quality domain. Intraclass correlation coefficients (ICC) were calculated in each domain to assess interrater reliability across guideline appraisals.

RESULTS

Nine guidelines meeting inclusion criteria were identified from a systematic search of the literature. The American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) guideline detailing tonsillectomy and postoperative management in pediatric patients received the highest average score, with a mean of 90.1% in the six areas of quality. Three guidelines scored higher than >60% in five domains or more, defining 'high' quality per AGREE II: AAO-HNS, Scottish Intercollegiate Guides Network (SIGN), and Ontario Ministry of Health CPGs. The highest-scoring domain was domain 4: Clarity of presentation (87.4%) across guidelines, while the lowest scoring domain was domain 5: Applicability (49.4%). Variability in scaled domain scores between all CPGs was relatively consistent across domains, with a mean standard deviation of 22.4%. The average ICC calculated across all six domains was 0.78, indicating 'strong agreement' between reviewers regarding guideline quality.

CONCLUSION

Of the nine available guidelines detailing pain management following tonsillectomy we identified, only three (33%) were deemed 'high'-quality after appraisal using the AGREE II instrument, suggesting a need for development of novel, methodologically rigorous CPGs.

Assessment and Comparison of Three Dimensional Exoscopes for Near-Infrared Fluorescence-Guided Surgery using Second-Window Indocyanine-Green

Objective

Compared to microscopes, exoscopes have advantages in field-depth, ergonomics, and educational value. Exoscopes are especially well-poised for adaptation into fluorescence-guided surgery (FGS) due to their excitation source, light path, and image processing capabilities. We evaluated the feasibility of near-infrared FGS using a 3-dimensional (3D), 4 K exoscope with near-infrared fluorescence imaging capability. We then compared it to the most sensitive, commercially-available near-infrared exoscope system (3D and 960 p). In-vitro and intraoperative comparisons were performed.

Methods

Serial dilutions of indocyanine-green (1–2000 μg/mL) were imaged with the 3D, 4 K Olympus Orbeye (system 1) and the 3D, 960 p VisionSense Iridium (system 2). Near-infrared sensitivity was calculated using signal-to-background ratios (SBRs). In addition, three patients with brain tumors were administered indocyanine-green and imaged with system 1, with two also imaged with system 2 for comparison.

Results

Systems 1 and 2 detected near-infrared fluorescence from indocyanine green concentrations of >250 μg/L and >31.3 μg/L, respectively. Intraoperatively, system 1 visualized strong near-infrared fluorescence from two, strongly gadolinium-enhancing meningiomas (SBR=2.4, 1.7). The high-resolution, bright images were sufficient for the surgeon to appreciate the underlying anatomy in the near-infrared mode. However, system 1 was not able to visualize fluorescence from a weakly-enhancing intraparenchymal metastasis. In contrast, system 2 successfully visualized both the meningioma and the metastasis but lacked high resolution stereopsis.

Conclusion

Three-dimensional exoscope systems provide an alternative visualization platform for both standard microsurgery and near-infrared fluorescent guided surgery. However, when tumor fluorescence is weak (i.e., low fluorophore uptake, deep tumors), highly sensitive near-infrared visualization systems may be required.

Reconstruction following transoral robotic surgery for head and neck cancer: Systematic review

We performed a systematic review to characterize reconstructive modalities and postoperative surgical outcomes following TORS resection. A search of the PubMed, SCOPUS, and EMBASE databases was conducted to identify studies describing patients undergoing reconstruction of TORS defects. Twenty-six studies met inclusion criteria, consisting of 260 patients who underwent TORS resection followed by reconstruction. Twenty-one studies reported tumor classification information, with TORS performed for 44 (23.0%) T1, 86 (45.0%) T2, 33 (17.3%) T3, and 28 (14.7%) T4 tumors. Eighteen distinct reconstructive modalities were described in the studies identified, including nine unique free flap types. The most commonly performed reconstruction was the radial forearm free flap (RFFF), accounting for 121/260 (46.5%) of reconstructions performed. Reported surgical complications included 5 pharyngocutaneous fistulae, 13 hemorrhagic complications, 24 infectious complications, and 5 free flap failures. Our findings demonstrate favorable surgical outcomes but minimal quantitative functional data to compare reconstructive options following TORS.

The Evolution of 5-Aminolevulinic Acid Fluorescence Visualization: Time for a Headlamp/Loupe Combination

BACKGROUND

The use of 5-ALA for intraoperative protoporphyrin IX (PpIX) fluorescent imaging in the resection of malignant gliomas has been demonstrated to improve tumor visualization, increase extent of resection, and extend progression-free survival. The current technique for visualization of 5-ALA consists of excitation and emission filters built into the operating microscope. However, there are notable limitations to this process, including low quantum yield, expense, and masking of surrounding anatomy.

METHODS

We present three cases in which three separate methods were employed for visualizing fluorescence. The devices reported are 1) a low-cost blue light flashlight and 2) a low-cost headlamp, and 3) the first reported case of the new Design for Vision® REVEAL™ FGS (Fluorescence Guided Surgery) 5-ALA fluorescent headlight and loupes. The aim of the study is to provide confirmation that tumor fluorescence can be observed using commercially-available products other than the microscope.

RESULTS

We demonstrate through three intraoperative cases that a variety of devices can produce visible fluorescence of the high-grade tumor and allow for simultaneous real-time visualization of the adjacent brain parenchyma and vasculature. The REVEAL™ FGS system appears to offer increased fluorescence emission compared to all other methods, including the microscope.

CONCLUSIONS

Our study demonstrates the feasibility of using blue/ultraviolet light supplied by a commercially available, inexpensive flashlight or headlamp to visualize 5-ALA fluorescence in high-grade gliomas. We also provide the first documentation of intraoperative use of the new Design for Vision® REVEAL™ FGS 5-ALA fluorescent headlight and loupes and report on the experience. Lack of an operative microscope capable of fluorescent illumination should not be a limiting factor in performing fluorescent-guided glioma resection.

Near-Infrared Imaging with Second-Window Indocyanine Green in Newly Diagnosed High-Grade Gliomas Predicts Gadolinium Enhancement on Postoperative Magnetic Resonance Imaging

PURPOSE

Intraoperative molecular imaging with tumor-targeting fluorophores offers real-time detection of neoplastic tissue. The second window indocyanine green (SWIG) technique relies on passive accumulation of indocyanine green (ICG), a near-infrared fluorophore, in neoplastic tissues. In this study, we explore the ability of SWIG to detect neoplastic tissue and to predict postoperative magnetic resonance imaging (MRI) findings intraoperatively.

PROCEDURES

Retrospective data were collected from 36 patients with primary high-grade gliomas (HGG) enrolled as part of a larger trial between October 2014 and October 2018. Patients received systemic ICG infusions at 2.5-5 mg/kg 24 h preoperatively. Near-infrared fluorescence was recorded throughout the case and from biopsy specimens. The presence/location of residual SWIG signal after resection was compared to the presence/location of residual gadolinium enhancement on postoperative MRI. The extent of resection was not changed based on near-infrared imaging.

RESULTS

All 36 lesions demonstrated strong near-infrared fluorescence (signal-to-background = 6.8 ± 2.2) and 100 % of tumors reaching the cortex were visualized before durotomy. In 78 biopsy specimens, near-infrared imaging demonstrated higher sensitivity and accuracy than white light for diagnosing neoplastic tissue intraoperatively. Furthermore, near-infrared imaging predicted gadolinium enhancement on postoperative MRI with 91 % accuracy, with visualization of residual enhancement as small as 0.3 cm³. Patients with no residual near-infrared signal after resection were significantly more likely to have complete resection on postoperative MRI (p value < 0.0001).

CONCLUSIONS

Intraoperative imaging with SWIG demonstrates highly sensitive detection of HGG tissue in real time. Furthermore, post-resection near-infrared imaging correlates with postoperative MRI. Overall, our findings suggest that SWIG can provide surgeons with MRI-like results in real time, potentially increasing resection rates.

Second-Window Indocyanine Green for Visualization of Hemangioblastoma: A Case Report With Two-Dimensional Operative Video

BACKGROUND AND IMPORTANCE

The proper differentiation of neoplastic tissue from adjacent brain parenchyma can pose a great challenge, especially in eloquent areas of the brain. With the novel technique, "Second-Window Indocyanine Green," injection of a near-infrared fluorophore (ICG) allows for intraoperative visualization of tumors by taking advantage of the compromised vasculature surrounding the tumor. Thus, such a technique may demonstrate utility for hemangioblastomas, which are hypervascular tumors of the central nervous system.

CLINICAL PRESENTATION

Here we present the case of a 39-yr-old male with a demonstrated cystic mass in the left cerebellum, with additional edema spreading towards the vermis. A total of 5 mg/kg of ICG was delivered intravenously 24 h prior to the operation. The tumor was approached via the infratentorial suboccipital approach. We observed strong near-infrared fluorescence through the intact dura, consistent with the tumor location. Surgical pathology confirmed a final diagnosis of cerebellar hemangioblastoma. There was complete resection of the tumor, with the patient discharged uneventfully.

CONCLUSION

We report the first successful case of fluorescence-guided surgery of a cerebellar hemangioblastoma using near-infrared fluorescence imaging with the Second-Window ICG technique. This joins a growing series of publications that demonstrate the efficacy of a novel application of ICG, a near-infrared fluorophore, in accurate intraoperative visualization of neoplastic tissue. While the use of a dedicated near-infrared platform (ie, the VisionSense Iridium [Visionsense, Philadelphia, Pennsylvania]) yields a higher signal-to-background ratio, a neurosurgical microscope (ie, the Leica OH6 [Leica Microsystems, Wetzlar, Germany]) may also provide a suitable option in cases where fluorescence is very strong.

Second window ICG predicts gross-total resection and progression-free survival during brain metastasis surgery

OBJECTIVE

Metastases are the most common intracranial malignancies and complete resection can provide relief of neurological symptoms and reduce recurrence. The authors' prospective pilot study in 2017 demonstrated promising results for the application of high-dose, delayed imaging of indocyanine green (ICG), known as second window ICG (SWIG), in patients undergoing surgery for brain metastases. In this prospective cohort study, the authors evaluated intraoperative imaging and clinical outcomes of treatment using SWIG.

METHODS

Patients were prospectively enrolled in an approved study of high-dose, delayed ICG (SWIG) and received 5 mg/kg (2014-2018) or 2.5 mg/kg (2018-2019) ICG 24 hours preoperatively. Intraoperatively, near-infrared (NIR) imaging was performed using a dedicated NIR exoscope. NIR images were analyzed and the signal-to-background ratio (SBR) was calculated to quantify fluorescence. Residual fluorescence on the postresection NIR view was compared and correlated to the residual gadolinium enhancement on postoperative MRI. Patient survival and predictive factors were analyzed.

RESULTS

In total, 51 intracranial metastases were surgically treated in 47 patients in this cohort. All 51 metastatic tumors demonstrated strong NIR fluorescence (mean SBR 4.9). In tumors ≤ 10 mm from the cortical surface, SWIG with 5 mg/kg ICG produced enhanced transdural tumor visibility (91.3%) compared to 2.5 mg/kg (52.9%; p = 0.0047). Neoplastic margin detection using NIR fluorescence compared to white light improved sensitivity, albeit lowered specificity; however, increasing the SBR cutoff for positive fluorescence significantly improved specificity without sacrificing sensitivity, increasing the overall accuracy from 57.5% to 72.5%. A lack of residual NIR fluorescence after resection was closely correlated with a lack of residual enhancement on postoperative MRI (p = 0.007). Among the 16 patients in whom tumor recurred at the site of surgery, postoperative MRI successfully predicted 8 cases, whereas the postresection NIR view predicted 12 cases. Progression-free survival rate at 12 months was greater for patients without residual NIR fluorescence (38%) than for those without residual enhancement on postoperative MRI (29%).

CONCLUSIONS

The current study demonstrates the clinical benefits of the SWIG technique in surgery for patients with brain metastases. Specifically, this technique allows for dose-dependent, transdural localization of neoplasms and improved sensitivity in neoplastic margin detection. Postresection residual fluorescence can be a powerful tool to evaluate extent of resection in conjunction with MRI, and it may guide decisions on brain metastasis management.

Somatostatin Receptor as a Molecular Imaging Target in Human and Canine Cushing Disease

OBJECTIVES

Fluorescence-guided surgery may improve completeness of resection in transsphenoidal surgery for Cushing disease (CD) by enabling visualization of residual tumor tissue at the margins. In this review we discuss somatostatin receptors (SSTRs) as targets for fluorescence-guided surgery and overview existing SSTR-specific imaging agents. We also compare SSTR expression in normal pituitary and corticotrophinoma tissues from human and canine CD patients to assess canines as a translational model for CD.

METHODS

A PubMed literature search was conducted for publications containing the terms canine, somatostatin receptor, Cushing's disease, and corticotroph adenoma. SSTR expression data from each study was documented as the presence or absence of expression or, when possible, the number of tumors expressing a given SSTR subtype within a group of tumors being studied. Studies that used reverse transcription polymerase chain reaction to quantify SSTR expression were selected for additional comparative analysis.

RESULTS

SSTR5 is strongly expressed in human corticotroph adenomas and weakly expressed in surrounding pituitary parenchyma, a pattern not conclusively observed in canine patients. SSTR2 mRNA expression is similar in human normal pituitary and corticotrophinoma cells but may be significantly higher in canine normal pituitary tissue than in corticotroph tumoral tissue. Limited data were available on SSTR subtypes 1, 3, and 4.

CONCLUSIONS

Further studies must fill the knowledge gaps related to species-specific SSTR expression, so using canine CD as a translational model may be premature. We do conclude that the expression profile of SSTR5 (i.e., high local expression in pituitary adenomas relative to normal surrounding tissues) makes SSTR5 a promising molecular target for FGS.

Combined fluorescence-guided surgery and photodynamic therapy for glioblastoma multiforme using cyanine and chlorin nanocluster

INTRODUCTION

Glioblastoma multiforme (GBM) is the most common primary intracranial malignancy; survival can be improved by maximizing the extent-of-resection.

METHODS

A near-infrared fluorophore (Indocyanine-Green, ICG) was combined with a photosensitizer (Chlorin-e6, Ce6) on the surface of superparamagnetic-iron-oxide-nanoparticles (SPIONs), all FDA-approved for clinical use, yielding a nanocluster (ICS) using a microemulsion. The physical-chemical properties of the ICS were systematically evaluated. Efficacy of photodynamic therapy (PDT) was evaluated in vitro with GL261 cells and in vivo in a subtotal resection trial using a syngeneic flank tumor model. NIR imaging properties of ICS were evaluated in both a flank and an intracranial GBM model.

RESULTS

ICS demonstrated high ICG and Ce6 encapsulation efficiency, high payload capacity, and chemical stability in physiologic conditions. In vitro cell studies demonstrated significant PDT-induced cytotoxicity using ICS. Preclinical animal studies demonstrated that the nanoclusters can be detected through NIR imaging in both flank and intracranial GBM tumors (ex: 745 nm, em: 800 nm; mean signal-to-background 8.5 ± 0.6). In the flank residual tumor PDT trial, subjects treated with PDT demonstrated significantly enhanced local control of recurrent neoplasm starting on postoperative day 8 (23.1 mm3 vs 150.5 mm3, p = 0.045), and the treatment effect amplified to final mean volumes of 220.4 mm3 vs 806.1 mm3 on day 23 (p = 0.0055).

CONCLUSION

A multimodal theragnostic agent comprised solely of FDA-approved components was developed to couple optical imaging and PDT. The findings demonstrated evidence for the potential theragnostic benefit of ICS in surgical oncology that is conducive to clinical integration.

Near-Infrared Fluorescence with Second-Window Indocyanine Green as an Adjunct to Localize the Pituitary Stalk During Skull Base Surgery

A potential application of near-infrared (NIR) fluorescence imaging using second-window indocyanine green (SWIG) is demonstrated. We hypothesized that because the pituitary lacks a blood-brain barrier, we might visualize the pituitary stalk using SWIG. A 52-year-old, right-handed man presented to our clinic for evaluation of progressive loss of vision. Physical examination was significant for loss of right peripheral vision and near-complete loss of left field vision. Prolactin was high-normal at 16.2 mg/dL. Brain magnetic resonance imaging demonstrated a 36-mm sellar mass extending superiorly and laterally crossing the intracranial left internal carotid artery, consistent with a nonfunctional pituitary macroadenoma. We elected to pursue left pterional craniotomy for resection. The patient was eligible for our SWIG clinical trial and consented to the study. SWIG is a novel, investigational technique using Food and Drug Administration-approved indocyanine green to enhance visualization of neoplastic tissue intraoperatively.^1-7 The patient received 2.5 mg/kg of indocyanine green intravenously approximately 24 hours preoperatively. Intraoperatively, under white-light microscopy, the tumor was easily identified and distinguished from the optic nerves and internal carotid artery. After debulking of the gross tumor, NIR visualization using a laser-equipped endoscope⁸ demonstrated strong NIR fluorescence in the pituitary stalk. Despite the distorted anatomy, this technique enabled us to confidently identify and preserve the pituitary stalk. Postoperatively, the patient had persistently high urine output that normalized in 24 hours without desmopressin (sodium 139-140 mmol/L); after uneventful recovery, he was discharged with mild improvement in visual function. This case demonstrated a potential use of our SWIG protocol. As the stalk demonstrates strong NIR fluorescence after high-dose indocyanine green administration, surgeons may be able to better localize and preserve the stalk even in complex skull base tumor cases where the anatomy may be significantly distorted.

Blockade of only TGF-β 1 and 2 is sufficient to enhance the efficacy of vaccine and PD-1 checkpoint blockade immunotherapy

Checkpoint inhibition has established immunotherapy as a major modality of cancer treatment. However, the success of cancer immunotherapy is still limited as immune regulation of tumor immunity is very complicated and mechanisms involved may also differ among cancer types. Beside checkpoints, other good candidates for immunotherapy are immunosuppressive cytokines. TGF-β is a very potent immunosuppressive cytokine involved in suppression of tumor immunity and also necessary for the function of some regulatory cells. TGF-β has three isoforms, TGF-β 1, 2 and 3. It has been demonstrated in multiple mouse tumor models that inhibition of all three isoforms of TGF-β facilitates natural tumor immunosurveillance and tumor vaccine efficacy. However, individual isoforms of TGF-β are not well studied yet. Here, by using monoclonal antibodies (mAbs) specific for TGF-β isoforms, we asked whether it is necessary to inhibit TGF-β3 to enhance tumor immunity. We found that blockade of TGF-β1 and 2 and of all isoforms provided similar effects on tumor natural immunosurveillance and therapeutic vaccine-induced tumor immunity. The protection was CD8⁺ T cell-dependent. Blockade of TGF-β increased vaccine-induced Th1-type response measured by IFNγ production or T-bet expression in both tumor draining lymph nodes and tumors, although it did not increase tumor antigen-specific CD8⁺ T cell numbers. Therefore, protection correlated with qualitative rather than quantitative changes in T cells. Furthermore, when combined with PD-1 blockade, blockade of TGF-β1 and 2 further increased vaccine efficacy. In conclusion, blocking TGF-β1 and 2 is sufficient to enhance tumor immunity, and it can be further enhanced with PD-1 blockade.

Abstract A054: Inhibition of TGF-beta isoforms 1 and 2 enhances therapeutic tumor vaccine efficacy

Transforming growth factor-beta (TGF-beta) is a pleiotropic cytokine comprised of three isoforms, TGF-beta1, 2, and 3, that exhibits immunosuppressive functions. In the context of immunosuppression, TGF-beta dampens activation and maturation of both innate and adaptive immune cells, including natural killer cells, macrophages, and dendritic cells, as well as CD4+ and CD8+ T cells. Thus, TGF-beta inhibition, like blockade of other negative regulators of immunity, provides a potential modality of cancer treatment that can be used in combination therapy. Although we have previously demonstrated that blockade of all three isoforms of TGF-beta using a monoclonal antibody increases tumor vaccine efficacy, as measured by the reduction in tumor growth and increase in the number of antigen-specific CTLs, the function of individual isoforms of TGF-beta in the framework of tumor immunity is not well understood. In this study, we examined whether it is necessary to block TGF-beta3, in addition to the two other isoforms of TGF-beta, to improve vaccine-induced tumor immunity against the syngeneic TC1 tumor model, a C57BL/6 lung epithelial cell line transfected with HPV-16 E6 and E7 genes. When the subcutaneous tumors became approximately 5 mm in diameter, the mice were immunized with a peptide-based vaccine that targets the E7 oncogene with or without the simultaneous administration of anti-TGF-beta antibodies with unique specificities for the three isoforms. Mice immunized with the vaccine alone exhibited slightly delayed tumor growth relative to the untreated control. This effect could be enhanced by the combination of anti-TGF-beta antibodies that neutralize all three isoforms of TGF-beta. Interestingly, blockade of only TGF-beta1 & 2 also improved vaccine efficacy to a similar degree as the blockade of all three isoforms, though neutralization of TGF-beta alone could not suppress tumor growth. Therefore, it is not necessary to inhibit TGF-beta3 to generate significant vaccine-induced anti-tumor immunity. Systemic depletion of CD8+ T cells using anti-CD8-depleting antibodies completely abrogated the tumor protection observed in mice immunized with vaccine alone or vaccine in combination with TGF-beta blockade, suggesting that the mechanism of anti-tumor immunity in these conditions relies entirely on CD8+ T cells. In vivo CTL assays revealed that anti-TGF-beta antibodies tended to increase the quality of CTL activity induced by the vaccine. To better understand the effect of treatment on the tumor microenvironment, we used flow cytometric analysis to examine T cells in the tumor and tumor draining lymph nodes. While the vaccine significantly increased the number of tumor antigen-specific CD8+ T cells and IFN-gamma producing T cells in both lymph nodes and tumors, TGF-beta inhibition at two weeks, but not one week, after vaccination further augmented the increase in the number of T cells infiltrating tumors. Vaccine in combination with blockade of TGF-beta1 & 2, regardless of TGF-beta3 inhibition, also led to the greatest increase in the number of T-bet-expressing CD4+ and CD8+ T cells in tumors. This observation implies that blockade of TGF-beta1 & 2 alone may be sufficient to improve therapeutic tumor vaccines by facilitating the infiltration of more Th1/Tc1-type T cells into tumors. Because several studies suggest that TGF-beta3 actually plays a protective role against tumorigenesis in a range of tissues, developing TGF-beta blockade strategies that do not inhibit this isoform could be beneficial in certain settings.

Citation Format: Katharine Clark, Faith C. Robertson, Emma De Ravin, Shingo Kato, Anja Bloom, Amer Mirza, Jay A. Berzofsky, Masaki Terabe. Inhibition of TGF-beta isoforms 1 and 2 enhances therapeutic tumor vaccine efficacy [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A054.

Abstract B137: Inhibition of TGF-beta1 and 2 facilitates therapeutic tumor vaccine efficacy

Targeting cell surface inhibitory receptors (checkpoint inhibitors) has established immunotherapy as a major modality of cancer treatment. However, the success of cancer immunotherapy is still limited as immune regulation of tumor immunity is very complicated and mechanisms of the regulation involved may also differ among different cancer types. In addition to checkpoints, other good candidates for immunotherapy are immunosuppressive cytokines. TGF-beta is a very potent immunosuppressive cytokine which has been shown to be involved in suppression of tumor immunity. TGF-beta has three isoforms, TGF-beta1, 2 and 3. It has been demonstrated in multiple mouse tumor models that inhibition of all three isoforms of TGF-beta facilitates natural tumor immunosurveillance as well as tumor vaccine efficacy. It also has been demonstrated that TGF-beta1 plays a critical role in the induction of Treg cells, IL-17-producing T cells and MDSCs. However, roles of other isotypes of TGF-beta are not well studied yet. In this study we asked whether it is necessary to inhibit TGF-beta3 to enhance tumor immunity induced by a tumor vaccine in a syngeneic TC1 tumor model. When the tumor reached at least 5 mm in diameter, the mice were given a peptide-based vaccine targeting HPV16 E7, which is an oncogene expressed in TC1 cells. Although the vaccine alone had minimal effects on tumor growth, combination with an anti-TGF-beta antibody that neutralizes all three isoforms significantly delayed tumor growth. A similar effect was obtained with an antibody that neutralizes only TGF-beta1 and 2 but not TGF-beta3. Thus, it is not necessary to block TGF-beta3 to overcome immune suppression. Flow cytometric analysis of immune cells in tumor draining lymph nodes and tumors showed that there was no difference in the number of Treg and MDSCs between mice with/without treatment. The vaccine significantly increased the number of tumor antigen-specific CD8+ T cells and IFN-gamma producing T cells in tumors. The TGF-beta inhibitor together with the vaccine increased the number of T cells infiltrating tumors two weeks after the vaccination, but not just one week after vaccination. The vaccine also induced a significant number of T-bet-expressing T cells (both CD4 and CD8) in tumors, and anti-TGF-beta, regardless of TGF-beta3 blockade, further increased the number of these cells. Together the results suggested that blockade of TGF-beta1 and 2 alone is sufficient to enhance therapeutic tumor vaccine efficacy by facilitating the induction of Th1/Tc1 type T cells. With the notion that TGF-beta3 might be beneficial for patients in some cancers, developing TGF-beta antagonists that do not inhibit TGF-beta3 may be lead to better outcomes.

Citation Format: Masaki Terabe, Faith C. Robertson, Shingo Kato, Emma De Ravin, Katharine Clark, Anja Bloom, Amer M. Mirza, Jay A. Berzofsky. Inhibition of TGF-beta1 and 2 facilitates therapeutic tumor vaccine efficacy. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr B137.