Phase II Clinical Trial of Intravenous Levothyroxine to Mitigate Pharyngocutaneous Fistula in Euthyroid Patients Undergoing Salvage Laryngectomy.

PURPOSE: Patients undergoing head and neck cancer surgery after prior radiation or chemoradiation are at high risk for wound complications. Hypothyroidism is a known risk factor for wound complications, especially fistulae after salvage total laryngectomy. The purpose of this phase II clinical trial is to investigate the effect of peri-operative intravenous levothyroxine supplementation on wound complications in patients undergoing salvage total laryngectomy. PATIENTS AND METHODS: Euthyroid patients previously treated with radiation/chemoradiation undergoing total laryngectomy were prospectively recruited (n=72). Post-operatively, intravenous levothyroxine was administered at a weight-based dose (1.3 mcg/kg/day) and transitioned to enteral dosing on day 7. Free T3, T4, and thyroid stimulating hormone (TSH) were collected and dosing was adjusted accordingly. The primary endpoints were rates of fistula and fistula requiring re-operation, compared to matched historical controls. All patients were monitored for adverse effects. RESULTS: The rate of post-operative hypothyroidism was 21% compared to 49% in a matched historic cohort. The rate of fistula was 18.1% while the rate of fistula requiring re-operation was 4.2%, significantly lower than rates in our historic cohort (34.6% and 14.8% respectively, p=0.02 and 0.01). Post-operative hypothyroidism and recurrent clinical stage predicted fistula requiring re-operation in multivariate analysis; other acute phase reactants were not predictive. There were no observed adverse events related to levothyroxine supplementation. CONCLUSIONS: Post-operative intravenous levothyroxine supplementation reduced rates of acute hypothyroidism, fistula, and fistula requiring re-operation in patients undergoing salvage total laryngectomy without adverse effects. Intravenous levothyroxine is a viable strategy to reduce wound complications in this high-risk patient population.

Application of Time-Driven Activity-Based Costing for Head and Neck Microvascular Free Flap Reconstruction.

OBJECTIVE: Traditional hospital accounting fails to provide an accurate cost of complex surgical care. Here we describe the application of time-driven activity-based costing (TDABC) to characterize costs of head and neck oncologic procedures involving free tissue transfer. STUDY DESIGN: Retrospective cohort study. SETTING: Single tertiary academic medical center. METHODS: An analysis of head and neck oncologic procedures involving microvascular free flap reconstruction from 2018 to 2020 (n = 485) was performed using TDABC methodology to measure cost across operative case and postoperative admission, using quantity of time and cost per unit of each resource to characterize resource utilization. Univariate and generalized linear mixed models were used to examine associations between patient and hospital characteristics and cost of care delivery. RESULTS: The total cost of care delivery was $41,905.77 ± 21,870.27 with operating room (OR) supplies accounting for only 10% of the total cost. Multivariable analyses identified significant cost drivers including operative time, postoperative length of stay, number of return trips to the OR, postoperative complication, number of free flaps performed, and patient transfer from another hospital or via emergency department admission (P < .05). CONCLUSION: Operative time and postoperative length of stay, but not operative supplies, were primary drivers of cost of care for head and neck oncology cases involving free tissue transfer. TDABC offers granular cost characterization to inform cost optimization through unused capacity identification and postoperative admission efficiencies.

Upfront neck dissection for treatment selection and improvement in quality of life as a novel treatment paradigm for deintensification in HPV+ OPSCC.

PURPOSE: Locoregionally advanced HPV+ oropharyngeal squamous cell carcinoma (OPSCC) has excellent cure rates, although current treatment regimens are accompanied by acute and long-term toxicities. We designed a phase II de-escalation trial for patients with HPV+OPSCC to evaluate the feasibility of an upfront neck dissection to individualize definitive treatment selection to improve quality of life without compromising survival. METHODS: Patients with T1-3, N0-2 HPV+ OPSCC underwent an upfront neck dissection with primary tumor biopsy. Patients with a single lymph node less than six centimeters, with no extracapsular spread(ECS), and no primary site adverse features underwent transoral surgery (Arm A). Patients who had two or more positive lymph nodes with no ECS, or those with primary site adverse features were treated with radiation alone (Arm B). Patients who had ECS in any lymph node were treated with chemoradiation (Arm C). The primary endpoint was quality of life at 1 year compared to a matched historical control. RESULTS: Thirty-four patients were enrolled and underwent selective neck dissection. Based on pathologic characteristics, 14 patients were assigned to arm A, 10 patients to arm B, and 9 to arm C. A significant improvement was observed in HNQOL compared to historical controls (-2.6 vs -11.9, p=0.034). With a median follow-up of 37 months, the 3-year overall survival was 100% and estimated 3-year estimated progression free survival was 96% (95% CI: 76-99%). CONCLUSION: A neck dissection driven treatment paradigm warrants further research as a de-intensification strategy.

Team-Based Surgical Approach to Head and Neck Microvascular Free Flap Reconstruction.

Importance: Because microvascular free flap reconstruction is increasingly used to restore function in patients with head and neck cancer, there is a growing need for evidence-based perioperative care. Objective: To assess the association of different team-based surgical approaches with intraoperative and postoperative outcomes for patients undergoing head and neck free flap reconstruction. Design, Setting, and Participants: This retrospective cohort study of 733 patients was conducted at an academic tertiary care medical center. Head and neck oncologic procedures involving microvascular free flap reconstruction with available intraoperative data collected from January 1, 2000, to December 31, 2021, were included. Main Outcomes and Measures: Patient characteristics including demographic characteristics and comorbid conditions, operative variables, length of stay, and postoperative outcomes were measured. Descriptive statistics and effect size measures were performed to compare the 3 intraoperative surgical team approaches, specifically single surgeon, separate 2-team approach, and integrated 2-team approach; 1:1 nearest neighbor matching without caliper was performed to compare single- vs 2-team and separate and integrated 2-team approaches. Effect size measures including Cramer V for dichotomous variables, the Kendall W coefficient of concordance for ordinal variables, and η2 for continuous variables were reported with 95% CIs to describe precision. Results: Among 733 cases, there were no clinically significant differences in patient demographic characteristics, clinicopathologic characteristics, and choice of free flap reconstruction based on intraoperative surgical team approach. The mean (SD) age was 58.7 (12.4) years, and 514 were male (70.1%). In terms of operative and postoperative variables, there was a difference in operative times and intraoperative fluid requirements among the 3 different techniques, with the integrated 2-team approach demonstrating a mean reduction in operative time of approximately 2 hours (η2 = 0.871; 95% CI, 0.852-0.887; mean [SD] operative time = 541 [191] minutes for the single-surgeon approach, 399 [175] minutes for the integrated 2-team approach, and 537 [200] minutes for the separate 2-team approach) and lower fluid requirements of greater than 1 L (η2 = 0.790; 95% CI, 0.762-0.817). In both unadjusted analyses and propensity score matching, there were no clinically significant differences in terms of ischemia time, use of pressors, postoperative complications (including free flap failure, number of return trips to the operating room, length of stay, or 30-day readmission) based on intraoperative team approach. Conclusions and Relevance: Findings suggest that the integrated 2-team surgical approach for complex head and neck microvascular reconstruction can be used to safely decrease operative time, with no difference in postoperative outcomes.

Use of neuromuscular blockade for neck dissection and association with iatrogenic nerve injury.

BACKGROUND: Cranial nerve injury is an uncommon but significant complication of neck dissection. We examined the association between the use of intraoperative neuromuscular blockade and iatrogenic cranial nerve injury during neck dissection. METHODS: This was a single-center, retrospective, electronic health record review. Study inclusion criteria stipulated patients > 18 years who had ≥ 2 neck lymphatic levels dissected for malignancy under general anesthesia with a surgery date between 2008 - 2018. Use of neuromuscular blockade during neck dissection was the primary independent variable. This was defined as any use of rocuronium, cisatracurium, or vecuronium upon anesthesia induction without reversal with sugammadex prior to surgical incision. Univariate tests were used to compare variables between those patients with, and those without, iatrogenic cranial nerve injury. Multivariable logistic regression determined predictors of cranial nerve injury and was performed incorporating Firth's estimation given low prevalence of the primary outcome. RESULTS: Our cohort consisted of 925 distinct neck dissections performed in 897 patients. Neuromuscular blockade was used during 285 (30.8%) neck dissections. Fourteen instances (1.5% of surgical cases) of nerve injury were identified. On univariate logistic regression, use of neuromuscular blockade was not associated with iatrogenic cranial nerve injury (OR: 1.73, 95% CI: 0.62 - 4.86, p = 0.30). There remained no significant association on multivariable logistic regression controlling for patient age, sex, weight, ASA class, paralytic dose, history of diabetes, stroke, coronary artery disease, carotid atherosclerosis, myocardial infarction, and cardiac arrythmia (OR: 1.87, 95% CI: 0.63 - 5.51, p = 0.26). CONCLUSIONS: In this study, use of neuromuscular blockade intraoperatively during neck dissection was not associated with increased rates of iatrogenic cranial nerve injury. While this investigation provides early support for safe use of neuromuscular blockade during neck dissection, future investigation with greater power remains necessary.

Patterns of recurrence in head and neck squamous cell carcinoma to inform personalized surveillance protocols.

BACKGROUND: Development of evidence-based post-treatment surveillance guidelines in recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC) is limited by comprehensive documentation of patterns of recurrence and metastatic spread. METHODS: A retrospective analysis of patients diagnosed with R/M HNSCC at a National Cancer Institute-designated cancer center between 1998- 2019 was performed (n = 447). Univariate and multivariate analysis identified patterns of recurrence and predictors of survival. RESULTS: Median overall survival (mOS) improved over time (6.7 months in 1998-2007 to 11.8 months in 2008-2019, p = .006). Predictors of worse mOS included human papillomavirus (HPV) negativity (hazard ratio [HR], 1.8; 95% confidence interval [CI], 1.2-2.6), high neutrophil/lymphocyte ratio (HR, 2.1 [1.4-3.0], disease-free interval (DFI) ≤6 months (HR, 1.4 [1.02-2.0]), and poor performance status (Eastern Cooperative Oncology Group, ≥2; HR, 1.91.1-3.4). In this cohort, 50.6% of recurrences occurred within 6 months of treatment completion, 72.5% occurred within 1 year, and 88.6% occurred within 2 years. Metachronous distant metastases were more likely to occur in patients with HPV-positive disease (odds ratio [OR], 2.3 [1.4-4.0]), DFI >6 months (OR, 2.4 [1.5-4.0]), and body mass index ≥30 (OR, 2.3 [1.1-4.8]). Oligometastatic disease treated with local ablative therapy was associated with improved survival over polymetastatic disease (HR, 0.36; 95% CI, 0.24-0.55). CONCLUSION: These data regarding patterns of distant metastasis in HNSCC support the clinical utility of early detection of recurrence. Patterns of recurrence in this population can be used to inform individualized surveillance programs as well as to risk-stratify eligible patients for clinical trials. PLAIN LANGUAGE SUMMARY: After treatment for head and neck cancer (HNC), patients are at risk of recurrence at prior sites of disease or at distant sites in the body. This study includes a large group of patients with recurrent or metastatic HNC and examines factors associated with survival outcomes and recurrence patterns. Patients with human papillomavirus (HPV)-positive HNC have good survival outcomes, but if they recur, this may be in distant regions of the body and may occur later than HPV-negative patients. These data argue for personalized follow-up schedules for patients with HNC, perhaps incorporating imaging studies or novel blood tests.

Tumor immune microenvironment alterations using induction cetuximab in a phase II trial of deintensified therapy for p16-positive oropharynx cancer.

BACKGROUND: We sought to characterize early changes in CD8+ tumor-infiltrating lymphocytes and tumor transcriptomes after induction cetuximab in a cohort with p16-positive oropharyngeal cancer on a phase II clinical de-escalation trial. METHODS: Tumor biopsies were obtained before and 1 week after a single cetuximab loading dose in eight patients enrolled in a phase II trial of cetuximab and radiotherapy. Changes in CD8+ tumor-infiltrating lymphocytes and transcriptomes were assessed. RESULTS: One week after cetuximab, five patients (62.5%) had an increase in CD8+ cell infiltration with a median (range) fold change of +5.8 (2.5-15.8). Three (37.5%) had unchanged CD8+ cells (median [range] fold change of -0.85 [0.8-1.1]). In two patients with evaluable RNA, cetuximab induced rapid tumor transcriptome changes in cellular type 1 interferon signaling and keratinization pathways. CONCLUSIONS: Within 1 week, cetuximab induced measurable changes in pro-cytotoxic T-cell signaling and immune content.

Neurotization of the radial forearm free flap improves swallowing outcomes in hemiglossectomy defects.

BACKGROUND: We examined the effect of free tissue neurotization on speech and swallowing outcomes for patients undergoing reconstruction of hemiglossectomy defects with a radial forearm free flap (RFFF). METHODS: A retrospective study was performed in patients with oral cavity squamous cell carcinoma undergoing a hemiglossectomy and reconstruction with a RFFF. Functional outcomes including nutritional mode, range of liquids and solids, and speech understandability were analyzed 1-year post-treatment. RESULTS: Eighty-four patients were included in this analysis, 41 of whom had neurotized flaps (49%). No significant differences in demographic or clinical variables were seen between the neurotized and non-neurotized groups. On multivariate analysis controlling for BMI, flap area, and N-classification, patients with neurotized flaps were significantly more likely to have normal range of liquids and solids and less likely to have a G-tube. CONCLUSIONS: Neurotization of RFFF reconstructing hemiglossectomy defects results in decreased G-tube dependence and improved range of liquids and solids.

Prognostic value of CD103+ tumor-infiltrating lymphocytes and programmed death ligand-1 (PD-L1) combined positive score in recurrent laryngeal squamous cell carcinoma.

OBJECTIVES: In an evolving era of immunotherapeutic options for persistent or recurrent laryngeal squamous cell carcinoma (LSCC), there is a need for improved biomarkers of treatment response and survival to inform optimal treatment selection and prognostication. Herein, our primary objective was to explore correlations between tumor infiltrating lymphocytes (TILs) and PD-L1 Combined Positive Score (CPS). Secondarily, we sought to explore their combined association with survival outcomes in patients with persistent or recurrent LSCC treated with salvage surgery. MATERIALS AND METHODS: This was a retrospective cohort study at a single academic medical center. Immunohistochemistry staining for TILs and PD-L1 was performed on a tissue microarray of persistent or recurrent LSCC pathologic specimens. Correlations between TIL subsets and PD-L1 CPS were examined using Pearson's correlation coefficient and survival outcomes were analyzed with the Kaplan-Meier method and log-rank tests. RESULTS: Only CD103+ TILs showed a statistically significant, weakly-positive correlation with PD-L1 CPS (r2 = 0.264, p < 0.015). No other TIL subsets correlated with PD-L1 CPS in our cohort. The most favorable survival outcomes were seen in patients with pathologic N0 tumors showing high CD103+ TILs and/or high PD-L1 CPS staining. CONCLUSION: Among patients with persistent or recurrent LSCC, CD103+ TILs only modestly correlated with PD-L1 CPS. A combined biomarker score incorporating CD103+ TILs and PD-L1 CPS greatly enhanced survival discrimination. This model may have additional utility in predicting the clinical benefit of immunotherapies in persistent or recurrent LSCC in the future.

Randomized Phase II Study of Physiologic MRI-Directed Adaptive Radiation Boost in Poor Prognosis Head and Neck Cancer.

PURPOSE: We conducted a randomized phase II multicenter clinical trial to test the hypothesis that physiologic MRI-based radiotherapy (RT) dose escalation would improve the outcome of patients with poor prognosis head and neck cancer. PATIENTS AND METHODS: MRI was acquired at baseline and at RT fraction 10 to create low blood volume/apparent diffusion coefficient maps for RT boost subvolume definition in gross tumor volume. Patients were randomized to receive 70 Gy (standard RT) or 80 Gy to the boost subvolume (RT boost) with concurrent weekly platinum. The primary endpoint was disease-free survival (DFS) with significance defined at a one-sided 0.1 level, and secondary endpoints included locoregional failure (LRF), overall survival (OS), comparison of adverse events and patient reported outcomes (PRO). RESULTS: Among 81 randomized patients, neither the primary endpoint of DFS (HR = 0.849, P = 0.31) nor OS (HR = 1.19, P = 0.66) was significantly improved in the RT boost arm. However, the incidence of LRF was significantly improved with the addition of the RT boost (HR = 0.43, P = 0.047). Two-year estimates [90% confidence interval (CI)] of the cumulative incidence of LRF were 40% (27%-53%) in the standard RT arm and 18% (10%-31%) in the RT boost arm. Two-year estimates (90% CI) for DFS were 48% (34%-60%) in the standard RT arm and 57% (43%-69%) in the RT boost arm. There were no significant differences in toxicity or longitudinal differences seen in EORTC QLQ30/HN35 subscales between treatment arms in linear mixed-effects models. CONCLUSIONS: Physiologic MRI-based RT boost decreased LRF without a significant increase in grade 3+ toxicity or longitudinal PRO differences, but did not significantly improve DFS or OS. Additional improvements in systemic therapy are likely necessary to realize improvements in DFS and OS.

Advancement of PI3 Kinase Inhibitor Combination Therapies for PI3K-Aberrant Chordoma.

Objectives Targeted inhibitors of the PI3 kinase (PI3K) pathway have shown promising but incomplete antitumor activity in preclinical chordoma models. The aim of this study is to advance methodology for a high-throughput drug screen using chordoma models to identify new combination therapies for chordoma. Study Design Present work is an in vitro study. Setting The study conducted at an academic research laboratory. Materials and Methods An in vitro study on automated high-throughput screening of chordoma cells was performed using a library of 1,406 drugs as both mono- and combination therapies with PI3K inhibitors. Combination indices were determined for dual therapies and synergistic outliers were identified as potential therapeutic agents. T (brachyury) siRNA knockdown in combination with PI3K pathway inhibition was also assessed. Results Fifty-nine combination therapies were identified as having potential therapeutic efficacy. Effective combinations included PI3K inhibitors with GSK1838705A (ALK/IGF-1R inhibitor), LY2874455 (VEGFR/FGFR inhibitor), El1 (selective Ezh2 inhibitor), and (-)-p-bromotetramisole oxalate (alkaline phosphatase inhibitor). The top ranking targets identified included ALK, PDGFR, VEGFR, aurora kinase, and BCL-2. T (brachyury) inhibition produced significant reduction in cell viability and growth; however PI3K inhibition in combination with T (brachyury) knockdown did not result in further reduction in growth and viability in vitro. Conclusion High throughput with in vitro combination screening is feasible with chordoma cells and allows for rapid identification of synergistic dual-therapies. Potential combination therapies and targetable pathways were identified. T (brachyury) knockdown produced significant reduction in cell viability, but did not show additional benefit with PI3K pathway inhibition in this model. Further in vitro and in vivo validation of these therapeutic combinations is warranted.

Financial Hardship in Patients With Head and Neck Cancer.

PURPOSE: Financial hardship is a growing concern for patients with cancer. Patients with head and neck cancer (HNC) are particularly vulnerable, given that a third leave the workforce following treatment. The goal of our study was to characterize financial hardship in the psychologic response (response to increased expenses) and coping behaviors (behaviors patients adopt to manage their care in the setting of increased expenses) domains in patients with HNC compared with patients with other cancers. METHODS: This was a retrospective cohort study of nationally representative public survey data from 2013 to 2018 in the National Health Interviews Survey, an annual cross-sectional household survey. We included respondents age ≥ 18 years who reported a diagnosis of cancer and identified a subset of patients with HNC. Our main outcomes were financial hardship in the psychologic response and coping behaviors domains. RESULTS: Our sample included a weighted population of 357,052 patients with HNC and 21.4 million patients with other cancers. Compared with patients with other cancers, patients with HNC reported greater levels of coping behaviors hardship (31% v 23%, P = .015), but similar levels of psychologic financial hardship (73% v 72%, P = .787). Medicaid or uninsured patients more often reported coping behaviors hardship. On multivariable analysis, HNC (odds ratio, 1.51; 95% CI, 1.01 to 2.24) was independently associated with coping behaviors hardship. CONCLUSION: To our knowledge, this is the first study to evaluate financial hardship in patients with HNC compared with patients with other cancers that includes Medicaid and uninsured patients, who are more often to have financial hardship. Patients with HNC have greater levels of hardship in the coping behaviors domain compared with patients with other cancers, but similar levels in the psychologic response domain.

A Consideration for Surgical Management in Select T4b Oral Cavity Squamous Cell Carcinoma.

OBJECTIVES: The role of surgery for conventionally "unresectable" (cT4b) oral cavity squamous cell carcinoma is unclear. We analyzed factors associated with overall survival in cT4b relative to cT4a oral cavity squamous cell carcinoma. METHODS: We identified 6830 cT4a and 522 cT4b oral cavity squamous cell carcinoma chemoradiation or surgery + adjuvant therapy patients in the National Cancer Data Base from 2004 to 2016. The main outcome was overall survival. Statistical analysis was performed using chi-squared tests, univariable and multivariable regression analysis. RESULTS: The cT4b group had a higher rate of positive margins (30.4% vs 21.3%, P = .009) and downstaging (41.2% vs 13.1%; P < .001) compared to cT4a, while only 1.7% were upstaged. cT4b surgery + chemoradiation patients had similar survival to cT4a surgery + radiation (HR 0.93; 95% CI, 0.70-1.25) and cT4a surgery + chemoradiation patients (HR, 0.92; 95% CI, 0.69-1.23), while cT4b surgery + radiation patients had worse OS (HR, 1.55; 95% CI, 1.05-1.47). CONCLUSIONS: Clinical T4b staging is a poor predictor of pathologic staging given a high rate of downstaging on final pathology. Surgical resection with adjuvant chemoradiation is an option in select cT4b oral cavity squamous cell carcinoma patients.

Tumor-Infiltrating Lymphocytes in Patients With Advanced Laryngeal Cancer Undergoing Bioselection.

OBJECTIVE: Bioselection to assess tumor response after induction chemotherapy has been introduced as an alternative treatment strategy to total laryngectomy for patients with advanced larynx squamous cell carcinoma (LSCC). Tumor-infiltrating lymphocytes (TILs) have proven to serve as prognostic biomarkers in head and neck cancer but have not been evaluated as a way to select patients for treatment paradigms. The aim of this study is to evaluate the role of pretreatment TILs in patients with advanced LSCC undergoing the bioselection paradigm. STUDY DESIGN: Retrospective study. SETTING: Tertiary care hospital. METHODS: Patients with advanced LSCC treated with bioselection and available tissue were included (N = 76). Patients were stratified into CD8-low and CD8-high cohorts by using the median TIL count. Kaplan-Meier survival analysis and multivariate cox regression were performed with SPSS version 26 (IBM). RESULTS: After controlling for tobacco use, tumor site, and stage, a high CD8 TIL count was an independent predictor of improved 5-year disease-specific survival (hazard ratio, 0.17 [95% CI, 0.03-0.84]; P = .03). CD8 TIL counts did not predict response to induction chemotherapy; however, subgroup analysis of patients treated with chemoradiation therapy revealed that CD8 TIL count was significantly associated with degree of response (P = .012). CONCLUSION: These findings support prior data published by our group showing that TILs are predictive of disease-specific survival in patients with head and neck cancer. CD8 TIL counts were significantly associated with degree of clinical response after induction chemotherapy. These results suggest that pretreatment assessment of tumor-infiltrating CD8 cells could be useful in selecting patients.

Honesty and Transparency, Indispensable to the Clinical Mission-Part II: How Communication and Resolution Programs Promote Patient Safety and Trust.

When patients are harmed by health care, concerns fan out in all directions. Patients and families confront a sea of uncertainty, contending with injuries that drain them physically, emotionally, and financially. Health care professionals experience a powerful mix of emotions, but are seldom afforded the time to process what happened or the resources to relieve suffering and prevent harm. Honesty, transparency, and empathy are indispensable to a comprehensive approach that prioritizes patient and family-centered response to unintended harm, clinical improvement, and redemptive peer review. Part 2 introduces the second of three pillars for advancing the clinical mission: communication and transparency.

Advancement in Cancer Stem Cell Biology and Precision Medicine-Review Article Head and Neck Cancer Stem Cell Plasticity and the Tumor Microenvironment.

Head and Neck cancer survival has continued to remain around 50% despite treatment advances. It is thought that cancer stem cells play a key role in promoting tumor heterogeneity, treatment resistance, metastasis, and recurrence in solid malignancies including head and neck cancer. Initial studies identified cancer stem cell markers including CD44 and ALDH in head and neck malignancies and found that these cells show aggressive features in both in vitro and in vivo studies. Recent evidence has now revealed a key role of the tumor microenvironment in maintaining a cancer stem cell niche and promoting cancer stem cell plasticity. There is an increasing focus on identifying and targeting the crosstalk between cancer stem cells and surrounding cells within the tumor microenvironment (TME) as new therapeutic potential, however understanding how CSC maintain a stem-like state is critical to understanding how to therapeutically alter their function. Here we review the current evidence for cancer stem cell plasticity and discuss how interactions with the TME promote the cancer stem cell niche, increase tumor heterogeneity, and play a role in treatment resistance.

CT and FDG-PET radiologic biomarkers in p16+ oropharyngeal squamous cell carcinoma patients treated with definitive chemoradiotherapy.

PURPOSE: To assess associations between imaging biomarkers from standard of care pre-treatment CT and FDG-PET scans and locoregional (LR) and distant metastatic (DM) recurrences in patients with p16+ oropharyngeal squamous cell carcinoma (OPSCC) treated with definitive chemoradiotherapy (CRT). METHODS: An institutional database from a single NCI-designated cancer center identified 266 patients with p16+ OPSCC treated with definitive CRT in our department from 2005 to 2016 with evaluable pre-treatment FDG-PET scans. Quantitative SUV metrics and qualitative imaging metrics were determined from FDG-PET and CT scans, while clinical characteristics were abstracted from the medical record. Associations between clinical/imaging features and time to LR (TTLRF) or DM (TTDMF) failure and overall survival (OS) were assessed using univariable Cox regression and penalized stepwise regression for multivariable analyses (MVA). RESULTS: There were 27 LR and 32 DM recurrences as incident failures. Imaging biomarkers were significantly associated with TTLRF, TTDMF and OS. FDG-PET metrics outperformed CT and clinical metrics for TTLRF, with metabolic tumor volume being the only significant feature selected on MVA: C-index = 0.68 (p = 0.01). Radiographic extranodal extension (rENE), positive retropharyngeal nodes (RPN+), and clinical stage were significant on MVA for TTDMF: C-index = 0.84 (p < 0.001). rENE, group stage, and RPN+ were significant on MVA for OS: C-index = 0.77 (p < 0.001). CONCLUSIONS: In the largest study to date of uniformly treated patients with CRT to evaluate both pretreatment CT and FDG-PET, radiographic biomarkers were significantly associated with TTLRF, TTDMF and OS among patients with p16+ OPSCC treated with CRT. CT metrics performed best to predict TTDMF, while FDG-PET metrics showed improved prediction for LRRFS. These metrics may help identify candidates for treatment intensification or de-escalation of therapy. STATEMENT OF TRANSLATIONAL RELEVANCE: Pre-treatment imaging features from standard-of-care PET/CT imaging show promise for predicting long-term outcomes following HPV-associated oropharynx cancer (HPV-OPC) therapy. This study comprehensively characterizes qualitative and quantitative pre-treatment imaging metrics associated with time to pattern-specific failure in a cohort of 266 patients treated uniformly with definitive chemoradiation. Multivariate analysis (MVA) for time to locoregional failure (TTLRF), time to distant metastatic failure (TTDMF), and overall survival (OS) was performed. FDG-PET metrics outperformed CT and clinical metrics for TTLRF. CT radiographic extranodal extension, positive retropharyngeal nodes, and stage strongly predicted TTDMF (combined C-index = 0.84, log rank p < 0.001). Number of smoking pack-years complemented clinical and imaging features only in patients without radiographic extranodal extension or positive retropharyngeal nodes. Time to pattern-specific failure is important for guiding treatment de-escalation strategies, which intend to reduce treatment-related toxicity in patients with relatively long expected survival times. This study suggests that PET/CT features should play a crucial role in future de-escalation trials and management of HPV-OPC patients.