Primary vs Secondary Endosseous Implantation After Fibular Free Tissue Reconstruction of the Mandible for Osteoradionecrosis

Importance

The clinical and financial implications of the timing of dental rehabilitation after a fibula free tissue transfer (FFTT) for osteoradionecrosis (ORN) and osteonecrosis (ON) of the mandible have yet to be established.

Objective

To compare the outcomes of primary implantation vs secondary implantation after FFTT for ORN and ON of the mandible.

Design, Setting, and Participants

A retrospective review was conducted of 23 patients at a single tertiary academic referral center undergoing primary implantation or secondary implantation after FFTT for ORN and ON from January 1, 2006, to November 10, 2015.

Interventions

All patients underwent FFTT with primary implantation (n = 12) or secondary implantation (n = 11).

Main Outcomes and Measures

Outcomes of FFTT, dental implantation, implant use, diet, speech, and disease-free survival were reviewed. Fixed unit costs were estimated based on the mean cost analysis.

Results

Twenty-three patients (7 women and 16 men; mean [SD] age, 62.4 [8.2] years [range, 24-81 years]) met the inclusion criteria. Of these, 18 had ORN and 5 had ON. Dental implantation was performed at the time of FFTT for 12 patients and was performed secondarily for 11 patients. There were a mean of 5.2 implants per patient performed, for a total of 121 implants. There was 1 complete flap failure in the primary implantation group. Neither flap nor implant complications were affected by the timing of the implantation. Overall, the implant survival rate was 95% (55 of 58) in the primary implantation group and 98% (62 of 63) in the secondary implantation group. Time from FFTT to abutment placement (primary implantation, 19.6 weeks; secondary implantation, 61.0 weeks) was significantly shorter after primary implantation (P < .001). There was no clinical difference in postoperative complications and implant outcomes for ORN vs ON. Improvement in speech and oral competence in the primary implantation group vs the secondary implantation group was not statistically significant, given an experiment-adjusted P = .001 set as significant (normal speech, 9 vs 3; P = .02; and normal oral competence, 9 vs 3; P = .02). Disease-free survival was 91% (20 of 22 patients) overall. Fixed unit (U) costs were 1.0 U for primary implantation and 1.24 U for secondary implantation.

Conclusions and Relevance

Patients undergoing primary implantation after FFTT for ORN and ON had a similar rate of complications compared with those undergoing secondary implantation. However, primary implantation allowed a faster return than secondary implantation to oral nutrition and prosthesis use. The fixed unit cost was reduced for those undergoing primary implantation. Although dental implantation was safe and effective in both groups, the decreased time to use and the decreased overall cost should prompt surgeons to consider primary implantation after FFTT for ORN and ON.

Level of Evidence

3.

Outcomes following TORS for HPV-positive oropharyngeal carcinoma: PEGs, tracheostomies, and beyond

OBJECTIVES

To review swallowing, airway and speech outcomes following transoral robotic surgery (TORS) ± adjuvant therapy for human papillomavirus associated oropharyngeal squamous cell carcinoma (HPV[+]OPSCC).

METHODS

Patients underwent TORS ± standard adjuvant therapy from 5/1/2007-5/31/2015. Clinical data were recorded and descriptive analysis was performed.

RESULTS

267 patients met criteria. All patients underwent surgery at Mayo, however, only 41/81 and 71/119 patients received RT and CRT at a Mayo Clinic site. A PEG was placed in 77 patients (3 prior to any treatment, 74 reactively during adjuvant therapy), with 3 PEG dependent and 3 partially PEG reliant at last follow-up. Tracheostomy was performed in 30 (11%) patients; 28 were decannulated. Swallow evaluations were completed for 20/81 undergoing RT and 50/119 undergoing CRT at a median of 3.8 and 7.6 months post-treatment, respectively. An unrestricted oral diet was reported by 5% following RT and 12% following CRT on the Functional Oral Intake Scale. HN-PSS normalcy of diet scores indicated a diet beyond soft chewable foods for 27% following RT and 46% following CRT. No restriction of place, food, or companion was reported for the HN-PSS for public eating in 13% after RT and 33% after CRT. Aspiration of thin liquid was present in 17% and 28% following RT and CRT, respectively. HN-PSS understandability of speech was "always understandable" in 60% and 63%, following RT and CRT, respectively. Hoarseness was reported in 56% and 45% following RT and CRT respectively.

CONCLUSION

Long-term PEG and tracheostomy dependence in this cohort is low. However, these outcomes under-represent the decrement in patient speech and swallowing following TORS ± standard adjuvant therapy for HPV(+)OPSCC.

Multi-institutional analysis of outcomes following transoral surgery for HPV-positive oropharyngeal squamous cell carcinoma in elderly patients

BACKGROUND

The incidence of human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (OPSCC) is rising, even in elderly patients. The outcomes of transoral surgery (TOS) in this population are not entirely known.

METHODS

A retrospective review was performed at two institutions from October 2003 to September 2016 on patients 70 years or older with HPV-related OPSCC treated with TOS.

RESULTS

A total of 75 patients were included with a mean age of 74 years (70-87 years). At a median follow-up of 35.7 months, 3-year overall survival was 81.5% and disease-specific survival was 94.3%. Advanced cT stage (odds ratio, 2.74; 95% confidence interval, 1.13-6.64) negatively impacted OS. Conjunctive consolidation was performed to create a staging system with patients older than 80 years, severe comorbidity, and cT3-4 having worse survival.

CONCLUSIONS

Elderly patients with HPV-related OPSCC treated with TOS have excellent survival and therefore should not be excluded from such therapy based on age alone.

Phase II Evaluation of Aggressive Dose De-Escalation for Adjuvant Chemoradiotherapy in Human Papillomavirus-Associated Oropharynx Squamous Cell Carcinoma

PURPOSE

The purpose of this study was to determine if dose de-escalation from 60 to 66 Gy to 30 to 36 Gy of adjuvant radiotherapy (RT) for selected patients with human papillomavirus-associated oropharyngeal squamous cell carcinoma could maintain historical rates for disease control while reducing toxicity and preserving swallow function and quality of life (QOL).

PATIENTS AND METHODS

MC1273 was a single-arm phase II trial testing an aggressive course of RT de-escalation after surgery. Eligibility criteria included patients with p16-positive oropharyngeal squamous cell carcinoma, smoking history of 10 pack-years or less, and negative margins. Cohort A (intermediate risk) received 30 Gy delivered in 1.5-Gy fractions twice per day over 2 weeks along with 15 mg/m² docetaxel once per week. Cohort B included patients with extranodal extension who received the same treatment plus a simultaneous integrated boost to nodal levels with extranodal extension to 36 Gy in 1.8-Gy fractions twice per day. The primary end point was locoregional tumor control at 2 years. Secondary end points included 2-year progression-free survival, overall survival, toxicity, swallow function, and patient-reported QOL.

RESULTS

Accrual was from September 2013 to June 2016 (N = 80; cohort A, n = 37; cohort B, n = 43). Median follow-up was 36 months, with a minimum follow-up of 25 months. The 2-year locoregional tumor control rate was 96.2%, with progression-free survival of 91.1% and overall survival of 98.7%. Rates of grade 3 or worse toxicity at pre-RT and 1 and 2 years post-RT were 2.5%, 0%, and 0%. Swallowing function improved slightly between pre-RT and 12 months post-RT, with one patient requiring temporary feeding tube placement.

CONCLUSION

Aggressive RT de-escalation resulted in locoregional tumor control rates comparable to historical controls, low toxicity, and little decrement in swallowing function or QOL.

Long-term survival of adjuvant high-dose (HDC) vs weekly cisplatin (WC) for human papilloma-virus (HPV) and non-HPV head and neck squamous cell carcinoma (HNSCC)

6071

Background: Phase III data suggests a benefit of HDC in the adjuvant setting, but the effect of HDC and WC on long term survival and for HPV+ HNSCC is unknown. Methods: Data from a published retrospective study (Geiger Oral Onc 2013) of HDC vs WC in resected HNSCC was updated. Overall survival (OS) and recurrence-free survival (RFS) was assessed by Kaplan-Meier method for all pts and by HPV status. Multivariate analyses were performed to assess impact of HPV status, smoking, age, HDC vs WC, and cumulative cisplatin dose ( < 200mg/m2 vs ≥200 mg/m2). Results: 51 patients (pts) received HDC and 53 WC. Median follow-up was 8.7 yrs (0.8-13.7). For the whole cohort, HDC had significantly improved OS over WC (p = 0.0095; 5- and 10-yr OS 84% and 80% vs 72% and 60%). No OS benefit for HDC was seen in pts with HPV+HNSCC (5- and 10-yr OS 90% and 87% for HDC and 81% and 81% for WC; p = 0.51). For HPV-negative HNSCC, OS had borderline significance with HDC vs WC (5- and 10-yr OS 73% and 68% vs 65% and 44%; p = 0.06). For the whole cohort, there was no difference in 5- and 10-yr RFS (78% and 74% for HDC vs 72% and 62% for WC; p = 0.32). When analyzed by HPV status, there was no difference in RFS with HDC or WC for either HPV+ (p = 0.43) or HPV-negative HNSCC (p = 0.97). On multivariate analyses of OS for all pts, only HPV status was significant (p = 0.0011; HR 0.27, CI 0.12-0.62). For HPV+ HNSCC, there was no significant predictor of OS. For non-HPV HNSCC, the benefit of HDC approached significance with a decreased risk of death (HR 0.38; p = 0.07). For all pts, those who received ≥200mg/m2 had significantly improved OS (5-yr 90% vs 72% and 10-yr 86% vs 61%; p = 0.004). By HPV status, cumulative dose had no significant effect on OS. Conclusions: OS is better with HDC and with cumulative dose > 200 mg/m2 in unselected patients. The benefit of cisplatin is likely higher for non-HPV HNSCC. A difference in OS with no difference in RFS suggests non cancer-related causes of death in the WC cohort. Ability to receive HDC could be a surrogate marker of comorbidity. [Table: see text]

Nodal and distant metastases in sinonasal mucosal melanoma: A population-based analysis

OBJECTIVES/HYPOTHESIS

Sinonasal mucosal melanoma (SNMM) is a rare malignant neoplasm. No study to date has analyzed the impact that nodal metastases and distant metastases at diagnosis have on overall survival (OS) and disease-specific survival (DSS).

STUDY DESIGN

Retrospective database review.

METHODS

The Surveillance, Epidemiology, and End Results database was queried for cases of SNMM. Descriptive statistics were used analyze patient demographic and clinicopathologic variables. The Kaplan-Meier model was used to analyze survival, and the Cox proportional hazards model was used for multivariate analysis.

RESULTS

Three hundred twenty-eight cases of SNMM were identified. The most frequent sinonasal anatomic location was the nasal cavity in 279 (73.0%) patients, followed by the maxillary sinus in 60 (15.7%) patients. Regional nodal metastases at diagnosis occurred in 33 (8.6%) patients, whereas distant metastases at diagnosis occurred in 41 (10.7%) patients. Five-year OS was 22.7%, and 5-year DSS was 26.8%. The presence of positive nodes at diagnosis (OS P < .0001, DSS P < .0001), distant metastases at diagnosis (OS P = .0442, DSS P = .0442), primary tumor site (OS P < .0001, DSS P < .0001), and increasing age (OS P = .0012, DSS P = .0016) were found to be significant as negative predictors of OS and DSS.

CONCLUSIONS

SNMM is a rare pathologic entity with a poor prognosis. The presence of nodal and distant metastases at diagnosis are negative prognostic factors in OS and DSS. These factors can be used in the development of new models of risk stratification and to inform treatment strategies and surveillance patterns.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:622-627, 2020.

Effect of proximal ligand substitutions on the carbene and nitrene transferase activity of myoglobin

Engineered myoglobins were recently shown to be effective catalysts for abiological carbene and nitrene transfer reactions. Here, we investigated the impact of substituting the conserved heme-coordinating histidine residue with both proteinogenic (Cys, Ser, Tyr, Asp) and non-proteinogenic Lewis basic amino acids (3-(3'-pyridyl)-alanine, p-aminophenylalanine, and β-(3-thienyl)-alanine), on the reactivity of this metalloprotein toward these abiotic transformations. These studies showed that mutation of the proximal histidine residue with both natural and non-natural amino acids result in stable myoglobin variants that can function as both carbene and nitrene transferases. In addition, substitution of the proximal histidine with an aspartate residue led to a myoglobin-based catalyst capable of promoting stereoselective olefin cyclopropanation under nonreducing conditions. Overall, these studies demonstrate that proximal ligand substitution provides a promising strategy to tune the reactivity of myoglobin-based carbene and nitrene transfer catalysts and provide a first, proof-of-principle demonstration of the viability of pyridine-, thiophene-, and aniline-based unnatural amino acids for metalloprotein engineering.

Origin of high stereocontrol in olefin cyclopropanation catalyzed by an engineered carbene transferase

Recent advances in metalloprotein engineering have led to the development of a myoglobin-based catalyst, Mb(H64V,V68A), capable of promoting the cyclopropanation of vinylarenes with high efficiency and high diastereo- and enantioselectivity. Whereas many enzymes evolved in nature often exhibit catalytic proficiency and exquisite stereoselectivity, how these features are achieved for a non-natural reaction has remained unclear. In this work, the structural determinants responsible for chiral induction and high stereocontrol in Mb(H64V,V68A)-catalyzed cyclopropanation were investigated via a combination of crystallographic, computational (DFT), and structure-activity analyses. Our results show the importance of steric complementarity and non-covalent interactions involving first-sphere active site residues, heme-carbene, and the olefin substrate, in dictating the stereochemical outcome of the cyclopropanation reaction. High stereocontrol is achieved through two major mechanisms. First, by enforcing a specific conformation of the heme-bound carbene within the active site. Second, by controlling the geometry of attack of the olefin on the carbene via steric occlusion, attractive van der Waals forces and protein-mediated π-π interactions with the olefin substrate. These insights could be leveraged to expand the substrate scope of the myoglobin-based cyclopropanation catalyst toward non-activated olefins and to increase its cyclopropanation activity in the presence of a bulky α-diazo-ester. This work sheds first light into the origin of enzyme-catalyzed enantioselective cyclopropanation, furnishing a mechanistic framework for both understanding the reactivity of current systems and guiding the future development of biological catalysts for this class of synthetically important, abiotic transformations.

A Randomized Single-Blinded Trial of Posttonsillectomy Liposomal Bupivacaine among Adult Patients

Objective

To determine whether liposomal bupivacaine (Exparel) is safe and effective in the management of posttonsillectomy pain among adult patients.

Study Design

A prospective single-blind randomized controlled trial.

Setting

An academic quaternary care center (Mayo Clinic, Rochester, Minnesota).

Subjects and Methods

From May 2015 to December 2016, 39 patients were randomized to receive oral pain medication and 8 mL of injected liposomal bupivacaine or oral pain medication alone for treatment of their posttonsillectomy pain. Visual analog scale pain intensity scores, oral pain medication usage, liquid oral intake, and complications were recorded for 2 weeks after the procedure.

Results

Thirty-nine patients were randomized, with 17 patients in the liposomal bupivacaine group and 22 in the control group. Fifteen patients in the liposomal bupivacaine group and 18 patients in the control group completed the study. Pain intensity score on postoperative day 1 ( P = .043) proved to be the only statistically significant result, with no difference noted in pain scores on postoperative days 2 to 14. There was no difference in pain medication usage, liquid oral intake, postoperative hemorrhage, or adverse events between groups.

Conclusions

The injection of liposomal bupivacaine in the posttonsillectomy wound bed demonstrates improved pain intensity scores for the first 24 hours after surgery with no adverse complications noted in comparison with patients who did not receive the injection. Given the limited pain reduction and increased cost, use of liposomal bupivacaine in adult tonsillectomy patients appears to have minimal indication for use.

Chemoselective Cyclopropanation over Carbene Y-H Insertion Catalyzed by an Engineered Carbene Transferase

Hemoproteins have recently emerged as promising biocatalysts for promoting a variety of carbene transfer reactions including cyclopropanation and Y-H insertion (Y = N, S, Si, B). For these and synthetic carbene transfer catalysts alike, achieving high chemoselectivity toward cyclopropanation in olefin substrates bearing unprotected Y-H groups has proven remarkably challenging due to competition from the more facile carbene Y-H insertion reaction. In this report, we describe the development of a novel artificial metalloenzyme based on an engineered myoglobin incorporating a serine-ligated Co-porphyrin cofactor that is capable of offering high selectivity toward olefin cyclopropanation over N-H and Si-H insertion. Intramolecular competition experiments revealed a distinct and dramatically altered chemoselectivity of the Mb(H64V,V68A,H93S)[Co(ppIX)] variant in carbene transfer reactions compared to myoglobin-based variants containing the native histidine-ligated heme cofactor or other metal/proximal ligand substitutions. These studies highlight the functional plasticity of myoglobin as a "carbene transferase" and illustrate how modulation of the cofactor environment within this metalloprotein scaffold represents a valuable strategy for accessing carbene transfer reactivity not exhibited by naturally occurring hemoproteins or transition metal catalysts.

Ewing sarcoma of the head and neck: The Mayo Clinic experience

BACKGROUND

Treatment options of Ewing sarcoma of the head and neck include surgery, radiotherapy (RT), and chemoradiotherapy. However, local control can be challenging.

METHODS

We conducted a retrospective review of all patients with head and neck Ewing sarcoma treated from 1972 to 2015 at a single tertiary care hospital.

RESULTS

Seventeen patients met criteria (median 21 years, range 5-58 years; 5 women). Mean follow-up was 10.4 years (range 2.2-39 years). Tumors occurred commonly in the cervical spine (5/17), the skull (3/17), and the paranasal sinuses (3/17). A total of 14 of 17 patients underwent surgical resection, 9 with gross total resection. After multimodality therapy, the 5-year overall survival (OS) and recurrence-free survival (RFS) was 87% and 75%, respectively.

CONCLUSION

Combined multimodal treatment resulted in a 5-year OS and RFS of 87% and 75%, respectively. Aggressive surgical resection with adjuvant chemoradiotherapy should be considered. Although negative margin surgery is the goal, subtotal resection may be acceptable in the setting of adjuvant treatment.

Atrophic Rhinitis: A Review of 242 Cases

Atrophic rhinitis is a debilitating nasal mucosal disease of unknown etiology. It is characterized by progressive nasal mucosal atrophy, nasal crusting, fetor, and enlargement of the nasal space with paradoxical nasal congestion. Primary atrophic rhinitis has decreased markedly in incidence in the last century. This probably relates to the increased use of antibiotics for chronic nasal infection. Secondary atrophic rhinitis resulting from trauma, surgery, granulomatous diseases, infection, and radiation exposure accounts for the majority of cases encountered by the rhinologist today. Excessive turbinate surgery has been both acquitted and accused in the literature as an etiology for secondary atrophic rhinitis. We saw 242 patients with the diagnosis of atrophic rhinitis between 1982 and 1999. The diagnosis was confirmed by physical examination, biopsy, and imaging studies. Patients were diagnosed with primary atrophic rhinitis if their condition developed in a previously healthy nose and secondary atrophic rhinitis if their condition developed after sinonasal surgery, trauma, or chronic granulomatous disease. Prevention and treatment of the disease is discussed.

Primary surgical management with radial forearm free flap reconstruction in T4 oropharyngeal cancer: Complications and functional outcomes

PURPOSE

Functional outcomes and complication rates after open surgery for advanced-stage oropharyngeal cancers are rarely reported. These measures are critical for choice of treatment modality and patient counseling. We describe the long term functional outcomes and associated complications of primary surgical management of T4 oropharyngeal cancers reconstructed with radial forearm free flaps.

MATERIALS AND METHODS

A retrospective review was performed of 40 patients with T4 oropharyngeal cancers treated between 2005 and 2015 at a tertiary care center.

RESULTS

Forty patients with T4 oropharyngeal cancers underwent open surgical resection and radial forearm free flap reconstruction at the time of surgery. Mandibulotomy was required in 33 (82.5%) cases. Thirty-five (87.5%) patients received adjuvant radiation or combined chemotherapy and radiation. Tracheostomy was performed in all patients, but every patient was eventually decannulated. Twenty (57.1%) patients required gastrostomy tube placement at some point during treatment; however, 91.4% were on a completely oral diet with a mean FOSS score of 1.6 by 1year after completion of treatment. The addition of adjuvant treatment was the only factor significantly associated with poorer FOSS scores. The overall rates of short and long-term complications were 60.0% and 57.1% respectively. The most common short and long-term complications were infection (30.0%) and velopharyngeal insufficiency (25.7%) respectively.

CONCLUSIONS

Traditional open surgical approaches to large tumors of the oropharynx carry higher complication rates than more recent advanced transoral approaches. However, they can still be utilized with excellent long-term functional results in certain cases of advance oropharyngeal cancers not amenable to transoral approaches. With careful reconstruction of oropharyngeal defects, over 90% of patients can achieve a completely oral diet.

Dural Invasion Predicts the Laterality and Development of Neck Metastases in Esthesioneuroblastoma

Objectives  Neck metastases in patients with esthesioneuroblastoma (ENB) constitute the most significant predictor of poor long-term survival. Recently, researchers discovered the existence of dural lymphatic channels that drain to the cervical lymph nodes. From this physiologic basis, we hypothesized that patients with ENB who develop dural invasion (DI) would exhibit a proclivity for neck metastases. Design  Retrospective review. Setting  Tertiary referral center. Participants  All patients treated for ENB from January 1, 1994 to December 31, 2015. Main Outcome Measures  Incidence, laterality, and recurrence rate of neck metastases by DI status. Results  Sixty-one patients were identified (38% female; median age 49, range, 10-80), 34 (56%) of whom had DI and 27 (44%) did not. Of patients with DI, 50% presented with or developed neck disease following treatment compared with just 22% of those without DI ( p  = 0.026). Bilateral neck disease was more common in patients with DI (11/34, 32%) compared with those without (2/27, 7%) ( p  = 0.018). Five-year regional recurrence-free survival rates were 88% for those without and 64% for those with DI ( p  = 0.022). Kadish C patients with DI were more likely to develop regional recurrence when compared with Kadish C without DI and Kadish A/B ( p  = 0.083). Further, Kadish C patients with DI displayed worse overall survival than Kadish C without DI and Kadish A/B. Kadish D patients displayed the worst overall survival. The difference in overall survival among these four groups was significant ( p  < 0.001). Conclusion  DI by ENB is associated with increased incidence of cervical nodal metastases, bilateral neck disease, worse regional recurrence-free survival, and poorer overall survival. These data support the division of Kadish C by DI status.

Oncologic outcomes of extended neck dissections in human papillomavirus-related oropharyngeal squamous cell carcinoma

BACKGROUND

Oncologic outcomes of human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (SCC) requiring resection of major muscular or neurovascular tissue during neck dissection for invasive nodal disease remain uncertain.

METHODS

Patients with HPV-related oropharyngeal SCC requiring resection of major muscular or neurovascular tissue during their neck dissections were retrospectively identified.

RESULTS

Seventy-two patients were included. Regional and distant recurrences occurred in 6% and 17% of patients. Advanced T classification, pathological node number of 5 or more, and omission of adjuvant therapy were associated with decreased disease-free survival (DFS). The addition of adjuvant chemotherapy was not associated with improved survival.

CONCLUSION

Patients with invasive nodal disease from HPV-related oropharyngeal SCC can be managed with up-front surgery and adjuvant therapy, as indicated with good regional control. Although distant recurrence was the primary site of failure, adjuvant chemotherapy was not associated with improved outcomes. The T classification, node number, and adjuvant radiotherapy are independent prognostic factors in this patient population.

Rates and Locations of Regional Metastases in Sinonasal Malignancies: The Mayo Clinic Experience

Objectives  The objective of this study was to identify factors that may influence the rate and location of regional metastasis in sinonasal malignancies (SNMs). Design  This is a retrospective review. Setting  This study was set at the single-institution tertiary referral center. Participants  A total of 299 patients were treated for SNMs from 1994 to 2014. Main Outcome Measures  The main outcome measures were incidence and distribution of regional metastases. Results  Several histologic subtypes were treated, with squamous cell carcinoma (28.4%), esthesioneuroblastoma (18.1%), and mucosal melanoma (12.4%) being the most common. Of the 299 patients, 59 (19.7%) developed a regional metastasis, either at presentation or during follow-up. Higher cumulative incidence of regional metastases was significantly associated with histologic type ( p ≤0.001) and invasion of the dura ( p  = 0.005), infratemporal fossa ( p  = 0.036), orbit ( p  = 0.020), or palate ( p  = 0.016). Ipsilateral level II lymph nodes were the most commonly involved nodes. Contralateral regional metastases were associated with higher risk histologic types ( p  = 0.005) and dural invasion ( p  = 0.008). Parotid metastases were associated with invasion of the facial soft tissue ( p  = 0.028), and retropharyngeal metastases were associated with invasion of the pterygoid plates and musculature ( p  = 0.030). Conclusion  Histologic type of SNM appears to be the most important factor in predicting the rate of regional metastases. Histologic type and invasion of certain neighboring structures may help define which lymphatic basins are at highest risk for metastasis.

Transoral Resection of Human Papillomavirus (HPV)-Positive Squamous Cell Carcinoma of the Oropharynx: Outcomes with and Without Adjuvant Therapy

BACKGROUND

With the rise of oropharyngeal squamous cell carcinoma associated with human papillomavirus (HPV), appropriate treatment strategies continue to be tailored toward minimizing treatment while preserving oncologic outcomes. This study aimed to compare the outcomes for those undergoing transoral resection with or without adjuvant therapy for HPV-related oropharyngeal carcinoma.

METHODS

A case-match cohort analysis was performed at two institutions on patients with HPV-related oropharyngeal squamous cell carcinoma. All the subjects underwent transoral surgery and neck dissection. The patients treated with surgery alone were matched 1:1 to those treated with surgery and adjuvant therapy using two groups identified as confounders: T-stage (T1/2 or T3/4) and number of pathologically positive lymph nodes (≤4 or >4).

RESULTS

The study identified 105 matched pairs, with a median follow-up period of 42 months (range 3.1-102.3 months). The patients were staged as T1/T2 (86%) or T3/4 (14%). Each group had five patients with more than four positive lymph nodes. Adjuvant therapy significantly improved disease-free survival (hazard ratio [HR] 0.067; 95% confidence interval [CI] 0.01-0.62) and was associated with a lower risk of local and regional recurrence (risk ratio [RR] 0.096; 95% CI 0.02-0.47). No difference in disease-specific survival (HR 0.22; 95% CI 0.02-2.57) or overall survival (HR 0.18; 95% CI 0.01-2.4) was observed with the addition of adjuvant therapy. The risk of the gastrostomy tube was higher for those receiving adjuvant therapy (RR 7.3; 95% CI 2.6-20.6).

CONCLUSIONS

Transoral surgery is an effective approach for the treatment of HPV-related oropharyngeal carcinoma. The addition of adjuvant therapy appears to decrease the risk of recurrence and improve disease-free survival but may not significantly improve overall survival.

Stereoselective olefin cyclopropanation under aerobic conditions with an artificial enzyme incorporating an iron-chlorin e6 cofactor

Myoglobin has recently emerged as a promising biocatalyst for catalyzing carbene-mediated cyclopropanation, a synthetically valuable transformation not found in nature. Having naturally evolved for binding dioxygen, the carbene transferase activity of this metalloprotein is severely inhibited by it, imposing the need for strictly anaerobic conditions to conduct these reactions. In this report, we describe how substitution of the native heme cofactor with an iron-chlorin e6 complex enabled the development of a biocatalyst capable of promoting the cyclopropanation of vinylarenes with high catalytic efficiency (up to 6,970 TON), turnover rate (>2,000 turnovers/min), and stereoselectivity (up to 99% de and ee) in the presence of oxygen. The artificial metalloenzyme can be recombinantly expressed in bacterial cells, enabling its application also in the context of whole-cell biotransformations. This work makes available a robust and easy-to-use oxygen-tolerant biocatalyst for asymmetric cyclopropanations and demonstrates the value of porphyrin ligand substitution as a strategy for tuning and enhancing the catalytic properties of hemoproteins in the context of abiological reactions.

Head and neck desmoplastic melanoma: Utility of sentinel node biopsy

PURPOSE

The utility of sentinel lymph node biopsy in desmoplastic melanoma has been questioned due to multiple reports of a low rate of occult nodal metastasis in this variant of melanoma. We describe a single institution experience with management of desmoplastic melanoma of the head and neck and discuss the utility of sentinel lymph node biopsy.

MATERIALS AND METHODS

A retrospective review was performed of 49 patients with desmoplastic melanoma of the head and neck at a tertiary care center from 1994 to 2014.

RESULTS

Sentinel lymph node biopsy was performed in 15 patients. Only 1 (6.7%) of these patients was found to have a positive sentinel node. Of the 46 patients without evidence of neck disease at presentation, 3 (6.5%) were found to have occult nodal disease or developed neck recurrences. When looking at the entire cohort, there were a total of 16 recurrences in 14 patients (28.6%). The majority (85.7%) of recurrences were either local or distant metastasis with only 2 (14.3%) recurrences being in regional lymph node basins. The overall rates of local, regional, and distant recurrences were 14.2%, 4.1%, and 10.2% respectively. The mixed pathologic subtype was not associated with a higher rate of nodal metastasis.

CONCLUSIONS

Desmoplastic melanoma has a low rate of occult nodal metastasis and a high propensity to recur locally or as a distant metastasis, regardless of regional node status. Our experience combined with the uncertain impact that sentinel node status has on survival raises the question of the utility of routine sentinel node biopsy in this specific variant of melanoma.