Pain control is comparable between opioid versus non-opioid management after otolaryngology procedures

Objective

The current study aims to measure patient-reported satisfaction with pain control using opioid and non-opioid medications after undergoing the following otolaryngology procedures: parathyroidectomy, thyroid lobectomy, total thyroidectomy, and bilateral tonsillectomy.

Materials and Methods

A prospective cohort study was performed at an academic medical center that included a telephone questionnaire and chart review. Opioid prescriptions, usage, and patient-reported pain outcomes were recorded. Bivariate analyses were used to compare opioid and non-opioid users.

Results

Of the 107 total patients undergoing otolaryngology procedures included in the study, 49 (45.8%) used an opioid for pain management postoperatively and 58 (54.2%) did not. Among the 81 patients who underwent endocrine procedures (parathyroidectomy, total thyroidectomy/lobectomy), most patients reported being "very satisfied" or "satisfied" with pain control whether they used opioids (n = 27/30, 90%) or not (n = 50/51, 98%). Of the 26 patients who underwent bilateral tonsillectomy, 19 (73%) were prescribed opioids and among these, most (n = 17/19, 89%) reported they were "very satisfied" or "satisfied" with pain control. In the non-opioid usage group, all patients (n = 7/7, 100%) reported they were "satisfied" with pain control. There was no statistically significant difference in patient-reported satisfaction with pain control between opioid and non-opioid users for any of the procedures listed.

Conclusion

The results of our study suggest that patients who did not use opioids have a similar level of satisfaction with pain control compared to those using opioids after thyroid, parathyroid and tonsillectomy surgeries. Considering the magnitude of the opioid crisis, providers should reassess the need for opioid prescriptions following certain ENT procedures.

Level of Evidence

IV.

Oncologic Safety of Close Margins in Patients With Low- to Intermediate-Grade Major Salivary Gland Carcinoma

Importance

Postoperative radiation therapy for close surgical margins in low- to intermediate-grade salivary carcinomas lacks multi-institutional supportive evidence.

Objective

To evaluate the oncologic outcomes for low- and intermediate-grade salivary carcinomas with close and positive margins.

Design, Setting, and Participants

The American Head and Neck Society Salivary Gland Section conducted a retrospective cohort study from 2010 to 2019 at 41 centers. Margins were classified as R0 (negative), R1 (microscopically positive), or R2 (macroscopically positive). R0 margins were subclassified into clear (>1 mm) or close (≤1 mm). Data analysis was performed from June to October 2023.

Main Outcomes and Measures

Main outcomes were risk factors for local recurrence.

Results

A total of 865 patients (median [IQR] age at surgery, 56 [43-66] years; 553 female individuals [64%] and 312 male individuals [36%]) were included. Of these, 801 (93%) had parotid carcinoma and 64 (7%) had submandibular gland carcinoma, and 748 (86%) had low-grade tumors and 117 (14%) had intermediate-grade tumors, with the following surgical margins: R0 in 673 (78%), R1 in 168 (19%), and R2 in 24 (3%). Close margins were found in 395 of 499 patients with R0 margins (79%), for whom margin distances were measured. A total of 305 patients (35%) underwent postoperative radiation therapy. Of all 865 patients, 35 (4%) had local recurrence with a median (IQR) follow-up of 35.3 (13.9-59.1) months. In patients with close margins as the sole risk factor for recurrence, the local recurrence rates were similar between those who underwent postoperative radiation therapy (0 of 46) or observation (4 of 165 [2%]). Patients with clear margins (n = 104) had no recurrences. The local recurrence rate in patients with R1 or R2 margins was better in those irradiated (2 of 128 [2%]) compared to observed (13 of 64 [20%]) (hazard ratio [HR], 0.05; 95% CI, 0.01-0.24). Multivariable analysis for local recurrence found the following independent factors: age at diagnosis (HR for a 10-year increase in age, 1.33; 95% CI, 1.06-1.67), R1 vs R0 (HR, 5.21; 95% CI, 2.58-10.54), lymphovascular invasion (HR, 4.47; 95% CI, 1.43-13.99), and postoperative radiation therapy (HR, 0.10; 95% CI, 0.04-0.29). The 3-year local recurrence-free survivals for the study population were 96% vs 97% in the close margin group.

Conclusions and Relevance

In this cohort study of patients with low- and intermediate-grade major salivary gland carcinoma, postoperative radiation therapy for positive margins was associated with decreased risk of local recurrence. In isolation from other risk factors for local recurrence, select patients with close surgical margins (≤1 mm) may safely be considered for observation.

Oral Cavity Cancer Surgical and Nodal Management: A Review From the American Head and Neck Society

Importance

Lymph node metastases from oral cavity cancers are seen frequently, and there is still inconsistency, and occasional controversies, regarding the surgical management of the neck in patients with oral cancer. This review is intended to offer a surgically focused discussion of the current recommendations regarding management of the neck, focusing on the indications and extent of dissection required in patients with oral cavity squamous cell carcinoma while balancing surgical risk and oncologic outcome.

Observations

The surgical management of the neck for oral cavity cancer has been robustly studied, as evidenced by substantial existing literature surrounding the topic. Prior published investigations have provided a sound foundation on which data-driven treatment algorithms can generally be recommended.

Conclusions

Existing literature suggests that patients with oral cavity cancer should be fully staged preoperatively, and most patients should receive a neck dissection even when clinically N0. Quality standards supported by the literature include separation of each level during specimen handling and lymph node yield of 18 or more nodes. Sentinel lymph node biopsy can be considered in select tumors and within a well-trained multidisciplinary team.

A Case Report of Refractory Postherpetic Neuralgia After Ramsay Hunt Syndrome Treated With Tympanic Nerve Neurectomy

Ramsay Hunt syndrome is a facial nerve palsy that arises from herpes zoster infection. In rare cases, postherpetic neuralgia is a complication following Ramsay Hunt syndrome. Pain management to address postherpetic neuralgia includes facial nerve blocks, medications such as gabapentin, carbamazepine and botulinum toxin injections, and pulsed radiofrequency. Despite the reported benefits for patients with glossopharyngeal nerve pain, neurectomy as a treatment has rarely been described. A 45-year-old patient visited our ENT clinic for chronic right-sided facial, ear, and jaw pain that persisted for 9 years following the development of Ramsay Hunt syndrome. She trialed multiple medications including gabapentin, carbamazepine, and botulinum toxin injections with minimal relief to her symptoms. The patient underwent a diagnostic myringotomy with topical application of lidocaine to the tympanic nerve. This resulted in temporary relief of her pain until the effects of the lidocaine subsided. The patient was subsequently offered lysis of the right tympanic nerve for more definitive management. The patient experienced significant pain reduction after the right tympanic neurectomy procedure. Chronic postherpetic neuralgia following Ramsay Hunt syndrome can cause significant impairment in a patient's quality of life. For patients with ear pain refractory to conservative management, a tympanic neurectomy can be considered.

Larynx Cancer: Reconstructive Options

Reconstruction for laryngeal cancer will depend on the defect left by surgical resection and patient-related factors such as medical comorbidities and history of previous radiation treatment. The goals of reconstruction are to preserve and/or restore the primary functions of the larynx (breathing, swallowing, voicing). Options include primary closure, locoregional flaps, and microvascular free tissue each with their advantages and disadvantages, which should be considered when planning reconstruction.

Assessing the role of ultrasound for the evaluation of adult neck masses

Objectives

The American Academy of Otolaryngology clinical practice guidelines recommend cross-sectional imaging or fine needle aspiration for any neck mass in an adult that persists beyond 2 weeks that is not convincingly related to a bacterial infection. We aimed to assess the role of ultrasound in the evaluation and management of neck masses.

Methods

A retrospective chart review was performed of adult patients evaluated in the Otolaryngology clinic at a single institution from December 2014 to December 2015 for a visible or palpable neck mass persistent beyond 2 weeks who had an ultrasound exam as part of their initial workup. Patients with a history of head and neck malignancy or those presenting wtih primary salivary or thyroid gland lesions were excluded. Sonographic features, demographics, imaging, and biopsy results were recorded.

Results

Of the 56 patients who met inclusion criteria, 36 (64.3%) received FNA or biopsy, of which 18 (50%) demonstrated malignant pathology. Twenty patients (35.7%) demonstrated benign features on ultrasound and did not undergo tissue sampling. Two of these 20 patients underwent subsequent cross-sectional imaging. Eight of these 20 patients were followed with serial ultrasound with an average of 3 exams over 14.7 months. The remaining 12 patients had spontaneous resolution of their adenopathy. None of these 20 patients was subsequently diagnosed with malignancy.

Conclusion

In this study, approximately one third of patients presenting with a visible or palpable neck mass were able to safely avoid cross-sectional imaging and/or tissue sampling when ultrasound demonstrated features consistent with benign pathology. Our results suggest that ultrasound can play a useful role in the initial evaluation and management of adults presenting with a neck mass.

Level of Evidence

IV.

Evaluating the Rising Incidence of Thyroid Cancer and Thyroid Nodule Detection Modes: A Multinational, Multi-institutional Analysis

Importance

There is epidemiologic evidence that the increasing incidence of thyroid cancer is associated with subclinical disease detection. Evidence for a true increase in thyroid cancer incidence has also been identified. However, a true increase in disease would likely be heralded by an increased incidence of thyroid-referable symptoms in patients presenting with disease.

Objectives

To evaluate whether modes of detection (MODs) used to identify thyroid nodules for surgical removal have changed compared with historic data and to determine if MODs vary by geographic location.

Design, Setting, and Participants

This was a retrospective analysis of pathology and medical records of 1328 patients who underwent thyroid-directed surgery in 16 centers in 4 countries: 4 centers in Canada, 1 in Denmark, 1 in South Africa, and 12 in the US. The participants were the first 100 patients (or the largest number available) at each center who had thyroid surgery in 2019. The MOD of the thyroid finding that required surgery was classified using an updated version of a previously validated tool as endocrine condition, symptomatic thyroid, surveillance, or without thyroid-referable symptoms (asymptomatic). If asymptomatic, the MOD was further classified as clinician screening examination, patient-requested screening, radiologic serendipity, or diagnostic cascade.

Main Outcomes and Measures

The MOD of thyroid nodules that were surgically removed, by geographic variation; and the proportion and size of thyroid cancers discovered in patients without thyroid-referable symptoms compared with symptomatic detection. Data analyses were performed from April 2021 to February 2022.

Results

Of the 1328 patients (mean [SD] age, 52 [15] years; 993 [75%] women; race/ethnicity data were not collected) who underwent thyroid surgery that met inclusion criteria, 34% (448) of the surgeries were for patients with thyroid-related symptoms, 41% (542) for thyroid findings discovered without thyroid-referable symptoms, 14% (184) for endocrine conditions, and 12% (154) for nodules with original MOD unknown (under surveillance). Cancer was detected in 613 (46%) patients; of these, 30% (183 patients) were symptomatic and 51% (310 patients) had no thyroid-referable symptoms. The mean (SD) size of the cancers identified in the symptomatic group was 3.2 (2.1) cm (median [range] cm, 2.6 [0.2-10.5]; 95% CI, 2.91-3.52) and in the asymptomatic group, 2.1 (1.4) cm (median [range] cm, 1.7 [0.05-8.8]; 95% CI, 1.92-2.23). The MOD patterns were significantly different among all participating countries.

Conclusions and Relevance

This retrospective analysis found that most thyroid cancers were discovered in patients who had no thyroid-referable symptoms; on average, these cancers were smaller than symptomatic thyroid cancers. Still, some asymptomatic cancers were large, consistent with historic data. The substantial difference in MOD patterns among the 4 countries suggests extensive variations in practice.

Techniques in Otolaryngology: Ultrasound-Guided Transcervical Fine-Needle Aspiration of Laryngeal Masses

Traditionally, laryngeal masses are diagnosed with direct laryngoscopy with biopsy under general anesthesia. The use of transcervical ultrasound–guided fine-needle aspiration for the diagnosis of base of tongue lesions, thyroid nodules, and cervical lymph node metastases has been well documented, and its use in the diagnosis of laryngeal masses has increased in recent years. We report a technique for office-based transcervical ultrasound–guided fine-needle aspiration for laryngeal masses without cervical metastasis (N0), with outcomes from 6 patients. Benefits of this approach included limited side effects, rapid in-office diagnosis, avoidance of aerosolizing procedures during the COVID-19 pandemic, and avoidance of tracheostomy.

Perioperative Topical Antisepsis and Surgical Site Infection in Patients Undergoing Upper Aerodigestive Tract Reconstruction

Importance

Surgical site infections (SSIs) after vascularized reconstruction of the upper aerodigestive tract (UADT) are associated with considerable morbidity. The association between perioperative prophylaxis practices, particularly topical antisepsis, and SSIs remains uncertain.

Objective

To assess the association between perioperative topical antisepsis and SSIs in patients undergoing vascularized reconstruction of the UADT.

Design, Setting, and Participants

This cohort study included patients from 12 academic tertiary care centers over an 11-month period, from July 1, 2020, to June 1, 2021. Patients undergoing open surgical procedures requiring a communication between the UADT and cervical skin with a planned regional pedicled flap, free flap, or both were included. Patients with an active infection at the time of surgical procedure were excluded.

Main Outcomes and Measures

The primary outcome measure was an SSI within 30 days of surgery. The association of demographic characteristics, perioperative antibiotic prophylaxis, surgical technique, and postoperative care with SSIs was assessed using univariable and multivariable analyses. The relative risk ratio and 95% CIs for developing SSI were calculated for each of the variables based on predetermined categories. Variables for which the relative risk 95% CI did not include the value of zero effect (relative risk = 1.00) were included in the multivariable model.

Results

A total of 554 patients (median age, 64 years; range, 21-95 years; 367 men [66.2%]) were included. Cancer ablation was the most frequent reason for surgery (n = 480 [86.6%]). Overall, the SSI rate was 20.9% (n = 116), with most infections involving the head and neck surgical site only (91 [78.4%]). The median time to SSI diagnosis was 11 days (range, 1-28 days). Topical antisepsis mucosal preparation was performed preoperatively in 35.2% (195) and postoperatively in 52.2% (289) of cases. Ampicillin and sulbactam was the most common systemic antibiotic prophylaxis agent used (n = 367 [66.2%]), with 24 hours being the most common duration (n = 363 [65.5%]). On multivariable analysis, preoperative topical antisepsis mucosal preparation (odds ratio [OR], 0.49; 95% CI, 0.30-0.77) and systemic prophylaxis with piperacillin and tazobactam (OR, 0.42; 95% CI, 0.21-0.84) were associated with a decreased risk of a postoperative SSI. The use of an osseous vascularized flap was associated with an increased risk of postoperative SSI (OR, 1.76; 95% CI, 1.13-2.75).

Conclusions and Relevance

Findings of this study suggest that preoperative topical antisepsis mucosal preparation was independently associated with a decreased risk of SSIs in a 12-center multi-institutional cohort. Further investigation of the association between individual perioperative practices and the incidence of postoperative SSIs is necessary to develop evidence-based protocols to reduce SSIs after UADT reconstruction.

Trends in Diagnosis of Noninvasive Follicular Thyroid Neoplasm With Papillarylike Nuclear Features and Total Thyroidectomies for Patients With Papillary Thyroid Neoplasms

Importance

Increasing detection of early-stage papillary thyroid neoplasms without improvements in mortality has prompted development of strategies to prevent or mitigate overtreatment.

Objective

To determine adoption rates of 2 recent strategies developed to limit overtreatment of low-risk thyroid cancers: (1) a new classification, noninvasive follicular thyroid neoplasm with papillarylike nuclear features (NIFTP), and (2) hemithyroidectomy for selected papillary thyroid carcinomas (PTCs) up to 4 cm in size.

Design, Setting, and Participants

This is a cross-sectional analysis of 3368 pathology records of 2 cohorts of patients from 18 hospitals in 6 countries during 2 time periods (2015 and 2019). Participating hospitals were included from the US (n = 12), Canada (n = 2), Denmark (n = 1), South Korea (n = 1), South Africa (n = 1), and India (n = 1). The records of the first 100 patients per institution for each year who underwent thyroid-directed surgery (hemithyroidectomy, total thyroidectomy, or completion thyroidectomy) were reviewed.

Main Outcomes and Measures

Frequency of diagnosis of NIFTP, PTCs, and thyroidectomies during the study period.

Results

Of the 790 papillary thyroid neoplasms captured in the 2019 cohort, 38 (4.8%) were diagnosed as NIFTP. Diagnosis of NIFTP was observed in the US, South Africa, and India. There was minimal difference in the total proportion of PTCs in the 2015 cohort compared with the 2019 cohort (778 [47.1%] vs 752 [44.5%]; difference, 2.6% [95% CI, -16.9% to 22.1%]). The proportion of PTCs eligible for hemithyroidectomy but treated with total thyroidectomy in the 2 cohorts demonstrated a decreasing trend from 2015 to 2019 (341 of 453 [75.3%] vs 253 of 434 [58.3%]; difference, 17.0% [95% CI, -1.2% to 35.2%]).

Conclusions and Relevance

Results of this cohort study showed that the 2 mitigation strategies for preventing overtreatment of early-stage thyroid cancer have had mixed success. The diagnosis of NIFTP has only been applied to a small proportion of thyroid neoplasms compared with expected rates. However, more patients eligible for hemithyroidectomy received it in 2019 compared with 2015, showing some success with this deescalation strategy.

Effect of PPIs on symptomatic hypocalcemia after thyroidectomy: A retrospective cohort study

OBJECTIVE

To determine differences in incidence and duration of postoperative symptomatic hypocalcemia between those taking and those not taking proton pump inhibitors (PPIs) at the time of total or completion thyroidectomy.

METHODS

A retrospective chart review of adult patients who underwent total or completion thyroidectomy at a tertiary medical center between January 2013 and January 2018 was performed. Development of symptomatic hypocalcemia, duration of symptoms, postoperative parathyroid hormone levels, PPI usage and emergency department (ED) visits were recorded.

RESULTS

Data from 371 patients were analyzed. Sixty of 371 (16.2%) patients developed symptomatic hypocalcemia. Sixteen of 89 (18.0%) patients on a PPI developed symptomatic hypocalcemia compared to 44 of 282 (15.6%) not on a PPI (P = .63). The overall average duration of symptoms was 4.3 days (SD [SD] 3.77 days). The average duration of symptoms in those on a PPI was 4.8 days (SD 2.8 days) compared to 4.2 days (SD 4.1 days) in those not on a PPI (P = 0.16). Six of 282 patients (2.1%) not taking a PPI had a postoperative ED visit, compared to two of the 89 patients (2.3%) taking a PPI (P = 1.00).

CONCLUSIONS

There was no clinically significant difference in incidence and duration of symptomatic hypocalcemia or ED visits after total or completion thyroidectomy between patients that were and were not taking PPIs perioperatively. While the decision to continue PPI should be made on an individual basis, these data suggest that patients may be counseled to continue their PPI perioperatively without increased risk of symptomatic hypocalcemia.

LEVEL OF EVIDENCE

3.

A case of secretory carcinoma of the submandibular gland with unusual immunohistochemical staining

Mammaglobin negative secretory carcinoma may be overlooked. It is important to assess the possibility of diagnosis when histology is suggestive and immunohistochemical staining for S-100 is positive even when staining for mammaglobin is negative.

Feasibility of In-office Fine-Needle Aspiration for Base of Tongue Tumors

We aim to demonstrate the feasibility of in-office transcervical ultrasound (TCUS)-guided fine-needle aspiration (FNA) of base of tongue (BOT) tumors in a single-institution. Retrospective chart review was performed and 3 patients met criteria, with BOT tumors ≥3 cm . Two patients had no cervical adenopathy, while FNA of a cervical lymph node was inconclusive in patient 3. Two patients had multiple medical comorbidities rendering them high risk for general anesthesia, and 1 patient had a BOT tumor obscuring visualization of the glottis, which would have precluded intubation and potentially required tracheostomy to proceed. All patients underwent successful in-office TCUS-guided FNA, with results showing squamous cell carcinoma. There were no related complications. In-office TCUS-guided FNA can be used for diagnosis of BOT lesions that are evident on ultrasound. This is beneficial in cases where general anesthesia is considered high risk. Additionally, 1 patient safely continued anticoagulation, and another was able to avoid tracheostomy. This technique is cost-effective as it avoids the expenses associated with operative intervention.

Nonadherence to Guideline Recommendations for Tympanostomy Tube Insertion in Children Based on Mega-database Claims Analysis

Objective To estimate the nonadherence rate of pressure equalization (tympanostomy) tube (PET) placement in the preceding 3-year period before release of the 2013 American Academy of Otolaryngology-Head and Neck Surgery Foundation clinical practice guideline (CPG). Study Design Analysis of the Truven Health MarketScan Research Databases (2010-2012). Subjects and Methods Medical claims data from 2010 to 2012 were analyzed. Children aged ≤12 years with otitis media (OM)-related diagnoses were identified. Adherence and nonadherence rates for OM and PET placement were analyzed through administrative codes extrapolated from the key action statements (KASs) of the CPG. KASs were aggregated to estimate the overall nonadherence and determine areas for quality improvement. Results A total of 9,726,411 visits with OM-associated codes among 3,710,730 children were identified: 2.9% (80,451 of 3,239,700) were considered nonadherent to KAS 1 because a code for PET placement occurred with a first episode of OM with effusion <3 months; 52.1% (14,534 of 27,913) underwent PET placement for OM with effusion of >3 months and had a concurrent hearing loss code. For those without hearing loss who underwent PET placement, 48.3% (52,921 of 109,583) had a diagnosis code indicating risk for speech, language, or learning problems. For each KAS, we found heterogeneity of computed nonadherence rates by region, age, and season. Conclusion Before guideline dissemination, we found low to moderate rates of nonadherence to guideline recommendation. Deeper analysis of mega-databases could provide better insights for measurement of guideline adherence. The expansion of administrative and clinical databases provides a unique opportunity to investigate the impact of CPGs.

Modeling alterations in sinonasal physiology after skull base surgery

BACKGROUND

Endonasal endoscopic skull base surgery (EESBS) often requires significant alterations in intranasal anatomy. For example, posterior septectomy (PS) with middle turbinate resection (MTR) is frequently performed to provide access to large sellar and clival tumors. However, little is known about the alterations that occur in sinonasal physiology. This study was designed to assess changes in sinonasal physiology after virtually performed endoscopic skull base surgery.

METHODS

Three-dimensional models of the sinonasal passage were created from computed tomography scans in three subjects with varying anatomy: no SD (SD), right anterior SD, and left anterior SD, respectively. Four additional surgery types were performed virtually on each model: endoscopic transsphenoidal approach (ETSA) with small (1 cm) PS (smPS), ETSA with complete (2 cm) PS, ETSA with smPS and right MTR, and ETSA with complete PS and right MTR. Computational fluid dynamics (CFD) simulations were performed on the 3 presurgery and 12 virtual surgery models to assess changes from surgery types.

RESULTS

Increased nasal airflow corresponded to amount of tissue removed. Effects of MTR on unilateral airflow allocation were unchanged in subject with no SD, worsened in leftward SD, and reversed in rightward SD. Severity of airflow and mucosal wall interactions trended with amount of tissue removed. MTR hindered flow interactions with the olfactory mucosa in subjects with SD.

CONCLUSION

CFD simulations on virtual surgery models are able to reasonably detect changes in airflow patterns in the computer-generated nasal models. In addition, each patient's unique anatomy influences the magnitude and direction of these changes after virtual EESBS. Once future studies can reliably correlate CFD parameters with patient symptoms, CFD will be a useful clinical tool in surgical planning and maximizing patient outcomes.

Nasopharyngeal Masses Arising from Embryologic Remnants of the Clivus: A Case Series

Objectives This study aims to (1) discuss rare nasopharyngeal masses originating from embryologic remnants of the clivus, and (2) discuss the embryology of the clivus and understand its importance in the diagnosis and treatment of these masses. Design and Participants This is a case series of three patients. We discuss the clinical and imaging characteristics of infrasellar craniopharyngioma, intranasal extraosseous chordoma, and canalis basilaris medianus. Results Case 1: A 16-year-old male patient with a history of craniopharyngioma resection, who presented with nasal obstruction. A nasopharyngeal cystic mass was noted to be communicating with a patent craniopharyngeal canal. Histology revealed adamantinomatous craniopharyngioma. Case 2: A 43-year-old male patient who presented with nasal obstruction and headache. Computed tomography (CT) and magnetic resonance imaging revealed an enhancing polypoid mass in the posterior nasal cavity abutting the clivus. Histopathology revealed chondroid chordoma. Case 3: A 4-year-old female patient with a recurrent nasopharyngeal polyp. CT cisternogram showed that this mass may have risen from a bony defect of the middle clivus suggestive of canalis basilaris medianus. Conclusions Understanding the embryology of the clivus is crucial when considering the differential diagnosis of a nasopharyngeal mass. Identification of characteristic findings on imaging is critical in the diagnosis and treatment of these lesions.

Image-guided Interstitial Photodynamic Therapy for Squamous Cell Carcinomas: Preclinical investigation

OBJECTIVE

Photodynamic therapy (PDT) is a clinically approved minimally invasive treatment for cancer. In this preclinical study, using an imaging-guided approach, we examined the potential utility of PDT in the management of bulky squamous cell carcinomas (SCCs).

METHODS

To mimic bulky oropharyngeal cancers seen in the clinical setting, intramuscular SCCs were established in six-to-eight week old female C3H mice. Animals were injected with the photosensitizer, 2-[hexyloxyethyl]-2-devinyl pyropheophorbide-a (HPPH; 0.4 μmol/kg, i.v.) and tumors were illuminated 24 hours post injection with 665 nm light. PDT as a single treatment modality was administered by surface illumination or by interstitial placement of fibers (iPDT). Magnetic resonance imaging was used to guide treatment and assess tumor response to PDT along with correlative histopathologic assessment.

RESULTS

Interstitial HPPH-PDT resulted in a marked change on T2 maps 24 hours post treatment compared to untreated controls or transcutaneous illumination. Corresponding apparent diffusion coefficient maps also showed hyperintense areas in tumors following iPDT suggestive of effective photodynamic cell kill. Histologic sections (H&E) confirmed presence of extensive tumor necrosis following iPDT.

CONCLUSIONS

These results highlight the potential utility of PDT in the treatment of bulky oropharyngeal cancers. The findings of our study also demonstrate the utility of MRI as a non-invasive tool for mapping of early tissue response to PDT.