Second Primary Tumors in Patients Presenting With Unilateral HPV-Associated Tonsillar Squamous Cell Carcinoma.

OBJECTIVE: To describe and compare rates of metachronous and synchronous second primaries of the contralateral tonsil in patients with primary HPV(+) tonsillar squamous cell carcinoma (SCC). STUDY DESIGN: Retrospective cohort study. MATERIALS AND METHODS: This is a single tertiary care center retrospective case series, from 2006 to 2019, of HPV(+) tonsillar SCC patients who underwent primary surgical resection with unilateral wide-field tonsillectomy or bilateral tonsillectomy for diagnostic or therapeutic purposes. A metachronous second primary is one diagnosed >6 months after completion of surgical treatment. A synchronous second primary is one diagnosed during bilateral tonsillectomy for unilateral HPV(+) tonsillar SCC. Rates of second primary and patient characteristics were compared using chi-square tests. RESULTS: About 303 patients underwent unilateral surgical resection +/- adjuvant therapy for HPV(+) tonsillar SCC. One (0.3%) developed a metachronous second primary in the contralateral tonsil 11.9 years following treatment. Fifty-seven patients with HPV(+) tonsillar SCC underwent bilateral tonsillectomy, and 37/57 (65%) had no clinical signs for contralateral disease. Of these, only 1/37 (2.7%) was incidentally found to have a synchronous second primary. Twenty patients underwent bilateral tonsillectomy due to clinical concern for contralateral disease. Of these, 3/20 (15%) were found to have a synchronous HPV(+) SCC in the contralateral tonsil. CONCLUSIONS: The prevalence of metachronous second primary after appropriate treatment of HPV(+) tonsillar SCC is very low (0.3%) and so is the chance of incidentally discovering a synchronous second primary during bilateral tonsillectomy (2.7%). We do not recommend bilateral tonsillectomy as a part of the routine algorithm in the surgical management of these patients. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:332-338, 2022.

Epidermotropic metastasis of squamous cell carcinoma of the tonsil: A case report with molecular confirmation.

Metastasis of oropharyngeal squamous cell carcinoma (SCC) to skin is uncommon and portends a poor prognosis. Clinical history and histopathology are key to discerning between metastatic disease vs de novo SCC of the skin. We describe a case of an HPV+ tonsillar SCC in a 77-year-old male, with metastasis to the neck skin. This case is unique because of prominent in situ epidermal involvement on skin biopsy specimen, complicating the distinction between primary and secondary disease. The nature of the lesion was resolved using next-generation sequencing of both the primary oropharyngeal SCC and skin lesion biopsy specimens. Both tumors showed identical ATR D1639G somatic mutations, while the skin lesion contained an additional POLE F1366L mutation. Clonal evolution of metastatic lesions is a well-described phenomenon; comparing the genetic profiles of primary and metastatic specimens can be useful in evaluating the tumor origin as well as identifying targetable genetic aberrations.

Lack of Conserved miRNA Deregulation in HPV-Induced Squamous Cell Carcinomas.

Squamous cell carcinomas (SCCs) in the anogenital and head and neck regions are associated with high-risk types of human papillomaviruses (HR-HPV). Deregulation of miRNA expression is an important contributor to carcinogenesis. This study aimed to pinpoint commonly and uniquely deregulated miRNAs in cervical, anal, vulvar, and tonsillar tumors of viral or non-viral etiology, searching for a common set of deregulated miRNAs linked to HPV-induced carcinogenesis. RNA was extracted from tumors and nonmalignant tissues from the same locations. The miRNA expression level was determined by next-generation sequencing. Differential expression of miRNAs was calculated, and the patterns of miRNA deregulation were compared between tumors. The total of deregulated miRNAs varied between tumors of different locations by two orders of magnitude, ranging from 1 to 282. The deregulated miRNA pool was largely tumor-specific. In tumors of the same location, a low proportion of miRNAs were exclusively deregulated and no deregulated miRNA was shared by all four types of HPV-positive tumors. The most significant overlap of deregulated miRNAs was found between tumors which differed in location and HPV status (HPV-positive cervical tumors vs. HPV-negative vulvar tumors). Our results imply that HPV infection does not elicit a conserved miRNA deregulation in SCCs.

A Unique Case of Primary EBV-Positive, HPV-Negative Nasopharyngeal Carcinoma Located in the Tonsil.

Nasopharyngeal carcinomas (NPC) are non-keratinizing squamous cell carcinomas of the nasopharynx associated with Epstein-Barr virus (EBV). When occurring outside of the nasopharynx, they are referred to as lymphoepithelioma-like carcinomas (LELCs) and present the same morphology as NPC. LELC have been described in other head and neck regions such as the salivary glands and the soft palate. LELC can also occur in the oropharynx, are associated with human papillomavirus (HPV) and are typically negative for EBV. We herein present a unique case of a 78-year-old Chinese male with EBV-positive, HPV-negative NPC of the left tonsil. His presenting symptom was a left-sided lymph node. There was no evidence of nasopharyngeal lesion seen on physical examination, PET and MRI. The patient was treated with curative-intent external beam radiotherapy which delivered 70 Gy (Gy) to the gross tumour and lymph nodes, and 56 Gy electively to the ipsilateral neck using a volumetric modulated arc therapy technique. This is the first case of primary tonsil EBV-positive NPC described in the literature.

Human Papillomavirus (HPV)-Related Carcinoma of the Oropharynx with Squamous Cell and Adenoid Cystic Carcinoma-Like Features: Report of a Case.

We describe the heretofore unreported case of an HPV-related carcinoma of the palatine tonsil with distinct areas of squamous cell- and adenoid cystic carcinoma-like differentiation in a 54-year old patient. The morphological, immunophenotypic and molecular findings of the tumor are illustrated. We discuss the parallels between the tumor and HPV-related multiphenotypic sinonasal carcinoma (HMSC) which is well-known to exhibit adenoid cystic carcinoma-like features. A review of the literature of high-risk HPV-associated non-squamous carcinomas of the oropharynx is presented.

New Clinicopathologic Scenarios of EBV+ Inflammatory Follicular Dendritic Cell Sarcoma: Report of 9 Extrahepatosplenic Cases.

EBV+ inflammatory follicular dendritic cell (FDC) sarcoma is an indolent malignant neoplasm of spindled FDCs with a rich lymphoplasmacytic infiltrate and a consistent association with Epstein-Barr virus (EBV). It occurs exclusively in the liver and spleen, with the exception of a few colonic examples. In this study, we report 9 extrahepatosplenic cases, including 4 occurring in previously undescribed sites, but all apparently anatomically related to the aerodigestive tract. The cases included 5 gastrointestinal tumors all presenting as colonic pedunculated polyps, 2 presenting as mesocolon mass, and 2 involving the palatine or nasopharyngeal tonsils. One patient with a colonic tumor was complicated by paraneoplastic pemphigus. The patients had a median age of 58 years, with female predominance (female:male=7:2). A favorable outcome was observed in 7 patients. Histologically, EBV+ inflammatory FDC sarcomas arising from these anatomic sites were similar to their hepatosplenic counterparts. Spindled to oval neoplastic cells with ill-defined cell borders were dispersed or formed loose whorled fascicles in a dense lymphoplasmacytic background. They had vesicular nuclei with distinct nucleoli and typically exhibited a range of nuclear atypia in the same case. The neoplastic cells showed variable expression of FDC markers and were labeled for Epstein-Barr virus-encoded RNA on in situ hybridization. These 9 cases thus broaden the clinicopathologic scenarios of EBV+ inflammatory FDC sarcoma. Recognition of the potential existence of this tumor type in extrahepatosplenic sites permits a correct diagnosis to be made.

Revisiting the Recommendation for Contralateral Tonsillectomy in HPV-Associated Tonsillar Carcinoma.

OBJECTIVE: Despite epidemiologic evidence that second primaries occur infrequently in HPV (human papillomavirus)-associated oropharyngeal squamous cell carcinoma, recent recommendations advocate for elective contralateral palatine tonsillectomy. We aimed to study this discordance and define the necessary extent of up-front surgery in a large contemporary cohort with long-term follow-up treated with unilateral transoral robotic surgery. We hypothesized that second primaries are discovered exceedingly rarely during follow-up and that survival outcomes are not compromised with a unilateral surgical approach. STUDY DESIGN: Retrospective cohort analysis. SETTING: Tertiary care academic center between 2007 and 2017. METHODS: Records for patients with p16-positive oropharyngeal squamous cell carcinoma of the tonsil and workup suggestive of unilateral disease who underwent ipsilateral transoral robotic surgery were analyzed for timing and distribution of locoregional recurrence, distant metastases, and second primary occurrence as well as survival characteristics. RESULTS: Among 295 included patients, 21 (7.1%) had a locoregional recurrence; 17 (5.8%) had a distant recurrence; and 3 (1.0%) had a second primary during a median follow-up of 48.0 months (interquartile range, 29.5-62.0). Only 1 (0.3%) had a second primary found in the contralateral tonsil. The 2- and 5-year estimates of overall survival were 95.5% (SE, 1.2%) and 90.1% (SE, 2.2%), respectively, while the 2- and 5-year estimates of disease-free survival were 90.0% (SE, 1.8%) and 84.7% (SE, 2.3%). CONCLUSION: Second primary occurrence in the contralateral tonsil was infrequent, and survival outcomes were encouraging with unilateral surgery. This provides a rationale for not routinely performing elective contralateral tonsillectomy in patients whose workup suggests unilateral disease.

Treatment of Early Stage Tonsil Cancer in the Age of Human Papillomavirus-Associated Malignancies.

OBJECTIVE: To investigate the patterns of care and outcomes of treatment of early stage tonsil cancers, controlling for human papillomavirus (HPV) status. STUDY DESIGN: Historical cohort study. SETTING: National Cancer Database (NCDB). METHODS: Review of the NCDB between 2010 and 2017 for all T1-2N0M0 tonsillar squamous cell carcinoma (SCC). Demographics, clinical characteristics, HPV status, treatment regimens, and survival were analyzed. RESULTS: A total of 4720 patients were identified with early stage SCC of the tonsil. Most were tested for HPV (2759 [58.5%]). Among tested patients, 1758 (63.7%) were positive for HPV and 1001 (36.3%) were negative for HPV. HPV-positive patients had higher 3-year survival compared to HPV-negative patients (93.2% vs 77.8%, P < .001). Among HPV-positive patients, there was no significant difference in survival between treatment cohorts. However, in the HPV-negative cohort, 3-year survival was higher in both bimodality surgical-based settings (tonsillectomy + neck dissection + radiotherapy, 86.0% vs chemoradiotherapy, 69.6%, P = .01) and for all surgical-based treatments when compared to nonsurgical management (84.6% vs 69.3%, P < .001). This difference was maintained in multivariable regression controlling for age, sex, comorbidities, clinical T stage, and treatments. In a subpopulation of HPV-negative patients propensity score matched by all factors significant in multivariable analysis, 3-year survival remained higher in the surgically treated group compared to the nonsurgically treated cohort (84.9% vs 67.1%, P < .001). CONCLUSIONS: Surgical- or radiation-based treatment resulted in similar survival in early stage HPV-positive tonsil cancer. Surgical-based treatments were associated with longer survival in HPV-negative cancers. These findings should be further investigated in a randomized prospective trial.

MRI-Based Assessment of the Pharyngeal Constrictor Muscle as a Predictor of Surgical Margin after Transoral Robotic Surgery in HPV-Positive Tonsillar Cancer.

BACKGROUND AND PURPOSE: Transoral robotic surgery is an emerging strategy for treating human papillomavirus-positive cancers, but the role of MR imaging in predicting the surgical outcome has not been established. We aimed to identify preoperative MR imaging characteristics that predispose the outcome of transoral robotic surgery toward an insecure (positive or close) surgical margin in human papillomavirus-positive tonsillar squamous cell carcinoma. MATERIALS AND METHODS: Between December 2012 and May 2019, sixty-nine patients underwent transoral robotic surgery at our institution. Among these, 29 who were diagnosed with human papillomavirus-positive tonsillar squamous cell carcinoma, did not receive neoadjuvant treatment, underwent preoperative 3T MR imaging, and had postoperative pathologic reports and were included in this retrospective study. Two neuroradiologists evaluated the preoperative MR imaging scans to determine the tumor spread through the pharyngeal constrictor muscle using a 5-point scale: 1, normal constrictor; 2, bulging constrictor; 3, thinning constrictor; 4, obscured constrictor; and 5, tumor protrusion into the parapharyngeal fat. The risk of an insecure surgical margin (involved or <1 mm) according to the MR imaging scores was predicted using logistic regression with the Firth correction. RESULTS: The interobserver agreement for the MR imaging scores was excellent (κ = 0.955, P < .001). A score of ≥4 could predict an insecure margin with 87.5% sensitivity and 92.3% specificity (area under the curve = 0.899) and was the only significant factor associated with an insecure margin in the multivariable analysis (OR, 6.59; 95% CI, 3.11-22.28; P < .001). CONCLUSIONS: The pre-transoral robotic surgery MR imaging scoring system for the pharyngeal constrictor muscle is a promising predictor of the surgical margin in human papillomavirus-positive tonsillar squamous cell carcinoma.

No association between HPV-status in tonsillar tissue and sexual behavior of the patients in a northern German population - Critical view of the link between HPV natural history and HPV-driven carcinogenesis.

HPV-infection in patients with HNSCC is reportedly correlated with sexual behavior, age, and tobacco/alcohol-consumption. HPV-infections of the oral cavity are regarded as sexually transmitted. Comparable data of patient populations outside the U.S. are sparse or missing. Questionnaires regarding sexual behavior, education tobacco- and alcohol-consumption, were given to 28 patients with tonsillar hyperplasia (H) and 128 patients with tonsillar carcinomas (CA), all with tissue-typed HPV-DNA-status performing PCR. Answers were correlated among groups and HPV-status. 106 questionnaires were analyzed. Comparisons between H- (n = 25) and CA- (n = 81) patients showed that CA-patients were older (61.1yrs ± 9.3) than H-patients (45.2yrs ± 11.9; p < 0.0001; Student's t-test); had a lower educational level (p = 0.0095); and lower number of sexual partners (p = 0.0222; Fisher's exact test). All groups showed a significant correlation between smoking and lack of HPV-DNA-positivity (p = 0.001). Further Fisher's exact tests and logistic regression analysis revealed in all 106 patients no significant correlations between tissue-HPV-status and the analyzed parameters. Despite the limited sample size, we were able to confirm the established correlation between smoking and tissue-HPV-status. The correlation between sexual behavior and HPV-infection was not confirmed. No consensus exists in the literature about the latter. Our data does not support the strict classification of oral HPV-infections and HPV-driven HNSCCs as STDs.

Human papillomavirus (HPV) in Chinese oropharyngeal squamous cell carcinoma (OPSCC): A strong predilection for the tonsil.

OBJECTIVE: Compared with Occident's data, the incidence of Human papillomavirus (HPV)-driven oropharyngeal squamous cell carcinomas (OPSCCs) had been reported as relatively low in Mainland China. The objective of this study was to report the integrated prevalence of HPV and Epstein-Barr virus (EBV), and further evaluate the different behaviors of HPV-positive and -negative OPSCCs in eastern China. METHODS: In a cohort of 170 nonmetastatic OPSCCs treated from January 2007 to July 2019, p16 protein expression, HPV genotypes, and Epstein-Barr virus-encoded RNA (EBER) were determined by immunohistochemistry (IHC) and in situ hybridization (ISH). The clinical and pathologic findings were further collected and analyzed to comprehensively reveal the behaviors of Chinese OPSCCs. RESULTS: Out of the 170 tumor tissues evaluated, 57.6% (98) samples had positive p16 expressions. A total of 65.1% (99/152) samples had positive HPV genotypes, besides HPV16 (92/152), HPV11, 18, 33, 53, and 58 were also detected. The positive rate of EBER was 7.2% (9/124), and the co-infection rate of EBV/HPV was 4.0%. Related to the unequal distributions of p16 expression, HPV-related tumors arisen from tonsillar and non-tonsillar accounted for 68.8% (75/109) and 37.7% (23/61) of their cases, respectively (P < .001). With a median follow-up time of 13.1 months, significant survival advantages of HPV-related OSPCC were observed; 1-year OS, PFS, RFS, and MFS were 83.2% vs 96.7% (P < .001), 71.6% vs 96.2% (P < .001), 77.7% vs 96.2% (P = .002), and 90.4% vs 100.0% (P = .024) in p16-negative and -positive cases, respectively. CONCLUSIONS: The relative percent of HPV-positive OPSCCs in this study is close to the positive rate in many Western countries and a strong predilection was discovered for the tonsillar. The EBV infection and co-infection of HPV/EBV were largely low. The prognosis of HPV-positive OSPCCs was more favorable than its negative counterpart.

High-risk human papillomavirus-mediated adenocarcinoma of palatine tonsil.

We describe the case of a human papillomavirus-mediated adenocarcinoma of palatine tonsil in a 51-year-old male. Histologically, the tumor exhibited a predominantly cribriform and tubular (glandular) growth of cuboidal and columnar cells with moderate amount of pale eosinophilic cytoplasm and oval or spindled nuclei with finely dispersed or coarse chromatin and small to medium-sized nucleoli. Foci of nuclear anaplasia and multinucleation, numerous mitotic figures, and necrosis (individual-cell and confluent) were seen. No squamous differentiation was identified. The tumor cells showed strong expression of CK7, p16 and HPV E6/E7 mRNA transcripts, and were negative for p40, CK5/6, AR, synaptophysin and chromogranin. Next generation sequencing showed 3 variants of unknown significance: FGF3 p.(R44fs); NF1 p.(S749 L) and POLE p. (S1506 L) with variant allele frequencies of 37 %; 20 %, and 17 % respectively. Chromosomal microarray analysis using single nucleotide polymorphism microarray (OncoScan) assay showed whole chromosomal gains of chromosomes 8 and 19, whole chromosomal losses of chromosomes 2 and 16, as well as segmental gains of chromosomes 3q25.31q29 (encompassing the PIK3CA gene), 17q21.31q25.3, 20p13q13.33, Xq28, and segmental losses of chromosomes 1q32.2, 6p25.1p21.1, 11q23.1q24.1, 12p11.22, 12p11.22, 14q24.1q32.33, 17p13.3q21.31 (encompassing the TP53 and NF1 genes). The results highlight the need to consider HPV testing in non-squamous cell carcinomas of the oropharynx.

HIV-Associated "Double-Hit" Lymphoma of the Tonsil: A First Reported Case.

Double-hit lymphoma (DHL) is a unique subtype of non-Hodgkin lymphoma characterized by atleast two rearrangements involving MYC, BLC2, and/or BCL6. These lymphomas are uncommon and aggressive, responding poorly to typical chemotherapy regimens. Lymphomas rarely arise from the oral cavity or tonsils, and those presenting as a neck mass are predominantly diffuse large B-cell lymphoma. To date, primary DHL of the tonsils has yet to be described in the literature. Here, we report a case of a 44 year-old male patient with well-controlled human immunodeficiency virus (HIV) who presented with a sore throat. He subsequently developed acute respiratory compromise due to a rapidly enlarging tonsillar mass. Pathologic and genetic analysis confirmed the presence of BCL6 and MYC rearrangements suggestive of DHL of the tonsils. In a young patient with HIV and a neck mass, it is essential that lymphoma remains on the list of differential diagnoses as prompt diagnosis and treatment may prevent complications from its rapid expansion.

Presurgical induction chemotherapy for squamous cell carcinoma of the tonsil.

OBJECTIVES/HYPOTHESIS: The indications for and efficacy of induction chemotherapy in the management of squamous cell carcinoma of the head and neck is controversial. With the advent of human papillomavirus (HPV)-related cancers, survival has improved significantly. Here we present a group of patients with tonsil cancer treated with induction chemotherapy followed by surgery. STUDY DESIGN: Retrospective cohort study. METHODS: Thirty-eight patients with tonsil cancer were treated with induction chemotherapy, consisting of cisplatin and docetaxel, followed by neck dissection and radical tonsillectomy. Twenty-six patients were HPV+, 28 were nonsmokers or long-term former smokers, and 28 were T1/T2. Fourteen patients required postoperative chemoradiotherapy (CRT). Median follow-up time was 4.1 years. RESULTS: A complete response to induction chemotherapy was achieved in 45% (17) of patients. In total, 76% (29/38) of patients were successfully treated: 53% (20/38) with chemotherapy and surgery alone, and 24% (9/38) required postoperative CRT. Almost 90% (23/26) of HPV+ and half (6/12) of HPV- patients are no evidence of disease (NED). HPV status is a significant prognostic factor (P = .02). Only 38% (5/13) of current smokers were NED compared to 96% (24/25) of nonsmokers (P = .0002). All HPV+ nonsmokers (20/20) were NED at last follow-up. CONCLUSIONS: In this study, the primary driver of prognosis was smoking status. HPV status and T stage were also important. The prognosis for HPV+ nonsmokers is extremely good; most likely regardless of treatment. Treatment failures have a poor chance of salvage, irrespective of treatment type. With the major exception of HPV- smokers, induction chemotherapy followed by surgery with selective CRT is a viable treatment option for tonsil cancer. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:1206-1211, 2020.

A global epidemic increase of an HPV-induced tonsil and tongue base cancer - potential benefit from a pan-gender use of HPV vaccine.

In 2007, human papillomavirus (HPV) type 16 was finally recognized as a risk factor, besides smoking and alcohol, for oropharyngeal squamous cell carcinoma (OPSCC), including tonsillar squamous cell carcinoma (TSCC), by the International Agency for Research against Cancer. Just before, in 2006, the Food and Drug Administration had approved Gardasil, the first vaccine against HPV16, 18, 6 and 11, for preventive vaccination women against cervical cancer. Concurrently, some Western countries, where smoking was decreasing, disclosed an epidemic increase in the incidence of OPSCC, especially of TSCC and base of tongue cancer (BOTSCC), together accounting for 80-90% of all OPSCCs, and mainly affecting men. The epidemic was later revealed to be due to a rise in HPV-positive cases, and scientists in the field suggested HPV vaccination also of boys. Globally, there are roughly 96 000 incident OPSCC cases/year of which 20-24% are caused by HPV, thereby accounting for around 22 000 OPSCC cases annually. Of these cases, 80-90% are due to HPV16 infection and would be prevented with the presently registered HPV vaccines. In Western countries, such as Sweden (with almost 400 TSCC and BOTSCC cases per year) and the United States, HPV prevalence in OPSCC is higher and around 70%. HPV vaccination of girls has been initiated in many countries, and the vaccines have been efficient and their side effects limited. HPV vaccination of boys has, however, been the exception, but should definitely not be delayed any further. It would benefit both girls and boys directly, and result in better and more robust herd immunity. Today, we have the possibility to eliminate several high-risk HPV types in the younger generations and avoid more than 600 000 cancer cases annually worldwide, and this possibility should be embraced by offering global pan-gender HPV vaccination.

Solitary cystic metastatic lymph node of occult human papillomavirus-related oropharyngeal cancer mimicking second branchial cleft cyst: A case report.

RATIONALE: Human papillomavirus (HPV)-related oropharyngeal cancer is becoming more common, the primary cancer AQ4 usually occult and appearing only as cystic cervical lymph node (LN) metastasis. Distinguishing between a benign cystic lesion and cystic LN metastasis is challenging given their similar radiologic and histologic appearances. PATIENT CONCERNS: A 54-year-old man presented with a bulging cystic mass measuring 6.4cm on the right side of neck. DIAGNOSES: Postexcision diagnosis was second branchial cleft cyst. After 2 years, the cystic mass recurred, and HPV-related tonsillar squamous cell carcinoma with cystic metastatic LNs was confirmed after wide tonsillectomy and neck dissection. The previous cystic lesion proved to be a cystic metastatic LN from the same malignancy with additional p16 immunostain. INTERVENTIONS: The patient was treated with adjuvant concurrent chemoradiation therapy. OUTCOMES: The patient was followed up in the outpatient department with no evidence of recurrence after 1 year. LESSONS: When an adult has a cystic mass in the upper neck, we must rigorously exclude it as a cystic metastatic LN of occult HPV-related oropharyngeal cancer. Additional p16 staining might be helpful.

Risk of post-operative, pre-radiotherapy contralateral neck recurrence in patients treated with surgery followed by adjuvant radiotherapy for human papilloma virus-associated tonsil cancer.

OBJECTIVE: One approach to reduce treatment-related morbidity for human papilloma virus (HPV)-associated tonsil cancer is omitting radiotherapy to the contralateral neck. Pathologic risk factors for early contralateral neck disease, however, are poorly understood. We report on the risk contralateral neck failures from the time of pre-operative diagnostic imaging to time of planning for adjuvant radiation in a single institution series of HPV-associated tonsillar cancer patients undergoing surgery followed by radiotherapy (RT). METHODS: Retrospective analysis of 123 patients with T1-T3 HPV-positive tonsillar squamous cell carcinoma treated between 2010 and 2016 with transoral robotic surgery and selective ipsilateral neck dissection followed by adjuvant RT. Contralateral neck recurrence was classified as the detection of a pathologic node in the contralateral neck prior to initiation of adjuvant RT. RESULTS: Seven patients (5.7%) developed contralateral neck disease/failure between the time of pre-operative diagnostic neck imaging and time of planning of adjuvant radiation. Increased ratio of positive/resected nodes [odds ratio (OR) 1.073, p = 0.005] was significantly associated with increased risk of contralateral neck recurrence, with a trend found for close/positive margins (OR 5.355, p = 0.06), tumor size (OR 2.046, p = 0.09), and total number of nodes positive (OR 1.179, p = 0.062). CONCLUSIONS: Patients who develop very early contralateral neck disease, between completion of ipsilateral neck dissection and the initiation of radiotherapy, have a higher ratio of positive nodes to total nodes resected in the ipsilateral neck. These findings suggest that proper selection of patients for omission of treatment of the contralateral, node-negative neck should be made with this in mind, with future studies needed to document the impact on toxicity and disease outcomes from such an approach. ADVANCES IN KNOWLEDGE: Pathologic risk factors in the dissected, ipsilateral neck in patients with tonsil cancer may inform the risk of contralateral neck failure. Patient selection for future, prospective efforts to examine sparing of the contralateral neck need to be based with these risk factors in mind.

A novel human in vitro papillomavirus type 16 positive tonsil cancer cell line with high sensitivity to radiation and cisplatin.

BACKGROUND: Human papillomavirus (HPV) is an established risk factor for oropharyngeal squamous cell carcinoma (OSCC). The aim was to establish cell lines from HPV-positive tonsil carcinomas to be used for treatment development. METHODS: Fresh samples from 23 HPV-positive tonsil carcinomas were cultivated in vitro. The established cell line was analyzed for viral characteristics, cell karyotype, TP53 status, and growth capabilities in nude mice. In vitro studies of sensitivities to radiation, cisplatin and cetuximab were performed. RESULTS: After 19 months (eight passages), one cell line, LU-HNSCC-26, was established in vitro and also grew as xenografts. The tumor was from a 48 year old non-smoking man with non-keratinizing, p16 positive tonsil OSCC, stage T2N0M0 with HPV16. It contained 19.5 (CV% 3.7) HPV16 copies/cell (passage 8). The complete HPV16 genome sequence was obtained. Episomal HPV16 was present with an E2/E7 ratio of 1.1 (CV% 2.6). In addition, HPV16 mRNA specific for the intact E2 gene was detected. The viral expression manifested 1.0 (CV% 0.1) E7 mRNA copies per HPV16 genome. The karyotype was determined and the cell line demonstrated wild type TP53. The ID50 for radiation was 0.90 Gy and the IC50 for cisplatin was 0.99 µmol/L. The cell line was inhibited to a maximum of 18% by cetuximab. CONCLUSIONS: We established an in vitro tonsil carcinoma cell line containing episomal HPV16. This is an important step towards efficient treatment development.