Survival impact of sequential chemotherapy following pembrolizumab for recurrent or metastatic head and neck squamous cell carcinoma.

BACKGROUND: Pembrolizumab alone or combined with chemotherapy is the standard of care for first-line treatment of patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) with positive programmed death-ligand 1 combined positive scores. However, data on second-line chemotherapy following pembrolizumab are scarce. METHODS: A single-center, retrospective study was conducted to determine the efficacies of pembrolizumab and pembrolizumab plus chemotherapy as first-line treatments and the efficacy of second-line chemotherapy for patients with R/M HNSCC who were refractory or intolerant to first-line treatment. RESULTS: Fifty-four patients were treated with pembrolizumab, and 29 received second-line therapy, with 27 opting for cetuximab-containing regimens. The median progression-free survival (PFS), overall survival (OS), and PFS on next-line therapy for first-line treatment were 4.7 (95% confidence interval [CI], 2.1-8.7), 22.1 (95% CI, 12.6-not reached), and 15.6 months (95% CI, 9.7-not reached) in the pembrolizumab group and 5.4 (95% CI, 3.3-6.8), 15.8 (95% CI, 8.6-not reached), and 13.7 months (95% CI, 8.1-not reached) in the pembrolizumab plus chemotherapy group, respectively. The overall response rate and median PFS for second-line treatment were 48.3% (95% CI, 30.4-67.0) and 6.1 months (95% CI, 2.30-8.84). The median OS for patients who received second-line treatment was 18.4 months, which was superior to the median OS of 6.0 months for patients who received the best supportive care (log-rank p = 0.10). CONCLUSION: This study indicates that cetuximab-containing second-line chemotherapy can improve outcomes in R/M HNSCC, even after first-line therapy failure or intolerance.

Safety and Efficacy of Gemcitabine Plus Cisplatin Against Recurrent/Metastatic Nasopharyngeal Carcinoma: A Retrospective Study.

BACKGROUND/AIM: Although gemcitabine plus cisplatin (GC) prolongs survival in patients with recurrent or metastatic nasopharyngeal carcinoma (R/M NPC) compared with fluorouracil plus cisplatin, no study has evaluated the efficacy and safety of GC in nonendemic regions, including Japan, yet. Therefore, we assessed the safety and efficacy of GC in Japanese patients with R/M NPC. PATIENTS AND METHODS: We retrospectively reviewed patients with R/M NPC who received GC treatment at the Aichi Cancer Center Hospital from January 2017 to March 2020. The main eligibility criteria were histologically confirmed NPC, Eastern Cooperative Oncology Group performance status (ECOG PS) of 0-2, and locally recurrent disease unsuitable for local treatment or metastatic disease. The regimen was administered every 3 weeks (gemcitabine, 1,000 mg/m2 on days 1 and 8; cisplatin, 80 mg/m2 on day 1). RESULTS: Fourteen patients (median age, 58 years) were included in the study. Two patients had an ECOG PS of 2 and 11 exhibited nonkeratinizing histology. Of the eight patients with measurable lesions, one exhibited complete response and seven exhibited partial response, with an objective response rate of 75%. Median progression-free survival and overall survival were 7.7 and 24.2 months, respectively. Common grade 3 or 4 adverse events included neutropenia (64%), thrombocytopenia (14%), and febrile neutropenia (14%). The median relative dose intensity of gemcitabine and cisplatin was 62% and 60%, respectively. No treatment-related deaths occurred. CONCLUSION: The GC regimen demonstrates promising activity and is tolerable in Japanese patients with R/M NPC.

Extent of thyroidectomy and paratracheal lymph node dissection in total pharyngolaryngectomy for pyriform sinus cancer, and recurrence, survival, and postoperative hypoparathyroidism: A multicenter retrospective study.

BACKGROUND: Total pharyngolaryngectomy (TPL) is standard treatment for hypopharyngeal cancer. However, extensive thyroidectomy and paratracheal nodal dissection (PTND) can cause hypoparathyroidism. We sought to determine the optimum extent of resection. METHODS: We analyzed the clinicopathological information of 161 pyriform sinus cancer patients undergoing TPL from 25 Japanese institutions. Rates of recurrence and risk factors for hypoparathyroidism, as well as incidence of pathological contralateral level VI nodal metastasis and stomal recurrence, were investigated. RESULTS: The extent of thyroidectomy and nodal dissection were not independent risk factors for recurrence. Incidences of contralateral level VI nodal involvement and stomal recurrence were 1.8% and 1.2%, respectively. Patients undergoing hemithyroidectomy/ipsilateral PTND did not develop stomal recurrence and had the lowest incidence of hypoparathyroidism. Prognosis in patients without tracheostomy prior to hemithyroidectomy/ipsilateral PTND was comparable to that with more extensive resections. CONCLUSIONS: Hemithyroidectomy/ipsilateral PTND may be sufficient for pyriform sinus cancer cases without tracheostomy.

Changes in serum DAMPs and cytokines/chemokines during near-infrared photoimmunotherapy for patients with head and neck cancer.

BACKGROUND: Near-infrared photoimmunotherapy (NIR-PIT) for head and neck cancer is a recently developed therapy. However, there is limited data on patients receiving NIR-PIT in real clinical settings. METHODS: Seven NIR-PIT sessions were administered to five patients with head and neck squamous cell carcinoma (HNSCC). Serum damage-associated molecular patterns (DAMPs) (HMGB1 and Hsp70 levels), and cytokine and chemokine production, were compared before and after NIR-PIT. RESULTS: The serum concentration of HMGB1 increased after NIR-PIT (p = 0.031, Wilcoxon test) in all patients except one who did not achieve a clinical response. Chemokines MIP-1α (CCL3) and MIP-1ß (CCL4) increased significantly 1-3 days after treatment (CCL3, p = 0.0036; CCL4, p = 0.0016, Wilcoxon test). A low pre-treatment neutrophil-to-lymphocyte ratio (NLR) was associated with a better response to therapy and survival. CONCLUSIONS: The release of DAMPs, and cytokine/chemokine production, were detected in the patients' peripheral blood. The baseline NLR may predict patient outcomes in response to NIR-PIT.

Indications for sentinel lymph node biopsy in node-negative oral cancers.

BACKGROUND: We aimed to define the indications for sentinel lymph node biopsy (SLNB), the third option for cervical treatment in oral cancer with negative cervical lymph nodes. METHODS: The greatest depth of invasion (DOI) and long diameter (LD) of the primary site were used as exposures. SLN metastasis was considered the outcome. RESULTS: In three trials conducted between 2009 and 2016, 158 patients were eligible and reassigned to this study group. The scatterplot based on the respective values of DOI and LD would eventually be divided into three sections. In cases of sections T1, T2, and T3, the proportions of SLN metastasis positivity were 21.3%, 35.3%, and 51.2%, respectively. In certain cases of T1 with 2 mm < DOI ≤ 5 mm and 8 mm < LD ≤ 20 mm, the proportion of SLN metastasis positivity was 40.9%. CONCLUSIONS: SLNB-navigated or assisted neck dissection can be added as an effective procedure for N0 neck control.

Association Between 18F-Fluorodeoxyglucose Uptake and Mutation Status of Epidermal Growth Factor Receptor in Sinonasal Tract Cancer.

BACKGROUND/AIM: The Warburg effect of cancer has been applied to detect various carcinomas though the 18F-fluorodeoxyglucose (18F-FDG) uptake on positron emission tomography with computed tomography (PET/CT). 18F-FDG-PET/CT in lung cancer predicted the mutation status of epidermoid growth factor receptor (EGFR). This study aimed to investigate whether 18F-FDG uptake parameters were significantly related to EGFR mutation status in patients with sinonasal tract squamous cell carcinoma (STSCC). PATIENTS AND METHODS: Twenty-nine tumor specimens of primary STSCC from patients with definitive treatment were collected. RESULTS: The 18F-FDG uptake from primary tumors was not different between mutant- and wild-status of EGFR on either Mann-Whitney U-test or the receiver operating curve. A metabolic tumor volume of ≥25 with the minimum p-value from the log-rank test for STSCC-specific survival was associated with a significantly shorter STSCC-specific, disease-free, local recurrence-free survival on the univariate and multivariate analyses adjusted for the clinical stage, treatment, and EGFR status. CONCLUSION: 18F-FDG-PET/CT did not predict mutation of the EGFR status in STSCC.

A novel technique in transoral robotic surgery: A case report of rotating and switching technique.

BACKGROUND: Transoral robotic surgery (TORS) for tongue base lesions located above the operative field is predominantly an upward procedure, which makes surgery difficult. METHODS: To illustrate our technique for this procedure, we report the case of an 82-year-old male with a p16-negative oropharyngeal carcinoma of the tongue base who underwent TORS. The field of view was turned upside down, and the operation switched the typical left- and right-arm functions. The daVinci Xi was docked, the 0° endoscope was rotated 180°, and the first arm was switched to the right hand and the third arm to the left hand. RESULTS: Although the lesion extended from the tongue base to the soft palate and mobile tongue, the planned resection line was followed. CONCLUSIONS: This technique improves operability by allowing downward manipulation and preventing the left and right arms from crossing. Further validation of the technique's effectiveness and safety is needed.

Predictive factors for dissection-free sentinel node micrometastases in early oral squamous cell carcinoma.

This sentinel node (SN) biopsy trial aimed to assess its effectiveness in identifying predictive factors of micrometastases and to determine whether elective neck dissection is necessary in oral squamous cell carcinoma. This retrospective study included 55 patients from three previous trials, with positive SNs. The relationship between the sizes of the metastatic focus and metastasis in non-sentinel node (NSN) was investigated. Four of the 55 largest metastatic focus were isolated tumor cells, and the remaining 51 were ranged from 0.2 to 15 mm, with a median of 2.6 mm. The difference of prevalence between 46 negative- and 9 positive-NSN was statistically significant with regard to age, long diameter of primary site and number of cases with regional recurrence. In comparing the size of largest metastatic focus dividing the number of positive SN, with metastaic focus range of < 3.0 mm in one-positive SN group, there were 18 (33%) negative-NSN and no positive-NSN. Regarding prognosis, 3-year overall survival rate of this group (n = 18) and other (n = 37) were 94% and 73% (p = 0.04), and 3-year recurrence free survival rate of this group and other were 94% and 51% (p = 0.03), respectively. Absolutely a further prospective clinical trial would be needed, micrometastases may be defined as solitary SN metastasis with < 3.0 mm of metastatic focus, and approximately 33% of neck dissections could be avoided using these criteria.

Utilization of ultrasound in photoimmunotherapy for head and neck cancer: a case report.

BACKGROUND: Photoimmunotherapy (PIT) is a new cancer treatment based on a different mechanism from conventional treatments that combines the administration of a photoabsorber and laser illumination. PIT has two characteristics: a high selectivity of target cells and the possibility of effects beyond the illuminated area. It is thus a potentially effective treatment for a wide variety of cancers. CASE PRESENTATION: We herein report a patient with oropharyngeal squamous cell carcinoma with superficial cervical lymph node recurrence. Intraoperative ultrasound confirmed the localization of the lesion and major vessels near the tumor. We punctured the tumor with catheters of laser illumination under ultrasound guidance. Laser illumination was able to be performed safely without causing serious adverse events, and the effect on the illuminated site was fully exhibited. CONCLUSIONS: Ultrasound allows for the intraoperative monitoring of each localized area and the puncture status easily in real-time. Accurate utilization of ultrasound is extremely important in PIT.

Impact of age for overall survival in head and neck sarcoma.

The purpose to the present study is to research the association between age at surgery and survival outcomes of patients with sarcoma in head and neck. Twenty-six patients with head and neck sarcoma who underwent by surgery from 2003 to 2017 were enrolled in the present observation study. Patients who did not undergo chemotherapy were significantly older age at surgery by Mann-Whitney U test. Fifty-five was the cutoff age that predicted death by receiver operating curve analysis. Shorter survival rates of overall, disease-specific, local recurrence-free and disease-free were associated with older age by log-rank test. Age (≥55 years/<55 years) was correlated with shorter overall survival by multivariate analysis of Cox's proportional hazards model adjusting with chemotherapy (absence/presence). In conclusion, older age predicts worse overall survival in head and neck sarcoma.

Hypothyroidism After Using Superior Thyroid Artery as A Recipient Artery.

OBJECTIVE: Superior thyroid artery (SThA) is a common recipient artery in free tissue transfer even after total pharyngolaryngoesophagectomy (TPLE) with hemithyroidectomy. The aim of this study was to evaluate whether the use of SThA as a recipient vessel affect thyroid function in patients undergoing TPLE with hemithyroidectomy. METHODS: From 2011 to 2020, 91 patients who underwent free jejunum transfer after TPLE with hemithyroidectomy were divided into two groups. In Group1 (n = 47), the contralateral SThA was used for the anastomosis. In Group2 (n = 44), other vessels were used. Retrospective chart review was performed comparing postoperative thyroid function between two groups. RESULTS: In group1, 17 patients presented hypothyroidism, 21 presented latent hypothyroidism and 9 presented no thyroid dysfunction comparing 15, 19, and 10 respectively in group 2. There were no significant differences between the two groups. CONCLUSION: Even after hemithyroidectomy, with inferior thyroid arteries are preserved, the SThA can be used as a recipient vessel. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:557-561, 2023.

Lymph Node Ratio in Head and Neck Cancer with Submental Flap Reconstruction.

This study aimed to investigate the relationship between the lymph node ratio (LNR) and survival results of patients with head and neck squamous cell carcinoma (HNSCC) reconstructed by a submental artery flap (SMAF) to limit tumor size. This study retrospectively recruited 49 patients with HNSCC who underwent both primary resection and neck dissection with SMAF reconstruction. The LNR was the ratio of the number of metastatic lymph nodes to the sum number of examined lymph nodes. A LNR of 0.04 was the best cut-off value for HNSCC-specific death on receiver operating curve analysis. Patients with LNRs > 0.04 were univariately related to cancer-specific, disease-free, distant metastasis-free, and locoregional recurrence-free survival than those with LNRs ≤ 0.04 by log-rank test. In a Cox's proportional hazards model with hazard ratio (HR) and 95% confidence interval (CI) adjusting for pathological stage, extranodal extension and or surgical margins, the LNR (>0.04/≤0.04) predicted multivariate shorter cancer-specific (HR = 9.24, 95% CI = 1.49−176), disease-free (HR = 3.44, 95% CI = 1.23−10.3), and distant metastasis-free (HR = 9.76, 95% CI = 1.57−187) survival. In conclusion, LNR for patients of HNSCC with SMAF reconstruction for limited tumor size was a prognostic factor for survival outcomes.

Near-Infrared Photoimmunotherapy for Oropharyngeal Cancer.

Human papillomavirus (HPV)-associated oropharyngeal cancer has a better prognosis than other head and neck cancers. However, rates of recurrence and metastasis are similar and the prognosis of recurrent or metastatic HPV-associated oropharyngeal cancer is poor. Near-infrared photoimmunotherapy (NIR-PIT) is a treatment involving administration of a photosensitizer (IRDye®700DX) conjugated to a monoclonal antibody followed by activation with near-infrared light illumination. It is a highly tumor-specific therapy with minimal toxicity in normal tissues. Moreover, NIR-PIT is expected to have not only direct effects on a treated lesion but also immune responses on untreated distant lesions. NIR-PIT with cetuximab-IR700 (AlluminoxTM) has been in routine clinical use since January 2021 for unresectable locally advanced or locally recurrent head and neck cancer in patients that have previously undergone radiotherapy in Japan. NIR-PIT for head and neck cancer (HN-PIT) is expected to provide a curative treatment option for the locoregional recurrent or metastatic disease after radiotherapy and surgery. This article reviews the mechanism underlying the effect of NIR-PIT and recent clinical trials of NIR-PIT for head and neck cancers, treatment-specific adverse events, combination treatment with immune checkpoint inhibitors, illumination approach and posttreatment quality of life, and provides a case of series of two patients who receive NIR-PIT for oropharyngeal cancer at our institution.

Role of Human Papilloma Virus and Lifestyle Factors in Overall Survival of Patients with Oropharyngeal Squamous Cell Carcinoma.

Background: Patients with human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) have a significantly better treatment response and overall survival (OS) rates than non-HPV-associated OPSCC. Objectives: We conducted the present study to further characterize the interplay between lifestyle risk factors, which are not only HPV status, but also smoking history and alcohol consumption, and the OS to optimize the treatment of patients with OPSCC. Materials and Methods: Between January 2006 and December 2013, 94 patients newly diagnosed with OPSCC were treated with curative intent at Aichi Cancer Center Hospital (Nagoya, Japan). To determine negative prognostic factors associated with the OS, univariate and multivariable Cox regression analyses were performed. Results: Of the 94 OPSCC patients, 53 (56.4%) were positive for HPV. The univariate analysis revealed that T classification, smoking history, alcohol consumption, and HPV status were significant determinants of the OS. In the multivariate analysis, adjusted for the clinical stage, smoking history, alcohol consumption, HPV status, and a smoking history of >10 pack-years was an independent negative prognostic factor for the OS among patients with OPSCC (HR: 10.4, 95 %CI: 1.34−80.6, p < 0.05). Conclusions: Smoking is a very important negative prognostic factor even in cases of HPV-associated OPSCC. The impact of smoking needs to be reaffirmed when deciding on treatment plans and de-escalation trials in OPSCC, even in cases of HPV-associated OPSCC.

A Case of Salvage Maxillectomy for Recurrent Oral Cancer After Boron Neutron Capture Therapy During the COVID-19 Pandemic.

BACKGROUND: During the COVID-19 pandemic, pedicle flaps instead of free flap transfer were recommended for head and neck reconstruction to reduce infection risk. Boron neutron-capture therapy in Japan was clinically approved in 2020 as a salvage radiotherapy for recurrent head and neck cancer following chemoradiotherapy. The efficacy and safety of salvage surgery following boron neutron-capture therapy remain unclear. CASE REPORT: We describe a 57-year-old male with crT4aN0M0 oral cancer after three different forms of radiotherapy including boron neutron-capture therapy, treated by salvage partial maxillectomy with both buccal fat pad and nasoseptal flaps. His postsurgical course was successful, without tracheostomy, and he had no Clavien- Dindo grade 3 or 4 complications. The pathological diagnosis was T4a squamous cell carcinoma with a negative surgical margin. No recurrence or metastasis had occurred at 113 days postoperatively. No opioid consumption was needed postoperatively. CONCLUSION: Pathological negative margins were achieved in this case and there were no severe complications. Further accrual of cases salvage surgery following boron neutron-capture therapy is required to clarify treatment strategies for recurrent head and neck cancer.

Metabolic Tumour Volume as a Predictor of Survival for Sinonasal Tract Squamous Cell Carcinoma.

BACKGROUND: High uptake of F18-fluorodeoxyglucose parameters for glucose metabolism is related to shorter survival in sinonasal tract cancer with various histological classifications. We investigated whether F18-fluorodeoxyglucose uptake parameters are associated with survival outcomes for patients with only squamous cell carcinoma (SCC) in the sinonasal tract that are treated either with surgery or nonsurgery. METHODS: We retrospectively observed F18-fluorodeoxyglucose uptake parameters on positron emission tomography with computed tomography for the primary tumour of SCC in 39 patients. Log-rank test or a Cox regression model with 95% confidence interval (95%CI) and hazard ratio (HR) were used for monovariable or multivariable analysis, respectively. We determined cut-off values of the F18-fluorodeoxyglucose uptake parameters using the lowest p value for monovariable sinonasal tract cancer-specific survival analysis. RESULTS: Monovariable analysis showed that patients with metabolic tumour volume (MTV) ≥ 21.8 had a shorter cancer-specific, disease-free and local recurrence-free survival than those with MTV < 21.8. After adjusting for age, gender, clinical stage and treatment group in the multivariable analysis, MTV (≥21.8/<21.8) was related to shorter cancer-specific (HR: 3.69, 95%CI: 1.17-12.0), disease-free (HR: 3.38, 95%CI: 1.19-9.71) and local recurrence-free (HR: 5.42, 95%CI: 1.59-20.3) survivals. CONCLUSIONS: MTV as advances in diagnostics of sinonasal tract SCC is a predictor.

A novel procedure of secondary voice prosthesis insertion from the inside out: The modified Fukuhara method.

OBJECTIVE: To present a new procedure for inserting a secondary voice prosthesis from the inside to the outside, which improves on the method previously reported by Fukuhara et al. METHODS: A flexible nasopharyngoscope was used to puncture pharynx (or transplanted jejunum) from the inside to the outside. In this method, it was possible to use the PROVOX® VegaTM Puncture Set as it is used for the placement of the voice prosthesis. RESULTS: We were able to place the PROVOX® VegaTM in all cases we experienced. Most of the cases had a history of radiation therapy. The time required for surgery ranged from 11-59 minutes (mean: 29 minutes) and there was no measurable amount of bleeding. CONCLUSION: This new method using the PROVOX® VegaTM Puncture Set, which is designed for the original purpose of voice prosthesis implantation, was therefore found to be safe and effective.

Should the Supraclavicular Lymph Nodes be Considered Regional Lymph Nodes in Cervical Esophageal Cancer?

BACKGROUND: The importance of supraclavicular lymph node (SCLN) metastases in esophageal cancer (EC) remains unknown. Few studies have reported on the prognostic impact of SCLN metastases on patients with cervical EC (CEC). This study aimed to investigate whether SCLNs should be considered regional lymph nodes and be dissected in patients with CEC. METHODS: This retrospective study enrolled 835 consecutive patients who underwent radical esophagectomy. Of these patients, 67 underwent radical surgery for CEC. These 67 patients were divided into three groups based on the presence of lymph node metastases with or without metastatic SCLNs or the absence of lymph node metastases. RESULTS: Of the 67 patients, 23 (34.3%) did not have metastatic lymph nodes (pN-negative group), 27 (40.3%) had metastatic lymph nodes except for metastatic SCLNs (pN-positive group without metastatic SCLN), and 17 (25.4%) had metastatic lymph nodes including metastatic SCLNs (pN-positive group with metastatic SCLNs). The 5-year overall survival rate was 58.4% for the pN-negative group, 46.2% for the pN-positive group without metastatic SCLNs, and 7.8% for the pN-positive group with metastatic SCLNs. The pN-positive group with metastatic SCLNs tended to show residual tumor cells and complications after surgery. The presence of metastatic SCLNs was a significantly poor prognostic factor (p = 0.004). The efficacy index was lowest for the lymph nodes in the supraclavicular region. CONCLUSIONS: The prognosis of the CEC patients with metastatic SCLNs was dismal. Although the cervical esophagus is located adjacent to the SCLNs, the SCLNs may be considered extra-regional lymph nodes in patients with CEC.

Lymph node ratio as a predictor for minor salivary gland cancer in head and neck.

BACKGROUND: We investigate whether pathological continuous variables of lymph nodes were related with survival results of carcinomas of minor salivary gland carcinoma in head and neck. METHODS: Forty-four cases with minor salivary gland carcinoma who underwent both primary resection and neck dissection were retrospectively enrolled. The pathological continuous variables were evaluated by the number of positive lymph nodes, lymph node ratio, and log odds of positive lymph nodes. Receiver operating curve analysis was used for the cut-off values of the carcinoma-specific death. Log-rank test and Cox's proportional hazards model were used for uni-/multi-variate survival analyses adjusting for pathological stage, respectively. RESULTS: Lymph node ratio = 0.05 as well as log odds of positive lymph nodes = - 2.73 predicted the carcinoma-specific death. Both lymph node ratio and log odds of positive lymph nodes were significantly related with survival outcomes by the univariate analysis. Lymph node ratio ≥ 0.05 was associated with shorter disease-specific (hazard ratio = 7.90, 95% confidence interval = 1.54-57.1), disease-free (hazard ratio = 4.15, 95% confidence interval = 1.48-11.2) and overall (hazard ratio = 4.84, 95% confidence interval = 1.05-24.8) survival in the multivariate analysis. CONCLUSION: A higher lymph node ratio of minor salivary gland carcinoma is a predictor of shorter survival results.

Factors predictive of the development of hypothyroidism after intensity-modulated radiation therapy for pharyngeal cancer.

BACKGROUND: Hypothyroidism is a common adverse event after radiotherapy for head and neck tumors and the incidence need to be re-evaluated because of using intensity-modulated radiotherapy (IMRT). AIMS/OBJECTIVES: Confirm the dose-volume effect of IMRT for pharyngeal cancer on hypothyroidism. MATERIALS AND METHODS: This was a retrospective analysis of patients underwent IMRT for pharyngeal cancer from June 2011 to May 2018. Patients were classified into group A (thyroid stimulating hormone (TSH) <5µU/ml), group B (5< =TSH < 10), and group C (10< =TSH) based on TSH over 36 months post-radiation. Radiation dose, thyroid volume, and the proportion of the thyroid that received X Gy or greater (Vx) were measured. RESULTS: Fifty-two patients were included in this work. Hypothyroidism developed in 33/52 (63%) patients, 13 in group B and 20 in group C. The mean radiation dose to the thyroid was 49.4 Gy and the median time until hypothyroidism was 39 months after irradiation. Hypothyroidism was significantly related to neck dissection (ND) and radiation dose to the thyroid. Patients whose thyroid received 45 Gy or more (V45) >67% had a significantly higher incidence of hypothyroidism. CONCLUSIONS AND SIGNIFICANCE: Patients with pharyngeal cancer who had ND and V45 to the thyroid >67% are at risk of hypothyroidism.