Carcinoma of unknown primary in the head and neck: The evaluation of the effectiveness of (18)F-FDG-PET/CT, own experience

Addressing positive multi-cancer early detection tests in head and neck Surgery: Experience with head and neck work up for high-risk referrals

OBJECTIVES

Blood-based multi-cancer early detection (MCED) tests are now commercially available. However, there are currently no consensus guidelines available for head and neck cancer (HNC) providers to direct work up or surveillance for patients with a positive MCED test. We seek to describe cases of patients with positive MCED tests suggesting HNC and provide insights for their evaluation.

METHODS

Retrospective chart review of patients referred to Otolaryngology with an MCED result suggesting HNC. Patients enrolled in prospective MCED clinical trials were excluded. Cancer diagnoses were confirmed via frozen-section pathology.

RESULTS

Five patients were included (mean age: 69.2 years, range 50-87; 4 male) with MCED-identified-high-risk for HNC or lymphoma. Only patient was symptomatic. After physical exam and follow-up head and neck imaging, circulating tumor HPV DNA testing, two patients were diagnosed with p16 + oropharyngeal squamous cell carcinomas and underwent appropriate therapy. A third patient had no evidence of head and neck cancer but was diagnosed with sarcoma of the thigh. The remaining two patients had no evidence of malignancy after in-depth workup.

CONCLUSIONS

In this retrospective study, 2 of 5 patients referred to Otolaryngology with a positive MCED result were diagnosed with HPV + oropharyngeal squamous cell carcinoma. We recommend that positive HNC MCED work up include thorough head and neck examination with flexible laryngoscopy and focused CT or MRI imaging. Given the potential for inaccurate MCED tissue of origin classification, PET/CT may be useful in specific situations. For a patient with no cancer identified, development of clear guidelines is warranted.

Updates in the management of unknown primary of the head and neck

Squamous cell carcinoma (SCC) from an unknown primary tumor (SCCUP) accounts for 2.0%–5.0% of all head and neck cancers. SCCUP presents as enlarged cervical lymph nodes without evidence of a primary tumor upon physical examination. Primary site detection is important to target treatment and avoid treatment-related morbidity. In this review, we discuss updates in SCCUP management. Diagnostic workup should focus on localization of the primary tumor in SCCUP. Initial workup centers on neck biopsy to confirm the presence of SCC. Given the increasing incidence of HPV-related SCC in the oropharynx, HPV testing is crucial. An HPV-positive status can localize the tumor to the oropharynx, a common site for occult tumors. Imaging includes neck CT and/or MRI, and PET/CT. After imaging, panendoscopy, palatine tonsillectomy or diagnostic transoral robotic surgery can facilitate high rates of primary tumor localization. Primary tumor localization influences treatments administered. SCCUP has traditionally been treated aggressively with large treatment fields to all potential disease sites, which can induce weight loss and swallowing dysfunction. As a result, primary localization can reduce radiation fields and provide possible de-escalation to primary surgical management. Advances in intensity-modulated radiation therapy and dose management also have the potential to improve functional outcomes in SCCUP patients. Given the improved prognosis associated with HPV-positive SCCs, HPV tumor status may also inform future treatment de-intensification to reduce treatment-related toxicity.

The usefulness of [18F]FDG-PET/CT in detecting and managing cancers with unknown primary site depends on histological subtype

We assessed the role of [18F]FDG-PET/CT in identifying and managing cancer of unknown primary site (CUP syndrome). We reviewed [18F]FDG-PET/CT scans of individuals with CUP syndrome recorded in clinical referral letters from 2012 to 2019. We evaluated the identification of primary tumor (PT) by [18F]FDG-PET/CT, according to histological subtype, and the impact on clinical management. The median age was 65 years, 36/64 males (56%). PTs were detected in 28/64 (44%) patients. Detection was significantly lower in patients with squamous cell carcinoma (SCC) than with other histologies combined, p = 0.034. Mean age, mean SUVmax (10.6 ± 6.0) and organ involvement were similar between patients with and without discovered PTs; and between patients with SCC and with other histologies combined. However, those with SCC were less likely than the others to present with multi-lesion involvement, p < 0.001. [18F]FDG-PET/CT interpretations apparently affected treatment of 8/28 (29%) patients with PT detected, and in none of the 35 whose PT was not discovered, p < 0.001. [18F]FDG-PET/CT appeared helpful in detecting PT in almost half the patients with CUP syndrome; the lowest rate was for patients with SCC pathology. PET/CT showed limited overall value in guiding clinical management, however benefited those with discovered PT.

Submandibular lymph node metastasis of occult thyroid carcinoma first suspected to be a salivary gland tumor: a case report

Background

When diagnosing and treating neck masses, various diseases need to be considered, including benign or malignant tumors, lymph node-related diseases, and cysts. Thus, there may be cases in which making a definitive diagnosis is difficult on the basis of blood testing and imaging alone.

Case presentation

The patient was an 80-year-old Japanese female who presented with swelling in the right submandibular area. Magnetic resonance imaging and ultrasonography revealed a solid tumor with inhomogeneous content continuous with the submandibular gland. Therefore, the clinical diagnosis was salivary gland tumor. Surgical treatment was performed, and intraoperative frozen-section examination demonstrated submandibular lymph node metastasis of thyroid carcinoma. After surgical treatment, blood test for thyroid gland function yielded normal results except for increased thyroglobulin levels. Further positron-emission tomography–computed tomography and ultrasonography were performed, in addition to fine-needle aspiration biopsy of the thyroid gland and other tests; however, no other thyroid abnormalities were observed. Fine-needle aspiration biopsy revealed no carcinomatous components. Close observational follow-up has been continued without thyroid gland treatment, and as of approximately 8 years postoperation, no recurrence, metastases, or thyroid carcinoma have developed.

Conclusion

The mass was lymph node metastasis of occult thyroid carcinoma. In general, occult thyroid carcinoma metastasizes to level II–V. To the best of our knowledge, this is the first report of submandibular lymph node metastasis alone of occult thyroid carcinoma.

Diagnostic performance of 18F-FDG PET/CT for the detection of occult primary tumors in squamous cell carcinoma of unknown primary in the head and neck: a single-center retrospective study

OBJECTIVE

To investigate the diagnostic performance of 18F-FDG PET/computed tomography (CT) for the detection of occult primary tumors in patients with squamous cell carcinoma of unknown primary (SCCUP) in the head and neck.

PATIENTS

From March 2016 to January 2020, 37 patients diagnosed as SCCUP before PET/CT were retrospectively reviewed. The diagnosis of SCCUP was made when an overt primary tumor location could not be found for histologically proven squamous cell cervical lymphadenopathy after a complete diagnostic workup which includes full medical history, physical examinations, flexible rhinolaryngoscopy and CT or MRI. The PET/CT images were visually assessed by two nuclear medicine radiologists. Histopathological investigations after the PET scan served as the reference standard.

RESULTS

The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of PET/CT for SCCUP were 71.4, 43.8, 62.5, 53.9 and 59.5%, respectively. PET/CT allowed identification of previously undetected lesions in 40.5% of the SCCUP patients. A total of 24 PET/CT scans indicated a positive result. Among them, nine were categorized into false-positive because of negative results from subsequent targeted and random biopsies. There were 13 PET/CT scans with a negative result, six of which, however, were revealed to have a primary site by subsequent random biopsies.

CONCLUSION

18F-FDG PET/CT was shown to be useful in detecting a primary tumor for SCCUP, but had limitations in terms of both false-positive cases and false-negative cases. Therefore, histopathological investigations such as targeted and random biopsy should be viewed as necessary practice irrespective of PET/CT results.

FDG PET/CT for metastatic squamous cell carcinoma of unknown primary of the head and neck

OBJECTIVE

The role of FDG PET/CT is uncertain in squamous cell carcinoma of unknown primary (SCCUP). Published data are limited by heterogeneity of pathology, varied diagnostic criteria, and small sample size.

MATERIALS/METHODS

This retrospective study was conducted in 40 patients who had FDG PET/CT for SCCUP. Prior to PET/CT, patients had underwent standard clinical evaluations including flexible rhinolaryngoscopy. The majority of the patients had anatomic imaging. All subjects had histopathological investigations, and follow-up data after PET/CT.

RESULTS

FDG PET/CT detected the primary in 16 of 40 patients (40%), and the most common locations of the primary were in the base of the tongue, palatine tonsil, and hypopharynx. There were 10 false positive and 6 false negative PET/CT scans. There was no difference in the mean SUVs of the suspected primary lesions between true and false positive groups. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy of FDG PET/CT for SCCUP in this patient cohort were 72.7% (16/22), 44.4% (8/18), 61.5% (16/26), 57.1% (8/14), and 60% (24/40), respectively. The tonsil was the site with the most false positive and false negative findings.

CONCLUSIONS

FDG PET/CT might be an effective single shot of whole-body imaging for detection of the primary in SCCUP. Low specificity remained the most notable weakness of FDG-PET in work-up for SCCUP. In addition to varied physiologic uptake or inflammatory related uptake in the common locations of the primary, the image indication bias might be another significant contributor of high false positive rate.

Cervical metastasis of gingival carcinoma misdiagnosed as branchiogenic carcinoma, a rare entity - report of a case and review of literature

BACKGROUND

A cervical cystic mass is associated with a number of pathologies that present with similar symptoms. These conditions are difficult to differentiate using fine-needle aspiration (FNA), ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI). Another dilemma in the differential diagnosis of cervical cystic masses is due to the controversies associated with the existence of branchiogenic carcinoma (BC). BC is an extremely rare disease that must be differentiated from other conditions presenting with cervical cystic masses, especially cystic metastasis from occult primary lesions.

CASE PRESENTATION

We present a case report of a right cervical cystic metastasis from a significantly small squamous cell carcinoma primary gingival lesion misdiagnosed as BC by histopathology. A 62-year-old female presented with a painless progressively enlarging cervical mass at the anterior edge of the sternocleidomastoid muscle in the right submandibular region. Preoperative MRI and US revealed a well-defined cystic round mass. Postoperative histological examination indicated BC. Positron emission tomography/computed tomography (PET/CT) revealed high 18F-FDG (18F 2-fluoro-2-deoxy-D-glucose) uptake in surgical regions with a SUV (standard uptake value) max 4.0 and ipsilateral nasopharynx with a SUVmax 4.4, without any distant metastasis. Pathologic results revealed nasopharyngeal lymphadenosis. Considering the low incidence of BC and the limitation of diagnosis in one institution, the patient was referred to another hospital. Physical examination detected a significantly small neoplasm (~3 mm diameter) in the right lower gingiva. Histopathological examination of the neoplasm revealed a well-differentiated squamous cell carcinoma. Surgery, including a partial mandibulectomy and modified neck dissection (neck level I-V and submental lymph nodes) were undertaken. Postoperative histopathological results revealed a well-differentiated squamous cell carcinoma of right lower gingiva and two metastatic lymph nodes in the 18 lymph nodes of level II. A month later, recurrence occurred in the right cervical level II. The patient was placed on postoperative concurrent chemo-radiotherapy and supportive care. The patient suffered from cachexia and survived for only six months after surgery.

CONCLUSIONS

In cases of cervical cystic masses that appear after the age of 40, clinicians should bear in mind that occult primary lesions should be excluded and examination of the gingiva should be undertaken. PET/CT has a limited role in identifying small occult primary lesions and a comprehensive physical examination must be carefully performed.

AHNS Series: Do you know your guidelines? Guideline recommendations for head and neck cancer of unknown primary site

This article reviews the clinical practice guidelines for head and neck oncology focusing on the management of head and neck cancers of unknown primary (CUP). The primary purpose of this series is to raise awareness of the current guidelines in head and neck oncology by reviewing the recommendations and the evidence supporting such recommendations, particularly those published by the National Comprehensive Cancer Network (NCCN). We review the importance of a thorough history and physical examination, the impact of the American Joint Committee on Cancer (AJCC) eighth edition changes and the importance of immunohistochemistry, the timing and type of imaging, the role of panendoscopy and tonsillectomy (palatine and lingual), and the role of surgery, radiation, and chemotherapy in the primary management of these tumors.

Comparison of dose distribution for head and neck cancer patients with and without dose painting escalation during radiotherapy realized with tomotherapy unit

OBJECTIVE

To determine and quantify the percentage dose increase to organs at risk (OARs) with multiple-level dose painting (DP) for patients with head and neck cancer in comparison with standard regimen.

METHODS

12 patients who had undergone fluorine-18 fludeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/CT scan were retrospectively enrolled. Two treatment plans-one using DP escalation and one without-were optimized for each patient base on PET/CT data. The following variables were assessed: dose to OARs and target volumes; execution time; equivalent uniform dose; and normal tissue complication probability.

RESULTS

No statistically significant differences in beam-on time were observed between plans with and without DP. However, significantly higher doses were observed for all DP-escalated plans in the OARs, with only two exceptions: the brain stem and V_60Gy for the mandible. Multiple-level DP resulted in dose increases ranging from 3.0% to 12.9%, depending on the OAR. The largest increase was seen for the parotid glands and the smallest for the mandible. Significant differences in the equivalent uniform dose were observed only for the parotid glands and spinal column, where the dose without DP was lower. The normal tissue complication probability for most OARs was very small.

CONCLUSION

Importantly, even though DP escalation resulted in higher doses to OARs vs conventional treatment planning, these usually did not exceed the dose tolerance levels. However, clinical trials are necessary to confirm the benefits of DP and to guarantee no additional toxicity. Advances in knowledge: Multiple-level DP by numbers resulted in 3.0-12.9% dose increase, depending on the OAR. Our findings may suggest that DP escalation to very high doses is feasible for about 83% of patients without higher toxicity; however, it still should be confirmed on a larger group of patients.

Squamous cell carcinoma of unknown primary tumor metastatic to neck nodes: role of elective irradiation

In patients with squamous cell carcinoma (SCC) metastases to neck lymph nodes and unknown primary tumor, the role of elective irradiation of uninvolved neck and potential mucosal primary sites is yet to be determined. The aim of this study was to review the experience treating SCC of unknown primary metastatic to neck nodes with surgery and postoperative radiotherapy (PORT) in Slovenia between 1995 and 2010 and to determine the importance of the extent of irradiated volume. For this purpose, the nationwide Cancer Registry of Slovenia database was used for identifying patients. 126 patients were identified. Involved-field PORT and extended-field PORT was used in 50 and 76 patients, respectively. At 5 years, locoregional control was 86 %, disease-specific survival 77 %, and overall survival 57 %. In multivariate analysis, the extent of irradiated volume has not been predictive for any outcome under study. Grade ≥3 acute and late radiotherapy-induced toxicities were more frequent in the extended-field PORT group. In conclusion, although not superior, involved-field PORT seems to be a preferred treatment option in SCC of unknown primary metastatic to neck nodes due to significantly reduced toxicity and better prospects for successful salvage.

Prognostic significance of monocarboxylate transporter expression in oral cavity tumors

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common type of cancer. The majority of patients present advanced stage disease and has poor survival. Therefore, it is imperative to search for new biomarkers and new alternative and effective treatment options. Most cancer cells rely on aerobic glycolysis to generate energy and metabolic intermediates. This phenotype is a hallmark of cancer, characterized by an increase in glucose consumption and production of high amounts of lactate. Consequently, cancer cells need to up-regulate many proteins and enzymes related with the glycolytic metabolism. Thus, the aim of this study was to characterize metabolic phenotype of oral cavity cancers (OCC) by assessing the expression pattern of monocarboxylate transporters (MCTs) 1, 2 and 4 and other proteins related with the glycolytic phenotype.

MATERIAL AND METHODS

We evaluated the immunohistochemical expression of MCT1, MCT4, CD147, GLUT1 and CAIX in 135 human samples of OCC and investigated the correlation with clinicopathological parameters and the possible association with prognosis.

RESULTS

We observed that all proteins analyzed presented significantly higher plasma membrane expression in neoplastic compared to non-neoplastic samples. MCT4 was significantly associated with T-stage and advanced tumoral stage, while CD147 was significantly correlated with histologic differentiation. Interestingly, tumors expressing both MCT1 and MCT4 but negative for MCT2 were associated with shorter overall survival.

CONCLUSION

Overexpression of MCT1/4, CD147, GLUT1 and CAIX, supports previous findings of metabolic reprograming in OCC, warranting future studies to explore the hyper-glycolytic phenotype of these tumors. Importantly, MCT expression revealed to have a prognostic value in OCC survival.