Читать книгу Essential Cases in Head and Neck Oncology - Группа авторов - Страница 50

Question: Which of the following would be appropriate next steps in the evaluation and management of this patient?

 Fine needle aspiration biopsy: yes/no. This is probably the best next step as it will likely yield a diagnosis. The use of ultrasound guidance is often helpful as these lesions may have a significant cystic component.

 Excisional biopsy of the neck mass: yes/no. Open surgical biopsies should be avoided, when possible, due to the concern for tumor seeding and disruption of surgical tissue planes. In instances where the clinical presentation suggests lymphoma and a fine needle aspiration shows lymphoid tissue, without evidence of carcinoma, an excisional biopsy can be considered. In these instances, the surgeon should discuss the option of sending the mass for a frozen section and if cancer is found intra‐operatively, a completion neck dissection and endoscopy should be performed.

 Computed tomography (CT) of the neck with IV contrast: yes/no. This is a potential next step as this will allow for evaluation of the neck and the upper aerodigestive tract.

 Neck ultrasound: yes/no. This is a potential next step as this will allow for evaluation of the neck mass and may be used to confirm correct needle placement during the FNA. Newer techniques have also allowed for transcervical evaluation of the oropharynx for potential primary lesions.

 Magnetic resonance imaging (MRI) of the neck: yes/no. This is a potential next step as this will allow for evaluation of the neck and the upper aerodigestive tract.

 Positron emission tomography (PET)/CT neck: yes/no. This is a potential next step as this will allow for evaluation of the neck and the upper aerodigestive tract as well as provide assessment of metastatic disease. It is important to note that typically a biopsy should demonstrate malignancy before obtaining a PET/CT.

Question: What additional testing may be performed of an FNA specimen to aid in diagnosis of an unknown primary?

Answer: Assessment for p16 and EBER. Molecular diagnostic testing should be performed to assist in identifying potential occult primary sites. Per the AJCC 8th Edition guidelines, p16 should be performed as a surrogate for human papillomavirus (HPV)‐associated oropharyngeal carcinoma. Likewise, Epstein–Barr virus‐encoded RNA (EBER) should be performed to evaluate for an occult nasopharyngeal primary carcinoma.

Question: What threshold for p16 immunohistochemistry (IHC) is typically used to define p16 positive disease?

Answer: 70%. Per the College of American Pathologists guidelines for HPV testing in head and neck carcinoma, pathologists should report p16 IHC positivity as a surrogate for HPV when there is at least 70% nuclear and cytoplasmic expression with at least moderate to strong intensity.

Fine needle aspiration is performed in the office under ultrasound guidance. The final pathology reveals nonkeratinizing squamous cell carcinoma (SCC) that is p16+.

Question: What imaging modality has the highest sensitivity for detecting the primary site in carcinoma of unknown primary?

FIGURE 7.1 This is a fused axial image of a PET/CT scan at the level of the oropharynx. Note the hypermetabolic left level II neck mass. There is fairly symmetric low‐intensity uptake in the patient's lingual tonsil tissue.

Answer: PET/CT. Multiple studies have demonstrated that PET/CT compared with contrast‐enhanced CT alone has a significantly improved rate of detecting the primary site of carcinoma. A prior systematic review of 7 studies demonstrates a sensitivity of 44% and a specificity of 97% with PET/CT.

PET/CT neck is performed showing a solid left level IIA lymph node without extranodal extension measuring 22 × 27 × 29 mm that demonstrates high‐grade hypermetabolism with max SUV of 16.4 (see Figure 7.1). No other lymph nodes meet the radiographic criteria for significance or demonstrate hypermetabolism. Symmetric FDG uptake is seen when comparing the left tongue base to the right (max SUV 4.2). There are no imaging findings to suggest systemic metastatic disease.

Question: Which of the following would be appropriate treatment options in the management of this patient?

 Panendoscopy: yes/no. This is an essential component of the patient's treatment since a primary site must be investigated.

 Tonsillectomy: yes/no. The palatine and lingual tonsils often harbor occult primary tumors. This particular patient has already undergone palatine tonsillectomy as a child but lingual tonsillectomy should be performed.

 Treatment with surgical resection: yes/no. As the patient has only one lymph node that is PET avid, surgical resection of the primary tumor (if identified) and left neck dissection may be curative.

 Treatment with radiation: yes/no. This disease may be cured with XRT to the neck and primary site (if identified).

 Treatment with chemotherapy: yes/no. Treatment with chemotherapy alone would have no role here. If upfront surgery is performed, the addition of chemotherapy to XRT is not indicated unless significant extracapsular spread or positive margins of the primary tumor are observed on final pathology. Clinical trials are currently underway to evaluate the safety and efficacy of de‐escalation of therapy.

After discussion in the multidisciplinary tumor board, an upfront surgical approach is advocated. The patient is taken to the operating room for panendoscopy, left selective II–IV neck dissection, and bilateral lingual tonsillectomy. Palatine tonsillectomy is not performed given the patient's prior tonsillectomy as a child and lack of residual tonsil tissue. No obvious primary site is identified on panendoscopy.

The final pathology report shows one out of 54 positive nodes. The pathologic node is 2.7 cm in maximum diameter without evidence of extranodal extension. A 0.7 mm primary tumor is identified within the left lingual tonsillectomy specimen with negative margins. There is no evidence of perineural invasion or lymphovascular invasion.

Question: Per the AJCC 8th Edition guidelines, what is the TNM stage for this carcinoma?

Answer: T1N1M0, Stage I. For HPV‐positive oropharyngeal SCC, there are separate staging systems for clinical versus pathologically confirmed disease following surgery. A 0.7 mm primary is staged as T1 disease. Following neck dissection, the presence of only one positive 2.7 cm node is staged as N1 disease. This disease is staged as T1N1M0 (given negative PET/CT for distant metastases) and is an overall stage I given the HPV positive nature of the cancer.

The patient is rediscussed in the multidisciplinary tumor board. Given the staging and clear margins, consensus decision is made for observation following surgery without the need for adjuvant therapy.