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ASCO Endorses CAP Guideline on HPV Testing in Head and Neck Carcinoma

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As reported in the Journal of Clinical Oncology by Carole Fakhry, MD, MPH, of Johns Hopkins School of Medicine, and colleagues, ASCO has endorsed the 2018 College of American Pathologists (CAP) guideline on human papillomavirus (HPV) testing in head and neck carcinoma. The endorsement was based on ASCO expert panel review of the CAP guideline. The panel was co-chaired by Dr. Fakhry and Bayardo Perez-Ordonez, MD, of the University Health Network Toronto. Key recommendations and ASCO qualifying statements are summarized/reproduced here.

Overall ASCO Qualifying Statement

CAP guidelines recommend high-risk (HR) HPV testing. ASCO endorses the importance of HPV tumor detection but qualifies that the term HR-HPV cannot be used interchangeably with p16 in all circumstances. HR-HPV should only be referred to when HPV-specific testing has been performed (including in situ hybridization, polymerase chain reaction for HR oncogenic HPV types). Instead, it is recommended that the general term “HPV tumor status” be used, because “HR-HPV” may be misleading. p16 can be considered a surrogate for HPV-positive tumor status strictly for oropharyngeal tumors, and only when HPV-specific testing has been ascertained can HR-HPV be used/asserted.

Recommendations

1. Pathologists should perform HR-HPV testing on all patients with newly diagnosed oropharyngeal squamous cell carcinoma, including all histologic subtypes. This testing may be performed on the primary tumor or on a regional lymph node metastasis when the clinical findings are consistent with an oropharyngeal primary tumor. [ASCO statement: The panel reinforces the need to determine HPV tumor status in newly diagnosed oropharyngeal squamous cell carcinoma.]

2. For oropharyngeal tissue specimens (ie, noncytology), pathologists should perform HR-HPV testing by surrogate marker p16 immunohistochemistry (IHC). Additional HPV-specific testing may be done at the discretion of the pathologist and/or treating clinician or in the context of a clinical trial. [ASCO statement: A small fraction of oropharyngeal tumors are not etiologically driven by HPV yet overexpress p16. Pathologists should be experienced with and have available confirmatory HPV testing.]

3. Pathologists should not routinely perform HR-HPV testing on patients with nonsquamous carcinomas of the oropharynx. [ASCO statement: When oropharyngeal tumors are poorly differentiated and there is uncertainty that the carcinoma is nonsquamous—for example, with neuroendocrine tumors—HPV tumor testing is warranted.]

4. Pathologists should not routinely perform HR-HPV testing on patients with nonoropharyngeal primary tumors of the head and neck.

5. Pathologists should routinely perform HR-HPV testing on patients with metastatic squamous cell carcinoma of unknown primary in a cervical upper- or mid-jugular chain lymph node.

6. For tissue specimens (ie, noncytology) from patients presenting with metastatic squamous cell carcinoma of an unknown primary in a cervical upper- or mid-jugular chain lymph node, pathologists should perform p16 IHC. Note: Additional HR-HPV testing on p16-positive cases should be performed for tumors located outside of level II or III (nonroutine testing) in the neck and/or for tumors with keratinizing morphology. [ASCO statement: p16 IHC alone may not be sufficient in this scenario. Additional confirmatory testing should be performed at the discretion of the pathologists and/or clinician. ASCO recommends HPV tumor detection for unknown primary in head and neck squamous cell cancer, independent of keratinizing morphology.]

7. Pathologists should perform HR-HPV testing on head and neck fine-needle aspiration squamous cell carcinoma samples from all patients with known oropharyngeal squamous cell carcinoma not previously tested for HR-HPV, with suspected oropharyngeal squamous cell carcinoma, or with metastatic squamous cell carcinoma of an unknown primary. Note: No recommendation is made for or against any specific testing methodology for HR-HPV testing in fine-needle aspiration samples. If the result of HR-HPV testing on the fine-needle aspiration sample is negative, testing should be performed on tissue if it becomes available. If pathologists use cytology samples for p16 IHC testing, they should validate the criteria (ie, cutoff) for a positive result. [ASCO statement: IHC alone may not be sufficient in this scenario, particularly with cytology material. Additional confirmatory testing should be performed at the discretion of the pathologists and/or clinician. ASCO recommends 70% cutoff for p16 IHC and use restricted to patient with known oropharyngeal squamous cell carcinoma.]

8. Pathologists should report p16 IHC positivity as a surrogate for HR-HPV in tissue specimens (ie, noncytology) when there is at least 70% nuclear and cytoplasmic expression with at least moderate to strong intensity. [ASCO statement: Tissue specimens that fail to meet the recommended threshold may still warrant more specific HR-HPV testing, if clinical features are consistent with HPV etiology.]

9. Pathologists should not routinely perform low-risk HPV testing on patients with head and neck carcinomas.

10. Pathologists should not repeat HPV testing on patients with locally recurrent, regionally recurrent, or persistent tumor if primary tumor HR-HPV status has already been established. If initial HR-HPV status was never assessed or results are unknown, testing is recommended. HPV testing may be performed on a case-by-case basis for diagnostic purposes if there is uncertainty regarding whether the tumor in question is a recurrence or a new primary squamous cell carcinoma.

11. Pathologists should not routinely perform HR-HPV testing on patients with distant metastases if primary tumor HR-HPV status has been established. HPV testing may be performed on a case by-case basis for diagnostic purposes if there is uncertainty regarding whether the tumor in question is a metastasis or a new primary squamous cell carcinoma.

12. Pathologists should report primary oropharyngeal squamous cell carcinomas that test positive for HR-HPV or its surrogate marker p16 as HPV-positive and/or p16-positive.

13. Pathologists should not provide a tumor grade or differentiation status for HPV-positive/p16- positive oropharyngeal squamous cell carcinomas.

14. Pathologists should not alter HR-HPV testing strategy based on a patient's smoking history.

More information is available at http://www.asco.org/head-neck-cancer-guidelines.

ASCO is the corresponding author of the Journal of Clinical Oncology article; e-mail: guidelines@asco.org.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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