WPOI-5 Can Be Accurately Identified During Intraoperative Consultation and Also Predicts Occult Cervical Metastases

Presentation: AHNS11
Topic: Oral Cavity
Type: Oral
Date: Wednesday, April 27, 2022
Session: 2:00 PM – 2:45 PM Best of Oral Abstracts
Authors: John E Beute, BA1; Lily A Greenberg, BA1; Lauren Wein, BA1; Eric M Dowling, MD2; Kayvon F Sharif, BA1; Ammar Matloob, MD3; Ippolito Modica, MD3; Daniel Chung, MD3; Mohemmed Nazir Khan, MD2; Raymond L Chai, MD, FACS2; Margaret S Brandwein-Weber, MD3; Mark L Urken, MD, FACS2
Institution(s): 1Thyroid, Head & Neck Cancer (THANC) Foundation; 2Department of Otolaryngology-Head and Neck Surgery, Icahn School of Medicine at Mount Sinai; 3Department of Pathology, Icahn School of Medicine at Mount Sinai


Introduction:

WPOI-5 is an American Joint Committee on Cancer (AJCC) 8th Edition registry data collection variable and a reporting element in the College of American Pathologists (CAP) synoptic for oral cancers. Here, we demonstrate that WPOI-5 can also predict occult cervical metastases (OCM).  Elective neck dissection (END) is usually performed when depth of invasion (DOI) ≥ 4 mm, which might be determined during frozen section. Intraoperative identification of WPOI-5 may impact intraoperative decisions, especially if DOI < 4 mm.  We show that WPOI-5 can be accurately identified during intraoperative consultations. 

Methods: The prospective arm is a single institution study examining concordance between intraoperative and final pathology WPOI identification.  Thirty patients from our institution were accrued over a period of 26 months. All patients underwent surgical resection of biopsy-proven oral cavity squamous cell carcinoma (OCSCC) (primary or recurrent). Affected subsites in the oral cavity included the oral tongue, floor of mouth, gingiva, buccal mucosa, hard palate, and retromolar trigone. Intraoperative frozen section findings were recorded and compared with corresponding permanent section results by a single pathologist with expertise in head and neck pathology. Tumors were classified as either non-aggressive (WPOI-3), WPOI-4, or WPOI-5.  The retrospective arm involved 228 OCSCC patients, pT1/pT2 cN0 (AJCC 8th Edition) treated with END; these specimens were evaluated for occult cervical metastases and WPOI.

Results: Of the 30 tumor samples evaluated prospectively, 7 are WPOI-5, 10 are WPOI-4, and 13 are non-aggressive on permanent pathology. Intraoperative consultation correctly assigned WPOI in 25 of 30 cases. The most common misidentification was “nonaggressive” on frozen to WPOI-4 on permanent (n = 4). With respect to identifying WPOI-5, the accuracy, sensitivity, and specificity are 96.7%, 85.7%, and 100.0%, respectively (Table 1). In the retrospective arm, WPOI-5 was significantly predictive of OCM in 79 pT1 patients as compared to WPOI-4 / WPOI-3 (p < 0.0001) (Table 2).  No significance was seen for pT2 OCSCC.  There were 20 pT1 patients with DOI < 4 mm: 2 were WPOI-5 and both had OCM.  There were 59 pT1 patients with DOI ≥ 4 mm: 24 were WPOI-5 and 11 of them had OCM.

Conclusions: There is a high accuracy of identifying WPOI-5 on frozen section; sampling error does not significantly impact its identification.  Due to the significant risk of OCM, including the subgroup not usually included in END (DOI < 4 mm), intraoperative identification of WPOI-5 in pT1 patients may also guide surgical decision-making in regard to management of regional lymph nodes. In addition, as there is a high risk of locoregional recurrence associated with WPOI-5 cancers, intraoperative identification of WPOI-5 may have implications for the extent of tumor resection.