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Depth of Tumor Invasion in Early Oral Tongue Squamous Cell Carcinoma Key in Determining Therapy

by Linda Kossoff •

How do pathologic features contribute to clinical outcomes of early oral tongue squamous cell carcinoma (OTSCC) relative to tumor depth of invasion (DOI) of > or < 4 mm?

Bottom Line: Consideration of adjuvant therapy is warranted when two or more adverse features are present in OTSCC with tumor DOI of > 4 mm, but may not be needed under similar circumstances when DOI is < 4 mm.

Background: DOI is a criterion for elective neck dissection (END) in early oral cavity squamous cell carcinoma (OCSCC) with a 4 mm DOI threshold. It has been unclear whether additional pathologic features such as perineural invasion (PNI), lymphovascular invasion (LVI), and worst pattern of invasion-5 (WPOI-5) should alter the therapeutic decision-making algorithm for OTSCC.

Study Design: Pathologic database study, with additional glass slide review.

Setting: Department of Otolaryngology–Head and Neck Surgery, University of California, San Francisco, Calif.

Synopsis: Researchers performed a retrospective pathologic slide and clinical chart review of 100 adult patients with small OTSCC (tumor < 2 cm) to clarify the influences of PNI, LVI, and WPOI-5 on clinical outcomes in relation to the clinically relevant threshold of DOI (4 mm). The aim was to help further delineate indications for END and adjuvant radiotherapy in small OTSCC. The researchers found that when DOI was ≤ 4 mm, rates of occult cervical metastases, locoregional recurrence (LRR), and disease-specific death (DSS) were very low, and the presence of any of the considered adverse features did not indicate a need for END. However, when DOI was > 4 mm, the presence of two or more adverse features was associated with higher LRR and/or worse DSS and overall survival. The study is in contrast to prior work, which showed that LVI is associated with higher rates of lymph node adverse pathologic features, controlling for a consistently measured DOI. Given the low event numbers, larger data sets will be necessary in future studies to permit more robust conclusions about the relationship of adverse features to recurrence and survival in DOI ≤ 4 mm tumors.

Citation: Larson AR, Kemmer J, Formeister E, et al. Beyond depth of invasion: adverse pathologic tumor features in early oral tongue squamous cell carcinoma. Laryngoscope. 2020;130:1715-1720. doi:10.1002/lary.28241.