Clinical underestimation of laryngeal cancer. Predictive indicators.

Objective: To evaluate the accuracy of clinical staging of advanced laryngeal cancer and to morphologically analyze the underestimated cases.

Design: We conducted a retrospective histopathologic study of larynges from patients who had had total laryngectomy and were seen over a 21-year period.

Setting: Academic tertiary referral medical center.

Participants: Forty-one patients had clinically staged T3 laryngeal cancer and 16 patients had T4 cancer.

Intervention: Patients all underwent wide-field total laryngectomy. All larynges were processed as whole-organ serial sections in the coronal plane.

Outcome Measure: The incidence of clinically underestimated laryngeal cancer. During this investigation, it became obvious that predictive indicators of thyroid cartilage involvement could be established.

Results: Clinical underestimation had been made in approximately 50% of all T3 laryngeal cancer cases. The extent of the cartilage involvement in the underestimated group was characterized by microinvasion without penetration; approximately 90% of the cartilage involvement affected the thyroid notch and adjacent area. We established five objective indicators of thyroid cartilage involvement: (1) extensive cartilage ossification (risk for cartilage involvement, 73%); (2) glottic fixation (54%); (3) transglottic cancer (74%); (4) tumor length longer than the entire vocal fold length or longer than 2 cm (66%); and (5) extensive involvement of the anterior commissure (67%).

Conclusions: Clinical underestimation of T4 laryngeal cancer was high because thyroid cartilage involvement was not accurately diagnosed. We believe our indicators of thyroid cartilage involvement will provide objective guidelines for laryngeal cancer staging and will contribute to more reliable clinical cancer-staging decisions.