Treatment and prognosis of subglottic cancers: a 10-year, multicenter, retrospective study in northern Japan

OBJECTIVES: Subglottic cancer is a rare malignancy for which limited data on its epidemiology, prognosis, recurrence, and laryngeal preservation are available. This multicenter, retrospective study aimed to elucidate the treatment outcomes of subglottic cancer compared with glottic and supraglottic cancers. MATERIAL AND METHODS: Sixty-six patients with subglottic cancer were identified among 1763 patients with laryngeal cancer treated with curative-intent surgery or (chemo)radiotherapy at 13 hospitals in northern Japan. Patients' characteristics, treatment modalities, recurrence patterns, and prognosis, including disease-free survival (DFS), overall survival (OS), disease-specific survival (DSS), and laryngeal-preservation survival (LPS), were compared across the three primary tumor subsites. Outcomes of subglottic cancer were further analyzed according to initial treatment. RESULTS: Compared with glottic and supraglottic cancers, subglottic cancer presented with more advanced T status, higher rates of total laryngectomy and recurrence, and poorer DFS, OS, DSS, and LPS. Analysis by stage indicated that subglottic cancer tended to show poorer DFS in stage III-IV cases. In subglottic cancer, (chemo)radiotherapy was effective for T1-2 disease, whereas T3-4 cases had a high local recurrence rate. Total laryngectomy provided good local control in T3-4 cases, but it was frequently followed by nodal recurrence and distant metastasis. CONCLUSION: Subglottic cancer demonstrated a more locally advanced presentation and poorer prognosis than other laryngeal subsites, a trend also observed in stage III-IV disease. Though initial surgery provided good local control in advanced subglottic cancer, it was associated with high rates of nodal recurrence and distant metastasis.