Optimising oncologic outcomes in pT3 glottic cancers treated by transoral laser microsurgery: the impact of adjuvant treatment.

[OBJECTIVE] The treatment strategy for cT3 glottic squamous cell carcinoma (SCC) is far from being standardised, and the role of adjuvant treatment(s) is not clearly defined. This study assessed the impact of adjuvant (chemo-)radiotherapy ([C]RT) for patients with pT3 glottic SCC treated by transoral carbon dioxide laser microsurgery (CO TOLMS) presenting adverse pathological features.

[METHODS] A multicentric retrospective study was conducted at 3 referral hospitals, including patients with pT3 glottic SCC treated from January 2010 to October 2023. Demographic, clinical, and histopathological data were collected, together with data on surgery, postoperative functional performance, adjuvant treatment(s) with (C)RT, and complications. Five- and 10-year overall (OS), disease-specific (DSS), disease-free (DFS), and total laryngectomy free survivals (TLFS) were estimated by Kaplan-Meier curves. Uni- and multivariate Cox proportional hazards regression models were used to determine independent risk factors for survivals.

[RESULTS] One hundred and forty-one patients treated with CO TOLMS for pT3 glottic SCC were included in the study. Twenty-six (18.4%) patients received adjuvant treatment(s): 19 (13.5%) received RT alone, and the remaining 7 (5%) received CRT. Five-year OS, DSS, DFS, and TLFS were 78.1%, 91.5%, 49.7%, and 64.8%, respectively. Age independently correlated with worse OS, DFS, and TLFS at both uni- and multivariate Cox analysis. Adjuvant therapy was an independent protective factor for recurrence or death (DFS) at univariate (hazard ratio [HR] 0.46, p = 0.03) and multivariate (HR 0.38, p = 0.01) Cox analysis.

[CONCLUSIONS] This study suggests that adjuvant treatment with (C)RT has a positive impact on DFS for pT3 glottic SCC treated by CO TOLMS. The similar OS, DSS, and TLFS observed in pT3 SCC treated by CO TOLMS alone and a selected group of unfavourable lesions needing adjuvant (C)RT show that adding such a treatment on top of conservative surgery may ensure good oncologic outcomes even in a selected subgroup of more aggressive glottic pT3. Further prospective studies should be conducted to validate these findings and confirm the relevance of adjuvant treatment(s) in this setting.