Role of radiotherapy in the multidisciplinary treatment of lacrimal gland adenoid cystic carcinoma

Background: The optimal treatment approach for lacrimal gland adenoid cystic carcinoma (LGACC) remains controversial. Objectives: We aim to demonstrate the value of radiotherapy (RT) in the multidisciplinary treatment of LGACC. Design: This was a retrospective cohort study. Methods: This study was conducted on 90 patients with LGACC treated from 2002 to 2023. We compared the overall survival (OS), progression-free survival (PFS), recurrence-free survival (RFS), and distant metastasis-free survival (DMFS) between those treated with surgery alone versus surgery plus postoperative radiotherapy (PORT). In addition, the ipsilateral visual outcome and ocular complications were evaluated. Results: The addition of radiotherapy significantly improved the 5-year RFS (63.4% vs 31.1%, p = 0.014) and PFS (56.8% vs 31.1%, p = 0.036) while showing no improvement in OS (79.7% vs 85.6%, p = 0.98) and DMFS (67.3% vs 70.1%, p = 0.70) compared to surgery alone. Further analysis indicated that, compared to the photon-RT group, the proton/carbon-ion group showed no significant differences in 5-year OS ( p = 0.7), RFS ( p = 0.37), PFS ( p = 0.45), and DMFS ( p = 0.57). Univariate (odds ratio (OR) = 0.14, 95% confidence interval (CI): 0.04–0.49, p = 0.002) and multivariate (OR = 0.16, 95% CI: 0.04–0.62, p = 0.008) logistic regression indicated that radiotherapy was a protective factor for local recurrence. Furthermore, among the long follow-up of 35 patients accepting eye-sparing surgery plus PORT, 13 patients (37.1%) had best-corrected visual acuity (⩾20/40) and 14 (40.0%) had severe vision loss (<20/200); furthermore, dry eye disease (100%, 35/35) and cataract progression (45.7%,16/35) are the most common ocular complications. Conclusion: Surgery plus radiotherapy is a safe and effective multidisciplinary treatment in improving local control with tolerable long-term ocular toxicity, but of limited impact on OS for LGACC.