Objectives: Tumors of the lacrimal sac are rare and life-threatening. Because of their rarity, no extensive clinical data on their management and prognosis exist. We investigated the application of definitive radiation therapy and its outcome in patients with lacrimal sac squamous cell carcinoma (LSSCC). Methods: We retrospectively studied 17 patients with LSSCC at a single institution between 2003 and 2017. All the patients were treated with definitive radiotherapy, and 11 patients were delivered with cisplatin-based chemotherapy. The patients’ clinical records were reviewed for symptoms, pathological types, the volume and dosimetry of the tumors and their adjacent structures, radiation coverage of lymph node drainage areas, treatment outcomes, and complications from definitive radiotherapy. Results: Median follow-up was 38.9 months, and age at diagnosis was 48 years.The 2-year and 5-year overall survival, progression-free survival, locoregional control, and disease metastasis-free survival rates were 94.1 and 84.7%, 88.2 and 73.5%, 93.8%, 94.1, and 78.4%, respectively. A total dose of 6600–7000 cGy was prescribed to the tumor. Levels Ⅰb, Ⅶa, Ⅷ, and Ⅸ were covered with the clinical target volume regardless of lymph involvement. Acute Grade 3 radiation dermatitis occurred in seven patients (17.6%), but no acute Grade 4 or Grade 5 toxicity of any type occurred. Seven (41.2%, 7/17) of the treated eyes had moderated vision impairments; 17.6% (3/17) of patients developed cataracts, and glaucoma and radiation retinopathy were found in 5.9% (1/17) of patients. Conclusions: Definitive radiotherapy could be a treatment option for those who refuse surgery or have unresectable LSSCC. Advances in knowledge: Radiation alone is a treatment option for LSSCC.

Objectives Optic nerve sheath meningioma (ONSM) is a rare benign tumour that accounts for approximately 2% of all orbital tumours. Radiotherapy has gradually become an important treatment for ONSM because of its good effect in preserving or improving vision. We aimed to explore the effect of radiotherapy on tumour control and vision preservation/improvement in patients with ONSM. Methods Forty-three patients with primary ONSM treated in our institution from 2015 to 2021 were enrolled. The irradiation dose was from 50.4 to 54 Gy with 28–30 fractions. We evaluated the tumour volume on MRI or CT, and visual acuity before and after the radiotherapy. Results Thirty-four patients (79%) experienced a vision decrease at diagnosis. The mean duration of follow-up was 54.1 months (ranges: 18–93, median: 56). Among 25 patients who had tumour evaluation using MRI, 16 patients (37.2%) showed stable tumours, 7 patients (16.3%) had tumour shrinkage, but 2 patients (4.7%) experienced tumour progression. Among the 39 patients performing vision acuity evaluation, 16 patients (37.2%) had vision improvement or recovery. 16 of the 23 patients without vision improvement demonstrated severe visual loss at diagnosis. Two patients had evidence of tumour progression during the follow-up. Additionally, 4 (10.2%) patients had dry eyes, 7 (17.9%) patients experienced watery eyes, and 3 (7.7%) patients had eye swelling. Patients with vision loss for more than 12 months had a lower possibility of vision recovery than those with vision loss for less than 12 months. Conclusions Radiotherapy such as IMRT, VMAT, and 3D-CRT plays an important role in the treatment of ONSM. The probability of vision recovery is lower in patients with severe vision loss at diagnosis or the duration of vision loss is more than 12 months.