Similar therapeutic effects of 125I seed radiotherapy and γ-ray radiotherapy on lacrimal gland adenoid cystic carcinoma

Abstract

Aim: To evaluate the survival outcomes of patients with lacrimal gland adenoid cystic carcinoma who underwent eye-sparing surgery combined with ¹²⁵I seed implantation radiotherapy or local external γ-ray radiotherapy.

Methods: In this retrospective comparative case series, the clinical records of 27 primary and 8 recurrent patients were reviewed. Univariate and multivariate analyses were used to identify risk factors associated with distant metastasis (DM), and the overall survival (OS) after the initial surgery was analyzed.

Results: The median follow-up after radiotherapy was 36mo (range 6-120mo). At the last follow-up after radiotherapy, 26 (74.3%) patients had no evidence of disease, 7 (20%) patients had DM, 2 (5.9%) patients died of DM, and 1 patient with DM was lost to follow-up. Univariate analyses showed that duration of symptoms, bone destruction, T stage classification, and wide excision surgery were risk factors influencing DM (P<0.05). The 5-year and 10-year OS rates after the initial surgery were 95.8% and 79.9%, respectively. The 5-year DM-free survival and disease-free survival rates after radiotherapy were 66.4% and 52.7%, respectively.

Conclusion: ¹²⁵I seed radiotherapy and local external γ-ray radiotherapy may have similar therapeutic effects in preventing DM. Patients with T1/T2 stage disease have a better prognosis than those with T3/T4 stage disease.

Keywords: 125I seed radiotherapy; adenoid cystic carcinoma; lacrimal gland; surgical excision; γ-ray radiotherapy.

Figure 1. Imaging finding and pathological features of ACC

A: CT of orbit showed that the tumour of right eye was large, almost invading the entire orbit, with unclear demarcation from the eyeball, and signs of bone destruction could be seen (arrow point); B: MRI showed large tumour and T1-weighted image was intermediate in intensity.

Figure 2. Survival analysis of patients with LGACC and the effect of different treatment and stages on the survival of LGACC

A: Kaplan-Meier OS curve of 35 cases of LGACC after initial surgery. The 5-year survival rate was 95.8% and 10-year survival rate was 79.9%. B: Kaplan-Meier the DFS curve of 35 patients after radiotherapy. C: Kaplan-Meier DM curve of 35 patients after radiotherapy. D: Kaplan-Meier survival curve between Treatment A and Treatment B. P=0.708 (log-rank test). E: Kaplan-Meier survival curve between WES and LES. P=0.123 (log-rank test). F: Kaplan-Meier survival curve between T1/T2 and T3/T4. P=0.015 (log-rank test).