Orbital Metastases: A Systematic Review of Clinical Characteristics, Management Strategies, and Treatment Outcomes

Simple Summary Orbital metastases may significantly worsen the functional status of oncological patients, leading to debilitating visual impairments. Surgical resection, orbital exenteration, and complementary therapies may result in heterogeneous clinical outcomes. In this systematic review, we aimed to comprehensively analyze the current literature on orbital metastases, describing clinical and imaging features, available management, and treatment outcomes. We found that most orbital metastases occur at later stages after primary tumors, frequently showing diffuse location within the orbit and rarely invading intracranial structures. Biopsy-only techniques were more frequently preferred in view of the less invasive approaches, but surgical resection and orbital radiotherapy were related to improved clinical outcomes. Although patients with primary breast cancer and patients undergoing resection showed superior prognoses, overall survival rates were generally poor, suggesting the need to better understand orbital metastases' microenvironments for devising optimal systemic treatment strategies. Background: Orbital metastases often lead to severe functional impairment. The role of resection, orbital exenteration, and complementary treatments is still debated. We systematically reviewed the literature on orbital metastases. Methods: PubMed, Scopus, Web-of-Science, and Cochrane were searched upon PRISMA guidelines to identify studies on orbital metastases. Clinical characteristics, management strategies, and survival were analyzed. Results: We included 262 studies comprising 873 patients. Median age was 59 years. The most frequent primary tumors were breast (36.3%), melanoma (10.1%), and prostate (8.5%) cancers, with median time interval of 12 months (range, 0-420). The most common symptoms were proptosis (52.3%) and relative-afferent-pupillary-defect (38.7%). Most metastases showed a diffuse location within the orbit (19%), with preferential infiltration of orbital soft tissues (40.2%). In 47 cases (5.4%), tumors extended intracranially. Incisional biopsy (63.7%) was preferred over fine-needle aspiration (10.2%), with partial resection (16.6%) preferred over complete (9.5%). Orbital exenteration was pursued in 26 patients (3%). A total of 305 patients (39.4%) received chemotherapy, and 506 (58%) received orbital radiotherapy. Post-treatment symptom improvement was significantly superior after resection (p = 0.005) and orbital radiotherapy (p = 0.032). Mean follow-up was 14.3 months, and median overall survival was 6 months. Fifteen cases (1.7%) demonstrated recurrence with median local control of six months. Overall survival was statistically increased in patients with breast cancer (p < 0.001) and in patients undergoing resection (p = 0.024) but was not correlated with orbital location (p = 0.174), intracranial extension (p = 0.073), biopsy approach (p = 0.344), extent-of-resection (p = 0.429), or orbital exenteration (p = 0.153). Conclusions: Orbital metastases severely impair patient quality of life. Surgical resection safely provides symptom and survival benefit compared to biopsy, while orbital radiotherapy significantly improves symptoms compared to not receiving radiotherapy.