Ling Paulina Gronczewska
Pathologists are at the forefront of personalised medicine, using molecular tools to tailor diagnoses, prognoses, and treatments. In ophthalmic pathology, one of the most significant developments in recent years has been the integration of gene expression profiling (GEP) into the management of uveal melanoma, the most common primary intraocular malignancy in adults in the United Kingdom (1). Traditionally risk stratification has been based on tumour size, cell morphology, and mitotic activity (2). The development of GEP assays, particularly DecisionDx-UM, has significantly improved prognostic accuracy in uveal melanoma, paving the way for personalised care based on molecular tumour profiling (3).
Understanding Gene Expression Profiling in Uveal Melanoma
Uveal melanoma is a highly aggressive cancer with a strong tendency to metastasise, particularly to the liver, which accounts for around 95% of metastases (4). Despite there being options for local treatment, approximately 50% of patients eventually develop systemic metastases (5). Hence, accurate risk stratification is essential for guiding surveillance and therapeutic decisions.
The DecisionDx-UM test analyses the expression of 15 genes—12 discriminating and 3 control genes—using RNA extracted from fine-needle aspiration biopsy samples (6). It classifies tumours into three categories: Class 1A (low metastatic risk), Class 1B (intermediate risk), and Class 2 (high risk), with studies having demonstrated that Class 2 tumours carry approximately a 70% risk of metastasis within five years, while Class 1A tumours have a risk of less than 5% (6, 7).
This molecular classification has been shown to outperform chromosomal analysis methods such as monosomy 3 detection and cytogenetic profiling in predictive accuracy and reproducibility (8).
Clinical Impact of GEP in Uveal Melanoma
1. Personalised Surveillance
GEP results directly inform surveillance intensity. Patients with Class 2 tumours are subjected to more frequent liver imaging, often ranging from every 3 to 6 months, to detect metastases early, while on the other hand, Class 1A patients may avoid excessive imaging, reducing unnecessary anxiety and healthcare costs (9).
2. Tailored Therapeutic Approaches
High-risk patients may be referred for adjuvant clinical trials aimed at delaying or preventing metastatic spread, such as those investigating immune checkpoint inhibitors or liver-directed therapies (10, 11). In some cases, GEP results also influence decisions regarding local therapy (12).
3. Patient Empowerment and Psychological Impact
Studies have shown that molecular prognostication provides psychological benefits, even when results are unfavourable. Patients report improved decision-making capacity and reduced uncertainty, especially when results are explained in conjunction with genetic counselling (13).
4. Advancement of Research and Registry Data
Large-scale use of GEP may also be able to facilitate the creation of prospective registries that track metastatic development, treatment outcomes, and quality of life, and various other metrics contributing to the evolving landscape of UM research (14).
Barriers to Widespread Implementation
Despite its benefits, several barriers hinder the global adoption of GEP in UM care:
1. Cost and Insurance Coverage
The DecisionDx-UM test costs around USD 8,000, and while it is covered by Medicare in the U.S., questions remain about its availability in low- and middle-income countries (15). This financial barrier is significant for both patients and healthcare systems.
2. Infrastructure and Technical Expertise
FNAB requires skilled ophthalmic oncologists, and GEP analysis must be performed in specialised laboratories. Many centres lack the infrastructure or trained personnel to perform these procedures effectively (16, 17).
3. Limited Clinician Familiarity and Confidence
Some clinicians, especially in community or non-academic settings, are unfamiliar with the interpretation of GEP results or are hesitant to rely on molecular data over traditional histopathological features (18, 19).
4. Ethical and Psychosocial Concerns
Delivering high-risk prognoses without adequate genetic counselling may increase patient anxiety or lead to misunderstandings about prognosis, particularly among populations with low health literacy (20).
Strategies for Overcoming Barriers
To address these challenges, several strategies can be implemented:
1. Health Policy and Reimbursement Reform
Governments and insurers should be encouraged to cover GEP testing by demonstrating its long-term cost-effectiveness in reducing metastatic surveillance burdens and improving patient outcomes (21).
2. Centralized Testing and Telemedicine
Peripheral hospitals can collaborate with centralized laboratories for testing, while teleophthalmology platforms can enable remote genetic counselling and GEP interpretation (22).
3. Clinician Education and Multidisciplinary Training
Interdisciplinary tumour boards, CME courses, and digital toolkits can enhance clinician familiarity with GEP and its integration into treatment planning (23).
4. Integration of Psychosocial Support
Providing genetic counselling as part of the testing protocol improves understanding, reduces distress, and supports shared decision-making between patients and clinicians (24).
Conclusion
Gene expression profiling has revolutionised the management of uveal melanoma, providing accurate prognostic information that can inform further steps. Unlike traditional histopathological techniques, GEP offers more meaningful classification that guides surveillance, informs treatment choices, and empowers patients. As the role of the pathologist continues to evolve, innovations like DecisionDx-UM illustrate how cutting-edge molecular diagnostics are reshaping ocular oncology.
However, to achieve equitable access to this exciting new technology, healthcare systems must address barriers related to cost, infrastructure, education, and psychosocial support. With coordinated efforts across policy, practice, and education, GEP can be fully integrated into frontline care, fulfilling its promise as a cornerstone of personalised medicine in ophthalmology.
References
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