International Validation of the American Joint Committee on Cancer's 7th Edition Classification of Uveal Melanoma

Abstract

Importance: Although an accurate uveal melanoma staging system is needed to improve research and patient care, the evaluation of eye cancer staging systems requires international multicenter data sharing to acquire a statistically significant analysis.

Objective: To assess patient mortality outcomes associated with uveal melanoma staging according to the 7th edition of the American Joint Committee on Cancer's AJCC Cancer Staging Manual.

Design, setting, participants: A committee was formed to create patient-specific data fields for patients with uveal melanoma. Ten subspecialty ophthalmic oncology centers from 4 continents shared data. Patient selection criteria included diagnosis of uveal melanoma from April 1, 2001, to April 1, 2011, adequate records to allow tumor staging by the AJCC criteria, and follow-up for metastatic melanoma.

Interventions: Primary treatments included local resection, radiation therapy, and enucleation.

Main outcomes and measures: Metastasis after initial tumor staging with 5- and 10-year Kaplan-Meier metastasis-free point estimates, depending on AJCC prognostic stages I through IV, tumor size category, and subclassification (defined by the presence of ciliary body involvement and/or extrascleral extension).

Results: A total of 3809 patients were entered into the database. Of these, 3377 records (88.7%) were complete. Primary ciliary body and choroidal melanoma was the diagnosis for 3217, and 160 had primary iris melanoma. Tumor size categories were T1 in 1115 (34.7%) of the 3217 patients, T2 in 1128 patients (35.1%), T3 in 789 patients (24.5%), and T4 in 185 patients (5.8%). The 5- and 10-year Kaplan-Meier metastasis-free point estimates by tumor size categories were 97% (95% CI, 95%-98%) and 94% (95% CI, 91%-96%) for T1 tumors, 85% (95% CI, 82%-88%) and 80% (95% CI, 75%-84%) for T2 tumors, 77% (95% CI, 73%-80%) and 68% (95% CI, 60%-74%) for T3 tumors, and 61% (95% CI, 49%-71%) (5-year only) for T4 tumors, respectively. Increasing tumor size was consistent with increased metastasis risk (P < .001). Subclassifications were significantly associated with increased risk of metastasis (P < .001). The AJCC prognostic and anatomical groupings were as follows: stage I, 1030 (32.0%); stage IIA, 1095 (34.0%); stage IIB, 710 (22.1%); stage IIIA, 282 (8.8%); stage IIIB, 79 (2.5%); and stage IIIC, 21 (0.7%). The 5- and 10-year Kaplan-Meier metastasis-free estimates for prognostic stages were 97% (95% CI, 95%-98%) and 94% (95% CI, 91%-96%) for stage I, 89% (95% CI, 86%-91%) and 84% (95% CI, 80%-88%) for stage IIA, 79% (95% CI, 75%-83%) and 70% (95% CI, 62%-76%) for stage IIB, 67% (95% CI, 59%-73%) and 60% (95% CI, 51%-68%) for stage IIIA, 50% (95% CI, 33%-65%) and 50% (95% CI, 33%-65%) for stage IIIB, and 25% (95% CI, 4%-53%) (5-year only) for stage IIIC, respectively. The 160 iris melanomas were too few for subgroup analysis.

Conclusions and relevance: Multicenter, worldwide, Internet-based data sharing was used to study a heterogenous patient population in ophthalmic oncology. Our results support the continued use of the 7th edition of the AJCCCancer Staging Manual for uveal melanoma.