The prognostic effect of American Joint Committee on Cancer staging and genetic status in patients with choroidal and ciliary body melanoma

Abstract

Purpose: To evaluate the prognostic effect of a combination of American Joint Committee on Cancer (AJCC) staging (7th edition) and genetic status in patients with posterior uveal melanoma.

Methods: A consecutive cohort of 153 patients with posterior uveal melanoma treated at Copenhagen University Hospital from January 1, 2009 through December 31, 2012 was followed until October 2014. Survival, AJCC stage, and cytogenetic data were registered. The AJCC stage was available for all patients, and cytogenetic information for chromosomes 3 and 8 was available for 139 patients. The individual and joint prognostic effects of AJCC staging and cytogenetic changes were evaluated by cumulative incidence curves and Cox proportional hazard models.

Results: An overall 5-year survival rate of 62% (95% confidence interval [CI]: 0.50-0.73) was observed. A normal genetic status of chromosomes 3 and 8, as found in 42 patients (30%), minimized the additional prognostic effect of AJCC staging. The frequency of tumors with normal genetic status decreased with increasing AJCC stage. Both AJCC stage III (hazard ratio [HR]: 11.0, 95% CI: 1.4-85.6) and abnormal copy number of chromosomes 3 (HR: 6.3, 95% CI: 1.4-28.3) and 8 (HR: 2.8, 95% CI: 1.03-7.8) were identified as significant predictors of a poor prognosis in the multivariate Cox regression analysis.

Conclusions: Identification of a normal genetic status of chromosomes 3 and 8 minimized the prognostic effect of AJCC staging, while a combination of genetic status and AJCC staging provided the most accurate prediction of survival in patients with an abnormal chromosomal status.

Keywords: AJCC staging; choroidal melanoma; chromosome 3; chromosome 8; ciliary body melanoma; prognostication.