Abstract
Purpose:
To delineate trends and factors affecting survival of patients with Squamous Cell Carcinoma of the Conjunctiva (SCCC) over the period 1979 to 2009.
Methods:
The National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Program Database (1973-2009) was analyzed using the SEER*Stat software. Cases for analysis were identified using histology codes for Squamous Cell Carcinoma (8070-8076,8078) and the site code for Conjunctiva (C69.0) from the International Classification for Diseases for Oncology Third Edition (ICDO-3). Relative survival rates were calculated using the Life Table method and adjusted for censoring events using the Ederer II method. Relative survival curves were compared using the Cox proportional hazards model with the level of significance of P≤0.005. The relative risk ratio was calculated for each factor.
Results:
For the period 1973 to 2009, 734 cases of SCCC were identified in the database. 732 (99.7%) of the these were identified histopathologically. 661 (90.0%) were reported by a hospital or lab. Patients were more likely to be male (573, 78.3%) than female (159, 21.3%) (p<0.0000001). After adjustment for their proportions in the US population, there was a statistically significant greater proportion of whites (87.4%) than blacks (3.7%) (x2=56.4, P<0.0000001). Age at diagnosis ranged from 6 to 98 years with a mean of 65.1 years. Length of follow-up ranged from 0 to 403 months with a mean of 75.8 months. Survival analysis was performed on all histopathologically confirmed cases. The relative survival rate after five years was 91.2% (90.0% in males and 94.6% in females). The ten-year relative survival rate was 84.9% (84.2% in males and 87.0% in females). Cox regression analysis with gender, race, year of diagnosis and age at diagnosis as covariants was performed. Survival was better for females than males (p=0.006); better for whites than blacks (p=0.035); and better for younger age (p=0.00). Year of diagnosis did not appear to affect survival (p=0.842).
Conclusions:
Analysis of data from the SEER Program database indicates a relatively low mortality from SCCC. Survival rates appear to be stable during the period 1973-2009. The five-year relative survival rates were similar to those found previously for cutaneuous squamous cell carcinoma. Female gender, white race, and younger age at diagnosis correlated with improved survival.
Keywords: 474 conjunctiva •
624 oncology