C. P. Probst1, C. T. Aquina1, A. Z. Becerra1, B. J. Hensley1, K. Noyes1, M. G. Gonzalez1, A. W. Katz2, J. R. Monson1, F. J. Fleming1 1University Of Rochester Medical Center,Surgical Health Outcomes & Research Enterprise,Rochester, NY, USA 2University Of Rochester Medical Center,Department Of Radiation Oncology,Rochester, NY, USA
Introduction:
Since the 1980s, combined modality treatment with radiotherapy (RT) and multi-agent chemotherapy has replaced abdominoperineal resection as the preferred definitive treatment for anal cancer. However, there is little data regarding factors affecting long-term overall survival (OS). This study examined the effect of patient, treatment, and hospital factors as well as year of diagnosis on overall survival.
Methods:
Patients with clinical stage I-III squamous cell carcinoma of the anus with complete information about RT treatment were selected from the 1998-2006 National Cancer Data Base. Bivariate analyses were used to examine differences in 5-year overall survival across patient, treatment, and facility characteristics. Kaplan-Meier curves compared survival differences between patients diagnosed from 1998-2002 and those diagnosed from 2003-2006. Subsequently, factors with a p-value <0.2 were entered into a Cox Proportional Hazards model to examine factors associated with 5-year OS. Factors that did not contribute to model fit were manually removed to produce an optimized final model.
Results:
Of the 11,027 patients that met inclusion criteria, 25% were clinical stage I, 49% clinical stage II and 26% clinical stage III. On Kaplan Meier analysis, minimal improvements in mean overall survival were noted for those diagnosed in later years compared to earlier years. Only 40% of patients were treated with guideline-indicated multi-agent chemotherapy and 45 Gray (Gy) RT dose. Additionally, suboptimal chemotherapy and radiation treatments resulted in reduced survival (Figure 1, p<0.001 for all comparisons). Within the multivariable analysis, numerous factors had a negative impact on OS. Compared to those receiving multi-agent chemotherapy and 45 Gy RT dose, increased hazard of death was observed in those treated with single-agent, no chemotherapy or RT dose less than 45 Gy (HR=1.10 95% CI=1.05-1.16) as well as those with both suboptimal chemotherapy regimen and RT dose (HR=1.35, 95% CI=1.26-1.45). Compared to patients with private insurance, decreased survival was observed among those with no insurance (HR=1.12, 95% CI=1.01-1.24), Medicaid (HR=1.20, 95% CI=1.10-1.30), and Medicare (HR=1.20, 95% CI=1.13-1.26). Compared to white patients, black patients had increased risk of death (HR=1.10 95% CI=1.02-1.19). Male sex was also an independent predictor of poor survival (HR=1.17, 95% CI=1.12-1.23).
Conclusion:
There has been minimal improvement in anal cancer survival over time. Sixty percent of patients are still undertreated, with widespread disparity in survival across patient groups. Utilization of a multi-disciplinary tumor board for anal cancer may help improve the delivery of appropriate treatment to all patients.
