An estimateed 5820 new cases(2140 men and 3680 women) of anal cancer involving the anus, and canal, or the anorectum will occur in the United States in 2011, accounting for approximately 2.1% of digestive system cancers. It has been estimated thay 770 deaths due to anal cancer will occur in the US in 2011. Although considered to be a rare type of cancer, the incidence rate of invasive anal carcinoma in the US. increased by approximately 1.9 fold for men and 1.5 fold for women from the period of 1973-1979 to 1004-2000(see risk factors, below).