Tumor is an abnormal growth of cells  that serves no purpose.Benign tumor is not a malignant tumor, which is  cancer. Most colonic tumors are benign epithelial polyps. Growth of a  benign tumor might be linked to Environmental toxins, such as exposure  to radiation, Genetics, Diet, Stress, Local trauma, injury, Inflammation  or infection. Types of Benign Tumors include  Adenomas and Fibromas. 
Related Journals of Benign Colorectal Disease
Archives in Cancer Research, Journal  of Imaging and Interventional Radiology, Journal of Universal Surgery,  Cancer Investigation, Journal of the National Cancer Institute.  Monographs,  Molecular Cancer, Supportive Care in Cancer.
Colorectal Cancer: Open Access received 92 citations as per Google Scholar report