Can rectal cancer occur when having a colonoscopy within 2 years prior?

Yes, rectal cancer can occur even if a colonoscopy was performed within the previous two years. While colonoscopies are effective at detecting and removing polyps that may develop into cancer, they do not guarantee that new cancers won't develop shortly afterward. Additionally, not all cancers or lesions may be detected during the procedure, depending on various factors such as the thoroughness of the exam and the presence of small or hidden tumors. Regular screenings and monitoring are essential for early detection.