Stage 1 rectal cancer 6 years ago- recurrence possible?

Yes: Recurrences are always possible, even up to 10 years out, but the majority of rectal cancers recur within 3-5 years. You should continue getting exams and colonoscopies, especially since you are young and healthy!

Yes but unlikely: In order to give a complete answer I would need much more information such as how was it treated. A major cancer operation including removal of lymph nodes or not, such as a transanal excision with no lymph nodes removed. In general however, we consider this cancer cured at the five year mark based upon research that shows there are very few recurrences after 5 years of follow up.