Hi Leon,
We, a family of three (father, mother, and a 13 years kid) have been permanent residents of Canada since 2010-08-14. We have had limitations for staying in Canada for the last 5 years. I, as the father of the family, holding an M.D. started a PhD course in the original country on Feb 2011 and the mother who is also a medical doctor was studying anesthesiology specialty outside Canada which finished about two years ago. We had a plan to start our permanent staying in Canada since then to be able to renew our PR cards on due date (the expiry date is 3rd of September, 2015); however, meanwhile I was diagnosed with low rectal cancer around 2 years ago (two major surgery, radiotherapy, chemotherapy, and disease free for 1 year) and I am under follow-up in the original country at present. my chemotherapist will allow me to travel by September 2015, just before our PR cards expiry dates. I am in relatively good health condition right now. My questions are 1) May we enter and stay in the Canada with our PR cards near expiry dates? 2) can we apply for renewing the PR cards regarding our excuses for being out of Canada and being unable to meet the RO (we just landed and stayed for 6 months in Canada)? 3)If not can I apply for Travel Document because I need to follow-up my disease at least for the next two years under supervision of my doctor each 6 month (4 short travel for about 1 week outside Canada in total).