Awfully sorry to hear about your need for chemo, and a lack of a passport and the ability to get one. If you mean this literally then travel in an out of the country becomes impossible, as does getting status in the country via the routes you spoke of. If we use that as a starting point then finding a good place here in Mexico to get chemo becomes a possible solution for you. Others have found what they thought was outstanding care of this type in Merida, where programs are well established. Here in Cancun Galenia Hospital is working to establish a program and has a couple of oncologists on the staff. Good luck with this, it's not easy under the best circumstances.
