Difficult situation. As a former HR person in the hospitality industry, I think it best to hit it on the head rather than hope they don't notice. They do, even if they don't say anything. When I saw a gap in a resume that wasn't explained, it said "prison or drug rehab." Those who would point out the gap by explaining they had taken time off to care for an ailing relative, travel or heal (or prison or rehab but they brought it up rather than tried to pretend it didn't happen) were seen more favorably. Of course, it also led to further questions which is why its better to be honest, even if it means more rejection. They will find out and with the grace period after you are hired, they will be able to let you go if you can't do the job with no recourse for you. There is also that pesky little clause in most contracts that says if you misled the company when you were hired, they can let you go without notice. A clause without an expiration date.
Remember that every limitation you bring to the table is one more reason they don't have to hire you. If you are going to need time off for treatments, you need to apply for jobs where this isn't a problem. If you can't lift boxes, don't apply for a stock position. If you tell them you have no limitations, you better make sure you don't have any. You will have to prove yourself. It will help if you spent the down time studying or at least keeping up with developments in your field. It sucks, but that is the reality.
Some companies will not hire you because of the cancer. Some won't have a problem because they have experience with it. Put on your armor and be ready.