To answer your question, which is also the title of your thread, whether you can leave Canada within a week after landing, the answer is yes, but with the following caveats.
1. Since the PR card is the *only* document that shall allow re-entry to Canada, you must be in possession of it as well when you are asked during boarding in foreign soil.
2. Since you don't have your PR card, you can apply for a one-time travel document that affirms you've landed. This, however, takes some time. You can opt for an emergency travel document application, but you must have a strong case for that. E.g. you must provide tickets and a good rationale.
3. I wouldn't advise it unless *really* necessary.
Well my question is that if I leave and give relatives address in canada, then relative can mail the card to me when i reach my home country, so I will be in posession of it when i land again in canada
my situation is somewhat related to the thread... my wife is in the USA and the immigration office already asked for her passport for visa stamping... (already approve of permanent residency) She plans to go home to the philippines first before landing here in canada.. Does she needs a travel document to enter canada or she just needs to land before her visa expires?