Chemotherapy is a very broad term, so it depends on what type of cancer you have, which drugs you will be taking, and how you'll be taking them. (Some drugs
are given orally, some by IV, some by at-home injection.)
Chemotherapy can be given for a very limited period of time, or it can be ongoing to keep the cancer under control. Doctors often discuss chemotherapy in terms of cycles, which can be confusing. There are many different drugs used and each drug can be given in a number of different "regimens" either by itself or in combination with other drugs. A chemotherapy regimen could be once a week for eight weeks, or once every two weeks for 8 cycles, which totals 16 weeks, or once every two weeks for six cycles, totalling 12 weeks.
Next time you see or talk to your doctor, ask her to be very specific about which chemotherapy drugs you are taking, how often you will be having chemotherapy, and how long your treatment will last. It's important to know this so you can plan for what to expect.