As my surgeon put it, every one or two percentage points may count. Of course they also may not. The problem is we don't know. Chemo scares everyone but some of us did not have such a bad time - I had no nausea at all, and no fatigue, the most common known side effects. As @Sister says, no-one can force you to stay on a course of treatment if you hate it - you can stop although you may already have some side effects, such as hair loss. Only you can decide how hard or great an obstacle those side effects may be. And your decision is completely legitimate. Cancer is hard for all sorts of reasons, not least making these sorts of decisions. It's also a reminder that much of life is unknown - whatever we plan, about almost anything, things may go differently. And different may not always be bad. Best wishes whatever you choose.