How long should a patient wait before starting chemotherapy and after the breast cancer surgery ?

No magic number.: The best answer is "as soon as possible", since there is no benefit to waiting (other than allowing a few weeks to recover from surgery). Many clinical trials require that chemotherapy be started within 6 weeks of surgery, but this, too, is arbitrary. I suggest that you talk to your medical oncologist and ask him/her what is best for you.

8-12 weeks: It depends on the type of breast cancer, but for most breast cancers, studies show that chemotherapy should be started by 12 weeks after surgery. After 12 weeks, the benefit from chemo starts to drop off. If your cancer is more aggressive (triple negative, er negative) you should probably start sooner, ie within 4-6 weeks.

Depends: In general chemotherapy is started 4 weeks after surgery, ofcourse if surgical wound is well healed and there are no signs of infection. Again, in general no longer than 8 weeks. Each case is different, talk to your oncologist.

12 weeks: Studies have shown that benefit from chemotherapy doesn't begin to drop off as long as it is started within 12 weeks of surgery. I take the type of cancer into consideration, though. For more aggressive breast cancers, i like to start chemo within 4-6 weeks. For the slower growing er+ cancers, within 12 weeks is fine and supported by data.