In most cases, breast reconstruction will not interfere with chemotherapy. If there are some complications that arise from your breast surgery like an infection, your oncologist may opt to postpone chemotherapy until that problem has been resolved.
However, if you are set to undergo radiation therapy, it is recommended that you complete that treatment before having breast reconstruction. Radiation can cause complications with the material in breast implants and diminish the cosmetic achievements of the surgery.
The good news is that studies have found no correlation between breast reconstruction and recurrence of cancer. If your cancer does return, breast reconstruction will not be an obstacle in your doctor discovering it.