How long do patients have to stay in hospital after mastectomy?

Depends. Hospital stay depends on each individual patient and their respective surgeries. In my practice, a patient who undergoes a routine, uneventful total mastectomy can be discharged home the day after surgery.
1 to 2 days. Most of my patients go home the next day. Reconstruction adds to the above due to pain therefore add a day tram flap patients- it maybe 4 to 5 days my observation my 85 year old patients after a simple mastectomy are dressed and waiting for me at 0600 the next day wondering why I am late to send them home! The 30 year olds stay 1 to 2 days but they have the above reconstructions.