Final answer:
The nurse should emphasize the importance of continuing breast self-examinations on the remaining breast for early detection of any signs of cancer, as this practice can lead to better outcomes.
Step-by-step explanation:
When discussing post-mastectomy care with a client who has undergone a left mastectomy, it is important for the nurse to stress the necessity of continuing to monitor for breast cancer signs. The correct response for the nurse would be option 3: she should continue to perform breast self-examination on her right breast. Performing regular self-examinations helps women become familiar with what is normal for their breasts, making it easier to detect any unusual changes such as lumps, thickening, or discharge that might indicate the presence of cancer. Since early detection is key to better outcomes in breast cancer treatment, maintaining vigilance on breast health remains crucial even after a mastectomy.