Final answer:
A middle-age client with cancer can benefit from using patient-controlled analgesia (PCA) because it offers the advantage of allowing the client to have complete control over the timing and quantity of doses.
Step-by-step explanation:
The advantage that patient-controlled analgesia (PCA) offers is that the client has complete control over the timing and quantity of doses.
With PCA, the client can quickly and effectively manage their pain by self-administering small doses of opioids as needed. This allows them to maintain a consistently tolerable level of pain and reduces the risk of overmedication or undermedication.
By having control over the PCA device, the client can also minimize the potential side effects of higher individual dosages or opioid medications.