Course depends partly on cancer origin. With disease progression most people become weaker and less and less aware of their surroundings. In vas majority, symptoms can be well palliated.
Commonest symptoms are pain, nausea, asthenia, dyspnea and constipation.
Addiction not an issue in appropriate opioid use in cancer pain control. If abuse history, opioid use still appropriate, although monitoring must be more vigilant. Tolerance to opioids does occur, especially with higher doses or prolonged use of any opioid. However, if pain control deteriorates it is simple to switch to another opioid. Constipation is very important side effect of all opioids, to which tolerance does not occur.