Symptom management: An important part of cancer care
ABSTRACTPhysicians can do a better job of palliating symptoms and improving the quality of life of cancer patients if they understand the principles of symptom management. We review the general principles of symptom management for fatigue, anorexia, constipation, dyspnea, nausea, and vomiting.
KEY POINTS
- Patients with advanced cancer typically suffer from multiple concurrent symptoms, which they rate as moderate or severe.
- The principles of symptom management include taking an aggressive detailed approach, prioritizing, and identifying symptom pathophysiology.
- Prescribed regimens should be specific and simple; physicians should consider the patient’s age and fragility, the cost of the treatment, and anticipated drug side effects.
- To ensure optimal palliation with the fewest possible adverse effects, reassess frequently, make one change at a time, and use rescue doses.
DYSPNEA IS COMMON, EVEN WITHOUT LUNG DISEASE
Dyspnea is the subjective perception of impaired breathing, which may include the sensation of breathlessness, chest tightness, air hunger, suffocation, or increased work of breathing.
At least half of patients with advanced cancer complain of dyspnea.1 Most have primary pulmonary malignancies or metastatic lung disease, but almost 25% have no documented lung involvement or underlying cardiopulmonary diagnosis to which to attribute it.38
Dyspnea is often very distressing. Palliative sedation is used more frequently for the relief of intractable dyspnea than for pain.39
Opioids are effective but underutilized for dyspnea
Although opioids are effective in both oral and parenteral formulations for the symptomatic management of dyspnea,40 the exact mechanism by which they improve dyspnea is unknown. Central control of respiration occurs in the medulla, and perception of dyspnea is mediated by the sensory cortex.
Opioids are underutilized by physicians other than palliative medicine specialists because of concern about respiratory depression. Appropriately titrated, opioids are safe and do not cause clinically significant respiratory depression.41
Allen et al42 showed that an opioid in low doses (diamorphine 2.5 mg subcutaneously) was effective and well tolerated in elderly patients with advanced pulmonary fibrosis who had not received opioids before.
Start low and go slow. An appropriate starting dose for a patient who has not been on opioids before may be morphine sulfate 2 mg intravenously (or a 5-mg immediate-release tablet by mouth) every 2 hours as needed for dyspnea. After 24 to 48 hours of an as-needed regimen, one can evaluate the patient’s response, tolerance, and dose requirement. If needed, parenteral infusion or a long-acting opioid preparation can be started with continued as-needed bolus dosing for breakthrough dyspnea.
We do not recommend writing opioid infusion orders with a “titrate to comfort” clause in the terminally ill. Increasing the rate of a continuous infusion does not provide the prompt symptomatic relief a bolus dose delivers. Dose accumulation and adverse effects are more likely when opioids are titrated in this fashion.
A Cochrane review showed that nebulized opioids are ineffective for dyspnea.43
Oxygen paradoxically does not improve dyspnea
Oxygen is commonly prescribed, although the literature does not indicate that it improves the sensation of breathlessness.44
A study by Clemens et al45 showed no correlation between dyspnea and oxygen saturation. It also found morphine to be superior to oxygen in subjective dyspnea, even in hypoxia.
A double-blind crossover study showed that ambient air delivered via nasal cannula was as effective as oxygen for dyspnea.46 The inexpensive and simple practice of a fan to blow ambient air on the patient’s face may help relieve dyspnea.
