WHILE virtually any cancer is capable of causing pain, those that most frequently require pain therapy are the invasive head and neck cancers, carcinoma of the lung, carcinoma of the breast, carcinoma of the pancreas, colorectal cancer, and carcinoma of the cervix. When making a decision about cancer pain therapy, it is important to recognize the phase of the disease, estimate the patient's longevity, and make an accurate diagnosis concerning the cause of the pain. The aphorism that pain in a cancer patient is due to the tumor until proved otherwise is undoubtedly true, but other causes of pain do exist and must be carefully separated from the pain of the cancer itself, for the therapies may be extremely different. As a general rule, destructive procedures should not be used in the early phases of cancer pain, for the primary therapy offers the best chance of pain relief. During an