What causes Cancer Pain ?

Learn what causes cancer pain and how you can work with your doctor to ensure your cancer pain is controlled.

Timothy Moynihan, M.D. [Extracted from MayoClinic.Com]
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Not everyone with cancer experiences cancer pain, but one of out three people undergoing cancer treatment does. If you have advanced cancer — cancer that has spread or recurred — your chance of experiencing cancer pain is even higher.

Cancer pain occurs in many ways. Your pain may be dull, aching or sharp. It could be constant, intermittent, mild, moderate or severe. Timothy Moynihan, M.D., a cancer specialist at Mayo Clinic, Rochester, Minn., offers some insight into cancer pain, reasons why people might not get the pain treatment they need and what they can do about it.

What causes cancer pain ?

Cancer pain can result from the cancer itself. Cancer can cause pain by growing into or destroying tissue anywhere near the cancer. Cancer pain can come from the primary cancer itself — where the cancer started — or from other areas in the body where the cancer has spread (metastases). As a tumor grows, it may put pressure on nerves, bones or other organs, causing pain.

Recent research has shown that cancer pain may not just be from the physical effect of the cancer on a region of the body, but also due to chemicals that the cancer may secrete in the region of the tumor. Treatment of the cancer can help the pain in these situations.

Cancer treatments — such as chemotherapy, radiation and surgery — are another potential source of cancer pain. Surgery can be painful, and it may take time to recover. Radiation may leave behind a burning sensation or painful scars. And chemotherapy can cause many potentially painful side effects, including mouth sores, diarrhea and nerve damage.

How do you treat cancer pain ?

There are many different ways to treat cancer pain. The ideal way is to remove the source of the pain, for example, through surgery, chemotherapy, radiation or some other form of treatment. If that cannot be done, pain medications can usually control the pain. These medications include :

Analgesics, such as aspirin or acetaminophen (Tylenol, others)
Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil, Motrin, others)

Weak opioid (derived from opium) medications, such as codeine
Strong opioid medications, such as morphine, oxycodone, hydromorphone, fentanyl or methadone

These drugs can often be taken orally, so they're easy to use. Medications may come in tablet form, or they may be made to dissolve quickly in your mouth. However, it you're unable to take medications orally, they may also be taken intravenously, rectally or through the skin using a patch.

Specialized treatment, such as nerve blocks, also may be applicable. Nerve blocks are a local anesthetic that is injected around or into a nerve, which prevents pain messages traveling along that nerve pathway from reaching the brain. Other therapies, such as acupuncture, acupressure, massage, physical therapy, relaxation, meditation and humor, may help.

In your experience, what are some reasons for not receiving adequate treatment for cancer pain ?

Unfortunately cancer pain is often undertreated. There are many factors behind that, some of which include :

Physician knowledge
One factor has to do with a doctor's knowledge and ability to treat and recognize pain. Some doctors and other health care professionals may not specifically ask about pain, which should be a normal part of every cancer patient's visit. Cancer patients should be asked if they are having any pain. If they are, the doctor should stop there and deal with the issue. Some doctors don't know enough about proper pain treatment. If this is the case, your doctor might refer you to a pain specialist. Other doctors may be concerned about prescribing pain medications because these drugs can be abused. However, people in pain are very unlikely to abuse pain medications.

Patient reluctance
A second factor might be a patient's own reluctance. Some people might not want to "bother" their doctors with the information, or they may fear that the pain means that their cancer is getting worse. Some are reluctant to report it or report it as thoroughly as they should because they're worried about what doctors or other people might think of them if they complain. They might feel that because they have cancer, they're supposed to have pain and be able to deal with it. That simply isn't true.
Fear of addiction. Another factor might be a person's fear of becoming addicted to the pain medications. This is something that we know doesn't typically happen if you take medications for pain. If you take them when you're not in pain or to get high, then, yes, you can get addicted. But the risk of addiction for people who take pain medications in an appropriate fashion — for pain — is very low, so this shouldn't be a concern.

Fear of side effects
Some people fear the side effects of pain medications. Many are afraid of being sleepy, unable to communicate with family and friends, acting strangely, or being seen as dependent on medications. People are also sometimes afraid that taking morphine may shorten their life. There is no evidence of any of these happening if the medication is dosed appropriately. And although strong pain medications can cause drowsiness when you first take them, that side effect usually goes away with steady dosing.

What side effects can you expect from cancer pain treatment, and what can you do about them ?

Each pain treatment may be accompanied by its own unique side effects. For example, radiation treatments may cause redness and a burning sensation of the skin. And, depending on what part of the body the radiation is applied to, the radiation may cause diarrhea, mouth sores or other problems, such as fatigue. Chemotherapy certainly can cause side effects, such as nausea, fatigue, infection and hair loss, but it can be effective in relieving pain if it shrinks the tumor. There are medications to help with nausea. Relaxation techniques also may help.

Pain medications each have their own unique side effects that should be reviewed with your doctor before taking them. One of the common side effects of the stronger pain medicines is constipation — common to opioids. It can be treated with appropriate bowel regimens as prescribed by your doctor, such as adding a stool softener and something to stimulate the bowels. Preventing constipation is much easier than treating it, so anyone who takes these strong pain medications should automatically begin a regimen to keep their bowels moving. Some of the other side effects of the strong pain medications include confusion, lethargy and sleepiness. The severity of these effects varies from person to person and commonly occurs with the first several doses. But once a steady amount of the medicine stays in your body, the side effects usually resolve. Hallucinations and behavior changes are uncommon.

The less potent pain medications actually may have more side effects, which also should be discussed with your doctor before taking them. For instance, anti-inflammatory drugs might damage your kidneys, cause ulcers or increase your blood pressure. Aspirin can cause gastrointestinal bleeding, and acetaminophen (Tylenol, others) can cause liver damage if you take too much.

When should you discuss cancer pain with your doctor, and what points should you bring up ?

Report any bothersome pain to your doctor. If there is a minor pain that goes away, don't worry about it. But if the pain interferes with your life or is persistent, it needs to be reported and should be treated. Although no one can guarantee that all pain can be completely eliminated, most pain can be lessened to the point where you can be comfortable.

It may help to keep track of your pain by noting how strong it is, where it's located, what makes it worse, what brings it on, what makes it better and anything else that happens when you have the pain. A pain-rating scale from 0 to 10 — with 0 being no pain and 10 being the worst pain you can imagine — may be helpful in reporting pain to your doctor. In addition, pay attention to what happens when you attempt to relieve your pain. If you take medicine, do you feel any ill effects from it? If it's a massage, hot or cold packs, or something physical that relieves the pain, those are important to report, too. Also note any ill effects of any pain medications.

What steps can you take to make sure you're receiving adequate cancer pain treatment ?

First, you need to talk to your doctor or health care provider if you're having pain. Second, you and your doctor should set a goal for pain management and monitor the success of the treatment against that goal. Your doctor should track the pain with a pain scale, assessing how strong it is. The goal should be to keep the pain at a level with which you're comfortable. If you aren't achieving that goal, talk to your doctor. If you're not getting the answers you need, request a referral to a facility more skilled in the care of pain, particularly a major cancer center. All major cancer centers have pain management programs. For the most part, the medications and treatment for pain are covered by standard insurance.