Radiation therapy is the use of radiation (x-rays, gamma rays, proton rays, and neutron rays) to kill cancer cells. Its main role is destroying or shrinking localized cancers (as opposed to cancers that have spread to distant parts of the body). About 60 percent of cancer patients get radiation at some point during their treatment. Some times radiation cures the disease, but if a cure is not possible, radiation can reduce tumor size to relieve pain or make surgery easier.
Certain types of cancers -such as Hodgkin's disease, some lymphomas, and prostate cancer-respond very well to radiation. In fact, sometimes radiation alone works best in these cancers. But for other cancers, radiation offers only partial benefit. For example, receiving radiation for advanced lung cancer increases your chances for living an additional five years by only 10 percent.
If radiation alone won't be enough to get the best results, you may need to have surgery, or chemotherapy, or both. Combining strategies often improves your odds of surviving. For example, radiation can shrink tumors, making them easier for the surgeon to remove. And if surgery doesn't "get it all," your doctors may use radiation to destroy or control the remaining cancer cells.
Of course, radiation kills normal cells about as effectively as it kills cancer cells. It's especially good at destroying cells that grow and divide quickly. That means cells in cancer tumors--but it also means normal cells, such as those of the skin, blood, immune system, and digestive tract. Fortunately, most normal cells are better at repairing radiation damage than are cancer cells.
To minimize damage to healthy cells, radiation treatments are usually given in small doses "fractions"--over a course of time, usually five to seven weeks. That gives cells a chance to recover. Healthy cells usually bounce back more quickly than cancer cells. By the next dose, they hold up better while the weakened cancer cells suffer another blow. By the end of treatment, hopefully all of the cancer cells have been destroyed.
Kinds of Radiation Used to Treat Cancer
Early radiation therapy used high-energy, ionizing electromagnetic X-rays and gamma rays composed of particles of energy called photons. These particles have no mass and no electrical charge. Photon rays are part of the electromagnetic spectrum, as are ultraviolet, visible, and infrared light; radio waves; and microwaves. They are called ionizing because they act by knocking out small atomic particles called electrons. Damaging a cell's molecules in this way disrupts its function, especially its ability to divide and make new cells. While this method is effective, the risk of side effects, including destruction of healthy tissue, is high.
Many cancer treatment centers provide newer, more focused forms of radiation therapy that have advantages over photon radiation in some circumstances. One example is neutron therapy. Neutron rays are very high energy rays composed of neutrons, which are particles that have mass but no electrical charge. These rays dont affect the tiny electrons. Instead, they go for bigger targets, destroying atoms in the cell's nucleus, In a sense, they wipe out the cell's headquarters rather than picking off a few soldiers guarding the front door. It's much harder for cells (whether cancerous or normal) to survive such an attack and to repair the damage.
Another advantage of neutron radiation is that, unlike conventional radiation, it can work even in the absence of oxygen. For that reason, neutrons can destroy cells hidden deep in the centers of large tumors. Neutron therapy is especially effective for the treatment of inoperable salivary gland tumors, bone cancers, and certain advanced cancers of the pancreas, bladder, prostate, and uterus.
Another new type of radiation therapy is proton radiation. Protons are particles that have mass and a positive electrical charge. Proton rays can be shaped to conform to the shape of the tumor more precisely than can x-rays or gamma rays. They thus allow delivery of higher radiation doses to tumors without increasing damage to the surrounding tissues. For these reasons, proton therapy is more effective than neutron therapy, requires fewer treatment sessions, and produces fewer side effects. The drawback is that proton radiation is not yet as widely available as the other methods.
Modes of Delivery
Traditionally, radiation therapy is delivered from a beam of radiation originating outside the body. This is called external beam therapy. Because the beam passes through the body before and after it gets to the tumor, it can injure tissue in its path.
To reduce such damage, physicians have developed new techniques that allow the radiation to emanate from inside the body. This method, called brachytherapy, involves the use of radioactive materials placed in small tubes, called seeds, that are implanted near the tumor (brachymeans "near"). Brachytherapy is especially useful in cases where surgery or radiation poses too great a risk of damage to tissues near the tumor, as is often the case in prostate cancer or cervical cancer. A newer form of brachytherapy, called high dose rate (HDR) brachytherapy, is more versatile than standard seed implantation and in many cases offers a more precise way to deliver this form of radiation.
Another method, known as radioimmunotherapy, is still in the experimental stage. This technique uses special protein molecules called antibodies. Attached to each antibody is a special radioactive molecule that emits gamma rays. Injected into the patient's bloodstream, the antibody carries its cargo through the body until it encounters a cancer cell. Then it attaches itself to a special receptor on the cell's surface. Once the antibody is docked, the gamma radiation is released directly at its target, spelling doom for the cancer cell. This new therapy is not widely available, but if it is of interest to you, please talk to your oncologist about it.
Before radiation therapy begins, your doctors will carefully evaluate the size and location of the tumor and its surrounding tissue. Their goal is to design the treatment as carefully as possible to aim the right dose of radiation at the target while minimizing the risk of adverse effects. They'll probably use magnetic resonance imaging (MRI) or computed tomography (CT scans) to map out their strategy. Depending on the Tumor's type, size, and location, the health care team will determine the total radiation dose, the number of sessions (fractions) needed, the interval between sessions, and whether to give each fraction from the same direction or from different directions.
In all cases, physicians will try to deliver only the dose needed, and only to the targeted area. To protect other parts of your body, they may construct a special shield. Newer techniques, such as 3-D conformal radiation and intensity-modulated radiotherapy (IMRT), can also reduce the amount of radiation that reaches healthy tissue. Your skin may be marked with ink or temporary tattoos to help achieve correct positioning for each treatment. In some cases, molds can be built to hold tissues in exactly the right place cach time.
Toxicity and Side Effects
Because it kills normal cells along with the diseased ones, radiation therapy can be highly toxic. Newer, more targeted radiation treatments are less dangerous than some of the older techniques, but there are still risks of anemia, nausea, vomiting, diarrhea, hair loss, skin burn, and sterility. Which of these complications arises depends on the total volume of the area being treated, the dose of radiation, and the area of the body in cluded in the field. For example, nausca occurs primarily if the abdomen is irradiated, whereas hair loss generally results from treatment of the head. The greater the total area being treated, the more likely it is that systemic effects such as anemia and fatigue will occur.
The side effects from radiation treatment occur in three different phases: early, intermediate, and late. The early side effects of radiation treatment occur while treatment is being given. Although these complications can be quite severe, they almost always completely resolve once the course of treatment is completed. Intermediate effects are those that appear weeks to months after the radiation treatment is completed. Late effects of radiation treatment, which are fairly rare, do not appear until many months or even years after therapy. These can include radiation necrosis (breakdown of a region of bone), pulmonary fibrosis (stiffening of lung tissue), secondary cancers, and scarring or hardening of tissues in the region exposed to radiation. Because these late effects are often extremely difficult to treat, the best strategy is to prevent them through the use of the natural therapies described later in this chapter.
Nausea and vomiting are more likely to occur when the dose is high or if treatment involves the abdomen or digestive tract. Sometimes nausea and vomiting occur after radiation to other regions, but in these cases the symptoms usually disappear within a few hours after treatment. Fatigue frequently starts after the second week of therapy and may continue until about two weeks after the therapy is finished. We recommend that patients limit their activities, cut back their work hours, take naps, and get extra sleep at night, but it is important to get some exercise in the form of tai chi, yoga, or stretching exercises to gently stimulate the circulation and the immune system.
Unlike chemotherapy, which is a systemic treatment designed to destroy cancer cells wherever they may be lurking in the body, radiation therapy is usually a local or regional therapy, affecting only the tumor and the immediately surrounding area. For this reason, many of the side effects are specific to the region of the body being treated. Typically there is some reddening of the skin, and the area may become irritated, dry, or sensitive. A skin reaction may progress to look like a sunburn.
The aloe plant has thick leaves that produce a slightly viscous, clear gel with many healing properties. The gel is 96 percent water the rest is various polysaccharides complex sugars), enzymes, minerals, and amino acids in solution.
The soothing and wound-healing effects of aloe vera have been chronicled since ancient times. Both Pliny (A.D. 23-79) and Dioscorides (first century A.D.) wrote of aloe's ability to treat wounds and heal infections of the skin. In 1935, physicians first successfully used the fresh juice to treat a patient suffering from facial burns due to X-rays.! The beneficial effects of aloe are now so well accepted that virtually every over-the-counter product for the topical treatment of burns, minor irritations, skin ulcers, and other skin disorders incorporates aloe into the formulation.
We recommend using pure, 100 percent aloe vera gel-the naturally occurring, undiluted material obtained directly from the leaves of the aloe plant. It is available at most drug stores and health food stores. If the skin has not been broken, the gel can be applied liberally to areas of inflammation and damage.
Treat the skin gently to avoid further irritation; bathe carefully using only warm water and mild soap. Avoid perfume and scented skin products and protect affected areas from the sun. We also recommend using aloe vera gel on areas of radiation burn (see box).
Dietary Support for Radiation Therapy
Please follow the guidelines give in Appendix B, Battling Cancer Through Diet. After the cancer is in remission, the guidelines provided in Chapter 2 can be followed. Several supplements deserve special mention:
Vitamin A and Beta-Carotene
Several studies have shown that vitamin A and its precursor, beta-carotene, offer significant benefits to people undergoing radiation therapy. For example, these compounds reduce inflammation after radiation treatment. This allows physicians to administer higher, and hopefully more effective, doses. In a study of advanced squamous cell carcinoma of the mouth treated with radiation therapy, beta-carotene (75 mg daily) significandy reduced the incidence of severe oral inflammation.
In addition to preventing some of the side effects of radiation therapy, vitamin A can also enhance the effectiveness of radiation therapy. Test tube studies have shown that vitamin A increases the sensitivity of cancer cells to radiation therapy. In animal studies, the effect of local radiation was enhanced by supplemental vitamin A and beta-carotene given during treatment. The animals receiving the antioxidant showed better tumor shrinkage and increased survival time. The results from these preliminary studies have been upheld in human studies.
We recommend taking an extra 75 mg of beta-carotene and 10,000 IU of vitamin A at least one week prior to radiation therapy. After this one-week usage, do not continue with these supplements at this dosage. You may supplement at a maintenance dosage of 15 mg of betacarotene and 5000 IU of vitamin A if you so desire.
Vitamin C therapy appears to be helpful during radiation therapy. In one human study, 50 cancer patients were given either vitamin C (5 daily doses of 1 g each) or placebo along with their radiation therapy. More complete responses to radiation were noted in the vitamin C group at one month (87 to 55 percent) and four months (63 to 45 percent) after treatment. Side effects tended to be fewer in the subjects given the vitamin C as well. We recommend a more modest intake of 500 to 1000 mg three times per day in light of our other antioxidant recommendations.
mans. At those extreme levels, it's not surprising that there might have been adverse effects on the cells.
In contrast, in another study, giving vitamin E to animals before, during, and after radiation enhanced the killing power of the beam and reduced the ability of cancer cells to divide. At the same time, the antioxidant protected normal cells from these effects. We recommend a dosage of 400 to 800 IU daily.
About Co-enzyme Q10 and Radiation
Curcumin and Quercetin
In 1998, a study was published warning that Co-enzyme Q10abbreviated to CoQ10 -reduced the effects of radiotherapy on small-cell lung cancer in mice. While this animal study did indeed show a significant inhibition of radiation damage to cancer cells, the oral dosage required to produce this effect was 40 mg/kg, a dose roughly equivalent to 2800 mg in an adult human. Borderline inhibition was found at 20 mg/kg (approximately equal to a 1400-mg adult human dose), and no inhibitory effect on radiotherapy was noted at 10 mg/kg CoQ10, a dose roughly equivalent to 700 mg in an adult human. Based on this information, the normal human dosage range for CoQ10 of 50 to 300 mg a day would appear to have no adverse impact on concurrent radiotherapy.
Curcumin and quercetin protect healthy cells against the harmful effects of radiation without reducing its effectiveness. You won't need to take both curcumin and quercetin. Quercetin reduced skin damage from radiation in patients with head and neck cancers, so it is probably the best choice for this type of cancer. For head and neck cancers, take
When to Use Curcumin or Quercetin (with Radiation)
|TYPE OF CANCER/TREATMENT
quercetin (200 to 400 mg daily). For other cancers being treated by radiation, take curcumin (200 to 400 mg daily). Continue for at least one month after the last radiation treatment. After this period, choose either quercetin or curcumin based on the type of cancer.
Maitake MD-Fraction or PSK/PSP
These mushroom products are discussed more thoroughly in Chapter 8. Take either maitake MD-fraction, or PSK/PSP, at either 1 mg per 2.2 pounds per day for the maitake products or 3000 mg for the PSK/PSP products. Continue at this dosage until the cancer is in remission, then cut the dosage in half. In one study, PSK used with radiation therapy in non-small-cell lung cancer increased the five-year survival up to 39 percent in stages I and II disease and 22 percent in stage III disease, compared with 16 percent and 5 percent, respectively, in the groups that did not receive PSK.
Melatonin is a hormone secreted by the pineal gland, a pea-sized gland at the base of the brain. It is available as a dietary supplement. MelaTonin produces benefits for people undergoing radiation therapy, according to preliminary evidence. In one human study, the effect of radiotherapy plus 20 mg a day of melatonin was compared to that of radiotherapy alone in 30 patients with brain cancer (glioblastoma). 16 Patients with this form of brain cancer generally live only about six months after diagnosis. But at the end of one year, 6 of the 14 patients receiving melatonin were still living, compared with just one of the 16 undergoing radiotherapy alone. The researchers also noted fewer side effects from radiation therapy in patients taking melatonin.
We recommend 20 mg per day at bedtime one week prior to radiation, to be continued until the cancer is in remission.
Alkylglycerols are compounds found in shark oil. In commercial alkylglycerols preparations, the high levels of vitamins A and D, along with other constituents found in shark liver oil, are removed. The effects of alkylglycerols in the treatment of radiation-induced leukopenia have been studied extensively. The major finding in most of these studies was that in radiation-treated cancer patients, alkylglycerols prevent the severe reduction in white blood cell counts and increase white blood cell production.
Alkylglycerols also exert immune-enhancing effects and can also increase cancer survival rate. In one study of a series of 350 patients with cervical cancer treated with alkylglycerols and given radiation therapy, there was a greater survival rate for one year and five years compared with a matched control group who did not receive alkylglycerols.
For protection from the damaging effects of radiation, we recommend a dosage of 1200 mg a day for at least one week before and after treatment. A dosage of 600 mg a day should be continued until normal white blood cell counts are achieved.