Up to 50 per cent of cancer patients will be treated with radiotherapy. It may be used exclusively, or as a back up to chemotherapy or surgery. Like chemotherapy, it comes with its own range of side effects. In this second part of our review of ortho
Nearly half a million patients in the US were treated with ionizing radiation in 1990, making radiotherapy one of the most widely used treatments for cancer.
Radiation was first used in medicine by Marie and Pierre Curie, the well known French pioneers, at the turn of the century. The radiation used to treat cancer is called "ionizing radiation" which affects rapidly dividing cells. Tumour cells, white blood cells, the cells lining the intestinal tract, and those lining the mouth, are all rapidly dividing cells, and are affected by radiation.
A breakthrough in the 1920s meant that doctors didn't have to depend upon natural sources of radiation anymore, they could produce it themselves, artificially. X-ray doses could also be measured and therefore controlled.
High energy radiation Cobalt-60 appeared in the 1950s and was used to treat cancer deep inside the body without burning the skin. By the 1960s, a new invention called the linear accelerator appeared which produced even higher energy.
Radiation beams vary widely in the energy they produce, from about 100 kilo electron volts (KeV) to 25 million electron volts (MeV). As a rule of thumb the higher the energy, the greater is the depth of penetration. Low energy beams deliver their highest dose at the skin. Beams with 25 MeV achieve their highest dose at a depth of about two inches.The newest measurement is the Gray (Gy); one Gy equals 100 rads.
Radiotherapy, chemotherapy, or combinations of the two treatments are used to fight tumours. Alternatively, surgery can be used as the first line of attack. However, there is no evidence anywhere that combining radiotherapy with chemotherapy and surgery produces substantial gain in overall cures (RCS Pointon, ed, Radiotherapy in Malignant Disease, Springer Verlag, New York, 1991).
Evidence is now emerging which suggests that radiotherapy is not quite the wonder cancer treatment it was originally thought to be. Not only does it spread the cancer, rather than eradicating it, in some cases it actually causes cancer in healthy cells.
Breast cancer patients may be at risk of developing lung cancer after radiation. In one study, of 31 patients who'd received radiotherapy for breast cancer, 19 went on to develop a lung cancer on average 17 years later mostly in the lung on the same side as the breast that had been irradiated (Med Onc, 1994; 11 (3-4): 121-5). Some oncologists believe that the lung is especially sensitive to radiation damage, either scar tissue or inflammation which would tend to argue against high dose radiotherapy for lung cancer (Strahl und Onk, 1995; 171 (9): 490-8). Breast cancer patients also risk soft tissue cancers of the breast (Int J Rad Onc, Biol, Phys, 1995; 31 (2): 405-10).
For Hodgkin's disease, radiotherapy, as well as chemotherapy, poses a risk of breast cancer years later (J Gyne, Ob et Biol Repro, 1995; 24 (1): 9-12). In rectal cancer, animal studies have demonstrated the descending colon may be especially susceptible to cancer caused by radiation, particularly after surgery where blood vessels are joined up (Dis Colon & Rec, 1995; 38 (2): 152-8).
Side effects also multiply when chemo and radiation are given together.
In cervical cancer, where radiation bullets are often inserted in the vagina, cervical smears performed later often show abnormalities, such as fibrosis, and damaged cells (Diag Cyto, 1995; 13 (2): 107-19). What this means over the long term is anyone's guess.
Although doctors are experimenting with maximum doses on diseases proving intractible, in many cases, higher doses of radiation may only lower survival. In one study examining the longer term effects of radiation for cervical cancer, survival and local absence of disease decreased with every additional day of treatment beyond 55 days, no matter how early or advanced the disease (Inter J Rad Onc, Biol, Phys, 1995; 32 (5): 1301-7).
Perhaps most worrying, radiation can be a slow motion time bomb, where side effects only show up years later. For instance, major urinary tract complications on patients treated for cervical cancer are most prevalent in the first three years, but can show up any time for 25 years (Int J Rad Onc, Biol, Phys, 1995; 32 (5): 1289-300). In children, growth and premature sexual development can occur with doses as low as 18 Gy (Inter J Rad Onc, Biol, Phys, 1995; 31 (5): 1113-21).
Delivered by machine or from radioactive implants, radiotherapy often carries with it a myriad of side effects, a large number of them serious.
The most common is fatigue, which occurs in most patients who receive therapy to a large area of their body. The skin also reddens, rather like a sunburn. Hair loss in the treated area is common. Radiation to the head and neck can damage the salivary or tear glands, and you're left with a permanently dry mouth or eyes. Radiation to the upper abdomen may cause nausea and vomiting, diarrhea and frequent trips to the toilet when the lower abdomen is treated (Effects of Radiation on Normal Tissues, Churchill Livingstone, New York, 1993).
Injuries to bone marrow are common and this leads to a weakened immune system. The bones may also be damaged and osteoporosis may occur.
Radiation also scars most of the tissues it hits. Each part of the body can only tolerate a fixed amount of radiation. Once a dose has been given, radiation shouldn't be given again.
In virtually every form of cancer, radiotherapy has caused other appalling damage, and a few studies give an indication of its high incidence. In one study, one third of patients receiving chemotherapy and radiation after surgery for rectal cancer ended up with major complications (Aus & NZ J Surg, 1995; 65 (10): 732-6).
We've also discovered that administering radiotherapy after surgery appears to cause more side effects than giving it before an operation. And that's even if it reduces local occurrences and all proper radiation techniques are used (Eur J Cancer, 1995; 31A(7-8): 1347-50).
With breast cancer, the most feared side effect is fibrosis, where the skin is scarred and damaged. Even when the scar tissue is cut out, the skin rarely heals properly (Strahl und Onk, 1996; 172 (1): 34-8).
Radiotherapy can also cause problems with reconstructive surgery afterward. Some 42 per cent of implants had problems with pain and poor fitting with women who'd been irradiated, compared with only 12.5 per cent of those who hadn't received radiotherapy (Plastic & Recon Surg, 1995; 96 (5): 1111-5).
With cervical cancer, patients can find they are incontinent after radiation therapy following hysterectomy (J Wound Ost & Contin Nurs, 1995; 22 (1): 64-7). Urinary problems also afflict men given pelvic radiation (Eur J Canc Care, 1995; 4 (4): 158-65).
In cervical and testicular cancer, treatment can cause a high percentage of infertility (Blood Rev, 1995; 9 (2): 93-116), although with men fertility might be able to be preserved if the dose to the unaffected testis is reduced to less than 2 Gy (Clin Onc, 1994; 6(6): 377-80). Furthermore, if similar doses are used on women when pelvises are irradiated, the percentage of women undergoing premature menopause or infertility is low (Inter J Rad Onc, Biol, Phys, 1995; 32 (5): 1461-4).
Nevertheless, half of women given radiotherapy for cervical cancer suffer sexual dysfunction (Int J Rad Onc, Biol, Phys, 1995; 31 (2): 399-404).
Radiation can also weaken your heart and vessels around the heart, causing narrowing of the arteries (Giorn Ital Di Cardiol, 1995; 25 (7): 877-84) and cause thryoid dysfunction in up to 45 per cent of patients given it for throat cancer (Clinic Otol, 1995; 20 (3): 254-7).
In head and neck cancer, radiation also can injure the brain (Am J Neuro; 1991; 12 (1): 45-62), possibly lowering the intelligence of children (Childs Nerv Syst, 1995; 11 (6): 340-5), and damage the hearing (Am J Oto, 1994; 15 (6): 772-80).
Another underappreciated problem is fractures in bones exposed to radiation.
This occurred in 6 per cent of patients with soft tissue sarcoma (Eur J Can, 1994; 30A (10): 1459-63). Patients whose pelvises are irradiated can suffer so much bone damage that they must undergo total hip replacement. But even this is not a satisfactory solution.
In one study of 56 patients undergoing joint replacement after radiation damage, 52 per cent had the hips loosen, probably due to the weakening of bones. Although surgeons can use reinforcement rings to hold the joints there, nearly a fifth still loosen. Patients are also at risk of infection (J Bone & Jt Srg (Brit vers): 1995; 77 (6): 847-52).
Bowel cancer patients given radiotherapy have a high risk of long term incontinence and major disturbances in bowel function, particularly when treatment is combined with chemotherapy (Ann Surg, 1994; 220 (5): 676-82).
Injuries caused by radiotherapy treatment invariably follow breast cancer surgery. And many of the women who have set up the British Radiotherapy Action Group Exposure (RAGE), after suffering catastrophic arm injuries caused by radiation therapy for breast or cervical cancer, probably didn't need the treatment anyway.
Radiotherapy damage has left some of RAGE's members with excruciating pain, dietary complaints and repeated corrective surgery.
However, in spite of the horror stories and years of research, 50 per cent of patients with cancer are treated with radiotherapy during the course of their disease.
As one article pointed out, "Technology has advanced with accelerated regimes. . . and new radiotherapy treatments. Yet still we are no further forward in dealing with toxicity from treatment. The focus of research has been on developing new cures, and only now are questions being raised about the quality of life of patients having radiotherapy treatment" (Eur J Canc Care, 1995; 4 (4): 158-65).
!AClive Couldwell & Lynne McTaggart
In vol 7 no 3, please note that the dosage of vitamin C given intravenously by Patrick Kingsley should have been 25g, and not 25mg, as reported.