The Efficacy of Radiotherapy
By Don Benjamin
There has never been a properly run randomised trial that showed that radiotherapy saved any lives or even produced a significant increase in survival for any type of cancer. Radiotherapy can reduce the rate of recurrence, but has never been found to increase overall survival. In rare cases radiotherapy can extend life for a while by shrinking a tumour that is threatening a vital organ.
In contrast to this there is quite a lot of good evidence suggesting that it does more harm than good.
1. For example a 1993 US study of the deaths of 470,000 cancer patients found that about 27% of those who didn't die from their cancer had died from their conventional cancer treatment that had mainly damaged the heart and respiratory system (mainly radiotherapy and chemotherapy)1. The authors of this study attributed the deaths to treatment because most of the extra deaths occurred in the year just after diagnosis.
2. A review of randomised trials of radiotherapy for breast cancer showed that it increased mortality, mainly from damage to the heart and respiratory system2,3.
3. A review of randomised trials of radiotherapy following surgery for early breast cancer showed that overall survival was not affected, with the reduction in deaths from breast cancer being accompanied by an equal increase in death from other causes due to the radiotherapy4.
4. A review of data on 2,128 patients from nine randomised trials of post-operative radiotherapy (PORT) for non-small cell lung cancer comparing post-operative radiotherapy plus surgery with surgery alone showed that after a median follow-up of 3.9 years there was a significant adverse effect of postoperative radiotherapy on survival (hazard ratio 1.21). This 21% relative increase in the risk of death is equivalent to an absolute detriment of 7% at 2 years, reducing overall survival from 55% to 48%5.
5. A review of randomised trials evaluating the effect of mammograms showed that although overall survival was not affected by treatment, the treatment had resulted in women who would have died of breast cancer instead dying of other causes, mainly ischemic heart damage and respiratory failure, probably due to the post-operative radiotherapy6.
6. An analysis was carried out over a 20-year period of the mortality of 960 Swedish operable breast cancer patients randomised to preoperative radiation therapy, postoperative radiotherapy or surgery alone between 1971 and 1976. The study analysed the number of myocardial infarctions (heart attacks), deaths from cardiovascular disease and ischaemic heart disease and correlated these factors against dosage of radiotherapy received by the heart.
Compared to the surgery only group the number of myocardial infarctions in the group receiving high dose radiotherapy was 30% higher, the number of cardiovascular disease deaths was 100% higher and the number of ischaemic heart disease deaths was 150% higher7.
Because the higher radiation dose caused increased cardiovascular and ischaemic heart disease deaths but not increased heart attacks overall, the authors concluded that the mechanism of damage was radiation-induced microvascular damage to the heart.
7. An analysis of trials comparing survival after adjuvant radiotherapy plus surgery with surgery alone for colorectal cancer showed that there was no significant overall improvement of survival from radiotherapy compared with surgery alone. As with the breast cancer case in item 3 above, the reduction in deaths from colorectal cancer was accompanied by a comparable increase in deaths from other causes8,9.
To counter this negative evidence, a review of the trials used in Item 3 above was re-analysed and by selecting some of the trials and ignoring others the authors claimed that “surgical adjuvant radiotherapy significantly improves overall survival of breast cancer patients [by 12.4%] provided that current techniques are used and treatment is given with standard fractionation. For the best sub-groups we observed an odds of death reduction of more than 20%. The results of this study stress the importance of reducing cardiovascular and other late toxicity in adjuvant radiotherapy for breast cancer.”10
The National Strategic Plan for Radiation Oncology makes the simple statement that "radiation treatment is a proven, cost effective treatment for cancer"11. To substantiate this claim it cites a Swedish Report that states that "radiotherapy is effective as a curative treatment of many cancers"12. The Swedish report in turn does not cite results from randomised trials. Instead it admits that the claims of efficacy of radiotherapy are not based on results from randomised trials but on clinical experience.
For example in the section called “What is Radiotherapy and Does it Work" it states that “there is no question that radiotherapy works, in the sense that it kills cancer cells…It can cure many different types of cancer…” It does not define "curative" but it is clear from the context of the Study that the word cure refers to the ability of radiotherapy to eliminate all cancer cells in small tumours and radiosensitive tumour. This assumes that the tumour is the disease. This does not refer to increased survival and there is no evidence presented in that Swedish Report than any such treatment is curative. The meaning of “cure” in this context can be gauged from the statement that “of all patients cured of cancer, the majority is cured by surgery alone (around 60%). For this statement it refers to a study by Tobias and Tattersal13,14. Yet there is no evidence from any randomised trials that surgery has any effect on survival for any type of cancer. So this definition of cure is based on the ability to remove the tumour and the patient surviving a minimum of 5 years. This does not mean any reduction in mortality has been achieved. The Swedish Report also states that Radiotherapy plays a curative role in the treatment of about 30-40% of patients, either as a sole agent, or as part of combined therapy15.
To justify why effectiveness has not been proven the Swedish Report states that “in all of medicine including radiotherapy, however, it is quite difficult and often impossible to organize randomized trials. One problem is that many techniques used in radiotherapy are considered clinically effective based on clinical experience, so withholding them from a patient to evaluate their scientific merit may be considered unethical…. For these and other reasons, other types of controlled prospective studies are more common than randomized trials…. Although the results of these types of studies are considered less valid and reliable than the results of randomized clinical trials, they may still provide valuable information on effectiveness.”
It is therefore a gross misuse of public funds to channel scarce health funds into equipment that has not been shown to be effective and has been shown to be harmful.
It is important that the principles of evidence-based medicine be applied to all such claims for funds. The Inquiry you refer to should start off which an investigation of why 35% of cancer patients are being given radiotherapy with no proven survival benefits rather than fewer than 5% who are likely to have their life extended temporarily by shrinking a tumour that is threatening a vital organ such as the bowel or brain.
2. Stjernswärd, J. Decreased survival in early operable breast cancer. Lancet 1974; ii: 1285-1286.
3. Cuzick J, Stewart H, Rutqvist L et al. Cause-Specific Mortality in Long-term Survivors of Breast Cancer Who Participated in Trials of Radiotherapy. J. Clin Oncol 1994; 12 (3): 447-453.
4.Early Breast Cancer Trialists’ Collaborative Group. Effects of Radiotherapy and Surgery in Early Breast Cancer – An Overview of the Randomised Trials. NEJM 1995; 333 (22): 1444-1455.
5. PORT Meta-analysis Trialists Group. Post-operative radiotherapy in non-small-cell lung cancer: systematic review and meta-analysis of individual patient data from nine randomised controlled trials. Lancet 1998; 352: 257-263
7. Gyenes G, Rutqvist LE, Liedberg A, Fornander T. Long-term cardiac morbidity and mortality in a randomized trial of pre- and postoperative radiation therapy versus surgery alone in primary breast cancer. Radiother Oncol 1998 (Aug); 48(2): 185-190.
8. Colorectal Cancer Collaborative Group. Adjuvant radiotherapy for rectal cancer: a systematic overview of 8507 patients from 22 randomised trials. Lancet 2001; 358: 1291-304.
10. Van de Steene J, Soete G, Storme G. Adjuvant radiotherapy for breast cancer significantly improves overall survival: the missing link. Radiother Oncol 2000 Jun;55(3):263-72.
12. Swedish Council on Technology Assessment in Health Care – Radiotherapy for Cancer.
13. Tobias J. Clinical practice of radiotherapy. Lancet 1992; 339: 159-164.
14. Tobias J, Tattersall M. Doing the best for the cancer patient. Lancet 1985; 1: 35-38.