Debunked: Dr. Peter Glidden: Chemotherapy only works 2% of the time

Dan Wilson

Senior Member


The video above features Dr. Peter Glidden claiming that chemotherapy does not work and that it is only used because it brings in huge profits for doctors. To back this up, he references a study published in 2004 in the journal Clinical Oncology. In this study, researchers looked back on 154,971 patient files to assess the efficacy of chemotherapeutic treatments in adult cancers. They conclude that:
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The overall contribution of curative and adjuvant cytotoxic chemotherapy to 5-year survival in adults was estimated to be 2.3% in Australia and 2.1% in the USA.
Dr. Glidden and many others cite these numbers as evidence that chemotherapy is not effective and that doctors are only interested in profiting from, rather than curing, cancers.
The data in this study, however, do not support such a conclusion. One problem is that many patients examined here did not undergo chemotherapy. This can happen for a number of reasons but cancer patients often don't need chemotherapy. Treatment options like surgery, radiation, and, now, immunotherapy have proven very successful in removing particular cancers at particular stages.

The second problem follows from the first. This study was designed to look at how often chemotherapy is successful compared to other treatments, not the survival rate of patients undergoing chemotherapy, as Dr. Glidden and others claim. What this study suggests is that, out of the 154,971 patients examined, chemotherapy was responsible for 3,306 of them surviving 5 years past their diagnosis. This means that with the 60% overall 5-year survival rate for cancer patients in Australia at the time this study was conducted, surgery and radiation were responsible for the other 89,676 patients' 5-year survival.

To make the interpretations of Dr. Glidden even weaker, the design of the study has multiple flaws that are best pointed out in a letter written to the journal. http://www.clinicaloncologyonline.net/article/S0936-6555(05)00077-4/pdf
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We are concerned that their approach underestimates the contribution of chemotherapy to the care of cancer patients. By using all newly diagnosed adult patients as a denominator, despite the fact that chemotherapy is not indicated for many of these patients, the magnitude of the benefit in many sub-groups is obscured. ...
Furthermore, the authors use a time-point of 5 years to assess effect on survival. This will underestimate the efficacy of chemotherapy because of late relapses. ... The paper also contains several inaccuracies and omissions. The authors omitted leukaemias, which they curiously justify in part by citing the fact that it is usually treated by clinical haematologists rather than medical oncologists. ... The authors do not address the important benefits from chemotherapy to treat advanced cancer. Many patients with cancers such as lung and colon present or relapse with advanced incurable disease. For these conditions, chemotherapy significantly improves median survival rates, and may also improve quality of life by reducing symptoms and complications of cancer.
So how effective is chemotherapy? What makes this question hard to answer is that there are over 200 chemotherapies or cancer related drugs. Not every drug is equally as effective and some cancers are more easily treated than others. What we can say is that chemotherapy can be an effective tool against cancers, especially when used in conjunction with other treatments. This has been shown throughout history with multiple examples of chemotherapeutic drugs drastically increasing survival rate in and even outright curing certain kinds of cancer.

In summary, people like Dr. Glidden who cite the "2%" study as they do seem to not understand or have read the full article. The negative perception surrounding chemotherapy is understandable, some treatments really do have awful side effects. Most doctors are not heartless but cancer is an ugly and unforgiving disease that has always pushed both doctors and patients to desperate attempts at prolonging life. Although chemotherapy can be an extremely difficult thing to do and witness, many drugs and treatment options do not have terrible side effects. If these issues become relevant to your life, it is important to seek the proper help and information from physicians but such things will not be found in advice given by Dr. Glidden.
 
That 2% study is muddied further because chemo isn't just one treatment, just like cancer isn't just one disease. It's also usually a piece in a greater puzzle, a stepping stone or follow up to other treatments or surgery, or even just a stop gap to keep the game going.

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che·mo·ther·a·py
ˌkēmōˈTHerəpē,ˌkemōˈTHerəpē/
noun
  1. the treatment of disease by the use of chemical substances, especially the treatment of cancer by cytotoxic and other drugs.
 
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It's also usually a piece in a greater puzzle, a stepping stone or follow up to other treatments or surgery,
Yes, in cases involving solid tumors it is desirable to simply remove the cancer with surgery. If all malignant cells are removed, it is much less likely to come back. Tumors that are too large to operate on, however, are common. Chemotherapy can be an effective way of shrinking the tumor to an operable size, thus bringing the patient to a much more "curable" state.
 
Slightly off topic but it could be argued that if chemo only worked 2% of the time many countries with socialised health care would not fund it.
Calling into question the funding for development and usage of chemotherapeutic drugs was the primary motivation driving research for the authors of the paper Dr. Glidden references.
 
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