In a prior blog, I listed arguments, that I have encountered over the years, against the the importance of precancer research. This is the last of six blogs where I respond to the arguments.
Argument. Treating precancers is not feasible for the majority of precancerous lesions that occur in humans. Reducing the incidence of cervical cancer by treating cervical precancer was possible only because the cervix can be inspected and sampled. There is no equivalent method to find and excise the precancerous lesions of pancreas, lung, prostate and breast. Therefore, procedures to detect and treat most precancers are not practical.
Response. As discussed in a prior blog, it is wrong to think that precancers must be detected and diagnosed prior to treatment.
The paradigm for treating cancer has been:
1. Detect the cancer (usually involves recognizing a sign or symptom or picking up the cancer on a screening text)
2. Diagnose the cancer (usually involves getting a tissue sample through a surgical procedure and sending the sample to a pathologist who renders a diagnosis indicating the type of tumor and its grade (level of malignancy). Diagnosis is sometimes supplemented with special studies, such as cytogenetics).
3. Stage the cancer (determining how far the tumor may have spread at the time of diagnosis)
4. Treat the cancer (one or more of surgery, chemotherapy, radiation therapy).
With precancers, we may be able to skip most of these steps, going straight to treatment. This is because the treatment for precancers can be simple and effective.
If a precancer can be eradicated with a relatively non-toxic systemic drug, or if the transition from precancer to cancer can be delayed with hormonal manipulation, or if the initiation step of carcinogenesis (leading to precancer development) can be blocked with a dietary supplement or a vaccine (e.g. Gardasil for cervical precancer), why not just forego the detection/diagnosis/staging steps?
The idea of receiving medical treatment for undiagnosed diseases is not new. How many people in the U.S. take statins, even though they have no reason to think that any of their arteries are significantly blocked by atheroma (never had stroke, never had angina, never had claudication, etc.)? How many people in the U.S. are treated for hypertension even if they've never had any of the associated diseases (never had renal failure, never had stroke, etc.)? Virtually everyone in the U.S. has been vaccinated for diseases they do not have (polio, smallpox, tetanus, etc.).
Intelligent people accept treatment for diseases they do not have, because they know how bad such diseases (myocardial infarction, stroke, kidney failure, polio, etc.) can be.
Treating precancers in high-risk people, avoiding the steps of precancer screening, detection, and diagnosis, is an option that we should be studying.
Prior blog in series
Copyright (C) Jules J. Berman 2008
key words: preneoplasia, premalignant, preneoplastic, incipient neoplasia, pre-cancer, dysplasia, metaplasia, intraepithelial neoplasia, premalignancy, premalignancies, precancers, precancerous, pretumor, carcinogenesis, pathology, cancer research, cancer funding, cancer research funding, funding for cancer research
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