Best Chance for Colon Cancer Survival – Don’t Let It Start

Two papers in the February 23, 2012, New England Journal of Medicine reported important findings in the fight against colon cancer. The first paper (Zuber, AG et al; Colonoscopic Polypectomy and Long-Term Prevention of Colorectal Cancer Deaths) conducted by American investigators establishes the benefit of polyp removal in the prevention of death from colorectal cancer. The study conducted upon 2,602 patients who had adenomas removed reveals a 53 percent reduction in mortality from colon cancer compared with the expected death rate from the disease in this population.

To put this into perspective – virtually no intervention in the advanced disease setting provides a survival advantage. The best we can usually do once the disease is established is an improvement in time to progression. When we do observe a true survival advantage it is usually in the range of a few percentage points and never of this magnitude. How might we explain this astonishingly positive result?

One way to view this finding is to reexamine the biology of cancer. One of the leading experts in the field, Bert Vogelstein, MD, from Johns Hopkins, explained colon carcinogenesis as a pattern of gene perturbations starting at atypia, progressing to carcinoma in situ and ending with invasive, metastatic disease. According to Dr. Vogelstein, the average colon cancer found in a patient at the time of colonoscopy has been present in that person’s colon for 27 years. From there it is only a hop, skip and a jump from one-centimeter adenomatous polyp to metastatic (lethal) disease, all playing out over the last three years in the natural history of the disease. Thus, cancer truly is a disease that doesn’t grow too much, but dies too little and interrupting this process while it is still slumbering can, it would seem, lead to cures.

What I find surprising is the success of the strategy. Since it is now well established that cancer can metastasize when it has achieved the rather diminutive proportions of 0.125 cubic centimeters or less and the average polyp can only be detected at one or more cubic centimeters, it is our good fortune that so many cancers chose not to (or could not) metastasize prior to detection. Reading between the lines, those 12 patients who died of colon cancer as opposed to the expected 25.4 are presumably those with early metastasizing disease. The next frontier will be the detection of these cancers when they are teenagers and not 20-somethings. It may be that proteomic analyses will provide an avenue for earlier detection in the future.

The second article is a European study (Quintero, E et al; Colonoscopy versus Fecal Immunohistochemical Testing in Colorectal-Cancer Screening) that compared colonoscopy with fecal blood testing in a large cohort of patients. While the rates of detection for colorectal cancer were similar, the rates of detecting both advanced and early adenomas, favored colonoscopy (p < .001). This study represents an interesting adjunct to the American study described above. Specifically, if the early detection (and removal) of adenomas can confer a survival advantage then it could be argued that colonoscopy by its virtue of it’s higher detection rate of these precancerous adenomas, is the preferred “screening” modality. With over 50,000 deaths attributed to colorectal cancer in the U.S. each year, the public health benefit of colonoscopies becomes an intersecting point of discussion. Until now, fecal occult blood testing yearly or sigmoidoscopies every several years has been considered equivalent to colonoscopies every 10 years starting at age 50. Do we need to move colonoscopies to the front of the line?

What is most interesting about both these reports is the low-tech nature of the study modalities – and the astonishing efficacy of their application. Colonoscopies have been conducted for decades. They are comparatively simple, do not require affymetrix chips, and yet provide demonstrable benefit that appears to exceed anything offered, to date, by the “genomic revolution.” Perhaps we should all keep an open mind about other comparatively low-tech methodologies that can provide survival advantages.

If It is Too Good to Be True . . .

The February 12, 2012, CBS 60 Minutes covered a story that has sparked a great deal of interest among cancer patients and medical professionals. The topic was an investigator named Anil Poti who, while working at Duke University developed a laboratory platform for the study of human lung cancer.

Using molecular profiling, Dr. Poti and his collaborators, reported their capacity to distinguish responding and non-responding cancer patients, providing survival curves that were nothing short of astonishing. I recall attending the original lectures given by these investigators at the American Association of Cancer Research meeting several years ago.

As an investigator in the field of drug response prediction, working in lung cancer I had a particular interest in their platform and I was extremely impressed by the outcomes they reported. At the time, I wondered how the static measurement of gene profiles could possibly characterize the nuances of human biology, to encompass the epigenetic, siRNA, pseudogene, non-coding DNA and protein kinetics that ultimately characterize the human phenotype. Nonetheless, with such compelling data I was prepared to be convinced.

That is until a relatively unheralded report in the Cancer Letter raised concerns by several biostatisticians regarding the reproducibility of Dr. Poti’s findings. And then more comments were followed by a full NIH investigation. A panel of biostatisticians was convened and a formal report provided the explanation for Dr. Poti’s excellent results.

They had been invented. The clinical outcomes were not real results. The findings had been retrofitted to match the patient responses and this was the subject of the 60 Minutes report.

What the 60 Minutes report did not address however, was the real problem. That being the inability of contemporary genetic profiling to truly define human biology. For all the reasons enumerated above, siRNA, non-coding DNA, etc., the simple measurement of gene sequences cannot accurately predict biological behavior. This is what the 60 Minutes reporters and the physicians they interviewed, never discussed. The problem at hand is not an errant investigator but an errant scientific community. Our love affair with the gene that began in 1953 (Watson and Crick) has now been confronted by a most heartbreaking example of infidelity (pun intended).

Genes do not make us what we are; they only (sometimes) permit us to become what we are, with the vagaries of transcription and translation lying between.

This leads us to the reasons I find this so critically important:

  1. I cannot stress strongly enough that this is NOT what I do. Genomic analysis (their work) and functional analysis (our work) are distinctly different platforms.
  2. I strenuously resist any attempt on the part of anyone to tar me or my work with this brush.
  3. It is precisely because genomic analysis cannot accurately predict cancer patient outcomes, that these investigators found it necessary to invent their data.
  4. Despite this, functional analyses can and do provide these types of predictive results in lung cancers and other diseases as we have reported in numerous publications.
  5. Finally, while imitation is the sincerest form of flattery, this is one instance in which I would prefer to decline the compliment.

Cancer Survivorship

Some of you may have read the January report from the American Cancer Society (ACS) that described a decline in U.S. cancer death rates by 1.8 percent per year in men and 1.6 percent per year in women during the period between 2004 to 2008.

These encouraging results have been touted as evidence of success in the war on cancer. The war on cancer itself began in December 1971, when then president Richard Nixon established a national priority to conquer this disease. Since that time, we have dedicated more than $200,000,000,000 to this effort and published literally millions of articles on the topic. Despite these efforts and tremendous resource allocations, the focus of this research effort, i.e. treatment of advanced malignancies, has provided limited successes.

If we drill down onto the ACS statistics we find that most of the survival changes reflect earlier detection and the successful application of cancer screening. Mammograms, colonoscopies, the use of PSA and the growing application of screening CT scans for lung cancer detection have, and will continue to have, a favorable impact on cancer statistics.

This is the good news. The bad news is that our success in treating advanced disease is almost non-existent. While there have been slow migrations in a favorable direction for the five-year survival rates in some malignancies, the big killers like lung and GI, have shown extremely limited progress. There are many reasons why cancer cures remain out of reach, but several changes could be implemented immediately to increase our rate of success.

First, we need to incorporate systems biology into cancer research. As opposed to analyte-based approaches like genomics that unravel one finding at a time, the field of biosystematics examines human cancer through the lens of interacting networks.

Second, we need to redouble our efforts in the study of basic metabolism and the growing field of metabolomics.

Third, we need to revamp the clinical trial process. Were investigators incentivized to achieve greater clinical successes, there were be fewer failed Phase II and Phase III trials. Contrary to the business world where success is rewarded, academic physicians today receive the same compensation for every patient treated, whether the intervention is successful or not. This has the unintended consequence of encouraging physicians to accrue patients to clinical trials with no focus on effective therapies. While it may be gratifying to the trialists to have successes, they receive the same compensation for their failures. Clinical investigators need skin in the game.

Finally, the regulatory environment is currently over-restrictive. The process should allow investigator-initiated efforts with more lenient review processes. The current environment that punishes dedicated physicians for stepping out of the established guideline therapies is thwarting progress and frightening dedicated investigators out of the field. Good faith efforts on the part of physicians using new drugs and combinations that document successes and failures, could unleash an army of clever physicians to utilize novel approaches to advance new therapies with little additional cost.

Lethal diseases, like advanced cancer, pose hurdles that require novel trial designs and less stringent controls. Patients confronting these illnesses should be allowed to receive therapies and should be granted the dignity to determine their own risk-benefit ratios when they confront life and death decisions. Simple consent forms could make available effective treatments while pharmaceutical corporations should be encouraged to provide drugs under the auspices of these patient-driven developmental trials.

While we applaud the discoveries of our colleagues in the field of genomics, and their analyte-driven platforms, we forget at our peril that medicine and most of its discoveries have been observational.

A Day at CHORI (Children’s Hospital of Oakland Research Institute)

As a hematology fellow at the Scripps Clinic in the 1980s, my friend and colleague Sheldon Hendler, MD, PHD, recommended that I read an article in Science magazine. The manuscript entitled “Cancer and Diet,” by Bruce Ames, PhD, described the mutagens and carcinogens to which we are exposed on a daily basis that are found in a normal diet. His paper then examined the defenses that we have developed as a species.

Dr. Ames has distinguished himself as a pioneer in the study of aging, degenerative disease and cancer and I have read many of his papers since then. You can imagine my delight when I received a phone call some months ago and found that my interlocutor was none other than Bruce Ames, inviting me to speak at his research institute.

On Tuesday, January 31, I traveled to Oakland to present a symposium. Dr. Ames arranged for me to meet many of his colleagues. The topics ranged from neuraminic acid residues expressed as neoantigens on dividing cancer cells, to antifungal agents as anti-cancer drugs. One discussion of particular interest surrounded sphingomyelin metabolism as an important mediator of tumor cell progression. A subject about which I knew little prior to this discussion but will certainly now examine with interest.

It is my hope that I might forge collaborations with some of these investigators. But, there is little that could have prepared me for the pleasure I experienced when sitting across the table from Dr. Ames, while sipping a freshly brewed espresso (deftly prepared by Dr. Ames himself), while we discussed Bruce’s six decades of extraordinary discoveries. Everywhere I looked was an award or a textbook that he had authored. Despite his many accomplishments he was humble, engaging and very witty.

My symposium that afternoon introduced the attendees to human tumor primary culture studies as predictors of response to cancer therapy. I then moved through the accumulated data supporting the clinical outcomes and finally examined our developmental work, finishing with our published collaboration with investigators at NYU and Cornell on the study of a novel class of Wnt inhibitors. Lively discussion ensued.

Among the attendees was Bengt Mannervik, who asked several good questions. I note his presence for he is one of the leading experts in the field of glutathione metabolism and a scientist who I had met several times before. As one of the fathers of glutathione s-transferase chemistry, Bengt’s work had influenced my earlier studies. It was an unexpected honor to have him in the audience, as a visiting professor on sabbatical from Uppsala.

As I have noted before, the reception from the scientists in these fora improves as they examine the data on its own merit, unaffected by the clinical dogma and politicking that contaminates so much discourse in medical oncology today. There was no agenda, just scientific interest and open discussion. It was a refreshing departure and a welcome opportunity to interact with open-minded investigators.

In the audience was Dr. Ames’ wife, Giovanna, a former professor of biochemistry at Berkeley, and a scientist whose work included the earliest discovery of the ABC transporters, now recognized as the basis for the human p-glycoprotein drug resistance mechanisms. At the end of the lecture, Giovanna Ames, impressed by the data, raised her hand and asked, “If what you need is a small portion of each patient’s tumor to conduct these studies, what do we have to do to be sure that every doctor sends you a piece of tumor?” While I’m not sure I that have the answer to her question, I am very sure that I like the way she thinks.