Is It Ethical to Deny Cancer Patients Functional Analyses?

The ethical standards that govern human experimentation have become an important topic of discussion. Clinical trials are conducted to resolve medical questions while protecting the rights and well-being of the participants. Human subject committees known as Institutional Review Boards (IRB’s) not only confront questions of protocol design and patient protection but also the appropriateness of the questions to be answered. The Belmont Report (1979) defined three fundamental principles i) respect for persons, ii) beneficence and iii) justice. These have been incorporated into regulatory guidelines codified in the code of federal regulations like 45 CFR 46.111. One historical experience offers an interesting perspective upon contemporary oncologic practice.

With advances in cardiac surgery in the1970s and 1980s, in both valvular and coronary artery bypass, an alarming amount of post-operative bleeding was being observed. To address this complication an enzyme inhibitor named Aprotinin was developed by Bayer pharmaceuticals. The drug works by preventing the body from breaking down blood clots (thrombolysis). This is critical for the prevention of postoperative bleeding. Concerns regarding its safety led to Aprotinin’s temporary withdrawal from the market, but those have been resolved and the drug is again available.

After Aprotinin’s introduction, clinical trials were conducted to test its efficacy. Initial results were highly favorable as the drug consistently reduced post-op bleeding. By December 1991, 455 patients had been evaluated providing strong statistical evidence that Aprotinin reduced bleeding by more than 70 percent. Despite this, trialists continued to accrue patients to Aprotinin versus “no treatment” studies. By December 1992, more than 2,000 patients had been accrued and by October of 1994, the number had increased to more than 3,800 patients. Yet the 75 percent risk reduction remained entirely unchanged. Thus, 3,400 patients at untold cost and hardship were subjected to the risk of bleeding to address a question that had long since been resolved.

In a 2005  analysis, Dean Fergusson et al, decried that it should have been evident to anyone who cared to review the literature that Aprotinin’s efficacy had been established. Further accrual to clinical trials beyond 1991 only exposed patients to unwarranted risk of bleeding, and had no possible chance of further establishing the clinical utility of the intervention. This stands as a striking lack of consideration for patient well-being. Fergusson’s review raises further questions about the ethics of conducting studies to prove already proven points. With this as a backdrop, it is instructive to examine functional profiling for the prediction of response to chemotherapy.

Beginning in 1997, a cumulative meta-analysis of 34 clinical trials (1,280 patients), which correlated drug response with clinical outcome was reported. Drug sensitive patients had a significantly higher objective response rate of 81 percent over the response rate of 13 percent for those found drug resistant (P < 0.0000001). This was met by the ASCO/Blue Cross-Blue Shield Technology Assessment published in Journal of Clinical Oncology (Schrag, D et al J Clin Oncol, 2004) that cried for further clinical trials. A subsequent meta-analysis correlated the outcome of 1929 patients with leukemia and lymphoma against laboratory results and again showed significantly superior outcomes for assay directed therapy (P <0.001) (Bosanquet AG, Proc. Amer Soc Hematology, 2007). In response, a second ASCO Guideline paper was published in 2011. (Burstein H et al J Clin Oncol, 2011) Although the authors were forced to concede the importance of the field, they concluded that “participation in clinical trials evaluating these technologies remains a priority.” Most recently we conducted a cumulative meta-analysis of 2581 treated patients that established that patients who receive laboratory “sensitive” drugs are 2.04 fold more likely to respond (p < 0.001) and 1.4 fold more likely to survive one year or more (p <0.02) (Apfel C. Proc Am Soc Clin Oncol 2013).

Slide Detail-smallEach successive meta-analysis has concluded, beyond a shadow of a doubt, that human tumor functional analyses (e.g. EVA-PCD) identify effective drugs and eliminate ineffective drugs better than any other tool at the disposal of cancer physicians today. Not unlike those investigators who continued to accrue patients to trials testing Aprotinin, long after the result were in, oncologists today continue to clamor for trials to prove something which, to the dispassionate observer, is already patently obvious. If we now pose the question “Is it ethical to deny patients functional analyses to select chemotherapy?” the answer is a resounding No!

Triple Negative Breast Cancer: Worse or Just Different?

The term “triple negative breast cancer” (TNBC) is applied to a subtype of breast cancers that do not express the estrogen or progesterone receptors. Nor do they overexpress the HER2 gene. This disease constitutes 15 – 20 percent of all breast cancers and has a predisposition for younger women, particularly those of black and Hispanic origin. This disease may becoming more common; although, this could reflect the greater awareness and recognition of this disease as a distinct biological entity.

On molecular profiling, TNBC has distinct features on heat maps. The usual hormone response elements are deficient, while a number of proliferation markers are upregulated.  Not surprisingly, this disease does not respond to the usual forms of therapy like Tamoxifen and the other selective estrogen response modifiers known as SERMs. Nonetheless, TNBC can be quite sensitive to cytotoxic chemotherapy. Indeed, the responsiveness to chemotherapy can provide these patients with complete remissions. Unfortunately, the disease can recur. Complete remission maintained over the first three to five years is associated with a favorable prognosis, with recurrence rates diminishing over time and late recurrences more often seen in estrogen receptor-positive cancers.

Triple negative breast cancer is not one, but many diseases.

MTOR-pathway-ger Among the subtypes are those that respond to metabolic inhibitors such as the PI3K and mTOR directed drugs. Another subset may respond to drugs that target epidermal growth factor. There are basal-types that may be somewhat more refractory to therapy, while a subset may have biology related to the BRCA mutants, characterized by DNA repair deficiencies and exquisite sensitivity to Cisplatin-based therapies. Finally, a last group is associated with androgen signaling and may respond to drugs that target the androgen receptor.

Some years ago, we used the EVA-PCD platform to study refractory patients with breast cancer and identified exquisite sensitivity to the combination of Cisplatin plus Gemcitabine in this patient group. We published our observations in the Journal of Clinical Oncology and the combination of Cisplatin or Carboplatin plus Gemcitabine has become an established part of the armamentarium in these patients.

The I-SPY-2 trial has now used genomic analyses confirming our observations for the role of platins in TNBC. This iSignal_transduction_pathways.svgn part reflects the DNA repair deficiency subtype associated with the BRCA-like biology. More recently, we have examined TNBC patients for their sensitivity to novel therapeutic interventions. Among them, the PI3K and mTOR inhibitors, as well as the glucose metabolism pathway inhibitors like Metformin. Additional classes of drugs that are revealing activity are the cyclin-dependent kinase inhibitors, some of which are moving forward through clinical trials.

One feature of triple negative breast cancer is avid uptake on PET scan. This reflects, in part, the proliferation rate of these tumors, but may also reflect metabolic changes associated with altered glucose metabolism. In this regard, the use of drugs that change mitochondrial function may be particularly active. Metformin, a member of the biguanide family influences mitochondrial metabolism at the level of AMP kinase. The activity of Metformin and related classes of drugs in triple negative breast cancer is a fertile area of investigation that we and others are pursuing.

When we examine the good response of many triple negative breast cancers to appropriately selected therapies, the potential for durable complete remissions and the distinctly different biology that TNBC represents, the question arises whether TNBC is actually a worse diagnosis, or simply a different entity that requires different thinking. We have been very impressed by the good outcome of some of our triple negative breast cancer patients and believe this a very fertile area for additional investigation

Mammography – The Evolving Story of a Diagnostic Tool

The use of low-dose radiation to detect occult breast malignancies can be traced to work done at the MD Anderson Cancer Center in the 1950s. Early published studies conducted by the “Egan technique,” correctly identified the majority of palpable cancers subsequently proven malignant at the time of surgery. As a diagnostic tool, mammography is an effective means of confirming the presence, and defining the extent, of breast pathology in woman at high risk for cancer, or who note a pamammogramslpable lump. No one is arguing the diagnostic use of this technique. Where the controversy has arisen over the last years is the use of mammography as a screening technique.

To clarify the use of terminology, screening techniques are applied to the general population to identify unrecognized disease. The popularity of mammography as a screening technique led to the recommendation that every woman over 40 should have an annual mammogram. The problem with screening techniques is that they apply a diagnostic tool to a population at low risk. This burdens the technology with numerous false positives, engendering  costs, risks, and toxicity for those who undergo unnecessary biopsies and surgery. The entire discussion came into sharper focus in the past week with the publication of a large Canadian study that examined the impact of mammographic screening over a 25-year follow up in women ages 40-59.

In this study, launched in 1980, more than 89,000 women were divided into two groups. One group underwent routine physical examination and the second group had routine physical examination combined with mammogram. There were 3,250 diagnoses of cancer in the 44,925 women who underwent mammography and 3,133 cancers diagnosed in the 44,910 women who underwent physical examination alone. Five hundred patients in the mammography group and 505 women in the control group died of their disease. While women who had mammograms were more likely to be diagnosed with breast cancer, this did not have an impact on their risk of dying from the disease. Furthermore, 22 percent of women with positive mammograms did not have cancer at definitive workup. The conclusion of paper and the accompanying editorial by Mette Kalager from Oslo, Norway, was that ”the rationale for screening by mammography needed to be urgently reassessed.”

What are the shortcomings of the study? Mammographers have claimed that the equipment used was suboptimal, leading to less sensitive detection that might have occurred with modern, high-quality digital equipment. There was also no group over 60. It is also theoretically possible that some patients obtained mammography after concluding the study, or had mammograms done during the study, contaminating the final results. Nonetheless, this is a high quality randomized study in a large population that fails to provide an impact upon survival for a widely used technique.

Prior meta-analyses conducted between the 1960s and 1980s revealed a reduction in deaths in breast cancer between 15 percent and 25 percent in the population of women age 50 to 69. Explanations for the disparity between the current study and those older studies may include the relative lack of sophistication of the population during the 1960s through 1980s, who might fail to evaluate a breast lump, thus, earlier detection would have a significant impact on those not responding to even physical evidence of disease.

A second confounding variable is the broad use of Tamoxifen, which has so profoundly influenced the natural history of breast cancer, that the earlier detection of breast cancer may be less important than the potent efficacy of anti-hormonal agents. This is an interesting wrinkle in the story, as it is contrary to most contemporary thinking that holds that early detection, not treatment is the principal influence upon better outcomes today.

So where does this study leave us?  There are several points that must be considered. The first is that mammography is a test not a treatment. Tests perform according to their performance characteristics, described as “sensitivity and specificity.” Within this framework mammograms are sensitive and specific enough to provide immense value ….in the right patient population, e.g. those at some risk for the disease in question. How you define that “risk” is the rub.

Mammograms identify the disease; they do not influence its biology. While some may demand that more sensitive equipment for the detection of disease be implemented, a different principle may underlie the findings. This would be that cancer, at virtually any stage of diagnosis, is a systemic disease with its own trajectory. Under this scenario, mammograms in an unselected population provide little more than a lead-time bias. This term is applied when a test identifies an event earlier than it might have been found, but has no impact on the ultimate outcome. Lead-time bias is a common phenomenon in screening techniques and has been the rallying cry for those who argue against PSA screening for men. Once again, the number of patients diagnosed versus the number of patients requiring intervention is the overarching dilemma.

While we seek to decipher the genetic basis of cancer using increasingly sophisticated genomic techniques, we recognize that cancer is common and that a substantial percentage of patients may not die of their disease. Cancer results from stresses that force cells to either die or seek novel mechanisms to survive. Deprived of estrogen, testosterone, nutrients, oxygen or growth factors, cells within the aging human body discover novel ways to stay alive, albeit to the detriment of the organism as a whole. However humbling, it can be argued, that it is pathways that aberrant cells pursue that guides the trajectory of the disease, largely independent of our roles as diagnosticians and treating physicians.