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Dr West

Retrospective Data and Real World Evidence: The Poor Stepchild of Clinical Trials?

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EvidenceMany physicians worship evidence-based medicine, which is generally a very good practice that ensures that medical practice isn’t dictated by our biases and assumptions but rather on interventions that we have proven show benefits that exceed their anticipated risks.  The optimal way to confirm value of an intervention is by a prospective randomized clinical trial, which is when we enroll a population of patients with the same general disease condition, ideally with no or few other significant medical issues that might cloud the interpretation of what the study intervention is doing, and then randomize them to either pursue what we’d consider the best current practice or an experimental approach that might be better but might also be no better, or even worse.  Other clinical trials may be smaller and may not randomize patients, but they all share a specific list of enrollment criteria, both things that are required in the potential participants (inclusion criteria) and other things that are specifically forbidden (exclusion criteria) to ensure that the study group is reasonably homogeneous.

Cancer treatments are essentially invariably approved on the basis of prospective clinical trials, most often randomized phase 3 trials (large studies of standard vs. investigational strategy), and this gives us confidence that these new approaches are effective.  Aside from the problem that this denies patients who are older and potentially sicker from the opportunity to participate in trials and receive new treatments that may be beneficial, this approach also leaves us wondering whether the treatments proven to help clinical trial candidates are as safe and beneficial for the teeming masses of other people who have complicating issues that would have disqualified them from the trials with such patients.  For example, the trial comparing the immunotherapy Keytruda (pembrolizumab) to standard combination chemotherapy as first line treatment for patients with high level expression of the protein PD-L1 on their tumor cells (a biomarker associated with a higher chance of benefit from immunotherapy) excluded patients who are unable to work or are in bed >50% of the time (performance status of 2 or higher — see here for more discussion), which is a significant minority of patients with advanced non-small cell lung cancer).  We might presume that more frail patients with high PD-L1 expression also do very well with Keytruda, but we can’t know that from the evidence we have.   Because sicker patients don’t have as strong an immune system as more fit patients, immunotherapy may not be as effective as we’d hope. In fact, my  limited experience of treating frail patients with Keytruda or other, similar immunotherapy agents has been quite disappointing, even when the patient has high PD-L1 expression that would lead us to be very hopeful of an excellent chance to respond well. 

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Dr West

FAQ: What is Adjuvant Therapy, and How Can It Help Patients with an Early Stage Cancer?

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When patients are found to have a cancer that is at an earlier stage that may be able to be cured with a “local therapy” such as surgery or radiation, we know that these cancers can recur months or years later, .This is presumably because of micrometastatic deposits traveling n the bloodstream, which cause distant recurrences, or in the region of the primary tumor, causing regional recurrences.

For many cancers, there is also a proven value in giving additional therapy to address the possibility of any invisible disease beyond what was seen on scans and by the surgeon.  This is often systemic therapy such as chemotherapy or targeted therapy, and it may also include radiation given along with or instead of systemic therapy.

When given before the potentially curative local therapy, this is called neoadjuvant (or sometimes pre-operative or induction) therapy. .When given following the local therapy, it is called adjuvant therapy, coming from the meaning of  the word adjuvant as “helper”. While there are certain advantages to a neoadjuvant approach, giving the additional treatment later has a couple of its own key advantages.

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Dr West

The Spectrum of Cancer Progression (50 Shades of Progression)

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Here’s a general summary of a thoughtful approach to how we might assess progression of disease, recognizing that it isn’t just a simple matter of a “yes/no” question of progression or not.  

And for those who want the pdf to print, here it is: 50 Shades of Cancer Progression

Feel free to leave questions. comments, objections, etc. here.I hope it’s helpful.

 

 


GRACE Video

Dr. Larry Einhorn: What is Your Opinion of Patients and Caregivers Searching the Internet for Information?

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Dr. Larry Einhorn, Distinguished Professor of Medicine at Indiana Univ and former ASCO president, discusses the trend of patients consulting Dr.Google – finding information of varied quality on the internet.


GRACE Video

Dr. Larry Einhorn: Are You Optimistic That a Supercomputer Such as Watson Will Be Able To Improve Cancer Care?

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Dr. Larry Einhorn, Distinguished Professor of Medicine at Indiana Univ and former ASCO president, gives his view on whether a supercomputer such as Watson will be able to use complex algorithms to improve cancer care.


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