Cancer genomic sequencing can help with more accurate cancer diagnosis, better prognosis prediction and identification of personalized therapy options based on the cancer genomic characteristics. However, despite the growing popularity and hype about benefits and utility of cancer genomic sequencing, there is only a fraction of patients that currently benefit from this.
For an individual who has recently been diagnosed with cancer and dealing with the shock of this diagnosis, there is a lot of questions of how, what, why and the next steps. They are overwhelmed with a lot of buzzwords and jargon, one of them being cancer genomic sequencing and personalized therapy.
What is tumor genomic sequencing and does everyone diagnosed with cancer need it?
Tumor genomic sequencing is the technique of getting a kind of molecular scan of the DNA extracted from the tumor cells obtained from a biopsy specimen or from the blood or bone marrow of the patient. This information provides the details on what regions of tumor DNA differ from non-tumor cell DNA and interpretation of the genomic sequencing data gives insight into the key genes and drivers of the cancer. There have been remarkable advancements in the sequencing technologies that have enabled getting genomic information of the tumor cheaper and more accessible for clinical use. Multiple research projects funded by different governments across the globe are collating data on the tumor genomic sequences of large numbers of cancer patients, along with their clinical history, treatment details and clinical outcomes, that have been made available for analysis in the public domain in projects such as: The Cancer Genome Atlas (TCGA), Genomic England, cBIOPortal and many others. Ongoing analysis of these large cancer population datasets has given key insights that is changing the landscape of cancer treatment protocols globally:
- Cancers of particular tissue origins such as all breast cancers or all lung cancers, that were earlier thought to be histologically similar and treated alike, are today recognized to be hugely variant and categorized into unique molecular subclasses that need to be treated differently.
- Even within a molecular subclass of a specific cancer indication, every individuals’ tumor genomic profile is different and unique.
- The genomic analysis of cancer DNA provides information on the main gene abnormalities (mutations) that are responsible for driving the disease and many of these have specific drugs designed to block their actions.
- Abnormalities of cancer DNA are helping better understand the underlying mechanisms the cancer cell is using for its continued and rapid growth and spread, and this is helping with the discovery of new and more targeted drugs.
Therefore, when it comes to a disease like cancer, that is associated with morbid and fatal consequences, every piece of information that helps with understanding the individual’s cancer characteristics is useful. Listed below are the top three reasons why cancer patients should consider sequencing their cancer DNA and consulting specialists with their results:
Helps with correct diagnosis
In many cases, the site and cause of the primary cancer is unclear and genomic sequencing of the tumor DNA can help with better identifying the primary tumor site and the key cancer genes. For such cases of rare cancers or cancers that were diagnosed late and have spread through different organs, understanding cancer characteristics can help with determining more suitable treatment options.
Helps with better prognosis
From the sequencing data one derives the genomic profile of the tumor DNA. Based on analysis of cancer population sequence data, patterns of different abnormalities have been correlated with disease severity and treatment response. Eg. Absence of the MGMT gene predicts better response with TMZ (Temodal) for patients with brain cancer glioblastoma multiforme. (Hegi ME et al, New Engl J Med, 2005) Presence of a TET2 gene mutation increases probability of response to a specific class of drugs called hypomethylating agents in leukemia patients. (Bejar R, Blood, 2014) This information therefore gives insight into the severity and characteristics of the disease and help with selecting a milder or more aggressive treatment.
Helps with finding a personalized treatment option
For many cancer patients that do not respond to the standard of care chemotherapy treatments, sequencing the tumor helps in better identifying the key abnormalities that can then be treated with more targeted drugs that have been developed more recently and can only be used in specific cases that have the required characteristic. In many of the stubborn, relapsed and resistant cancers, genomic profiling of the tumor DNA will facilitate access and enrollment in clinical trials testing new and innovative targeted drugs or finding unique alternative and personalized drug options (therapy) based on the cancer characteristics.
The bottom line is that genome sequencing is becoming more mainstream for patients diagnosed with cancer today. Like the detailed blue-prints that the architect creates before initiating a construction project, genomic data is the blue-print of a patient’s cancer and can help the clinician with personalizing the treatment based on the specific cancer characteristics and hence expected to be beneficial for cancer treatment. A reality check about the status and wonders of tumor sequencing and cancer profiling have been well explained in a recent article by David H. Freedmen in ‘The Newsweek’ on 7/16/19. He cautions that despite the successes of targeting each patient’s unique tumor via precision medicine, there is only a fraction of the patients that currently benefit from this. (https://www.newsweek.com/2019/07/26/targeting-each-patients-unique-tumor-precision-medicine-crushing-once-untreatable-cancers-1449287.html)
Cancer patients often have to deal with different chemotherapy side effects which affect their quality of life and look out for alternative therapies for cancer. Taking the right nutrition and supplements based on scientific considerations (avoiding guesswork and random selection) is the best natural remedy for cancer and treatment related side-effects.