Reviewed By: Pramod Kerkar, MD, FFARCSI

Precision medicine has been gaining popularity in recent years. Precision medicine allows doctors to select treatments that have a higher chance of success with patients based on a genetic understanding of their disease. Due to the personalized manner of this treatment, precision medicine is also known as personalized medicine. While the idea of precision medicine is not new, it is only with the recent advances in science that doctors have been able to speed up research in this field. One such field that has benefitted greatly from precision medicine is cancer treatment. Precision medicine or therapy makes use of the patient's DNA to then guide drug selection that is deemed to be superior to standard chemotherapy. This type of precision cancer treatment makes use of genetic clues from the patient's own tumor. Studies have shown that patients who receive precision therapy experience a tumor shrinkage rate that is six times more than what is achieved with regular chemotherapy. How precision cancer treatment works and if it is successful across the various types of cancer is what we will explore today.

What is Precision Cancer Treatment?

With advances in science, the concept of personalized cancer treatment has today become a reality. Precision cancer medicine is a novel approach to cancer care that is looking to leverage new advances and knowledge with regards to the actual pathogenesis of cancer to more precisely target treatment. Most or nearly all of is a result of abnormal genes or faulty gene regulation. In precision cancer treatment, doctors make use of genetic clues from the patient's own cancer or tumor in order to create specifically targeted therapies. This novel concept of treatment has shown to achieve a 6 times higher tumor shrinkage rate as compared to regular chemotherapy. Using precision and appropriately targeted therapy doctors are also able to increase the length of time before the cancer returns in patients. The success rate of precision cancer treatment has been substantiated by results from over 350 clinical trials.

How Does Precision Cancer Treatment Work?

Precision cancer treatment attempts to treat cancer by targeting the specific DNA mutations in each patient that allow these tumors to grow and spread. Drugs that are developed for precision cancer treatment are more likely to help the immune system find and destroy cancer cells in a better and more targeted manner. These medications also block cancer cell division and stop the signals that give rise to new tumor-feeding blood vessels. The same precision medicines can also order the cancer cells to 'commit suicide', so to speak.

What Are Some Examples Of Precision Cancer Treatment?

Some of the leading examples of targeted cancer therapies include the breast cancer drug trastuzumab (Herceptin), the lung cancer drug erlotinib (Tarceva), and the melanoma drug dabrafenib (Tafinlar). All these precision medications work to inhibit the growth of cancer by interfering with the very signals that boost tumor growth.

These precision cancer treatments allow cancer patients to receive lifesaving treatment as the researchers and doctors have the time to analyze their cancer before actually beginning the treatment.

Is Precision Cancer Treatment Used Frequently?

However, in spite of the fact that researchers are progressing each day, precision cancer medicine is yet to become a part of routine care for most cancer patients. There are many new treatments that are designed to target a particular change in the DNA are in the testing phase right now in many precision medicine clinical trials. There are some clinical trials that are accepting patients having different types and stages of cancer. Other clinical trials do not segregate patients by types and stages of cancer and accept a variety of patients having cancer. The key factor in all these clinical trials is that your tumor must be having a genetic modification that can be targeted by these precision cancer treatments being tested.

What are the Types of Precision Cancer Treatments?

While there have been many breakthroughs in the field of cancer research, these three fields are at the fore when it comes to precision cancer therapies. These include: advanced genomic testing, targeted therapies and immunotherapy.

Advanced Genomic Testing

This is one of biggest breakthroughs in recent years to drive precision cancer treatment. Advanced genomic testing identifies the particular mutations in the DNA of cancer cells. It is possible that some types of cancers have no mutations, while others have several, while yet others have only one. Any number of mutations is a driving factor behind the growth of the tumor. By recognizing this mutation through advanced genomic testing, doctors are able to recommend a precision cancer treatment for targeting only the cells within that mutilation. The drawback of advanced genomic testing is that it is not recommended for all patients.

Targeted Cancer Therapies

Targeted therapies make use of substances or drugs to seek out the specific genes or proteins that are specific to cancer cells or are responsible for influencing their behavior. Upon reaching this target, these drugs are capable of killing the cancer cell or provide additional help to other treatments such as chemotherapy, to provide better results. More research needs to be conducted in this field and again, similar to advanced genomic testing, not all cancer types can be treated with targeted therapies.

Immunotherapy

Immunotherapy functions in the same manner as our immune system. It is a generalized category of cancer therapies that make use of the body's own immune system to fight cancer cells. Attacking cancer cells is a tricky procedure as being the body’s own cells, many of them escapes their normal defenses. Cancer cells avoid attack by therapies by sending out deceptive signals to immune cells, appearing to be normal. This is where immunotherapy drugs come into play. Immunotherapy drugs, known as checkpoint inhibitors, disrupt these deceptive signals and expose cancer cells to be harmful to the body, thus allowing the immune system to attack and kill them. Being a new category of treatment, immunotherapies are also only available to certain patients who meet the criteria. However, there are many new clinical trials that are researching more on the potential uses of immunotherapy.

What are the Advantages of Precision Cancer Treatment?

The advantage of precision cancer treatment is that with the use of advanced genetic testing, gene mapping analyses have opened up many avenues for patients who have rare or unusual and hard to treat cancers. There are now many options available for those as well whose tumors did not respond positively to conventional cancer treatments. Precision medicine does not follow the regular method of just treating cancer patients based on their cancer type, stage, and medical history. Precision cancer medicine goes deeper to the basic genetic level to find a better treatment protocol. This approach has made it possible for defining cancer by its molecular structure, rather than by where it is located as has been the norm over all these years.

Who is Eligible for Precision Cancer Treatment?

Not everyone is eligible for precision cancer treatment. The fact is that in spite of all the advances, precision cancer medicine does not apply to everyone. You will have to undergo a biopsy first to determine which genetic changes are present in your cancer. During the biopsy, your doctor will remove a small piece of cancer and it will be sent to a laboratory. A machine called a DNA sequencer will then look for and identify any genetic changes that may be causing cancer/tumor to grow. This process of looking for genetic changes in the cancer is known as DNA sequencing, genomic testing, or even tumor profiling. Then if there is a targeted drug or treatment available and approved for your type of cancer, your doctor will need to determine if the genetic change in your cancer can be targeted by the available treatment. For example, people having melanoma, breast, lung, or colon cancer, rectal cancer, and some forms of leukemia, undergo a testing for their cancers to determine the genetic changes once they are initially diagnosed. It is possible that over a period of time, additional genetic changes can drive your cancer to either get worse or even come back. The entire process of genetic testing will need to be repeated in this case. On the other hand, if there is no approved precision treatment for your type of cancer, your doctor may still go ahead with genetic testing to see if you are eligible to join a precision medicine clinical trial.

Conclusion

It is important to stress, however, that precision cancer treatment is still an evolving field and while rapid developments are being made, much still needs to be learned about this treatment. Patients and their family members have to remember that not all genetic mutations have a known treatment option as of today and advanced genomic testing is also not suitable for all patients. Genetic tumor testing is advancing as researchers keep finding new information on how cancer cells grow and spread. Researchers are trying to discover and solve the issue of drug resistance- a problem that can potentially limit how well these precision treatments work. This technology has made it possible for doctors to actually consider using a more precise treatment option in the ongoing search to treat cancer.

Also Read:

Pramod Kerkar

Written, Edited or Reviewed By:

, MD,FFARCSI

Pain Assist Inc.

Last Modified On: September 22, 2018

This article does not provide medical advice. See disclaimer

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