Proton Therapy: How It Could Change The Outcome of Paediatric Cancer – HuffPost

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Aug 05 2017

Today, cancer is no longer on the list of incurable diseases, thanks to medical developments in the last few decades. Yet, it is hard to ignore the fact that cancer does alter the lives of patients. We know of many adults that have undergone not just physical but an emotional overhaul during their cancer journey - some of them returning to life with an altered perspective and unending empathy for people around them after having been through the trials and trauma of chemotherapy and radiation.

For children, it might be a totally different story. For many of them, the effects of cancer treatment do not begin until later in life resulting in other health concerns. In fact, studying these late effects is the research focus of many medical researchers in the field of pediatric cancer. Many of these effects are the result of how chemotherapy works - in order to kills the cancerous cells, it destroys a good number of healthy cells as collateral damage.

I recently spoke with Dr. Ramesh Rengan, medical director of Seattle Cancer Care Alliance (SCCA) Proton Therapy Center in Seattle, Washington, and a long-term researcher in the field of novel radiation approaches with immune therapies in the treatment of cancer. Dr. Rengan is an active voice for proton therapy emerging as an increasingly effective and less harmful way to treat specific types of cancers, particularly pediatric cancers and those that occur close to vital organs.

Here are a few excerpts from our interview:

The SCCA Proton center works on an alternative treatment method for cancer. Can you tell us more about it?

At the SCCA Proton Therapy Center, we use highly targeted proton beam radiation to treat cancer. By precisely focusing on the tumor, proton therapy minimizes radiation exposure to surrounding healthy tissue, thereby reducing the risk of short- and long-term radiation-related side effects. Our center is currently the only proton therapy center in the Pacific Northwest.

How does proton therapy work?

The fundamental concept underlying all cancer treatment is to deliver a lethally effective treatment to the cancer and only the cancer, be it chemotherapy, surgery or radiation. The challenge for the oncologist is to design a way to deliver this treatment with specificity to the tumor while minimizing the damage to the surrounding organs. What really dictates the long-term clinical outcome for the patient is not just the number of cancer cells that we kill but the balance between that and the number of healthy cells that are injured in the course of treatment.

Standard radiation uses X-ray beams that enter and pass through the patient to the tumor and exit the other side. However, because X-rays penetrate so well, all tissue that lies in front of and beyond the tumor is exposed to radiation, which can be potentially harmful to the patient.

Protons, due to their mass, stop within the patient and do not continue to pass through the body. We can therefore calibrate the proton beam to stop within the tumor itself. Additionally, due to their positive charge, protons deposit most of their radiation at the point where they stop, rather than near the point of entry into the patient as X-rays do. As a result of these properties, protons concentrate the radiation dose delivery to the tumor itself. This more targeted form of radiation is especially useful for pediatric cancers, where any excess radiation exposure to healthy, developing organs can be potentially harmful.

What are the benefits of proton therapy over other types of cancer treatments?

Protons allow radiation to be delivered to the tumor while significantly minimizing collateral radiation exposure to surrounding healthy tissue. That benefit pays dividends in the near term because it reduces exposure, and it drives additional future benefits as patients continue with their lives after treatment, such as fewer secondary cancers. The precision that protons allow is particularly beneficial for patients whose tumors are near critical organs or structures, such as the brain, bladder, rectum, heart or spinal cord; patients whose cancers have recurred after initial radiation treatment; and patients whose organs are particularly sensitive to radiation exposure, such as children and adults with certain genetic syndromes.

For what kind of cancers is the proton therapy most effective ?

Although protons can be used to treat most cancers that require radiation, this treatment has been best established for tumors that lie in close proximity to radiosensitive vital organs, such as central nervous system tumors and eye tumors. For pediatric patients, protons have become an indispensable tool, as children are particularly vulnerable to the negative effects of radiation. Therefore, proton treatment for many pediatric tumors is a well-established standard of care, despite the limited access to proton therapy centers worldwide. Today, we also treat tumors in the head and neck, lung, breast, esophagus and gastrointestinal system, as these tumors are often situated next to radiosensitive vital organs. As such, the role of protons is being actively investigated in ongoing clinical trials in these disease locations.

Are protons a stand-alone treatment, or is it best used in conjunction with other therapies?

Proton therapy can often be used in combination with chemotherapy and surgery, similar to standard radiation treatment.

How is proton therapy improving?

Access to clinics, lowered cost, optimized technology to treat a broader range of tumors and use of a combination of approaches to treatment are the biggest recent leaps we have made with proton treatment.

Its important to understand that protons initially were postulated in the treatment of cancer in a paper published in 1946. Protons are not new as a modality, having been around since the 1950s. It has taken a long time for the technology to become relatively cost-efficient and be feasibly delivered in a hospital-based or stand-alone outpatient clinical setting such as the Seattle Cancer Care Alliance Proton Therapy Center.

Growth has been deliberate and incremental: the first hospital-based proton center opened in the 90s. Today there are 20 proton centers in North America, but the real promise of proton treatment is being realized now. During the next 10 years, we expect to see that number triple or quadruple, as the cost of building a center has been rapidly decreasing while proton beam technology has been simultaneously improving.

Are protons the best choice for everyone?

Protons are just as effective as X-rays in killing cancer cells but generally require less exposure to surrounding healthy tissues in order to deliver this treatment to the cancer, so they are a potential option whenever radiation is called for in the curative treatment of cancer. However, protons are only a single tool in the ever-increasing arsenal against cancer. As such, protons are the best treatment for some patients, but not for others. The decision regarding whether protons are the right choice for a given patient is made by a proton-experienced radiation oncologist in conjunction with members of the multidisciplinary cancer care team and the patient.

What do you believe are the next big revolutions in cancer treatments?

The big revolution in cancer treatment will come from our increasing ability to deliver effective therapies to the tumor with absolute specificity. For example, that is the founding principle behind cancer immunotherapy, namely, to turn our immune system against the cancer. Similarly, the greater our ability to focus our radiation beam or our scalpels at purely the cancer and minimize the impact to the surrounding organs, the greater the benefit to our patients.

In the past few years we have made fundamental paradigm shifts in the way we treat cancer. Today we attack cancer by exploiting the unique genetic characteristics of the tumor to design drugs that attack the cancer by homing in on their gene signature. Even with these modern advancements, it must be mentioned that cancer is not just treated with one method alone; a combination of weapons is used to effectively cure most cancers. One might say that it takes a village to effectively treat a cancer patient.

Much of the early history of cancer treatment had focused on maximizing the lethality of our weapons against the cancer, either by increasing the radiation or chemotherapy dose or by performing larger and more radical surgery to remove the tumor. We now recognize that the impact of these treatments on healthy tissue can have an even greater negative effect on the clinical outcome than the positive benefit of killing the tumor. In short, we dont need a bigger gun or bomb, but rather a smarter bomb that equally emphasizes supporting the health of the patient and the destruction of the cancer. Protons are ideally suited to this evolution in cancer care.

Devishobhais the founder ofKidskintha,a happy place to jumpstart conversations around family and millennial parenting, living in India. You can find her voiceon the Huffington Post,LifeHack, Parent.co,Addicted2Success, Inc.com, Entrepreneur, Tiny Buddha,SivanaEast and others on a range of topics. You can get yourself equipped for happy parenting with one hack a week for an entire year (each one backed by science).

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Proton Therapy: How It Could Change The Outcome of Paediatric Cancer - HuffPost

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