Radiation therapy - the use of high-energy particles or waves in the treatment of cancer and other conditions - is an important treatment protocol for curing or shrinking cancer, preventing cancer recurrence and providing palliative relief in metastatic disease. It is also an effective treatment for some noncancerous growths, blood disorders, thyroid disease and other conditions.
Since the X-ray was first identified by William Roentgen in 1894 (a discovery that earned the scientist a Nobel Prize), radiation therapy has evolved into a powerful treatment therapy to be used alone or in conjunction with other cancer treatments. Approximately 60 percent of patients in the US undergoing cancer treatment will receive radiation therapy.
Although early scientists recognized the value of radiation, they needed to learn how to harness this powerful energy to provide the greatest benefit while sparing surrounding healthy tissue and organs from radiation dose.
Early on, doctors administered the highest radiation dose tolerated, as quickly as possible. But during the 1920s and ‘30s, Dr. Claude Regaud discovered a more effective delivery method. By breaking the original radiation dose into smaller doses spread over a longer period of time - an approach known as fractionation - Dr. Regaud was able to achieve the desired results with less skin damage. Fractionation remains an important principle in radiation therapy today.
One of the limitations of early X-ray machines was in delivering the cancer-fighting beams to deep lying tumors without causing skin damage. This led to the development of the Cobalt-60 radiotherapy machine, followed by linear accelerators - machines that produced high energy beams capable of penetrating deep inside the body to reach tumors without causing excessive skin and tissue damage.
Additionally, early in the history of radiotherapy, radiation was placed nearby or inserted into the tumor using a technique known as brachytherapy. This reduced injury and side effects for patients. Marie and Pierre Curie’s discovery of radium at the close of the nineteenth century became the necessary stepping-stone for brachytherapy. Initially, radium was inserted in an operating room setting requiring the skills of a surgeon. However, they lacked the training of radiobiology and radiotherapy. Finally in the 1960s, facilities and programs were created to formally train medical residents in “straight” radiotherapy. Now they developed the necessary skill set to deliver external beam radiotherapy and superficial and internal brachytherapy.
The continued quest to deliver high doses of radiation to the tumor and minimize dose to surrounding normal tissue has been the Holy Grail of our discipline. By the 1990s, 3-D conformal radiotherapy, a delivery system with improved accuracy that allows radiation to be targeted to a specific shape and intensity, was being used. Intensity-modulated radiation therapy (IMRT), one of the many treatment options available here at Ackerman Cancer Center, is an example of an advanced form of 3-D conformal radiotherapy.
Other more recent advances include image-guided radiation therapy (a treatment approach that utilizes linear accelerators and imaging machines to ensure radiation is delivered to the targeted area) and proton therapy, the most advanced radiation treatment therapy available today.
While not new - the proton was discovered in 1920 and was used to treat cancer as early as the 1950s - the first clinical proton therapy treatment center did not open until 1990.
A unique feature of proton therapy is that the proton beam can be precisely targeted to the tumor location, where it stops to deliver the bulk of its energy. While radiation systems utilizing photons can target tumors similar to proton therapy systems, the photon’s energy travels through the tumors, putting healthy tissue and organs at risk.
Although no single treatment is right for every patient, proton therapy is often a good choice for patients with critically located malignancies such as breast, lung and spinal cancers. Proton therapy reduces the risk of damage to normal tissue and organs, decreases the chance of secondary malignancies and eliminates some of the side effects seen in traditional radiation therapy. You can learn more about proton therapy treatment at Ackerman Cancer Center here.
The advances in radiation therapy over the past decades are astounding. With continued research and evolving technology, I am confident we will see many exciting advances in years to come.
Ryan Perkins, MD