Radiation: Friend from Foe
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Radiation: it’s what turned Bruce Banner into a rampaging green beast and created the giant mutant lizard, Godzilla. In popular culture, we usually associate radioactivity with something sinister and lethal. However, in the medical scene, it has become a revolutionary force in cancer treatment.
With one in three people diagnosed with cancer in their lifetime, the disease has built up an infamous reputation for being deadly and incurable. People often associate abnormal cell growth with cancer, but in reality, nearly all people have some abnormality in cell division. Cells constantly die and reproduce in our bodies, and at times, there can be errors in cell division that lead to more cell production than there should be. In these cases, our DNA damage repair system chimes in and helps fend off these unwanted cells before they spread through our body and become cancerous.
Despite our body’s defense mechanisms against abnormal cell division, untreated abnormal cells can reproduce and spread through tissues via our circulatory system, leading to the formation of malignant tumors and cancer. As old as cancer is, civilizations throughout history have approached this disease using different methods. Texts from ancient Egypt show that doctors used cauterization, which required using a hot instrument to kill infected tissues. Other ancient methods included bloodletting and treating the patient with a variety of herbs.
Fortunately, at the turn of the 20th century, scientists became more knowledgeable about the true biology of cancer and significant progress was made in combating the disease. One notable treatment that emerged during this era is radiation therapy, which came with the accidental discovery of the X-ray by German physics professor Wilhelm Conrad Roentgen in 1896. Two years later, Marie Curie and her husband, Pierre Curie, further expanded on the field of radiology by identifying radium and polonium as the elements behind the science of radiation. Curie successfully isolated pure, metallic radium in 1910 and worked on radiology during World War I to examine the potential of radium as a cancer therapy. The conceivable power of radiation and its effect on the human body inspired the concept of utilizing ionizing radiation to kill off the malignant cells in cancer. Despite these discoveries, scientists still lacked information concerning the properties and mechanisms of radiation therapy. This led to early treatments having more side effects than beneficial results. In fact, early radiologists tested on themselves to find the right amount of radiation to kill cancer cells while leaving healthy cells untouched, but they often developed leukemia from prolonged exposure to radiation.
Alongside radiation therapy, chemotherapy emerged as a popular form of cancer therapy in the 20th century. Unlike radiation therapy, which is usually a local treatment that aims energy beams solely where the malignant tumor is, chemotherapy involves the circulation of powerful drugs in the bloodstream and is considered a more systemic treatment. Though they handle cancer in different ways, both treatments share similar goals in curing, controlling, and relieving tumors. They both aim to shrink or eradicate tumors while lessening the pain of cancer. Patients can receive either chemotherapy, radiation therapy, or both depending on consultation with their doctor. In these cases, chemotherapy usually precedes radiation therapy to weaken a tumor before using ionizing radiation on the site.
Over the years, radiation therapy improved so that it was not only effective in eradicating cancer cells but also in limiting side effects. During radiation therapy, normal cells can also be affected in the process, which can cause permanent hyperpigmentation, skin irritation, and other abnormalities. Technological advances in the late twentieth century promoted better and more efficient forms of radiation therapy by visualizing the precise location of the cancer tumor in order to successfully and safely eradicate the cancer cells before spreading. For instance, conformal radiation therapy (CRT) uses CT images and special computers to precisely map the location of cancer in three dimensions. Additionally, conformal proton beam radiation therapy focuses radiation on cancer by using proton beams rather than x-rays, and can bring more radiation to the cells while reducing damage to nearby cells. Chemical modifiers or radiosensitizers have also been implemented, as they make the cancer cells more sensitive to radiation and increase its effectiveness.
Since the initial discovery of radiation, we have harnessed the treatment to our advantage and turned potentially harmful energy into a life-saving therapeutic. Radiation therapy is used to treat over 60 percent of cancer patients today, and that number is projected to increase as improvements are continuously being made in this field. Technological advancements, along with animal and in vivo studies with controlled trials, have led to many breakthroughs in the mechanisms of radiation therapy. By continuing this pattern of experimental studies, the future of radiation therapy garners progress.