Cancer is a malignant tumor that occurs when cells in the body mutate and divide indiscriminately, destroying surrounding cells and is the number one cause of death. Thanks to advances in radiation therapy and chemotherapy, cancer survival rates have increased, but side effects remain a major challenge. New treatments, such as targeted therapies, are being developed, but they are not effective against all cancers and there are resistance issues. Scientists are still working to conquer cancer.
Cancer remains the overwhelmingly leading cause of death. Many people have experienced the death of someone close to them from cancer. What is it about cancer that frightens us so much?
In order to maintain life, our bodies break down old cells and divide new ones. However, for some reason, mutations occur that cause cells to divide more than necessary, forming a convex shape like a lump, which is called a tumor. Malignant tumors that continue to grow and destroy normal cells around them are called cancer. Cancer is not just about the growth of a tumor; it has a complex effect on multiple systems in the body, posing a threat unlike any other disease. What makes cancer particularly dangerous is that it often starts out with no symptoms, and then rapidly progresses to a point where it can be fatal. This makes cancer a scary and uncertain disease, and makes it easy to miss the right time for treatment.
While the incidence of cancer is increasing every year due to modern lifestyles, environmental pollution, and changing dietary habits, the good news is that cancer survival rates are also steadily increasing. This is due to rapidly advancing diagnostic technologies and treatments, as well as increased awareness of the importance of cancer prevention and early diagnosis. In particular, radiation therapy and chemotherapy with anticancer drugs are contributing significantly to improved survival rates. But how do these treatments work, and how are they evolving?
Radiation therapy is a cancer treatment that has been widely used since the discovery of X-rays by German physicist Wilhelm Conrad Röntgen in 1895 and the invention of high-energy radiation therapy machines in the 1950s. Radiation therapy is a treatment that uses high-energy radiation to directly kill cancer cells. Radiation is a stream of fast-moving particles and short-wavelength electromagnetic waves that penetrate the body and cause ionization. Radiation therapy works on the principle of killing cancer cells by causing chemical changes to the DNA and cell membranes that are essential for life.
While radiation therapy has the advantage of painlessly eliminating cancer cells, it has the side effect of damaging normal cells in addition to cancer cells. To solve this problem, specialized radiotherapy treatments have recently been developed that use CT and MRI to reconstruct the location, size, and shape of tumor cells in 3D to focus radiation on cancer cells only. In addition to radical radiotherapy, which aims to cure cancer, palliative radiotherapy, which eases the condition of cancer patients, is also being used to minimize side effects. Thanks to these technological advances, radiation therapy is becoming increasingly effective, and the ability to focus radiation on specific areas to minimize damage to surrounding tissues is becoming a key part of cancer treatment.
The establishment of the cell theory at the end of the 19th century led to rapid advances in the life sciences and spurred scientists to develop anticancer drugs. The development of anti-cancer drugs in earnest began with sulfur mustard, a poisonous gas used by the German army during World War I. Since then, various types of anticancer drugs that target cancer cells have been developed through various studies and experiments. Anticancer drugs are categorized in different ways depending on how they work to stop cancer cells from growing, dividing, and differentiating. For example, there are alkylating agents, which bind directly to DNA and cause damage, and antimetabolites, which inhibit cancer cell proliferation by competing with normal metabolites in the DNA replication process.
However, anticancer drugs can affect not only cancer cells but also normal cells. In particular, because anticancer drugs are designed to take advantage of the rapidly dividing nature of cancer cells, they are also likely to damage rapidly dividing tissues, such as hair follicles and mucosal cells in the digestive system. For this reason, patients undergoing chemotherapy can experience side effects such as hair loss, canker sores, and impaired organ function. However, new treatments are being developed to reduce these side effects, and efforts continue to be made to minimize the side effects of cancer treatment.
To address these issues, targeted therapies are being developed that selectively attack only cancer cells. Targeted therapies are anticancer drugs that work by targeting molecular structures or cell signaling pathways that are only present in certain cancer cells, and are designed in a way that maximizes protection of normal cells. They block the survival of cancer cells in several ways, including signaling pathway inhibitors and angiogenesis inhibitors. Examples include Avastin, which stops cancer cells from growing by inhibiting new blood vessels, and Glivec, which is known for treating chronic myeloid leukemia.
However, targeted therapies are not effective against all types of cancer, and because they only respond to specific targets, their effectiveness is limited by the type of cancer and the patient’s condition. In addition, targeted therapies are difficult to develop and expensive, which makes them a financial burden. Resistance to the drugs can develop, especially with long-term administration, which can lead to decreasing treatment effectiveness. To solve this problem, researchers are using biological indicators to develop personalized treatments that are optimized for each patient, which is expected to become a new direction in cancer treatment.
Cancer is a disease with a long history, having been detected in the prostate glands of mummies as far back as 2200 years ago. But with the advances of modern science and technology, cancer treatments have come a long way in just a few decades. Scientists will never stop working to conquer cancer, and it will no longer be something to be feared, but something that can be managed and treated on a daily basis.
