Cancer is a complex disease that is caused primarily by a number of natural and man-made factors. Worldwide, cancer is the second most common cause of deaths, after cardiovascular diseases. Since ancient times, cancer treatment has involved a combination of a number of different therapeutic modalities.
Cancer Treatment Methods
Surgery is the foremost form of cancer therapy; even today, it is considered as an effective approach for many cancer types. Surgery involves the removal of tumor tissue and some nearby tissues. The first cancer surgery was conducted in 1846, wherein an entire tumor along with lymph nodes was removed.
The major limitation to surgical treatment of cancer is that it cannot prevent spreading of tumor cells through the blood stream. It is an efficient method to eliminate those types of cancers that have not metastasized or spread to different parts of the body. It is also used to reduce tumor size; however, it rarely results in complete remission since tracing all the tumor sites in a patient’s body is difficult.
Radiation therapy, also known as radiotherapy, involves the use of cell damaging radiations to treat cancerous or benign tumors. Discovered in 1895, the aim of this therapy is destruction of cancer cells without harming the nearby cells. Radiation therapy can be used as the first cancer treatment or as an adjuvant therapy to destroy the cells that remain after a surgery or chemotherapy. In addition, doctors may use radiation therapy to reduce the size of tumors, relieve symptoms (such as pain and pressure) and improve patient’s quality of life; such type of treatment is palliative radiation therapy.
Radiation therapy offers an effective treatment approach, but there are some known side effects associated with its use. The high amount of radiation required for the procedure is the primary cause of the adverse effects. This type of therapy has been shown to cause skin problems, fatigue and other site-specific damages.
Chemotherapy involves the use of drugs to destroy cancer cells. These drugs usually act by stopping or slowing down the rate of cancer cell growth. However, the therapy may pose a threat to healthy cells as well, thereby, causing side effects. In 1956, the first metastatic cancer (rare tumor called choriocarcinoma) was cured using methotrexate. Chemotherapy is also used after surgical procedure to destroy any remaining cancer cells; such type of therapy is referred to as adjuvant therapy.
Chemotherapy eliminates the frequently dividing cancer cells, however, due to lack of specificity, rapidly proliferating normal cells within the body also get affected by the chemotherapeutic drug. Some of the commonly affected healthy cell types, include cells present in hair follicles, digestive system, mouth and blood. Other drawbacks of this therapy include fatigue, pain, nerve damage, loss of concentration and thinking capability, and sexual and reproductive problems.
In the past few years, great strides have been made in the field of personalized medicine; targeted therapies, such as ADCs, are on the forefront of next generation technologies that are anticipated to revolutionize the cancer treatment landscape. These therapies are theoretically capable of overcoming the setbacks associated with cytotoxic chemotherapeutics that are known to kill or damage healthy cells as well. The targeted therapies are designed to identify specific antigens that are expressed only on the surface of cancer (target) cells so that the effects of the cytotoxin/drug are focused on the elimination of cancerous cells. Due to the specificity component, the approach reduces the chances of damaging normal cells.
A popular approach utilized by targeted therapies is anti-angiogenesis or the inhibition of new blood vessel formation. Once this is achieved within the bulk tumor, transformed cells are not able to receive oxygen / nourishment from blood vessels and eventually die.