20.15: Cancer Therapies

Cancer therapies are various modes of treatment, such as surgery, radiation therapy, and chemotherapy that are administered to cancer patients.

However, cancer treatments can pose several challenges, as therapies used to kill cancer cells are generally also toxic to normal cells. Moreover, cancer cells mutate rapidly and can develop resistance to chemical agents or radiation therapy. Besides, all types of cancer cells may not respond to the same therapy. Some cancer cells respond to one therapy, while some respond to another, reflecting different kinds of mutations present in different cancer cells. The type of treatment to be administered to a patient depends on the type of cancer and its stage of advancement. Therefore, while some patients can be treated with only one type of treatment, most cases need a combination of various therapies that can be either implemented together or over a period of time.

The combination of different treatment methods has many benefits over the use of a single treatment method:

1. One treatment method may be more effective at a certain stage of cancer, while another may be more beneficial at another stage. Therefore, using different therapies at different times during cancer treatment increases the likelihood of curing more than a single therapy.
2. Using different therapies at the same time can increase the overall effectiveness due to a synergistic effect and is, therefore, a competent strategy for treatment.
3. The use of a single therapy on tumor cells may need higher doses that can affect the healthy tissues and vital organs of the body. Administration of two therapy methods at once reduces the dosage and hence, causes lesser damage to the body.

For example, osteosarcoma or cancer of the bones was conventionally treated with limb amputation to prevent the spread of cancer cells to the rest of the body. However, the use of radiation therapy along with chemotherapy has been an effective treatment regime that can get rid of all cancer cells at once without the need for amputation.

Additionally, recent advances in cancer research have also led to the development of personalized medicine where treatment can be tailored according to the genetic changes in the patient during the course of cancer progression.

Cancer is one of the leading causes of death in humans and is therefore considered an important health problem throughout the world.

Some of the most commonly used cancer therapies include surgery, radiotherapy, chemotherapy, immunotherapy, and hormone therapy.

Surgery is the surgical removal of a solid tumor that is contained in one area. For example, in the case of basal cell carcinoma, surgery is often used to remove the cancerous lesion and some of the surrounding healthy tissues.

However, in cases where removal of the whole tumor may cause damage to the organ or the body, surgery can be used to remove only a certain portion of the tumor. The remaining tumor cells can be treated with the help of other therapies.

Radiation therapy uses high doses of radiation to damage DNA inside the tumor cells. While tumor cells can usually tolerate minor DNA damage, they are hypersensitive to a higher amount of damage.

This means that while irradiated cancer cells can continue to divide for some time due to impaired cell cycle checkpoint responses, once they accumulate enormous DNA damage, it eventually leads to their death.

The surrounding normal cells can also be affected by the radiation, but since these normal cells have efficient DNA repair mechanisms, they are able to survive the radiation therapy.

Chemotherapy uses anti-cancer drugs to target fast-growing cells in the body. Besides killing the rapidly dividing cancer cells, such drugs also affect other fast-growing cells in the body, such as hair follicles and blood cells. This may cause short or long-term side effects in the patient undergoing chemotherapy.

In contrast to chemotherapy, immunotherapy uses cancer vaccines, immunomodulators, and monoclonal antibodies to aid the immune system in recognizing and targeting the cancer cells in the body.

Some cancers, such as prostate cancer, are fueled by hormones produced in the body. Hormone therapy is used in such cases to block the production or action of hormones and help slow down the growth of cancer cells.

The type of therapy to be administered to a patient depends on the type of cancer and its stage of advancement. Therefore, while some patients can be treated with only one type of treatment, most cases need a combination of various therapies.

• Cancer Therapies - Various treatment methods administered to cancer patients.
• Chemotherapy - The use of chemical agents to treat cancer by killing cancer cells.
• Radiation Therapy - Cancer treatment method using radiation to kill cancer cells.
• Synergistic Effect - The enhanced effectiveness of combined therapies in cancer treatment.
• Personalized Medicine - Treatment tailored according to genetic changes during cancer progression.

• Define Cancer Therapies - Understand various treatment methods (e.g., chemotherapy, radiation therapy).
• Contrast Chemotherapy vs Radiation Therapy - Grasp their different mechanisms and usages (e.g., some cancers respond to only one).
• Explore Combination Therapy - Get insights on synergistic effects and lesser damage to healthy tissues (e.g., osteosarcoma treatment).
• Explain Personalized Medicine - Understand how it uses genetic changes to tailor treatment.
• Apply in Context - Recognize scenarios where different treatment methods are most effective.

• What is Chemotherapy and how does it fight cancer?
• How does Radiation Therapy differ from Chemotherapy in treating cancer?
• What are the merits of combining cancer therapies?

• Students - Grasps complex cancer therapy concepts and their practical applications.
• Educators - Provides a comprehensive outlook on teaching the topic of cancer therapies.
• Researchers - Broadens understanding of cancer treatment methods.
• Science Enthusiasts - Offers deep insight into the evolving landscape of cancer treatments.