New Age of Cancer Treatments… Putting an End to Cancer
Cancer is a collection of diseases related to the uncontrolled growth of abnormal cells. Starting anywhere in the body, the cells begin to divide without stopping and spread into other tissues. Normal cells grow and divide as the body needs them and when they grow old or become damaged, they die, and new cells take their place. Cancer cells differ from normal cells in many ways. Cancer cells are less specialized than normal cells, and hence cancer cells continue to divide without stopping.
Moreover, cancer cells ignore signals that normally call among cells to stop dividing or begin a process known as programmed cell death, or apoptosis, that gets rid of body’s unneeded cells. Cancer influence the normal cells, molecules, and blood vessels that surround and feed a tumor. Cancer cells are also able to evade the immune system and some cancer cells can hide from it as well.
Cancer is a genetic disease caused by changes in genes that control the way our cells grow and divide. Genetic changes could be inherited from our parents or also arise because of damage to DNA caused by cancer-causing environmental exposures including chemicals in tobacco smoke, and radiation, such as ultraviolet rays coming from the sun. Each cancer has a unique combination of genetic changes accumulating as they grow.
Types of Cancer
There are different types of cancer depending on the organs or tissues where the cancers form. The 5 main types are:
Carcinoma: The most common type of cancer, formed by epithelial cells, which are the cells that cover the surfaces of the body.
Sarcoma: Cancers formed in tissues like muscle, tendons, blood vessels, lymph vessels, and tissue around joints.
Leukemia: Cancers that begin in the blood-forming tissue of the bone marrow are called leukemias.
Lymphoma: Lymphoma is cancer that begins in lymphocytes (T cells or B cells).
Brain and Spinal Cord Tumours: Brain tumors can be benign or malignant.
Cancer Staging and classical Cancer treatment
Staging is a way of describing how far cancer has grown. Staging determines what cancer treatment regimen would be beneficial for a certain individual. If a cancer is restricted to a single site, then a local treatment such as surgery or radiotherapy could be enough to rid the body of the cancerous cells. If a cancer has spread (metastasized), then systemic treatments like chemotherapy, hormone therapy, and biological therapies would be required.
Emerging Cancer Treatments and Shortcomings
Targeted therapy works on components like genes, proteins, and blood vessels that help cancer cells grow and spread as opposed to traditional cancer drugs like chemotherapy, which act on all fast-growing cells. As therapy is matched to a patient’s tumor, it may work better than other cancer treatment options and with fewer side effects.
Examples of targeted cancer treatment include:
- Herceptin for treatment of breast cancers that have the HER-2 gene mutation.
- Gilotrif and Erbitux block EGFR preventing the growth of colorectal and lung cancers.
- Tafinlar and Zelboraf for melanomas that have a mutated BRAF gene.
Targeted cancer therapy has promise, but the kinds of cancers that can be treated right are limited as more targets need to be discovered to widen the scope of treatment.
Every cancer is different. Personalized or precision medicines are tailored cancer treatment to a person’s tumor. Unique mutations in a tumor can help decide which treatment is likely to work best.
Discovery of more genes and mutations resulting in cancer would help improve the scope and efficiency of personalized cancer treatment.
These treatments help your body’s own immune system to recognize and eliminate cancer cells the same way it does bacteria and viruses.
Antibodies that seek out cancer cells attach themselves to antigens on those cells and sends out a signal that tells other immune cells to launch an attack. They are designed to target specific antigens found on cancer cells. They can be administered alone or linked to toxic substances like chemotherapy drugs that kill cancer cells.
- Preventive vaccines, which aim to prevent cancer.
- Therapeutic) vaccines, which strengthen the immune system to fight cancer.
The U.S. has approved two preventive vaccines against human papillomavirus (HPV) and hepatitis B virus and a treatment vaccine for metastatic prostate cancer.
Interferons and interleukins control the growth and activity of immune cells. They help to boost the immune system’s response to cancer.
The scope of monoclonal antibodies has to be improved as not all antigens are the same and cancer cells do have a tendency to mutate and become resistant. Also, the fact that immune therapy is administered in late-stage patients with an already weakened immune system, restricts the scope of the treatment.
CAR T-cell therapy:
CAR T-cell therapy is a cancer treatment that manipulates T cells to attack cancers more effectively. T cells are first removed from ones’ blood and then genetically modified to target cancer cells.
In 2017, the FDA approved Tisagenlecleucel (Kymriah), the first CAR T-cell therapy, to treat children and some young adults with acute lymphoblastic leukemia (ALL).
Extending the promise of CAR T-cell immunotherapy to a substantial number of cancer patients is challenging as cells must be developed that have specificity against the key tumor antigens for a specific tumor type. Moreover, logistical obstacles limit widespread application of CAR T-cell immunotherapy as it takes weeks to prepare CAR T cells. The process requires multiple steps including apheresis of autologous T cells, genetic modification, and expansion before reintroducing them into the patient. This lengthy manufacturing process can be problematic as fulminant relapses occurring in many patients in the meanwhile do not allow safe delays for cell manipulation and expansion of CAR T cells.