Cancer: Treatments and Prevention

 

Treatments for cancer

Cancer treatment depends on the type of cancer, the stage of the cancer (how much it has spread), age, health status, and additional personal characteristics. There is no single treatment for cancer, and patients often receive a combination of therapies and palliative care. Treatments usually fall into one of the following categories: surgery, radiation, chemotherapy, immunotherapy, hormone therapy, or gene therapy.

1) Surgery

Surgery is the oldest known treatment for cancer. If a cancer has not metastasized, it is possible to completely cure a patient by surgically removing the cancer from the body. This is often seen in the removal of the prostate or a breast or testicle. After the disease has spread, however, it is nearly impossible to remove all of the cancer cells. Surgery may also be instrumental in helping to control symptoms such as bowel obstruction or spinal cord compression.

Innovations continue to be developed to aid the surgical process, such as the iKnife that "sniffs" out cancer. Currently, when a tumor is removed surgeons also take out a “margin” of healthy tissue to make sure no malignant cells are left behind. This usually means keeping the patients under general anesthetic for an extra 30 minutes while tissue samples are tested in the lab for “clear margins”. If there are no clear margins, the surgeon has to go back in and remove more tissue (if possible). Scientists from Imperial College London say the iKnife may remove the need for sending samples to the lab.

In a study carried out at Washington University School of Medicine in 2014, researchers found a way of visualizing cancer cells using high-tech glasses designed to make it easier for surgeons to distinguish between cancerous and healthy tissue. Viewed through the glasses, cancer cells appear to glow blue under a special light, thanks to a fluorescent marker injected in the tumor that attaches only to cancerous and not to healthy cells. Also, the lighter the shade of blue, the more concentrated the cancer cells are.

Promising results of an early small trial at Duke University Medical Center in Durham, NC have suggested a new injectable agent that makes cancer cells in a tumor fluoresce, could help surgeons remove all of the cancerous tissue on the first attempt. Tests continue to be carried out.

2) Radiation

Radiation treatment, also known as radiotherapy, destroys cancer by focusing high-energy rays on the cancer cells. This causes damage to the molecules that make up the cancer cells and leads them to commit suicide. 

Radiotherapy utilizes high-energy gamma-rays that are emitted from metals such as radium or high-energy x-rays that are created in a special machine. Early radiation treatments caused severe side-effects because the energy beams would damage normal, healthy tissue, but technologies have improved so that beams can be more accurately targeted. Radiotherapy is used as a standalone treatment to shrink a tumor or destroy cancer cells (including those associated with leukemia and lymphoma), and it is also used in combination with other cancer treatments.

3) Chemotherapy

Chemotherapy utilizes chemicals that interfere with the cell division process - damaging proteins or DNA - so that cancer cells will commit suicide. These treatments target any rapidly dividing cells (not necessarily just cancer cells), but normal cells usually can recover from any chemical-induced damage while cancer cells cannot. Chemotherapy is generally used to treat cancer that has spread or metastasized because the medicines travel throughout the entire body. It is a necessary treatment for some forms of leukemia and lymphoma. Chemotherapy treatment occurs in cycles so the body has time to heal between doses. However, there are still common side effects such as hair loss, nausea, fatigue, and vomiting. Combination therapies often include multiple types of chemotherapy or chemotherapy combined with other treatment options.

4) Immunotherapy

Immunotherapy aims to get the body's immune system to fight the tumor. Local immunotherapy injects a treatment into an affected area, for example, to cause inflammation that causes a tumor to shrink. Systemic immunotherapy treats the whole body by administering an agent such as the protein interferon alpha that can shrink tumors. Immunotherapy can also be considered non-specific if it improves cancer-fighting abilities by stimulating the entire immune system, and it can be considered targeted if the treatment specifically tells the immune system to destroy cancer cells. These therapies are relatively young, but researchers have had success with treatments that introduce antibodies to the body that inhibit the growth of breast cancer cells. Bone marrow transplantation (hematopoetic stem cell transplantation) can also be considered immunotherapy because the donor's immune cells will often attack the tumor or cancer cells that are present in the host.

5) Hormone therapy

Several cancers have been linked to some types of hormones, most notably breast and prostate cancer. Hormone therapy is designed to alter hormone production in the body so that cancer cells stop growing or are killed completely. Breast cancer hormone therapies often focus on reducing estrogen levels (a common drug for this is tamoxifen) and prostate cancer hormone therapies often focus on reducing testosterone levels. In addition, some leukemia and lymphoma cases can be treated with the hormone cortisone.

6) Gene therapy

The goal of gene therapy is to replace damaged genes with ones that work to address a root cause of cancer: damage to DNA. For example, researchers are trying to replace the damaged gene that signals cells to stop dividing (the p53 gene) with a copy of a working gene. Other gene-based therapies focus on further damaging cancer cell DNA to the point where the cell commits suicide. Gene therapy is a very young field and has not yet resulted in any successful treatments.

Using cancer-specific immune system cells to treat cancer

Scientists from the RIKEN Research Centre for Allergy and Immunology in Yokohama, Japan, explained in the journal Cell Stem Cell (January 2013 issue) how they managed to make cancer-specific immune system cells from iPSCs (induced pluripotent stem cells) to destroy cancer cells.

The authors added that their study has shown that it is possible to clone versions of the patients’ own cells to enhance their immune system so that cancer cells could be destroyed naturally.

Hiroshi Kawamoto and team created cancer-specific killer T-lymphocytes from iPSCs. They started off with mature T-lymphocytes which were specific for a type of skin cancer and reprogrammed them into iPSCs with the help of “Yamanaka factors”. The iPSCs eventually turned into fully active, cancer-specific T-lymphocytes - in other words, cells that target and destroy cancer cells.

Cancer prevention

Quitting smoking can significantly decrease your risk of getting cancer. 

Cancers that are closely linked to certain behaviors are the easiest to prevent. For example, choosing not to smoke tobacco or drink alcohol significantly lower the risk of several types of cancer - most notably lung, throat, mouth, and liver cancer. Even if you are a current tobacco user, quitting can still greatly reduce your chances of getting cancer.

Skin cancer can be prevented by staying in the shade, protecting yourself with a hat and shirt when in the sun, and using sunscreen. Diet is also an important part of cancer prevention since what we eat has been linked to the disease. Physicians recommend diets that are low in fat and rich in fresh fruits and vegetables and whole grains. 

Certain vaccinations have been associated with the prevention of some cancers. For example, many women receive a vaccination for the human papillomavirus because of the virus's relationship with cervical cancer. Hepatitis B vaccines prevent the hepatitis B virus, which can cause liver cancer.

Some cancer prevention is based on systematic screening in order to detect small irregularities or tumors as early as possible even if there are no clear symptoms present. Breast self-examination, mammograms, testicular self-examination, and Pap smears are common screening methods for various cancers.

Researchers from Northwestern University Feinberg School of Medicine in Chicago reported in the journal Circulation that the 7 steps recommended for protection against heart disease can also reduce the risk of developing cancer,. They include being physically active, eating a healthy diet, controlling cholesterol, managing blood pressure, reducing blood sugar and not smoking.

Targeting cancers for new drug therapies

Researchers at The Institute of Cancer Research reported in the journal Nature Reviews Drug Discovery (January 2013 issue) that they have found a new way of rapidly prioritizing the best druggable targets online. They managed to identify 46 previously overlooked targets.

The researchers used the canSAR database together with a tool and were able to compare up to 500 drug targets in a matter of minutes. With this method, it is possible to analyze huge volumes of data to discover new drug targets, which can lead to the development of effective cancer medications.

The scientists analyzed 479 cancer genes to determine which ones were potential targets for medications. Their approach was effective - they found 46 new potentially “druggable” cancer proteins.

Not only will this approach lead to much more targeted cancer drugs, but also considerably cheaper ones, the authors added.

Source Link: https://www.medicalnewstoday.com/info/cancer-oncology/treatments-for-cancer.php