Immunotherapy also known as biological therapy is a method of treatment that uses different parts of person’s immune systems such as special cells, organs or substances that provide protection against various infections to fight against diseases such as skin cancer. In cancer immunotherapy the immune system of body counters with cancer cells.
These different rapidly dividing cells are sometimes able to hide from immune system of the body leading to life threatening disorder. The immunotherapy for skin cancer is developed to alert the immune system towards these abnormal cells in order to locate and destroy them more efficiently. The fact that immune system can be used to treat skin cancer cells provide evidence that the cancer cells possesses surface molecules that can be detected by body’s immune system such as tumour associated antigens that are most probably protein in nature and some are carbohydrates.
Characteristics of Immunotherapy
- It is effective in slowing down the growth of cancer cells.
- Inhibits the spreading of cancer to other organs of body.
- Effective to boost the immune response to destroy cancer cells in better way.
- Helps to deliver drug such as toxins, chemotherapy specifically to cancerous cells thus protecting normal cells from destruction.
Types of Immunotherapy
Immunotherapy is effective treatment method and has been approved as first line method in several types of cancers. It is beneficial treatment in patients that exhibit resistance against radiation & chemotherapy treatment. This treatment technique falls into different categories:
- Checkpoint inhibitors: Helps to disrupt the signals that make cancerous cells to evade from immune response
- Monoclonal antibodies: Helps to trigger immune response
- Cytokines therapy: Helps to regulate and direct the immune response.
- Cancer vaccines: Helps to treat and control cancer by targeting immune response.
- Cellular therapy: Helps to evoke anti tumour response.
1.Monoclonal antibodies for skin cancer treatment
Antibodies are synthesized by B cells to fight against various types of infections. In case of skin cancer the antibodies fight disease by targeting the cells of cancer & altering their growth. Monoclonal antibodies are synthesized artificially in laboratory to target cancer cells. And when subjected intravenously help to alter skin cancer cells in different way such as;
- These antibodies attach to cancer cell, tag them so to be recognized by immune cells.
- Block the part of cancer cells that enable infinite growth rate.
- Antibodies along with radiotherapy that is radioimmunotherapy destroy cancer cells specially leaving normal cells unaffected. (Targeted therapy).
- Monoclonal antibodies also deliver drugs directly to cancer cells (chemotherapy).
- Different types of monoclonal antibodies for cancer treatment have been approved by FAD and are commercially available: Mabthera ,nivolumab (Opdivo)& Yervoy
2. Checkpoint Therapy for skin cancer treatment:
A checkpoint is a regulation mechanism of human immune system to stop T cells for attacking normal cells in the body, by slowing down the immune response. Many cancerous cells have ability to send signals that confuse the T cells and they activate the pathway and stop them from killing. As a result cancer cells hide from immune system and thus continue to grow.
These inhibitors block checkpoint proteins so immune cells are able to attack and destroy cancer cells. Checkpoint inhibitors therapy effectively treats non small lung cell cancer, kidney cells, Hodgkin’s lymphoma but melanoma skin cancer is most targeted cancer in this regard.
In order to fight cancer the two checkpoint pathways can be blocked;
- PD-L1 inhibitors: These inhibitors target checkpoint known as PD-L present on T cell. It helps to target various cancers such as kidney, bladder & melanoma skin cancer. The main role of PD-L1 is to stop T cells for targeting other body cells. PD-L1 inhibitors such as keytruda, tecentariq target PD-L1 to block it and thus boosting the immune response.
- CTLA4 inhibitors: It helps to block CTLA4 checkpoint present on T cells. Such as yervoy helps to enhance immune response to target skin cancer cells.
3. Adoptive T cell transfer for skin cancer treatment:
This method of treatment is based on enhancing the innate ability of T cells to target cancer. The researchers are able to isolate T cells from patients and then detect the cells more active to fight against cancer or then genetically modify the genes in the lab to work proactively. They are then able to synthesize these cells in laboratory. The modified cells are returned to the patient body. This treatment helps to lessen the impact of melanoma and skin cancer.
4. Cytokine therapy for cancer treatment:
Normal cells are able to synthesize cytokines that play important function in immune response working against various tumours. Cytokines modulate immune response and this modulating ability is useful to design drug in order to generate stronger immune response for the treatment of cancer. Man made cytokines is useful to treat individuals with melanoma. Interferon and interleukins when use along can shrink advance melanomas in about 10-20% patients. However, these cytokines are applicable when used along with chemotherapy for IV stage melanoma.
- Interferon’s: Immune cells generate interferon which interfere with growth of virus. This are suitable for treating cancer such as interferon gamma, for treatment of chronic myeloid leukaemia, melanoma and hairy cell leukaemia. Interferon are effective for their anti tumour effects in animal models. The chances for thicker melanoma are relatively high to come back after surgery to other part of body than thinner melanoma. Interferons acts as adjuvant after surgery in order to prevent re-entry. Although this does not improve the survival chances, but it helps to delay the recurrence of melanoma.
- Interleukin: Interleukin generate immune response effects. In general, it promotes the T effector and T regulatory cell functions and thus applicable for the treatment of various cancers such as malignant melanoma and renal cell carcinoma.
5. Vaccines for melanomas skin Cancer Treatment:
In order to treat skin cancer, vaccines are medications that trigger the immune system. There are two types of vaccines:
- Prophylactic vaccines: These are preventive vaccines helps to prevent cancer development.
- Therapeutic vaccines: Also known as treatment vaccines help the immune system to fight against existing cancerous cells.
BCG vaccines are suitable to treat tuberculosis. Although it does not cause serious issues in human but quite helpful to activate immune response. BCG vaccine is sometimes applied to treat 3rd stage melanomas through intravenous injection.
6. Imiquimod Cream
Imiquimod also known as zyclara is a class of drug that is apply on skin as a cream. This drug is effective in activating the immune system against skin cancer cells. Early stage of skin cancers is curable by this cream,, by applying on sensitive area of face. This cream is also effective for melanomas which spread all over the skin. Zyclara is not suitable for advanced melanomas. The cream is applied for three months 3 to 5 times a week sometimes may lead to serious skin allergy.
Route of administration:
Different types and routs of immunotherapy for skin cancer treatment are:
- Orally: Immunotherapy in the form of capsules and tablets that can be swallow.
- Intravenously: Immunotherapy subjected directly into veins.
- Topically: Immunotherapy in the form of creams that can be rubs onto skin. suitable for early skin cancer.
- Intravesically: Immunotherapy subjected directly to bladder.
Negative impact of immunotherapy
Immunotherapy can cause many side effects although the impact is not that strong which in case of chemotherapy & radiations. The side effects of immunotherapy depend on heath status of patients, type of cancer, and stage of cancer. The most pronounce side effects are skin reactions. Such as:
- Swelling, pain, soreness, rashes, itchiness, redness
- Flu like symptoms
- Fever, fatigue, weakness, chills, dizziness, headache, blood pressure fluctuations, Joint aches
- Other drawback includes;
- Diarrhea, birth defects, sinus congestion and increase risk of other infections.
Skin cancer immunotheapies aid in treatment by means of cells of immune system. However, each have its own merits and demerits and research is still going on to find best possible treatment option for cancer treatment.