Melanoma Skin Cancer Problems Biology Essay
Melanoma is a type of skin cancer. It is the least common type of skin cancer but the most dangerous one. According to the American Cancer Society, less than five per cent of skin cancer cases are melanoma cases but melanoma is responsible for the majority of skin cancer-related death.19 Melanocyte is a type of skin cells which produces pigment melanin to protect the skin from harmful ultraviolet rays. When the skin is exposed to too much ultraviolet rays, the DNA in melanocytes will be damaged and it may grow uncontrollably and become cancerous, resulting in melanoma.22 Melanoma is highly curable in its early stage. However, if left untreated, it may spread to other parts of the body such as lungs, lymph nodes and brain which can be fatal.3,10 So, what is the treatment available for melanoma?
Spot Melanoma: ABCD Guide to Identifying MelanomaFig.1 ABCD rule for diagnosis of melanoma.7
where melanoma can spread
Fig.2 Common places for melanoma to spread to.3
The primary treatment for melanoma at all stages is surgery to remove the tumour. Thin melanoma is easier to cure compared to thick melanoma. The table below shows the staging system of the tumour which is usually based on the thickness, ulceration and condition of the tumour as stated in the book "Facing Cancer".1
Tumour <1.5mm deep
Tumour 1.5mm-4mm deep
Tumour in one area of the lymph nodes
Other condition like spreading of tumour to other organs
Some of the skins are removed during the first biopsy to determine the stage of melanoma. There are a few types of operation that the doctor may perform in order to remove the tumour. These include simple excision, wide local excision, lymphadenectomy and sentinel lymph node biopsy.
Simple excision is a minor surgery in which the surgeon will cut away the cancer cells together with some normal skin cells around which is referred to as the margin. Usually simple excision is used for stage I melanoma. Local anaesthesia is injected into the affected area to numb it. Scar may be left as the wound is stitched back after the surgery.17
Wide Local Excision
Wide local excision, also known as re-excision is carried out after the diagnosis of melanoma through biopsy whereby the site is excised again. More skin around the cancer site will be removed in order to ensure that there is no more melanoma cell. The margin and excision guidelines can be referred to the diagram below.17
Fig.3 Excision guideline for melanoma WLE-wide local excision; SNB-sentinel node biopsy2
Another type of surgery is the lymphadenectomy, also known as the lymph node dissection. The lymph nodes in the region that are most likely to contain the spreading cancer cells are surgically removed using this type of surgery. The nodes removed are examined under the microscope to see whether they contain the melanoma cells. Lymph node dissection comes with a number of risks as lymph nodes are situated near important anatomical structures and might lead to side effects, for example, seroma and lymphoedema.18 Therefore, it must be performed by a skilled surgeon.
Sentinel Lymph Node Biopsy
Since lymph node dissection will lead to many complications, a technique called the sentinel lymph node biopsy has been developed to reduce the risk. Sentinel lymph node is the first lymph node or group of nodes that the cancer cells are most possibly spread to from the original tumour. In this biopsy, the sentinel lymph node is removed during the surgery.
Sentinel lymph node biopsy of the skin. Three-panel illustration showing a radioactive substance and/or blue dye is injected near the tumor (first panel), the injected material is detected visually and/or with a probe (middle panel), and the sentinel nodes (the first lymph nodes to take up the material) are removed and checked for cancer cells (last panel).
Fig. 4 Sentinel lymph node biopsy12
A radioactive substance or dye is injected near the tumour and the dye is allowed to flow through the lymph ducts to the sentinel nodes. The injected dye is detected using a probe. The first lymph node to receive the dye is removed for biopsy and the tissues are examined for cancer cells. If no cancer cells are found in the first lymph node, it is not necessary to remove more lymph nodes.1,12 Hence, lymph node dissection is seldom used in the surgery treatment for melanoma.
Surgery is the primary treatment for melanoma, especially during the first few stages. This means of treating melanoma is appropriate as the cancer tumour can be removed directly during surgery. The success rate is affected by a few factors which include the stages of melanoma and the age of the patient. If melanoma has not spread to other places, usually it is highly curable by surgery with success rate up to 97% according to the American Cancer Society.21 There is also clinical trial showing that having sentinel lymph node biopsy is better than a "watch and wait" approach in helping melanoma patients.15
"This important trial provides further evidence that sentinel node biopsy should be a standard component of the staging and treatment of patients with early-stage melanoma," said Scott Saxman, M.D., of the National Cancer Institute's Cancer Therapy Evaluation Program.15
melanoma survival 3.2
Fig. 5 Graph showing five-year survival rate for melanoma23 (http://info.cancerresearchuk.org/cancerstats/types/skin/survival/)
The graph has shown increase in the five-year relative survival rate in both sexes from 1971 to 2006. In my opinion, this is due to the improvement in the technology used in the surgical treatment for melanoma. Sentinel node biopsy has also contributed to this increase as it helps doctor to look for cancer in the sentinel node in the first place so that it will not be too late to only realise that the cancer has spread after noticing the lymph node swelling.
Social and Economic Implications
People with melanoma suffer social implication. Some might only have a minor impact while some major one due to the different severity of their disease. The news of being diagnosed with melanoma is a bombshell. It has the same potential as other types of cancer of being able to split and form a secondary tumour. Patient will suffer sadness, fear, depression and more. Having surgery might leave scar where the melanoma is removed. It might not affect one much if the scar is small or not easily seen. However, some people have to deal with greater physical changes where the scar is larger or found on a very visible part of the body. This will lead to low self-esteem and the way they usually socialise with people, even their close one.8
People diagnosed with melanoma need financial support for surgery to cure their skin cancer. Not everyone can afford the cost of treatment, especially the poor. In addition, they might require hospitalisation and regular checkups to check for the recurrence which need another amount of money for the fee. All these will cause financial burden to patients and their families. Some might end up being unable to support their own living and even their families'. As shown in the figure below, according to United States National Cancer Institute, the national expenditures for melanoma in 2006 along was $1.906 billion.4http://ctprgraphs.cancer.gov/_cgserv/?@_CPRVF_1zZw_1tbK
Fig.6 Estimates of national expenditures for cancer care4
Benefits and Risks
The benefit of surgery as the treatment for melanoma is that it is claimed to have the highest success rate among all other treatment. Surgery usually cures the early stages of melanoma. There is high chance for people diagnosed with melanoma of early stages to fully recover from the cancer. The scars left behind nowadays are smaller compared to before. Patients can always request for minute scarring which might cost more and need longer time of recovery.16
One of the disadvantages of using surgery to treat melanoma is that it is hard to cure the cancer if it has spread to other parts of the body such as lungs and brain. Having surgery at this stage usually does not cure the cancer but rather helping to control the cancer and relieving the symptoms and pain on the patients.17
Another risk of having surgery comes from the lymph node dissection. Unlike sentinel lymph node biopsy, lymph node dissection might leave a long term side effect that is lymphedema whereby the lymphatic system is damaged resulting in swelling in the limb. Patients will need to exercise, use elastic stockings or compression sleeves to reduce the swelling. Besides, having lymph node removed, it will be harder for the area around it to fight against infection. Unless necessary, the doctor will not perform this surgery due to its side effect and the pain from the surgery.17,20
Chemotherapy is a type of cancer treatment which uses drugs to kill the cancer cells or prevent them from dividing and spreading, Chemotherapy can be used as an alternative means to treat melanoma and is usually used as treatment for advanced melanoma that has spread to the other parts of the body. It can be also used to treat tumour recurrence. The anti-cancer drugs can either be taken orally or being injected into the veins, allowing the drugs to flow through the bloodstream and attack the cancer cells. The most commonly used chemotherapy drug is dacarbazine (DTIC). It can be used together with other types of chemotherapy drugs which include carmustine (BCNU), vinblastine and cisplastin. Chemotherapy may have some side effects which include hair loss, diarrhoea, nausea and fatigue.5,6 Different patients will have different side effects depending on the type of drugs given and how the patient individually reacts to the drugs given.
Another class of chemotherapy drugs is anti-angiogenic drug which acts in a different way as the anti-cancer drugs. This type of drug prevents new blood vessels to form around the cancer cells and nourish them. Hence, the cancer cells will be unable to grow. Examples for this class of drug are thalidomide, angiostatin and endostatin. According to the Skin Cancer Foundation of New York, these drugs are still being researched and hoping to improve and combine them with other drugs.11
Fig.7 Regional or isolated limb perfusion6 (http://www.cancerhelp.org.uk/type/melanoma/treatment/chemotherapy-for-melanoma)
Regional or isolated limb perfusion is a type of chemotherapy in which the blood supply is temporarily disconnected from the limb where the cancer is located. The blood flow is connected to a pump and oxygen is constantly added to the warmed blood. High dose of chemotherapy drugs are added to the circulation without having any side effect on the unaffected part of the body. If the drugs are warmed beforehand, it is called hyperthermic isolated limb perfusion.5,6 It is believed Diagram showing regional limb perfusion
that high dose of drugs can destroy cancer cells more effectively.
Radiation therapy is another alternative solution for melanoma. It uses high-energy ray to kill cancer cells, shrink tumour or relieve symptoms. This therapy is usually used for advanced melanoma that has spread to other organs.13 The HealthDay news on 2 November 2009 has reported that an Australian study shows that having radiation therapy after surgery lowers the risk of melanoma recurrence.9
There are two types of radiation therapy, namely internal radiation therapy and external radiation therapy. For internal radiation therapy, needles, seeds or catheters that are sealed with radioactive substances are placed near the cancer or directly into the tumour.12
On the other hand, external radiation therapy focuses radiation on the malignant tumour from outside the body to kill the cancer cells. The doctor will first use a machine called simulator to identify the location to be given the treatment. During the planning session, the doctor will make ink marks or pinprick tattoo. The radiation therapy machine will direct radiation at the markings and kill the cancer cells during the treatment.14Patient having treatment
Radiation therapy is usually done five days per week for several weeks. The treatment is not painful and only takes a few minutes. Radiation therapy does not make a person radioactive so it is safe to be with other people after the treatment.
The book "Facing Cancer" by Theodore A. Stern and Mikkael A. Sekeres provides a good guide for people diagnosed with cancer, their families and caregivers. It is written by leading physicians in psychiatry and oncology field with many works, articles and books published. Therefore, the information of this book should be reliable and valid. It also provides useful websites for references such as website of U.S. National Cancer Institute (www.cancer.gov) and the Skin Cancer Foundation (www.skincancer.org). However, the information of the book itself on melanoma is quite brief as it only provides a general idea on what melanoma is and the treatment for melanoma.
The other source that is the American Cancer Society (ACS) is the largest community-based voluntary health organisation in the United States. ACS hopes to eliminate cancer which is a major health problem in the world. I think the information retrieved from ACS website (www.cancer.org) is very trustable as the information and articles provided are constantly being reviewed by professional staffs and the information also agrees with other website. It provides information on various types of cancer, guidelines in preventing, diagnosing and treatment for cancer. It also provides support for those who are in need and invests in cancer research. So, this source should be valid.
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