[Overview].
Malignant melanoma is prevalent in white people. QueenS-Land in Australia is known as a region with high incidence of malignant melanoma in the world. The incidence of malignant melanoma in China is not high, but due to the lack of awareness of its seriousness among doctors and patients, it is usually too late when it is diagnosed, and the treatment results are extremely unsatisfactory. The disease is most likely to occur between the ages of 30 and 60. The rare juvenile malignant melanoma Spity reported 13 cases aged 1.5 to 12 years. The younger age group is generally less malignant and has a better prognosis after surgical resection. There is almost no difference in gender, but the location of the lesion is related to gender, with males predominating in the trunk and more females than males in the limbs.
Treatment measures
(A) Surgical treatment
1, biopsy surgery: for suspected malignant melanoma, the lesion together with the surrounding 0.5cm ~ lcm of normal skin and subcutaneous fat should be removed as a whole for pathological examination, if confirmed as malignant melanoma, according to the depth of its infiltration, and then decide whether to perform additional extensive excision. Generally, excision or biopsy is not performed unless the lesion has already formed an ulcer, or if the lesion is so large that a single excision would cause disfigurement or disability and must be confirmed by pathology. In a prospective analysis, the World Health Organization Malignant Melanoma Treatment and Evaluation Collaborative Center concluded that excisional biopsy not only has no adverse effect on prognosis, but also can be used to understand the depth and extent of infiltration of the lesion, which is conducive to the development of a more reasonable and appropriate surgical plan.
2. Scope of resection of primary lesion: The old view that the resection of lesion must include 5 cm of normal skin has been discarded. Most of the tumor outer scientists for thin lesions, thickness of ≤1mm, only 1cm of normal skin outside the edge of the tumor, for lesions thicker than 1mm should be 2cm ~ 3cm from the edge of the tumor for extensive excision. For malignant melanoma located at the extremity, finger (toe) amputation is often required.
3.Regional lymph node dissection
Indications: Regional lymph node dissection is performed in patients with positive sentinel lymph or stage III on the basis of enlarged resection of primary foci. Principles: 1. regional lymph nodes should be fully cleared, 2. the base of the involved lymph nodes must be completely cleared. 3. the number of resected and examined lymph nodes is as follows: inguinal > 10, axillary > 15, cervical > 15. 4. inguinal region, if the number of superficial femoral lymph node metastases is clinically found to be > 3, selective iliac fossa and closed lymph node dissection is performed. 5. if pelvic imaging suggests a positive lymph nodes or positive cloquet lymph nodes then regional lymph node clearance of the iliac fossa and foramen ovale is required.
Scope of regional lymph node dissection: For cervical lymph node dissection of malignant melanoma in the head and neck, the lymph nodes in the parotid area, subchin and submandibular triangle should be removed if the primary lesion is located in the face; if the lesion is located in the occipital area, the lymph nodes in the posterior cervical triangle should be removed. For malignant melanoma in the upper extremities, axillary lymph node dissection should be performed, and for those in the lower extremities, inguinal or iliac inguinal lymph node dissection should be performed. For malignant melanoma occurring in the chest and abdomen, ipsilateral axillary or inguinal lymph node dissection should be performed respectively.
4. Palliative resection: For those with large lesions and distant metastases that are not suitable for radical surgery, as long as the anatomical conditions permit, reduction of accumulation or palliative resection can be considered in order to relieve ulcer bleeding or pain.
(B) Radiation therapy Except for some very early freckled malignant melanoma, which is effective for radiation therapy, other primary foci are generally ineffective. Therefore, radiation therapy is generally not used for primary lesions, but for metastatic lesions. At present, the commonly used radiation doses are: for superficial lymph nodes, soft tissues and metastases in the chest, abdominal cavity and pelvis, each irradiation is ≥500cCy, twice a week, total 2000~4000cCy, for bone metastases each time 200~400cCy, total 3000cCy or more.
(C) Chemotherapy
1.Single drug
Nitrosoureas: They have certain efficacy on melanoma. The comprehensive literature reports that BCNU treated 122 cases of melanoma with an efficiency of 18%, MeCCNU treated 108 cases with an efficiency of 17%, and CCNU treated 133 cases with an efficiency of 13%.
GaiIanl reported the best efficacy of DTIC, treating 28 cases of melanoma with a dose of 350mg/m2 for 6 days and a course of 28 days, with an efficiency of 35%.
2, combination of drugs: malignant melanoma is not very sensitive to chemotherapy, but the combination of drugs can improve the efficiency and reduce toxic reactions, the commonly used combination of chemotherapy programs are as follows.
Program (DTIc, ACNu, VCR) is the preferred chemotherapy program for melanoma. Dosing: DTIcloo ~ 200mg, iv d1 ~ 5ACNUl00mg iv d1VCR 2mg iv d1, repeated every 21 days.
Regimen (DTIC, DDP, BCNU, TAM) Usage: DTIC 220mg/m2, IV d1~3/3w, DDP 25mg/m2, IV d1~3w, BCNUl 50mg/m2, IV d1/6w, TAM 10mgPO, 2/d. Effective rate 52.5%.
Protocol (CCNU, BLM, DDP) Usage: CCNU 80mg/m2, oral, d1/6w, BLMl5u/m2, sedation d3-7/6w, DDP 40mg/m2, sedation d8/6w. 48% effective rate.
(iv) Immunotherapy The self-resolution of malignant melanoma indicates that it is related to the immune function of the body. BCG can be used by skin scratching method, intratumoral injection and oral administration. For small local lesions, BCG can be injected intra-tumorally with an efficiency of 75% to 90%. In recent years, interferon, ILA-2 and lymphokine-activated killer cells (LAK cells) and other biological response modifiers have been tested and have achieved certain effects.
[Etiology].
The exact etiology of malignant melanoma is not clear, but recently it has been pointed out that secondary sunburn (with blister formation) plays a greater role in the causation of the disease than general sun exposure. White people are susceptible. ②Black people or dark-skinned people rarely suffer from this disease, and if it occurs, it is mainly in the skin of the feet and palms where the skin is white. Most scholars believe that about half of the malignant melanoma occurs on the basis of existing nevi. This is an autosomal genetic disorder in which the body is covered with large, flat, flat, irregularly shaped, thin, and differently colored nevi, one or more of which are malignant melanomas in most patients. Some people with this syndrome, but without a genetic predisposition, should also be closely monitored for the appearance of malignant melanoma. (6) Large congenital nevi with more than 2 cm have an increased risk of malignant transformation.
Pathological changes
(A) Pathological classification
1. Superficial extension type. It accounts for about 70% and can be found anywhere on the body surface. It first expands outward along the superficial layer of the body surface, and then expands longitudinally and deeply to the deeper layers of the skin, which is called the “vertical development stage” of the disease.
2.Nodular type. It accounts for about 15% and is also seen anywhere on the body surface. It mainly develops vertically and invades the subcutaneous tissue, which is easy to have lymphatic metastasis and is more fatal.
3.Extremity nevus type. It accounts for about 10%, mostly occurs in palms, soles, nail beds and mucous membranes, etc.
4.Freckled nevus. It accounts for about 5% of the total number of black freckles that have existed on the face for a long time since the elderly. This type grows horizontally and can expand out 2cm to 3cm or more in all directions.
5.Radiation growth of undifferentiated malignant melanoma.
6.Malignant melanoma with malignant transformation of huge hairy nevus.
7.Malignant melanoma of oral, vaginal and anal mucosal origin.
8.Malignant melanoma with unknown primary site.
9.Malignant melanoma originating from blue nevus.
10.Malignant melanoma of visceral origin.
11.Childhood malignant melanoma originating from intradermal nevus.
(B) Growth pattern According to the way of growth and spread of tumor cells, it can be divided into radiation growth phase and vertical growth phase. It is common in the early stage of freckle type, superficial spreading type and limb malignant melanoma, which can last for several years, and because the primary foci do not metastasize to the lymphatic tract or rarely to the lymphatic tract during this period, a simple surgical excision can achieve good results. When the tumor infiltrates deeply into the dermis and subcutaneous tissue, it is called vertical growth, and nodular melanoma can enter the vertical growth phase directly without the radiation growth phase.
（A real milestone development in the study of malignant melanoma is the recognition that the risk of metastasis and prognosis are closely related to the thickness of the lesion and the level of skin invasion. Measuring the thickness of malignant melanoma lesions in millimeters is a more accurate and comparable standard among pathologists, and is now the standard for estimating the risk of lymph node metastasis and determining prognosis. At present, some famous treatment centers in the world are very popular with the direct measurement of tumor thickness by microscope proposed by Breslow in 1970 to estimate the prognosis, they divided the tumor thickness into ≤0.75mm, 0.75~1.5mm and >1.5mm, and some authors divided >1.5mm into several grades to further observe the relationship between tumor thickness and prognosis.
Clinical manifestations
In order to carefully examine skin lesions in detail, good light and handheld magnification are essential. Pigmented lesions with the following changes often suggest the possibility of early malignant melanoma: ① color: most malignant melanomas have brown, black, red, white or blue mixed unevenly, and should be particularly alert when skin nevi show color changes. ②Margins: often jagged and jagged changes, which are caused by the tumor spreading and expanding to the surrounding area or self-regeneration. ③Surface: not smooth. It is often rough and accompanied by scaly or flaky desquamation. Sometimes there is exudate or blood oozing, and the lesion may be higher than the skin surface. The skin around the lesion may appear edematous or lose its original skin luster or turn white or gray. ⑤ Abnormal sensation: local itching, burning pain or pressure pain is often present. When the above changes occur, it strongly suggests the suspicion of malignant melanoma, and it can be said that once any changes occur in skin nevus, excisional biopsy should be performed to remove malignant melanoma without fail.
Prevention
Avoiding sunlight as much as possible and using sun screen are important primary prevention measures, especially for those high-risk groups, it is more important to strengthen education for general public and professionals to improve the three early detection, early diagnosis and early treatment.
[Prognosis].
(a) The depth of tumor infiltration Tumor thickness is closely related to the prognosis. Balch et al. (1982) reported the efficacy analysis of 1442 cases of malignant melanoma, in which the 5-year survival rate of 357 cases with primary foci ≤0.75mm was 89%, and only 25% of those with ≥4mm.
(B) Lymph node metastasis The 5-year survival rate of those with metastasis in l-3 lymph nodes was 41%-58%, and that of those with metastasis in more than 4 nodes was 8%-26%. Although both lesion thickness and lymph node metastasis are important factors affecting prognosis, lymph node metastasis seems to have a greater impact on prognosis.
（The prognosis of malignant melanoma varies according to the location of the lesion, and it is generally believed that the prognosis is worst if the lesion is located in the trunk, followed by the head and neck, and better if it is located in the limbs.
（According to Morton’s standard of wide excisional range, the excisional range is 2cm-3cm from the tumor edge for lesion thickness ≤0.75mm, 3cm-4cm for thickness >0.75mm and ≤4mm, and 5cm from the tumor edge for wide excision for thickness >4mm, which can reduce the local recurrence rate. Inadequate local excision can make the local recurrence rate as high as 27%~57%, and once local recurrence occurs, it is difficult to make a very thorough wide excision; the same is true for the treatment of regional lymph nodes.
(v) Age and gender The prognosis of rare juvenile malignant melanoma is better, and the prognosis of patients with malignant melanoma under 45 years of age is better than that of older patients. The prognosis of female patients is significantly better than that of males in terms of gender.