Melanoma Staging

Melanoma is fundamentally different from moles. Moles are a common skin condition caused by the accumulation of melanin and will not affect your health. However, melanoma is a serious tumor that can threaten life and health. When you find that you have melanoma, you should go to the hospital for diagnosis and treatment in time to ensure early detection, early treatment, and early recovery.

Melanoma looks ordinary, but many people may misunderstand it as a mole. However, in fact, the public's understanding of it is far from enough. Melanoma has stages, and the treatment methods at different stages are also different. In general, melanoma is divided into four stages: one, two, three, and four. The specific symptoms of each stage are as follows:

Stage I and II: The tumor is localized, with a thickness of ≤1.5 mm, without infiltration of the surrounding skin or lymph nodes or distant metastasis. The 5-year survival rate is mainly related to the thickness of the tumor (and some other characteristics) and ranges widely, from 95% in stage IA (tumor ≤1 mm, no ulceration, Clarka grade I) to less than 50% in stage IIC (tumor >4 mm with ulceration).

Stage II: The thickness of the primary lesion is >1.5mm, and there is no metastasis. The 5-year survival rate is approximately 80%.

Note that analyzing stage I and stage II disease based on the prognostic factors mentioned above can more accurately predict the patient's prognosis.

Stage III: When the tumor begins to infiltrate the surrounding skin and regional lymph nodes (for example, if the tumor grows in the forearm, it may invade the axillary lymph nodes). The 5-year survival rate depends on the number of invaded lymph nodes and whether it is micrometastasis or macrometastasis (the former refers to invasion observed under a microscope, and the latter refers to lymph nodes enlarged to the point where they can be touched). For patients with only one microscopic lymph node metastasis, the 5-year survival rate is 70%, but for patients with more than three obvious lymph node metastases, the survival rate is only 15%.

Stage IV: The cancer has spread beyond the regional lymph nodes (such as distant skin, lymph nodes, and other organs in the body). The 5-year survival rate is only 10%.

For stage I~II lesions without lymph node metastasis, surgery is the preferred treatment. Amputation, excision of the tumor beyond 5 cm, and selective lymphadenectomy are no longer performed for the treatment of malignant melanoma. The margins of tumor resection are determined based on pathological and clinical conditions, and regular lymph node dissection is performed for high-risk patients using surveillance lymph node biopsy, and the scope of surgery tends to be more conservative. In 1992, the US NIH recommended: the resection margin for carcinoma in situ (Clark I degree) is 0.5 cm, the margin is 1 cm for tumors less than 1 mm thick, the margin is 2 cm when the tumor is 1-2 mm thick, and the margin is 2 cm when the tumor is 2-4 mm thick, and the margin is 3 cm when the tumor is thicker than 4 mm. Ackerman et al. [10] reported 936 cases of malignant melanoma with lesion thickness <1 mm, surgical margin of £2 cm, and no local recurrence.

It is not clear whether preventive regional lymph node dissection improves the efficacy of treatment. When there is lymph node metastasis, therapeutic dissection should be performed. Postoperative radiotherapy is effective for patients undergoing non-radical surgery. It is generally believed that for lesions with a thickness of ≤1 mm, preventive regional lymph node dissection is not necessary, while for lesions with a thickness greater than 3.5-4 mm, the long-term survival rate is low, and even if preventive regional lymph node dissection is performed, the improvement in efficacy is not obvious. For patients in between, prophylactic regional lymph node dissection may be a treatment option to improve survival.

In case of class III lesions, therapeutic lymph node dissection can be performed simultaneously to control local disease and regional lymph node metastasis. Although no randomized studies have confirmed whether therapeutic lymph node dissection can improve survival, retrospective data show that the palliative effect of therapeutic lymph node dissection is certain. Since the number of lymph node metastases is related to prognosis, it can also provide guidance for the next step of treatment. Some people believe that when patients with malignant melanoma develop enlarged lymph nodes, there is a 90% chance that the disease is metastatic, and after therapeutic lymph node dissection, the 5-year survival rate is 19~38%. A retrospective analysis of 133 cases showed that the median survival time of patients with 1, 2, 3 and 4 or more superficial lymph node metastases was 90, 78, 49 and 15 months, respectively, while that of patients with deep lymph node metastases was 53, 42, 14 and 9 months, respectively. There is a certain incidence of complications after radical resection of local lesions and lymph node dissection. Some authors reported that the incidence of flap necrosis was 7%, wound infection was 10%, and lymphedema was 24%. The lymphedema may increase to 40% over time.

Because stage IV disease is prone to widespread metastasis to other sites, the role of surgery in the treatment of asymptomatic metastatic lesions remains controversial. In a retrospective analysis, the survival rate of those who underwent elective surgery was better than that of the control group. A small number of patients were able to achieve long-term survival, with a 2-year survival rate of 10~20%. However, this has not yet been supported by the results of randomized studies. Surgical treatment is only suitable for patients with single-site metastasis without local lesions or local recurrence and who can tolerate surgery. Immunotherapy should be given after surgery.

Therefore, melanoma has different stages. Patients and their families must not generalize, refer to other people's successful cases casually, or be overly nervous. In surgical treatment, it is also necessary to clearly distinguish the stages before a diagnosis can be made and later surgical treatment can be performed to ensure the patient's health.