Prognostic Factors for Patients with Clinical Stage I Melanoma of Intermediate Thickness (1.51–3.99 mm)* A Conceptual Model for Tumor Growth and Metastasis

Abstract

Fourteen variables were tested for their ability to predict visceral or bony metastases in 177 patients with clinical Stage I melanoma of intermediate thickness (1.51 - 3.39 mm). A Cox multivariate analysis yielded a combination of four variables that best predicted bony or visceral metastases for these patients: 1) mitoses greater than 6/min 2 (p = 0.0007), 2) location other than the forearm of leg) p = 0.009, 3) ulceration width greater than 3 mm (p = 0.04), 4) microscopic satellites (p = 0.05). The overall prognostic model chi square was 32.40 with 4 degrees of freedom (p less than 10 (-5). Combinations of the above variables were used to separate these patients into at least two risk groups. The high risk patients had at least a 35% or greater chance of developing visceral metastases within five years, while the low risk group had greater than an 85% chance of being disease free at five years. Criteria for the high risk group were as follows: 1) mitoses greater than 6/mm 2 in at least one area of the tumor, irrespective of primary tumor location, or 2) a melanoma located at some site other than the forearm or leg and histologic evidence in the primary tumor of either ulceration greater than 3 mm wide or microscopic satellites. The low risk group was defined as follows: 1) mitoses less than or equal to 6/mm 2 and a location on the leg or forearm, or 2) mitoses less than or equal to 6/mm 2 and the absence in histologic sections of the primary tumor of both microscopic satellites and ulceration greater then 3 mm wide. The number of patients in this series who did not undergo elective regional node dissection (N = 47) was probably too small to detect any benefit from this procedure. Based on survival rates from this and other studies, it is estimated that approximately 1500 patients with clinical Stage I melanoma of intermediate thickness in each arm of a randomized clinical trial would be needed to detect an increase in survival rates from elective regional node dissection.

Prediction of Sentinel Lymph Node Micrometastasis by Histological Features in Primary Cutaneous Malignant Melanoma

“…[1][2][3][4][5][6][7] Age of the patient and pathological features, such as ulceration, microsatellitosis, lymphatic invasion, and extensive regression, may likewise adversely affect prognosis. [1][2][3][4][5][6][7] The presence of regional or distant metastasis is the most powerful prognostic factor available 1,[8][9][10][11][12] and takes precedence over primary tumor characteristics. Melanoma has been shown to metastasize to the regional lymph nodes in a systematic fashion, with "skip" metastases within a nodal group being rare.…”

“…13 The historical experience with elective lymph node dissection for patients with intermediate-or high-risk primary cutaneous melanomas has shown that approximately 20% of clinically node-negative patients harbor microscopic lymph node metastases in the regional draining lymph node beds. 7,13,14 It has recently become possible to identify this subset of patients with occult microscopic regional lymph node involvement 14 without subjecting all patients at risk to a lymph node dissection, which involves the formal resection of all lymph nodes in a regional basin. The use of lymphoscintigraphy for presurgical mapping enables the qualified surgeon to STUDY identify for selective biopsy the few anatomical lymph nodes at risk for metastatic spread.…”

“…26,27 In our series, approximately 22% of patients with intermediate-and high-risk primary cutaneous melanoma had microscopic lymph node metastases, a finding consistent with other studies. 7,13,14 Select subsets were found to have a much higher or slightly lower incidence. These observations are important both for patient counseling and for understanding the relationship between primary tumor characteristics and regional metastasis.…”

Intraoperative identification of sentinel lymph node in patients with malignant melanoma

“…in the group with a thickness of 1.5-2.99 mm there were two out of nine (22%) cases with positive sentinel node compared with 7 out of 26 (26%) in the group with thickness above 3.0 mm. This is perhaps not surprising as the proponents of elective lymphadenectomy claim that the risk of developing regional node disease increases with the thickness of the primary melanoma and propose that elective lymph node dissection is beneficial in those patients with intermediate thickness tumour (1.5-4.0 mm) (Das Gupta, 1977;Day, 1982).…”

Prognosticators of melanoma, the melanoma report, and the sentinel lymph node

“…Therapy and prognostication depend on the pathologist's ability to accurately identify by light microscopy the vertical growth phase, as it defines the point in lesional evolution when a melanoma acquires the ability to metastasize and to kill the patient. [12][13][14][15] Radial vs Vertical Growth Phase…”