Identification of higher risk thin melanomas should be based on Breslow depth not Clark level IV.

There is good prognostic correlation for the two microstaging systems, Breslow depth and Clark level, commonly used to stage melanomas. Many investigators have reported that Breslow depth is the superior microstaging method. Although Clark level has been dropped from most of the proposed American Joint Committee on Cancer (AJCC) melanoma staging system, the AJCC system still includes Clark Level IV as a criterion for upstaging thin melanomas. The authors sought to determine whether this is appropriate, based on melanoma patient data in the Duke Comprehensive Cancer Center database. Of the 8833 patients registered between January 1, 1970 and December 31, 1995, complete data on Breslow depth and Clark level was available for 4560 patients who were without nodal or metastatic disease at presentation. Ten-year survival was measured from the date of excision of the primary tumor until death from melanoma and analyzed using Kaplan-Meier and Cox proportional hazard methodologies. When analyzed separately, both increased Breslow thickness and Clark level correlated with shorter survival times. During subgroup analysis, Breslow thickness remained a significant prognostic indicator of survival at Clark Levels III and IV. Conversely, at narrow levels of Breslow thickness (i.e., 0-0.75 mm, > 0.75 -1.0 mm, > 1.0-1.5 mm) survival times were indistinguishable between Clark Levels III and IV. For the broader Breslow thickness interval of 0-1.0 mm, a barely significant difference between Clark Levels III and IV could be obtained. However, for this thickness range, even greater differences in survival could be obtained by merely comparing Breslow subgroups (i.e., < or = 0.8 mm vs. > 0.8-1.0 mm, < or = 0.9 mm vs. > 0.9-1.0 mm). The authors' data suggested that, after controlling for Breslow depth, Clark level was not a good prognostic indicator for survival. If the AJCC's objective is to design a classification system that will reliably predict the higher risk melanomas, then the system should be based on tumor thickness, which is clearly a better prognostic indicator, and should not be modified because of Clark level.

Owen SA ，Sanders LL ，Edwards LJ ，Seigler HF ，Tyler DS ，Grichnik JM ... -  《CANCER》

Breslow thickness and clark level in melanoma: support for including level in pathology reports and in American Joint Committee on Cancer Staging.

Thickness is known to be an important survival prognosticator for cutaneous melanoma, but controversy exists as to whether Clark level of invasion retains prognostic significance once thickness has been accounted for. A recent proposal to eliminate Clark level from the staging system for melanoma of the American Joint Committee on Cancer (AJCC) prompted the authors to investigate whether level adds useful prognostic information to Breslow thickness. They used the data base of the New York University Melanoma Cooperative Group (NYU-MCG) Registry. The analysis was based on 919 patients with AJCC Stage I or II melanomas diagnosed between 1972 and 1982 and followed for an average of 10.9 years. Melanoma thicknesses were divided into 4 categories (< or = 0.75, 0.76-1.50, 1.51-4.00, and >4.00 mm). Patients were cross-classified according to tumor thickness and Clark level (II-V). For each combination of thickness and level, the Kaplan-Meier survival curve and 10-year survival proportion were computed, using death from melanoma as the outcome. The impact of Clark level on survival was evaluated for each of the thickness categories. The Cox proportional hazards model was used to assess the simultaneous effect of thickness and level on survival while controlling for other important prognostic factors, i.e., age, tumor location, and presence or absence of ulceration. Level of invasion was a significant predictor of death from melanoma in each of the four thickness categories. Likewise, in the Cox analyses, level was a significant prognostic variable, even after thickness was included in the model and regardless of whether thickness was treated as a categoric or a continuous variable. These results confirm that both tumor thickness and level of invasion are important independent prognostic factors in AJCC Stage I and II melanomas. The authors recommend that Clark levels be kept as criteria in the AJCC staging system and be included in pathology reports. [See editorial on pages 491-6, this issue.]

Marghoob AA ，Koenig K ，Bittencourt FV ，Kopf AW ，Bart RS ... -  《-》

Sentinel lymph node biopsy for the T1 (thin) melanoma: is it necessary?

Nahabedian MY ，Tufaro AP ，Manson PN 《ANNALS OF PLASTIC SURGERY》

Sentinel lymph node micrometastasis and other histologic factors that predict outcome in patients with thicker melanomas.

Cherpelis BS ，Haddad F ，Messina J ，Cantor AB ，Fitzmorris K ，Reintgen DS ，Fenske NA ，Glass LF ... -  《JOURNAL OF THE AMERICAN ACADEMY OF DERMATOLOGY》

American Joint Committee on Cancer clinical stage as a selection criterion for sentinel lymph node biopsy in thin melanoma.

Vaquerano J ，Kraybill WG ，Driscoll DL ，Cheney R ，Kane JM 3rd ... -  《-》