Ultrasound examination of sentinel nodes in the initial assessment of patients with primary cutaneous melanoma.

BACKGROUND: The value of targeted high-resolution ultrasound (US) examination in detecting sentinel lymph node metastases in patients with newly diagnosed primary cutaneous melanomas has not yet been fully evaluated. The aim of this study was to determine the threshold size of metastatic melanoma deposits in SLNs able to be detected by targeted US examination before initial melanoma surgery. METHODS: A total of 304 patients presenting with primary cutaneous melanomas had SLNs identified by lymphoscintigraphy and then examined in situ by the same physician with high-resolution US. Within 24 hours, the SLNs were removed for histopathologic assessment of sections stained conventionally and with immunohistochemical markers for S100 protein and HMB45 antigen. RESULTS: Metastatic disease was present in SLNs from 33 node fields in 31 patients. The US results in seven of these cases were suggestive of metastatic disease. Twenty-six node fields contained positive nodes not detected by US. Undetected deposits had diameters <4.5 mm. CONCLUSIONS: These results suggest that a targeted US examination of SLNs can detect metastatic melanoma deposits down to approximately 4.5 mm in diameter. However, most metastatic melanoma deposits in SLNs are considerably smaller than this at the time of initial staging, and US therefore cannot be considered cost-effective in this setting.

Histopathologic excision margin affects local recurrence rate: analysis of 2681 patients with melanomas < or =2 mm thick.

OBJECTIVE: Prospective trials have shown that 1-cm and 2-cm margins are safe for melanomas <1 mm thick and > or =1 mm thick, respectively. It is unknown whether narrower margins increase the risk of LR or mortality. SUMMARY BACKGROUND DATA: To determine the relationship between histopathologic excision margin, local recurrence (LR) and survival for patients with melanomas < or =2 mm thick. METHODS: Data were extracted from the Sydney Melanoma Unit database for all patients with cutaneous melanoma < or =2 mm thick, diagnosed up to 1996. Patients with positive excision margins or follow-up <12 months were excluded, leaving 2681 for analysis. Outcome measures were LR (recurrence <5 cm from the excision scar), in-transit recurrence, and disease-specific survival. Factors predicting LR and overall survival were tested with Cox proportional hazards analysis. RESULTS: Median follow-up was 83.8 months. LR was identified in 55 patients (median time to recurrence, 37 months). At 120 months, the actuarial LR rate was 2.9%. Five-year survival after LR was 52.8%. In multivariate analysis, only margin of excision and tumor thickness were predictive of LR (both P = 0.003). When all patients with a margin <0.8 cm in fixed tissue (corresponding to a margin of <1 cm in vivo) were excluded from analysis, margin was no longer significant in predicting LR. Thickness, ulceration, and site were predictive of survival, but margin was not (P = 0.49). CONCLUSIONS: Histopathologic margin affects the risk of LR. However, if the in vivo margin is > or =1 cm, it no longer predicts risk of LR. Patient survival is not affected by margin.

Lymphedema after complete axillary node dissection for melanoma: assessment using a new, objective definition.

OBJECTIVES: The objectives of this study were to define appropriate criteria for assessing the presence of lymphedema, and to report the prevalence and risk factors for development of upper limb lymphedema after level I-III axillary dissection for melanoma. SUMMARY BACKGROUND DATA: The lack of a consistent and reliable objective definition for lymphedema remains a significant barrier to appreciating its prevalence after axillary dissection for melanoma (or breast carcinoma). METHODS: Lymphedema was assessed in 107 patients (82 male, 25 female) who had previously undergone complete level I-III axillary dissection. Of the 107 patients, 17 had also received postoperative axillary radiotherapy. Arm volume was measured using a water displacement technique. Change in volume of the arm on the side of the dissection was referenced to the volume of the other (control) arm. Volume measurements were corrected for the effect of handedness using corrections derived from a control group. Classification and regression tree (CART) analysis was used to determine a threshold fractional arm volume increase above which volume changes were considered to indicate lymphedema. RESULTS: Based on the CART analysis results, lymphedema was defined as an increase in arm volume greater than 16% of the volume of the control arm. Using this definition, lymphedema prevalence for patients in the present study was 10% after complete level I-III axillary dissection for melanoma and 53% after additional axillary radiotherapy. Radiotherapy and wound complications were independent risk factors for the development of lymphedema. CONCLUSIONS: A suggested objective definition for arm lymphedema after axillary dissection is an arm volume increase of greater than 16% of the volume of the control arm.