Frequency of nonsentinel lymph node metastasis in melanoma

The efficacy of 99mTc-rituximab as a tracer for sentinel lymph node biopsy in cutaneous melanoma patients

Background

The sentinel lymph node (SLN) status is a vital prognostic factor for malignant melanoma (MM) patients. There is increasing evidence that a radioactive agent, rather than its combination with blue dye, is sufficient for a SLN biopsy (SLNB). Thus, we discussed the efficacy of ^99mTc-rituximab as a tracer in MM patients.

Methods

A total of 502 consecutive patients with MM who underwent SLNB were enrolled in this study. All participants were peritumorally injected with ^99mTc-rituximab before imaging, and scanned with single-photon emission computed tomography-computed tomography (SPECT-CT) to detect the number and location of the SLN. A gamma detection probe was employed to detect radioactive SLNs in operation. Follow up was conducted to observe whether nodal or distant recurrence occurred.

Results

The SLNs were successfully imaged via SPECT-CT and harvested from all 502 participants. No drainage tube was indwelled and 32 (6.3%) participants experienced the following complications: seroma (n=26, 5.2%), wound infections or lymphangitis (n=6, 1.2%), sensory nerve injuries (n=4, 0.8%). There were 380 patients who were diagnosed as SLN-negative and 122 (24.2%) were SLN-positive. A total of 85 SLN-positive patients received complete lymph node dissection, and 28 (32.9%) had additional positive lymph nodes. During a median follow-up of 24 months, 28 participants were found to have a false negative (FN) SLN. The FN rate was 18.7%. A higher T stage was a predictive factor for FN [odds ratio (OR) 1.77; P<0.05]. There was no significant difference in the positive or FN rate between the acral and cutaneous groups.

Conclusions

The radiopharmaceutical ^99mTc-rituximab could be employed as a simple and safe tracer in acral and cutaneous melanoma SLN biopsies.

Microscopic tumor burden in sentinel lymph nodes predicts synchronous nonsentinel lymph node involvement in patients with melanoma

PURPOSE

We and others have demonstrated that additional positive lymph nodes (LNs) are identified in only 8% to 33% of patients with melanoma who have positive sentinel LNs (SLNs) and undergo complete therapeutic LN dissection (cTLND). We sought to determine predictors of additional regional LN involvement in patients with positive SLNs.

PATIENTS AND METHODS

Patients with clinically node-negative melanoma who underwent SLN biopsy (1991 to 2003) and had positive SLNs were identified. Clinicopathologic factors, including extent of microscopic disease within SLNs, were evaluated as potential predictors of positive non-SLNs.

RESULTS

Overall, 359 (16.3%) of the 2,203 patients identified had a positive SLN. Positive non-SLNs were identified in 48 (14.0%) of the 343 patients with positive SLNs who underwent cTLND. On univariate analysis, several measures of SLN microscopic tumor burden, one versus three or more SLNs harvested, tumor thickness more than 2 mm, age older than 50 years, and Clark level higher than III were predictive of positive non-SLNs; primary tumor ulceration and number of positive SLNs had no apparent impact. On multivariable logistic regression analysis, measures of SLN microscopic tumor burden were the most significant independent predictors of positive non-SLNs; tumor thickness more than 2 mm and number of SLNs harvested also predicted additional disease. A model was developed that stratified patients according to their risk for non-SLN involvement.

CONCLUSION

In melanoma patients with positive SLNs, SLN tumor burden, primary tumor thickness, and number of SLNs harvested may be useful in identifying a group at low risk for positive non-SLNs and be spared the potential morbidity of a cTLND.

[Sentinel lymph node in melanoma]

The procedure of sentinel node biopsy (SNB) has emerged as an important advance especially with respect to staging of malignant melanoma. Elective (prophylactic) lymph node dissection that had been practiced in primary melanoma with a suspected increased risk of (clinically occult) lymphatic metastasis has been replaced by SNB. Patients with proven metastatic involvement of the sentinel node (12-25%) can be specifically selected for regional lymph node dissection. Metastatic involvement of the sentinel node (SN) is a significant independent prognostic factor. The value of detecting metastasis by highly sensitive diagnostic tools such as RT-PCR is just as uncertain as is the therapeutic benefit of operative or conservative therapies in sentinel node-positive patients with respect to improving prognosis and is currently under study.

The prognostic importance of tumor mitotic rate confirmed in 1317 patients with primary cutaneous melanoma and long follow-up

BACKGROUND

The late Dr. Vincent McGovern (1915 to 1983) was an international authority on melanoma pathology and one of the first to suggest that assessment of tumor mitotic rate (TMR) might provide useful prognostic information. Data for a large cohort of patients, now with extended follow-up, whose tumors had been assessed by Dr. McGovern were analyzed to reassess the independent prognostic value of TMR in primary localized, cutaneous melanoma.

METHODS

Information was extracted from the Sydney Melanoma Unit database for 1317 patients treated between 1957 and 1982 for whom there was complete clinical information and whose primary lesion pathology, which included tumor thickness, ulcerative state, and TMR, had been assessed by Dr. McGovern. All these assessments were made according to the recommendations of the Eighth International Pigment Cell Conference, held in Sydney in 1972 under the auspices of the International Union Against Cancer. Factors predicting melanoma-specific survival were analyzed with the Cox proportional hazards regression model.

RESULTS

Stage, according to the recently revised American Joint Committee on Cancer Staging System (which is based on tumor thickness and ulceration) was the most predictive factor for survival (P<.0001). This was followed by primary lesion site (P<.0001), patient age (P=.0005), and TMR (P=.008).

CONCLUSIONS

TMR was confirmed to be an important independent predictor of survival of patients with primary cutaneous melanoma. However, its predictive value was less than it was when assessed according to the 1982 revisions of the 1972 TMR recommendations.