It would be great if you could just have an ultrasound of the nodal basin near your lesion to determine whether or not there are any positive nodes hiding in there! However, there's this:
It has been suggested that preoperative US could avoid the need for sentinel node (SN) biopsy, but in most single-institution reports, the sensitivity of preoperative US has been low.
Preoperative US data and SNB results were analyzed for patients enrolled at 20 centers participating in the screening phase of the second Multicenter Selective Lymphadenectomy Trial. Excised SNs were histopathologically assessed and considered positive if any melanoma was seen.
SNs were identified and removed from 2859 patients who had preoperative US evaluation. Among those patients, 548 had SN metastases. US was positive (abnormal) in 87 patients (3.0%). Among SN-positive patients, 39 (7.1%) had an abnormal US. When analyzed by lymph node basin, 3302 basins were evaluated, and 38 were true positive (1.2%). By basin, the sensitivity of US was 6.6% and the specificity 98.0%. Median cross-sectional area of all SN metastases was 0.13 mm; in US true-positive nodes, it was 6.8 mm. US sensitivity increased with increasing Breslow thickness of the primary melanoma (0% for less than/= to1 mm thickness, 11.9% for greater than/= to 4 mm thickness). US sensitivity was not significantly greater with higher trial center volume or with pre-US lymphoscintigraphy.
In the MSLT-II screening phase population, SN tumor volume was usually too small to be reliably detected by US. For accurate nodal staging to guide the management of melanoma patients, US is not an effective substitute for SN biopsy.
SO - in this study - because it had been hypothesized that doing an ultrasound of nodes near a melanoma lesion before surgery could identify whether, OR NOT, there was melanoma present in those nodes, indicating a need, OR NOT, for surgery - these researchers looked at the nodes of 2,859 peeps via ultrasound before they underwent sentinel node removal. Of those 2,859 melanoma patients, 548 had a sentinel node that was positive for melanoma. Of those 548, only 87 had a positive node identified on their preoperative ultrasound.
Clearly, that's not good enough. If we were to rely on US to find positive nodes, this study indicates that 461 of these 548 melanoma peeps would still be walking around with:
1) A positive sentinel node that they didn't know they had - period.
2) A missed opportunity to realize their real status as a Stage III melanoma patient and relinquish their opportunity for viable adjuvant care.
I wish sentinel nodes could be evaluated by a simple procedure like an US. However, the state of the technology is not there yet. Maybe someday. For what it's worth. - c