SPECT/CT Detects of Lymph Node Metastasis in Melanoma Patients

Single-photon emission computed tomography/CT can help detect positive sentinel lymph nodes, resulting in a higher rate of disease-free survival among patients with melanoma, say researchers in a study published today in JAMA. This  hybrid technique also could reduce current high false positive rates by providing additional pre-operative anatomical information to surgeons.

Depending on the tumor depth, melanoma can metastasize early into regional lymph nodes, wrote the authors. “Sentinel lymph node excision (SLNE) is probably the most important diagnostic and potentially therapeutic procedure for patients with melanoma. The histologic status of the sentinel lymph node is the most relevant prognostic factor for overall survival in patients with melanoma, independent of primary tumor thickness.”

Researchers analyzed findings of 403 patients with melanoma and clinically negative lymph nodes who underwent sentinel lymph node excision (SLNE) with or without preoperative SPECT/CT. Between March 2003 and October 2008, 254 patients underwent SLNE without preoperative SPECT/CT – the standard group. Between November 2008 and April 2011, all sentinel node scintigraphies were performed as SPECT/CT in 149 patients. The SPECT/CT allowed SLNE in the head and neck more frequently. Only 2 percent SLNE occurred in the standard group compared with 23.5 percent in the SPECT/CT group.

Eight hundred thirty tree SLNs were removed among the 403 patients. There were 2.40 SLNs per patient in the SPECT/CT group and 1.87 per patient in the standard group. Of the 358 excised SLNs in the SPECT/CT group, 51 (14.2 percent) showed metastatic involvement. Fifty four of the 475 SLNs in the standard group (11.4 percent) showed metastatic involvement.

Forty one patients (27.5 percent) in the SPECT/CT cohort and 48 (18.9 percent) in the standard cohort were found to have positive SLNs.

“The local relapse rate in the SPECT.CT cohort was lower than in the standard cohort (6.8 percent vs. 23.8 percent), which prolonged four-year disease-free survival (93.9 percent vs. 79.2 percent),” wrote the authors.