The Added Value of a Single-photon Emission Computed Tomography-Computed Tomography in Sentinel Lymph Node Mapping in Patients with Breast Cancer and Malignant Melanoma

Abstract

Single-photon emission computed tomography-computed tomography (SPECT-CT) allows for physiological and anatomical co-registration in sentinel lymph node (SLN) mapping and offers additional benefits over conventional planar imaging. However, the clinical relevance when considering added costs and radiation burden of these reported benefits remains somewhat uncertain. This study aimed to evaluate the possible added value of SPECT-CT and intra-operative gamma-probe use over planar imaging alone in the South African setting. 80 patients with breast cancer or malignant melanoma underwent both planar and SPECT-CT imaging for SLN mapping. We assessed and compared the number of nodes detected on each study, false positive and negative findings, changes in surgical approach and or patient management. In all cases where a sentinel node was identified, SPECT-CT was more accurate anatomically. There was a significant change in surgical approach in 30 cases - breast cancer (n = 13; P 0.001) and malignant melanoma (n = 17; P 0.0002). In 4 cases a node not identified on planar imaging was seen on SPECT-CT. In 16 cases additional echelon nodes were identified. False positives were excluded by SPECT-CT in 12 cases. The addition of SPECT-CT and use of intra-operative gamma-probe to planar imaging offers important benefits in patients who present with breast cancer and melanoma. These benefits include increased nodal detection, elimination of false positives and negatives and improved anatomical localization that ultimately aids and expedites surgical management. This has been demonstrated in the context of industrialized country previously and has now also been confirmed in the setting of a emerging-market nation.

The impact of sentinel lymph node mapping with hybrid single photon emission computed tomography/computed tomography in patients with melanoma. Comparison to planar radioisotopic lymphoscintigraphy

“…The addition of SPECT/CT in SLN mapping also eliminates false positive results. It may detect unspecific hot foci that might be incorrectly considered SLNs by PLS [23,27]. In our study, SPECT/CT excluded two false positives, one case of truncal and one case of lower limb melanoma.…”

“…Despite the favorable results of SPECT/CT over conventional PLS in patients with melanoma, some authors still believe its use should not be mandatory because the two imaging modalities present similar sensitivities in most cases. Moreover, SPECT/CT is more expensive, requires extra time, and delivers an additional, yet low radiation dose [8,27,28]. It has been suggested that this method should only be used in patients with non-visualization of SLN on planar imaging, where drainage pattern is variable or unpredictable and when conventional imaging is difficult to interpret [8,29,30]; however, the introduction of improved SPECT/CT systems and advanced detection techniques have led to a higher number of identified SLNs and better surgical workflow, without increasing the overall operation time [31].…”

Comparison of 99mTc-Labeled Colloid SPECT/CT and Planar Lymphoscintigraphy in Sentinel Lymph Node Detection in Patients with Melanoma: A Meta-Analysis

“…One additional record was retrieved after cross checking the references. The characteristics of the 20 studies [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ] selected for the meta-analysis were presented in Table 1 . Only 17/19 studies with a total number of 1438 patients were available for the calculation of the pooled DR of the SPECT/CT and PL.…”