Added-value of SPECT/CT to lymphatic mapping and sentinel lymphadenectomy in gynaecological cancers

Abstract

Lymphatic mapping and sentinel lymphadenectomy (LM/SL) have been successfully used in pre-treatment nodal staging of gynaecological cancers. We hypothesised the added-value of LM/SL plus SPECT/CT in patients with early stage of cervical cancer and vulvar cancer. A prospective, single-center, diagnostic, open label, active control, non-randomized clinical trial has been conducted in 7 patients with FIGO IA-IB1 cervical cancer and 7 patients with FIGO stage I-II-IIIcN0 vulvar cancer. All patients underwent LM/SL plus SPECT/low-dose CT and complete lymph node dissection (CLND) according to the standard of care. In case of negative hematoxylin-eosin staining, serial sections of the SLNs were analysed by immunohistochemistry and high molecular weight cytokeratin. Primary outcome measures were the detection rate, the sensitivity (SV), the negative predictive value (NPV), the diagnostic accuracy (DA) for anatomic localisation of SLNs, and the impact on management of SPECT/CT guided LM/SL versus CLND. The secondary outcome measure was the patient tolerability and operating time of LM/SL guided SPECT/CT versus CLND. https://ichgcp.net/clinical-trials-registry/NCT00773071 All 14 patients were enrolled into the 1-day research protocol with dual-tracer LM/SL and SPECT/CT. Additional SLNs were detected on SPECT/CT compared to conventional planar imaging. Hot and cold > 1cm SLNs were detected on SPECT/CT. Detection rate, SV, NPV, DA were 100% in both groups; false negative rate was 0%. Rate of SLN metastases was 28.5% in cervical cancer and 42.9% in vulvar cancer. Impact on treatment was 28.5% and 14.3% in cervical cancer and vulvar cancer patients, respectively. SPECT/CT was well tolerated by all patients and operating time for LM/SL was within 30 min. No adverse events were reported with a time frame of 1-to-3 years. In early stage of gynaecological cancers, SPECT/low-dose CT is technically feasible and of clinical added-value for LM/SL.

Keywords: LM/SL; SPECT/CT; cervical cancer; vulvar cancer.

Figures

Figure 1

A FIGO stage IB1 cervical cancer with unilateral pelvic SLNs on planar imaging and bilateral pelvic SLNs on SPECT/CT. A. Planar imaging showed 2 SLNs (SLN1 and SLN2, white arrows) on the right side of the pelvis. B. SPECT/low-dose CT evidenced 4 SLNs (SLN1, SLN2, SLN3, SLN4, white arrows) on both sides (2 right and left external iliac SLNs and 2 right and left common iliac SLNs), which were precisely localised at surgery as blue-stained and hot SLNs. At the final pathology, 5 SLNs and 15 non-SLNs were analysed, which were all free of tumour. SLN: sentinel lymph node. Inj: injection site.

Figure 2

A FIGO stage II vulvar cancer with hot SLNs on SPECT/CT not seen on planar imaging. A. Planar imaging showed no SLN. B. SPECT/low-dose CT revealed 2 hot left inguinal femoral SLNs (white arrows), which were invaded by tumour with macro-metastases > 2 mm at the final pathology. SLN: sentinel lymph node. Inj: injection site.

Figure 3

A FIGO stage II vulvar cancer with hot and ‘cold’ SLNs > 1 cm on SPECT/CT. A. a right inguinal femoral hot SLN > 1 cm (white arrow) and (B) a right inguinal femoral ‘cold’ SLN > 1 cm (white arrow), which were massively invaded by tumour (> 75% tumour involvement) at the final pathology. SLN: sentinel lymph node. Inj: injection site.