Pre-operative Evaluation of Lateral Pelvic Lymph Node Metastasis in Lower Rectal Cancer: Comparison of Three Different Imaging Modalities

Abstract

Objectives: The pre-operative diagnostic value of detecting lateral pelvic lymph node (LPLN) metastasis with magnetic resonance imaging, multidirectory computed tomography, and positron emission tomography/ computed tomography was investigated in lower rectal cancer patients. Methods: We retrospectively evaluated, using the three different modalities, the metastatic status of LPLNs in four regions, including both the internal iliac and the obturator, in 46 patients affected by lower rectal cancer patients who underwent LPLN dissection. The size inclusion criterion for LPLN metastasis was set at 6 mm in the short axis diameter. Histological examination was performed for determining the false positive and negative rate of LPLNs metastasis detection. Results: Among 184 LPLNs regions, 17 (9%) were positive for metastasis. The region-based sensitivity, specificity, and accuracy rate did not differ among the three tested diagnostic modalities. Moreover, a significant increase in these rates could not be observed when the modalities were combined. Of 184 regions, 8 (4.4%) were false negative, whereas 2 (1.1%) were false positive. The histological pattern of metastatic regions did not differ in 8 false negative LPLNs. Conclusions: Each modality had a similar detection power for LPLNs metastasis, with a cut-off value at 6 mm in the short axis diameter. However, the sensitivity of all the modalities was slightly low, along with the number of false negative LPLNs. Further reduction of the false negative rate with these modalities may be difficult because of an inherent limitation of current imaging technologies to accurately detect lymph node metastases.

Efficacy of positron emission tomography in diagnosis of lateral lymph node metastases in patients with rectal Cancer: a retrospective study

“…To select the patients with LLN metastases for LLND, high specificity might be crucial. The results of this study and those of previous studies using CT and MRI for predicting metastases have been compared in Table 7 [ 8 , 10 , 11 , 18 – 20 ]. Compared to the previous studies, the sensitivity was particularly higher and FN rates were lower in this study.…”

“… 2009 104 MRI 4 mm (short axis) 87% 87% 52% 97% 87% Akasu et al [ 10 ] 2009 104 MRI 3 mm (short axis) 93% 81% 45% 99% 83% Matsuoka et al [ 11 ] 2007 51 MRI 5 mm (short axis) 67% 83% – – 78% Ishibe et al [ 19 ] 2016 84 MRI 10 mm (short axis) 43.8% 98.5% 87.5% 88.2% 88.1% Amano et al [ 20 ]. 2019 46 MRI 6 mm (short axis) 35.3% 97% 54.6% 94% 91.3% Amano et al [ 20 ] 2019 46 CT 6 mm (short axis) 35.3% 100% 100% 96.7% 94% This study 2020 84 PET SUV max 1.5 82.4% 93.4% 58.3% 97.9% 92.3% This study 2020 84 MDCT 10 mm (short axis) 64.7% 95.4% 61.1% 96.0% 92.3% This study 2020 84 MDCT 7 mm (short axis) 70.6% 82.1% 30.8% 96.1% 81.0% ...…”

Efficacy of Positron Emission Tomography in Diagnosis of Lateral Lymph Node Metastases in Patients with Rectal Cancer: A retrospective study

“…To select the patients with LLN metastases for LLND, high speci city might be crucial. The results of this study and those of previous studies using CT and MRI for predicting metastases have been compared in Table 5 [8,10,11,[18][19][20]. Compared to the previous studies, the sensitivity was particularly higher and FN rates were lower in this study.…”

>b<Estudo crítico, termográfico e terapêutico dos tumores circum-anais e dos adenocarcinomas apócrinos de saco anal caninos>/b<

“…A limitação dessa forma de avaliação consiste na incerteza de que um aumento e/ou heterogeneidade de um linfonodo possa significar de fato uma metástase ou apenas uma reação ao processo inflamatório que é observado junto às neoplasias, falsos negativos também podem ocorrer (AMANO et al, 2020;KHAN;MASROOR;KHANDWALA, 2020). O estadiamento clínico do grupo AGCA foi realizado somente em relação ao tamanho tumoral (T), por se tratar de uma neoplasia benigna e não ocasiona metástases, sendo que a maioria das formações eram estágio T1 e T2, não tivemos T4, presumimos que seja devido ao crescimento mais lento dos ZANUTO, E. B. M. adenomas, podendo demorar muitos meses para alcançar um estadiamento T3 ou T4 (TUREK, WITHROW, 2013).…”

“…por Anderson et al (2013) e Majeski et al (2017. Porém, como esses tumores se apresentam geralmente junto a intensa inflamação, esses linfonodos podem ser apenas reativos e não metastáticos, conforme discutido previamente (AMANO et al, 2020;KHAN;MASROOR;KHANDWALA, 2020) sendo necessários estudos histopatológicos para confirmação de metástase. Wouda et al (2013) referiram em seu estudo que todos os linfonodos alterados no exame tomográfico, após confirmação por histopatológico eram metastáticos.…”