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

Abstract

Background The presence of lateral pelvic lymph node (LLN) metastasis is an essential prognostic factor in rectal cancer patients. Thus, preoperative diagnosis of LLN metastasis is clinically important to determine the therapeutic strategy. The aim of this study was to evaluate the efficacy of preoperative positron emission tomography/computed tomography (PET/CT) in the diagnosis of LLN metastasis. Methods Eighty-four patients with rectal cancer who underwent LLN dissection at Osaka University were included in this study. The maximum standardized uptake value (SUVmax) of the primary tumor and LLN were preoperatively calculated using PET/CT. Simultaneously, the short axis of the lymph node was measured using multi-detector row computed tomography (MDCT). The presence of metastases was evaluated by postoperative pathological examination. Results Of the 84 patients, LLN metastases developed in the left, right, and both LLN regions in 6, 7, and 2 patients, respectively. The diagnosis of the metastases was predicted with a sensitivity of 82%, specificity of 93%, positive predictive value of 58%, negative predictive value of 98%, false positive value of 7%, and false negative value of 18% when the cutoff value of the LLN SUVmax was set at 1.5. The cutoff value of the short axis set at 7 mm on MDCT was most useful in diagnosing LLN metastases, but SUVmax was even more useful in terms of specificity. Conclusions The cutoff value of 1.5 for lymph node SUVmax in PET is a reasonable measure to predict the risk of preoperative LLN metastases in rectal cancer patients.

Efficacy of PET/CT in diagnosis of regional lymph node metastases in patients with colorectal cancer: retrospective cohort study

“…A previous report showed that a cut-off value of 7 mm for lymph node short-axis diameter is a useful criterion for the diagnosis of lateral lymph node metastasis in patients with rectal cancer. Similarly, the present study showed that a 7 mm short-axis diameter was also an effective cut-off for the diagnosis of regional lymph node metastasis 17 . Several reports have described criteria of lymph node short-axis diameter for metastasis diagnosis, and the 7 mm cut-off used in this study is in keeping with these previous reports 7–9 .…”

“…Several reports have described criteria of lymph node short-axis diameter for metastasis diagnosis, and the 7 mm cut-off used in this study is in keeping with these previous reports 7–9 . The usefulness of the lymph node SUVmax measurement for the diagnosis of lateral lymph node metastasis for patients with rectal cancer has been previously reported, with a lymph node SUVmax of 1.5 being the optimal cut-off value for this purpose 17 as used in this study. These findings collectively suggest that a lymph node SUVmax of 1.5 is a universal criterion for diagnosing lymph node metastasis of colorectal cancer.…”

“…The PET parameters included the maximal standardized uptake value (SUVmax). The SUVmax in the region of interest (ROI) was used as a representative value for assessing FDG uptake in the lesion 17 .…”

“…18 F-fluorodeoxyglucose ( 18 F-FDG) PET/CT, which is a modality that reflects the biological activity of the tumour itself, has been used widely for preoperative evaluation of colorectal cancer 15 , 16 . A previous report demonstrated the efficacy of PET/CT for the preoperative diagnosis of lateral lymph node metastases in patients with rectal cancer 17 . This study aimed to assess the effectiveness of PET/CT and determine the optimal cut-off values for the preoperative diagnosis of regional lymph node metastasis in colorectal cancer.…”

The Utility of 18F-FDG-PET–CT Metabolic Parameters in Evaluating the Primary Tumor Aggressiveness and Lymph Node Metastasis of Nasopharyngeal Carcinoma

“…In particular, the study found a strong correlation between the mediastinal LNM SUV max , the primary tumor SUV peak , and the occurrence of mediastinal LNM in patients with NSCLC. 35 PET–CT metabolic parameters have also been used to predict LNM in other tumors, such as vulvar cancer, 36 esophageal squamous cell carcinoma, 37 breast cancers, 38 rectal cancer, 39 and gastric cancer. 40 In addition to some similarities, differences between the findings of our study and those of previous studies were noted.…”