A new strategy based on fluorodeoxyglucose-positron emission tomography for managing liver metastasis from colorectal cancer

Tumor-to-blood pool ratio of 18F-fluorodeoxyglucose-positron emission tomography's standardized uptake value as a useful parameter indicating malignant transformation in pancreatic branch-duct intraductal papillary mucinous neoplasm compared to the international Fukuoka guidelines: a retrospective cohort study from surgical resections

BACKGROUND

Identifying malignant transformation in pancreatic branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) remains challenging, but the standardized uptake value (SUV) obtained from 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET)/CT has the potential to become a valuable parameter for differentiation. This study aimed to assess the effectiveness of SUV of FDG-PET/CT in distinguishing low-grade dysplasia (LGD), high-grade dysplasia (HGD), and intraductal papillary mucinous carcinoma (IPMC) within BD-IPMNs.

METHODS

We assessed 58 patients with confirmed BD-IPMN undergoing surgery between 2008 and 2022. Receiver operating characteristic curves were plotted using the tumor-to-blood pool ratio (TBR) of FDG-PET/CT in two scenarios: one considering HGD + IPMC as positive and the other considering only IPMC as positive.

RESULTS

In the cohort of 58 cases, there were 39 females, and the median age was 71 years. The median TBR value was 1.45 (range, 0.35-25.44). The TBRs exhibited a significant correlation with each histopathology (p < 0.001). Furthermore, in the multivariate analysis, TBR was independently significant in both scenarios, with HGD + IPMC defined as malignant (p = 0.001) and with only IPMC defined as malignant (p = 0.024).

CONCLUSIONS

TBR might have the potential to serve as a valuable parameter for indicating malignant transformation in pancreatic BD-IPMNs.

Detection of Liver Lesions in Colorectal Cancer Patients Using 18F-FDG PET/CT Dual-Time-Point Scan Imaging

OBJECTIVE

The aim of this study was to evaluate the diagnostic performance of dual-time-point fluorine-18-fluorodeoxyglucose positron emission computed tomography/computed tomography (18F-FDG PET/CT) compared to conventional early imaging for detecting colorectal liver metastases (CRLM) in colorectal cancer (CRC) patients.

METHODS

One hundred twenty-four consecutive CRC patients underwent dual-time-point imaging scans on a retrospective basis. Histopathological confirmation and/or clinical follow-up were accepted as the gold standard. Standard uptake values (SUV), signal-to-noise ratio (SNR), retention index (RI), tumor-to-normal liver ratio (TNR), and lesion sizes were measured for early and delayed PET scans. The diagnostic performance of early and delayed images was calculated on a per-patient basis and compared using McNemar's test.

RESULTS

Among the 124 patients, 57 (46%) had CRLM, 6 (4.8%) had benign lesions, and 61 (49.2%) had no concerning lesions detected. Smaller CRLM lesions (<5 cm3) showed significantly higher uptake in the delayed scans relative to early imaging (p < 0.001). The SUV and TNR increased significantly in delayed imaging of all metastatic lesions (p < 0.001). The retention index of all CRLM was high (40.8%), especially for small lesions (54.8%). A total of 177 lesions in delayed images and 124 in standard early images were identified. In a per-patient analysis, delayed imaging had significantly higher sensitivity (100% vs. 87.7%) and specificity (91.0% vs. 94.0%) compared to early imaging (p-value = 0.04).

CONCLUSIONS

The detection of liver lesions using dual-time-point PET/CT scan improves the sensitivity and specificity for the detection of colorectal liver metastasis.

Clinical strategy of conversion therapy and surgical treatment for liver metastases from colorectal cancer

Colorectal cancer is one of the common malignant tumors of the digestive system in clinical practice. Due to the anatomical characteristics of the colorectum itself, colorectal cancer is prone to liver metastasis. Approximately 15%-25% of colorectal cancer cases are complicated with liver metastasis at diagnosis, 15%-25% are complicated with liver metastasis after radical resection of colorectal cancer, and 80%-90% with liver metastasis cannot undergo radical resection initially. The 5-year survival rate is less than 5%, and liver metastasis is the main cause of death in patients with colorectal cancer. In recent years, with the clinical application of effective chemotherapy and molecular targeted drugs, as well as the rapid development of surgical techniques, an individualized safe, efficient, fast, treatment plan can be formulated according to patients' age, primary colorectal tumor location, degree of differentiation, Ras and B-Raf gene status, tumor size, number and distribution of metastases in the liver. By shrinking the tumor volume in the liver and increasing the residual liver volume, liver metastatic tumors can undergo surgical resection or disease-free status can be achieved in patients with liver metastasis. As a result, patients with colorectal liver metastases can achieve a 5-year survival rate of 30%-57%, which greatly improves the prognosis after operation. According to the postoperative adverse factors, individualized preventive measures are worked out to reduce the impact of adverse factors and improve the prognosis of patients with colorectal liver metastases. In this paper, we systematically discuss the clinical strategy of conversion therapy and surgical treatment for unresectable colorectal cancer liver metastases by reviewing the relevant domestic and foreign literature, so as to provide a theoretical reference for the selection of clinical treatment and program for patients with unresectable colorectal cancer liver metastases.

FDG-PET for preoperative evaluation of tumor invasion in ampullary cancer: A retrospective analysis

BACKGROUND

Tumor invasion is the most significant prognostic factor in ampullary cancer and is thus a crucial factor in decision making for treatment. Endoscopic ultrasound can be performed to evaluate tumor invasion, but its diagnostic accuracy varies depending on the endoscopist. This study aimed to assess the usefulness of fluorodeoxyglucose positron emission tomography (FDG-PET) for preoperatively predicting tumor invasion in ampullary cancer.

METHODS

We retrospectively evaluated 44 patients with ampullary cancer (adenoma, n = 6; adenocarcinoma, n = 38) who underwent surgical resection. The SUVmax of the ampullary tumor site was assessed using FDG-PET, and the correlation among tumor invasion, lymph node metastasis, and other clinicopathological factors was evaluated.

RESULTS

The SUVmax of the ampullary tumor site gradually increased depending on the extent of tumor invasion (p = 0.0075). Moreover, the SUVmax was significantly different between ≤T1a and ≥T1b, which is an indication for endoscopic papillectomy or surgical resection (p = 0.0015). The SUVmax of the ampullary section was significantly correlated with lymph node metastasis (p = 0.035).

CONCLUSION

The SUVmax of the ampullary tumor site is correlated with tumor invasion and lymph node metastasis in ampullary cancer. Thus, FDG-PET can be a useful modality for preoperative staging and treatment strategy.

The metabolic clinical risk score as a new prognostic model for surgical decision-making in patients with colorectal liver metastases

BACKGROUND AND OBJECTIVES

Selection for surgery in patients with colorectal liver metastases (CRLM) remains inaccurate. We evaluated if CRLM baseline metabolic characteristics, assessed by [18]F-fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸ FDG-PET/CT), could predict postoperative outcomes.

METHODS

In a retrospective series of patients undergoing surgery for CRLM, we defined two groups: the long-term survival (LTS) and early relapse (ER) groups, where the postoperative recurrence-free survivals were ≥5 years or <1 year, respectively. We analyzed the patients in whom baseline ¹⁸ FDG-PET/CT was available. Clinicopathologic parameters, clinical risk score (CRS), and baseline ¹⁸ FDG-PET/CT characteristics were compared between LTS and ER groups. A metabolic CRS (mCRS) was implemented, adding one point to the standard five-point CRS when the highest tumor standardized uptake values (SUV_max )/normal liver mean SUV (SUV_mean(liver) ) ratios were >4.3, defining low- and high-risk mCRS by scores of 0 to 2 and 3 to 6, respectively.

RESULTS

From a series of 450 patients operated for CRLM (mean follow-up of 58 months), we included for analysis 23 and 30 patients in the LTS and ER groups, respectively. Clinicopathologic parameters and CRS were similar in the LTS and ER groups. Median SUV_max /SUV_mean(liver) ratios were higher in ER vs LTS patients (4.2 and 2.8, P = .008, respectively). mCRS was increased in ER patients (P = .024); 61% of LTS patients had low-risk mCRS and 73% of the ER patients had high-risk mCRS (P = .023).

CONCLUSIONS

¹⁸ FDG-PET/CT characteristics combined with traditional CRS may represent a new tool to improve selection for surgery in patients with CRLM.

FDG-PET reflects tumor viability on SUV in colorectal cancer liver metastasis

BACKGROUND

Liver resection is the most effective procedure for colorectal cancer liver metastasis (CRLM); however, early recurrence is an important problem that affects the postoperative prognoses of patients with CRLM. We previously suggested a therapeutic algorithm for CRLM using fluorodeoxyglucose-positron emission tomography (FDG-PET) and revealed the applicability of FDG-PET in predicting the prognosis after liver resection of CRLM. In this study, we assessed the correlation between FDG-PET and biological viability such as proliferation or metabolic activity.

METHODS

We retrospectively evaluated 61 patients who underwent hepatectomy for CRLM. We assessed hypoxia inducible factor-1α (HIF-1α), pyruvate kinase isozyme M2 (PKM2), glucose transporter 1 (GLUT1), and Ki-67 expression via immunohistochemistry and evaluated the correlation between standardized uptake value (SUV) and these factors.

RESULTS

High HIF-1α, PKM2, and GLUT1 expression were positively correlated with high SUV expression (P = 0.0444, 0.0296, and 0.0245, respectively). Ki-67 and SUV were also positively correlated (P = 0.00164). HIF-1α expression and PKM2 expression were significantly correlated (P = 0.0430), and PKM2 expression and GLUT1 expression were extremely significantly correlated (P < 0.0001).

CONCLUSION

SUV reflected tumor proliferation or metabolic factors in CRLM. FDG-PET could be a useful modality for assessing tumor viability and may provide useful information regarding the appropriate treatment strategy for CRLM.