Role of FDG-PET/CT in detection of recurrent disease in colorectal cancer. Nucl Med Commun. 2010;31:590-596. [PMID: 20300042 DOI: 10.1097/mnm.0b013e328338a120]

Circulating Tumor DNA, Imaging, and Carcinoembryonic Antigen: Comparison of Surveillance Strategies Among Patients Who Underwent Resection of Colorectal Cancer-A Systematic Review and Meta-analysis

BACKGROUND

Almost one-third of colorectal cancer (CRC) patients experience recurrence after resection; nevertheless, follow-up strategies remain controversial. We sought to systematically assess and compare the accuracy of carcinoembryonic antigen (CEA), imaging [positron emission tomography (PET) and computed tomography (CT) scans], and circulating tumor DNA (CtDNA) as surveillance strategies.

PATIENTS AND METHODS

PubMed, Medline, Embase, Scopus, Cochrane, Web of Science, and CINAHL were systematically searched. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was used to assess methodological quality. We performed a bivariate random-effects meta-analysis and reported pooled sensitivity, specificity, and diagnostic odds ratio (DOR) values for each surveillance strategy.

RESULTS

Thirty studies were included in the analysis. PET scans had the highest sensitivity to detect recurrence (0.95; 95%CI 0.91-0.97), followed by CT scans (0.77; 95%CI 0.67-0.85). CtDNA positivity had the highest specificity to detect recurrence (0.95; 95%CI 0.91-0.97), followed by increased CEA levels (0.88; 95%CI 0.82-0.92). Furthermore, PET scans had the highest DOR to detect recurrence (DOR 120.7; 95%CI 48.9-297.9) followed by CtDNA (DOR 37.6; 95%CI 20.8-68.0).

CONCLUSION

PET scans had the highest sensitivity and DOR to detect recurrence, while CtDNA had the highest specificity and second highest DOR. Combinations of traditional cross-sectional/functional imaging and newer platforms such as CtDNA may result in optimized surveillance of patients following resection of CRC.

Comparison of 18FDG-PET/CT and conventional follow-up methods in colorectal cancer: A randomised prospective study

BACKGROUND

A surveillance program was performed in colorectal cancer (CRC) patients after surgery, to diagnose asymptomatic recurrence.

AIMS

To assess whether 18-FDG positron emission tomography/CT (PET/CT) improved the detection of recurrence during a 3-year follow-up.

METHODS

A multicentre, two-arm randomised prospective trial comparing different 36-month follow-up strategies. Complete colonoscopy was performed at baseline and after 3 years and clinical exams with imaging every 3 months. The conventional arm (A) received carcinoembryonic antigen, liver echography, and alternated between lung radiography and computed tomography (CT) scans. The experimental arm (B) received PET/CT.

RESULTS

A total of 365 patients with colon (79.4%) or rectal cancer (20.6%), stages II (48.2%) or III (50.8%), were enroled in this study. At 36 months, intention-to-treat analysis revealed recurrence in 31 (17.2%) patients in arm A and 47 (25.4%) in arm B (p = 0.063). At 3 years, 7 of 31 relapses (22.5%) in arm A were surgically treated with curative intent, compared to 17 of 47 (36.2%) in arm B (p = 0.25). The rates of recurrence and new cancers were higher in arm B than arm A (p = 0.038).

CONCLUSIONS

PET/CT follow-up every 6 months did not increase the rate of recurrence at 3 years or the rate of surgically treated recurrence compared with conventional follow-up.

Locally recurrent rectal cancer: what the radiologist should know

Despite advances in surgical techniques and chemoradiation therapy, recurrent rectal cancer remains a cause of morbidity and mortality. After successful treatment of rectal cancer, patients are typically enrolled in a surveillance strategy that includes imaging as studies have shown improved prognosis when recurrent rectal cancer is detected during imaging surveillance versus based on development of symptoms. Additionally, patients who experience a complete clinical response with chemoradiation therapy may elect to enroll in a "watch-and-wait" strategy that includes imaging surveillance rather than surgical resection. Factors that increase the likelihood of recurrence, patterns of recurrence, and the imaging appearances of recurrent rectal cancer are reviewed with a focus on CT, PET CT, and MR imaging.

Use of semiquantitative analysis in local recurrence of colorectal carcinoma with 18F-FDG PET/CT: A myth or a truth?

OBJECTIVE

Recurrence of colorectal cancer is mostly seen within the first 2 years after surgery. The most frequent site of recurrence is the postsurgical areas and its surroundings. The purpose of this study was to evaluate the usefulness of semiquantitative analysis of ¹⁸Fluorine fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in determining recurrence of colorectal carcinoma in the operation site.

MATERIAL AND METHODS

Files of 35 patients with colorectal carcinoma (25 men, 10 women, mean age: 59.25±2.82 years, range: 27-80 years) who were treated with surgery and underwent FDG PET/CT scanning for restaging of colorectal carcinoma and showing increased FDG uptake in the postsurgical area, were retrospectively analysed. Besides calculating SUVmax of the areas showing FDG uptake, SUVmax of physiological colonic activity was also obtained and SUVmax of lesion/SUVmax of colonic wall (RSUVmax), was calculated. Characteristics of FDG uptake were classified according to histological analysis or clinical and imaging follow-up.

RESULTS

In 17 of 35 patients (49%) the standard of reference for the final diagnosis was histologic analysis and in 18 (51%), final diagnosis was based on imaging and clinical follow-up. In 15 of 35 patients (43%) the etiology of increased FDG uptake was recurrence and in 20 (57%), FDG accumulation was observed due to benign etiology. The difference between the mean of the results of SUVmax in patients with recurrent disease and with no evidence of recurrence was statistically significant (P=.030). For SUVmax, a cut-off value for recurrence was calculated as 9.51 with a sensitivity of 80% and a specificity of 70%. In terms of RSUVmax results, a statistically significant difference was also observed between mean values in patients with recurrent disease and in those without (P=.002). ROC analysis demonstrated that the best predictive value of RSUVmax for recurrence was 1.75 with a sensitivity of 67% and specificity of 95%.

CONCLUSIONS

Semiquantitative analysis of FDG PET/CT may be used in detecting recurrent disease of patients with colorectal carcinoma. Eliminating interfering physiological colonic activity in analysis may have an incremental effect on the success of this technique, by means of increasing the specificity.

Clinical Significance of Fluorine-18-fluorodeoxyglucose Positron Emission Tomography/computed Tomography in the Follow-up of Colorectal Cancer: Searching off Approaches Increasing Specificity for Detection of Recurrence

Background

Nearly 40% of colorectal cancer (CRC) recurs within 2 years after resection of primary tumor. Imaging with fluorine-18-fluorodeoxyglucose (^l8F-FDG) positron emission tomography/computed tomography (PET/CT) is the most recent modality and often applied for the evaluation of metastatic spread during the follow-up period. Our goal was to study the diagnostic importance of ¹⁸F-FDG-PET/CT data of maximum standardized uptake value (SUVmax), total lesion glycolysis (TLG) and the difference of SUVmax on dual-time imaging in CRC.

Patients and methods

We examined the SUVmax value of lesions on control or restaging ¹⁸F-FDG-PET/CT of 53 CRC patients. All lesions with increased SUVmax values were confirmed by colonoscopy or histopathology. We compared PET/CT results with conventional imaging modalities (CT, MRI) and tumor markers (carbohydrate antigen 19-9 [Ca 19-9], carcinoembryonic antigen [CEA]).

Results

Mean SUVmax was 6.9 ± 5.6 in benign group, 12.7 ± 6.1 in malignant group. Mean TLG values of malignant group and benign group were 401 and 148, respectively. ¹⁸F-FDG-PET/CT was truely positive in 48% of patients with normal Ca 19-9 or CEA levels and truely negative in 10% of cases with elevated Ca 19-9 or CEA. CT or MRI detected suspicious malignancy in 32% of the patients and ¹⁸F-FDG-PET/CT was truely negative in 35% of these cases. We found the most important and striking statistical difference of TLG value between the groups with benign and recurrent disease.

Conclusions

Although SUVmax is a strong metabolic parameter (p = 0.008), TLG seems to be the best predictor in recurrence of CRC (p = 0.001); both are increasing the specificity of ¹⁸F-FDG-PET/CT.

The added value of PET/Ce-CT/DW-MRI fusion in assessment of hepatic focal lesions: PET/Ce-CT/DW-MRI fusion in hepatic focal lesion

INTRODUCTION

The liver hosts a variety of benign and malignant tumors. Accurate diagnosis can be challenging in certain cases, especially in patients with a history of malignancy or in those with underlying liver pathology, such as cirrhosis.

OBJECTIVES

To evaluate the added clinical value of multi-modality liver imaging utilizing PET/Ce-CT/DW-MRI for characterization of hepatic focal lesions (HFL) and compare it with each diagnostic modality when interpreted alone.

METHODS

The study included 35 patients with HFL. They were 7 females & 28 males; their age ranged from 41 to 78years, all patients underwent PET/Ce-CT and DW-MRI scans. Ce-CT, PET and DW-MR images were reviewed independently, and then combined PET/Ce-CT, PET/DW-MRI and PET/Ce-CT/DW-MRI scans were analyzed. The results were correlated with histopathology or clinical/imaging follow-up.

RESULTS

The 35 patients had 98 focal lesions. Fifty-three lesions were finally diagnosed as primary hepatocellular carcinoma, 18 lesions were metastases, 7 lesions were lymphoma and 20 lesions were benign. On a patient based analysis; the sensitivity, specificity, PPV, NPV and accuracy were 100%, 67%, 94%, 100% and 94% for PET/Ce-CT compared to 97%, 83%, 97%, 83% and 94 % for DW-MRI, respectively. Combined PET/Ce-CT/DW-MR scans raise those parameters up to 100%. On a lesion based analysis; the sensitivity, specificity, PPV, NPV and accuracy were 94%, 75%, 94%, 75%, 90% for PET/Ce-CT compared to 94%, 95%, 99%, 97% and 94 % for DW-MRI, respectively. All these parameters were 100 % with PET/Ce-CT/DW-MRI.

CONCLUSIONS

The addition of DW-MRI to PET/Ce-CT is valuable in the characterization of hepatic focal lesions.

Value of 18F-FDG PET-CT in surveillance of postoperative colorectal cancer patients with various carcinoembryonic antigen concentrations

AIM: To evaluate the value of positron emission tomography (PET)/computerized tomography (CT) in surveillance of colorectal cancer (CRC) patients with different carcinoembryonic antigen (CEA) concentrations.

METHODS: One hundred and six postoperative CRC patients who had suspected recurrence or metastasis and received fluorodeoxyglucose (FDG) PET/CT within one week were included in this study. The final diagnosis was confirmed by histological examination or clinical follow-up over at least six months.

RESULTS: The sensitivity, specificity, and accuracy of FDG PET/CT were 95.2%, 82.6%, and 92.5%, and 94.8%, 81.4% and 92.8%, respectively, in the case- and lesion-based analyses. The sensitivity and accuracy of FDG PET/CT significantly differed from CT in both analyses (χ² = 8.186, P = 0.004; χ² =6.201, P = 0.013; χ² =13.445, P = 0.000; χ² =11.194, P = 0.001). In the lesion-based analysis, the sensitivity, specificity, and accuracy of FDG PET/CT in the abnormal CEA group were 97.8%, 82.6%, and 95.6%, compared with 81.3%, 80%, and 80.6% for patients with normal CEA levels. In case-based analysis, the sensitivity, specificity, and accuracy of FDG PET/CT were 97.2%, 77.8%, and 95% in abnormal CEA group. Only in lesion-based analysis, the sensitivity and accuracy of FDG PET/CT in the abnormal CEA group were significantly superior to those in the normal CEA group (χ² =6.432, P = 0.011; χ² =7.837, P = 0.005). FDG PET/CT changed the management in 45.8% of patients with positive scans.

CONCLUSION: FDG PET/CT showed superior diagnostic value and is an advisable option in surveillance of postoperative CRC patients with a vague diagnosis.

Detection of resectable recurrences in colorectal cancer patients with 2-[18F]fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography

PURPOSE

To evaluate the usefulness of 2-[(18)F]fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) in the early detection of resectable recurrences of colorectal cancer (CRC) and the impacts on the clinical disease management.

METHODS

FDG-PET/CT was performed on patients with elevated serum carcinoembryonic antigen (CEA) levels >5 ng/mL (Group 1) or suspicious recurrences without rise in serum CEA levels (Group 2). The results were analyzed on the basis of histological data, disease progression, and/or clinical follow-up. Recurrence was defined as evidence of recurrent lesions within 6 months of the FDG-PET/CT scan. Resectable recurrences and changes in management were calculated based on medical records.

RESULTS

In our study, 128 consecutive FDG-PET/CT analyses (n=49 in Group 1 and n=79 in Group 2) were performed on 96 recruited patients. Recurrences were proven in 63. The overall sensitivity, specificity, and accuracy of FDG-PET/CT were 98.4%, 89.2%, and 93.8%, respectively, and were 100%, 88.9%, and 95.9% in Group 1 and 96.9% and 89.4% and 92.4% in Group 2, respectively. Surgical resections were performed in 38.7% (12/31) of Group 1 patients and 53.1% (17/32) of Group 2 patients. FDG-PET/CT induced changes in planned management in 48.4% (62/128) of all patients, which included 63.3% (31/49) of Group 1 patients and 39.2% (31/79) of Group 2 patients (p=0.008). After a follow-up, 3.4% (1/29) of patients who underwent surgical resection of recurrent lesions and 34.3% (11/34) patients who did not undergo resection died at the end of study (p=0.004).

CONCLUSIONS

The surgical resection of limited recurrent disease, as determined by FDG-PET/CT, improves the survival of CRC patients. FDG-PET/CT should be performed not only in patients with elevated serum CEA levels, but also in those in whom recurrences are suspected to improve the early detection of resectable disease.

Value of Surveillance (18)F-FDG PET/CT in Colorectal Cancer: Comparison with Conventional Imaging Studies

PURPOSE

To assess the value of PET/CT for detecting local or distant recurrence in patients who undergo surgery for colorectal cancer (CRC) and to compare the accuracy of PET/CT to that of conventional imaging studies (CIS).

METHODS

Tumor surveillance PET/CT scans done between March 2005 and December 2009 of disease-free patients after surgery with or without adjuvant chemotherapy for CRC were retrospectively studied. CIS (serial enhanced CT from lung base to pelvis and plain chest radiograph) were performed within 1 month of PET/CT. We excluded patients with distant metastasis on initial staging, a known recurrent tumor, and a lack of follow-up imaging. The final diagnosis was based on at least 6 months of follow-up with colonoscopy, biopsy, and serial imaging studies in combination with carcinoembryonic antigen levels.

RESULTS

A total of 262 PET/CT scans of 245 patients were included. Local and distant recurrences were detected in 27 cases (10.3%). On case-based analysis, the overall sensitivity, specificity, and accuracy were 100, 97.0, and 97.3% for PET/CT and 85.1, 97.0, and 95.8% for CIS, respectively. On lesion-based analysis, PET/CT detected more lesions compared to CIS in local recurrence and lung metastasis. PET/CT and CIS detected the same number of lesions in abdominal lymph nodes, hepatic metastasis, and peritoneal carcinomatosis. PET/CT detected two more metachronous tumors than did CIS in the lung and thyroid gland.

CONCLUSION

PET/CT detected more recurrences in patients who underwent surgery for CRC than did CIS and had the additional advantage of evaluating the entire body during a single scan.

¹⁸F-Fluorodeoxyglucose positron emission tomography/computed tomography finds answers in cancer patients with increasing tumor markers and negative or equivocal conventional imaging modalities

BACKGROUND

The increase in tumor markers with negative or equivocal conventional imaging modalities represents a serious dilemma in the follow-up of previously treated cancer patients. Positron emission tomography/computed tomography (PET/CT) has emerged as a useful tool in oncological imaging in staging and restaging of most cancers.

OBJECTIVE

This study explored the potential role of ¹⁸F-fluorodeoxyglucose (FDG) PET/CT in the detection and localization of tumor recurrence in cancer patients with increasing serum tumor markers and negative or equivocal conventional imaging modalities.

MATERIALS AND METHODS

This prospective study was conducted on 105 previously diagnosed and treated cancer patients with different pathologies. All patients were referred for ¹⁸F-FDG PET/CT scans because of increasing tumor markers with negative or equivocal conventional imaging modalities. All patients underwent whole-body ¹⁸F-FDG PET/CT scans. The findings were confirmed by clinical and/or radiological follow-up of at least 12 months and histopathologically whenever possible.

RESULTS

PET/CT detected recurrence and/or metastases in 90 patients (85.7%), including 17 recurrences, 50 metastases, and 23 recurrences and metastases. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of PET/CT scans were 95.7, 100, 100, 73.3, and 96.2%, respectively. These parameters were 95, 100, 100, 69, and 95% for PET scans alone and were 91.5, 100, 100, 57.9, and 92.3% for CT scans alone.

CONCLUSION

¹⁸F-FDG PET/CT is a powerful diagnostic tool in restaging of cancer patients. In most cases, PET/CT provides accurate results and helps resolve the clinical dilemma encountered in oncological patients with increasing serum tumor markers and negative or equivocal findings in conventional imaging modalities.

Cost of pretherapeutic staging of patients with colorectal cancer metastases in a French population

BACKGROUND

Little is known about the economic burden of pretherapeutic staging of patients presenting colorectal cancer metastases.

OBJECTIVE

The aim of this study was to estimate the cost of pretherapeutic staging and identify cost determinants for 132 patients presenting colorectal metastases and living in the north-east of France.

METHOD

Staging cost was estimated using direct medical costs from the point of view of the French Health Insurance System. Independent factors were identified using a linear regression model, and bootstrap resampling was used to estimate unbiased standard errors and 95% confidence intervals.

RESULTS

The overall mean cost for pretherapeutic staging was estimated to be 1534€ [95% CI: 1250€-1818€]. Staging costs increased significantly with the number of medical procedures performed during the staging, and according to health care patterns (in-patient hospital stay versus out-patient episodes, public versus private care).

CONCLUSION

These results could now be used to estimate the impact of new imaging techniques on clinical practices and pretherapeutic staging costs.