Serum CEA testing in the post-operative surveillance of colorectal carcinoma

Circulating Tumor DNA Testing in Curatively Resected Colorectal Cancer and Salvage Resection

Importance

Serial circulating tumor DNA (ctDNA) has emerged as a routine surveillance strategy for patients with resected colorectal cancer, but how serial ctDNA monitoring is associated with potential curative outcomes has not been formally assessed.

Objective

To examine whether there is a benefit of adding serial ctDNA assays to standard-of-care imaging surveillance for potential curative outcomes in patients with resected colorectal cancer.

Design, Setting, and Participants

In this single-center (City of Hope Comprehensive Cancer Center, Duarte, California), retrospective, case cohort study, patients with stage II to IV colorectal cancer underwent curative resection and were monitored with serial ctDNA assay and National Cancer Center Network (NCCN)-guided imaging surveillance from September 20, 2019, to April 3, 2024. The median duration of follow-up was 26 months (range, 2-54 months).

Interventions

Serial ctDNA assays were performed every 3 months for 2 years and every 6 months for the 3 following years in conjunction with NCCN-guided radiographic surveillance.

Main Outcomes and Measures

The primary outcome was the proportion of patients with clinical benefit from ctDNA testing, defined as the proportion of patients with a newly positive ctDNA assay and negative scheduled imaging (most recent or concurrent) that subsequently led to early imaging confirmation of recurrence, followed by curative-intent intervention with no evidence of recurrence at the time of data cutoff. Recurrence was categorized by ctDNA recurrence, radiographic recurrence, or concurrent ctDNA and imaging recurrence. Salvage resections and associated durable remissions were described within each of the 3 categories. Descriptive statistics were used to characterize the patient population.

Results

In total, 184 patients (median age, 59 years [range, 32-88 years]; 97 female [52.7%]) were included in this study, and 129 (70.1%) had stage II to III disease. Forty-five patients (24.5%) had ctDNA or imaging-confirmed recurrence. Of these 45 patients, 14 had radiographic recurrence with negative ctDNA, and 11 had concurrent ctDNA and imaging recurrence. Twenty of 45 patients had ctDNA positivity with negative imaging at first ctDNA positivity; 6 had reflex imaging that was positive for recurrence, and 14 continued with serial imaging and ctDNA monitoring. Ten of 14 patients had subsequent recurrent disease, 3 patients had a spontaneous clearance of ctDNA, and 1 patient remained imaging negative 7 months after positive ctDNA, after which she was lost to follow-up. Altogether, 11 of 20 patients with ctDNA recurrence without initial concurrent imaging recurrence had subsequent metastasectomy, and only 3 were disease-free at the cutoff date in April 2024, representing 1.6% of the surveilled population.

Conclusions and Relevance

In this cohort study of patients with stage II to IV colorectal cancer who underwent curative-intent resection, the addition of serial tumor-informed ctDNA assay to the standard NCCN-recommended surveillance had limited clinical benefits. Additional prospective research is needed to clarify the value of ctDNA testing in the surveillance setting.

Surveillance strategies following curative resection and non-operative approach of rectal cancer: How and how long? Review of current recommendations

Different follow-up strategies are available for patients with rectal cancer following curative treatment. A combination of biochemical testing and imaging investigation, associated with physical examination are commonly used. However, there is currently no consensus about the types of tests to perform, the timing of the testing, and even the need for follow-up at all has been questioned. The aim of this study was to review the evidence of the impact of different follow-up tests and programs in patients with non-metastatic disease after definitive treatment of the primary. A literature review was performed of studies published on MEDLINE, EMBASE, the Cochrane Library and Web of Science up to November 2022. Current published guidelines from the most authoritative specialty societies were also reviewed. According to the follow-up strategies available, the office visit is not efficient but represents the only way to maintain direct contact with the patient and is recommended by all authoritative specialty societies. In colorectal cancer surveillance, carcinoembryonic antigen represents the only established tumor marker. Abdominal and chest computed tomography scan is recommended considering that the liver and lungs are the most common sites of recurrence. Since local relapse in rectal cancer is higher than in colon cancer, endoscopic surveillance is mandatory. Different follow-up regimens have been published but randomized comparisons and meta-analyses do not allow to determine whether intensive or less intensive follow-up had any significant influence on survival and recurrence detection rate. The available data do not allow the drawing of final conclusions on the ideal surveillance methods and the frequency with which they should be applied. It is very useful and urgent for clinicians to identify a cost-effective strategy that allows early identification of recurrence with a special focus for high-risk patients and patients undergoing a “watch and wait” approach.

Colorectal Cancer: Postoperative Follow-up and Surveillance

Follow-up and surveillance form an important aspect of care in patients with colorectal cancers (CRC). Most recurrences will occur within 2 years of surgery and 90% by 5 years. Follow up protocols have not been well defined in stage I disease and the approach should be individualized. As 40% of patients with stages II and III will develop recurrences, intensive postoperative follow-up strategy is recommended for them. It includes visit to the clinician for clinical examination, serum carcinoembryonic antigen (CEA), computed tomography (CT) of the chest and abdomen, colonoscopy, and flexible proctosigmoidoscopy in rectal cancers. Surveillance should be undertaken in those who are medically fit for repeat surgical procedures or for chemoradiotherapy. The concept of intensive post operative surveillance is based on the fact that some of these patients can have resectable/curable recurrence.

Predictive performance of TPA testing for recurrent disease during follow-up after curative intent surgery for colorectal carcinoma

BACKGROUND

The aim of the present study was to investigate the predictive performance of serial tissue polypeptide antigen (TPA) testing after curative intent resection for detection of recurrence of colorectal malignancy.

METHODS

Serum samples were obtained in 572 patients from three different hospitals during follow-up after surgery. Test characteristics of serial TPA testing were assessed using a cut-off value of 75 U/L. The relation with American Joint Committee on Cancer stage and the potential additive value of tissue polypeptide antigen testing upon standard carcinoembryonic antigen (CEA) testing were investigated.

RESULTS

The area under the receiver operating characteristic curve of TPA for recurrent disease was 0.70, indicating marginal usefulness as a predictive test. Forty percent of cases that were detected by CEA testing would have been missed by TPA testing alone, whilst most cases missed by CEA were also not detected by TPA testing. In the subpopulation of patients with stage III disease predictive performance was good (area under the curve 0.92 within 30 days of diagnosing recurrent disease). In this group of patients, 86% of cases that were detected by CEA were also detected by TPA.

CONCLUSIONS

Overall, TPA is a relatively poor predictor for recurrent disease during follow-up. When looking at the specific subpopulation of patients with stage III disease predictive performance of TPA was good. However, TPA testing was not found to be superior to CEA testing in this specific subpopulation.

A Prospective Study of Comparing Multi-Gene Biomarker Chip and Serum Carcinoembryonic Antigen in the Postoperative Surveillance for Patients with Stage I-III Colorectal Cancer

BACKGROUND

Circulating biomarkers can predict clinical outcomes in colorectal cancer patients. The aim of the study was to evaluate the feasibility of our multigene biomarker chip for detecting circulating tumor cells for postoperative surveillance of stage I-III colorectal cancer patients.

MATERIALS AND METHODS

In total, 298 stage I-III colorectal cancer patients were analyzed after curative resection between June 2010 and October 2014. During each follow-up, a postoperative surveillance strategy, including ESMO Guidelines Working Group recommendations and the biochip, was used.

RESULTS

After a 28.4-month median follow-up, 48 (16.1%) patients had postoperative relapse. Univariate analysis revealed that the postoperative relapse risk factors were rectal tumor, perineural invasion, elevated preoperative and postoperative serum carcinoembryonic antigen levels, and positive biochip results (all P < 0.05). Multivariate analyses revealed that postoperative relapse correlated significantly with elevated postoperative serum carcinoembryonic antigen levels (odds ratio = 4.136, P = 0.008) and positive biochip results (odds ratio = 66.878, P < 0.001). However, the sensitivity (P = 0.003), specificity (P = 0.003), positive (P = 0.002) and negative (P = 0.006) predictive values, and accuracy (P < 0.001) of the biochip for predicting postoperative relapse were significantly higher than those of elevated postoperative serum carcinoembryonic antigen levels. Moreover, the median lead time between positive biochip result and postoperative relapse detection was significantly earlier than that between elevated postoperative serum carcinoembryonic antigen level and postoperative relapse detection (10.7 vs. 2.8 months, P < 0.001). Furthermore, positive biochip results correlated strongly with lower disease-free survival and overall survival of colorectal cancer patients (both P < 0.001).

CONCLUSION

Compared with conventional serum carcinoembryonic antigen detection, our multigene chip aided more accurate and earlier prediction of postoperative relapse during stage I-III colorectal cancer patient surveillance. In clinical practice, this biochip may facilitate early postoperative relapse diagnosis in colorectal cancer patients.

The diagnostic accuracy of carcinoembryonic antigen to detect colorectal cancer recurrence - A systematic review

INTRODUCTION

Carcinoembryonic Antigen (CEA) has been used as a tumor marker in the follow-up of colorectal cancer for more than 40 years. Controversy exists regarding its diagnostic applicability due to a relatively low sensitivity and a questionable effect on mortality. The aim of this review was to assess the diagnostic accuracy of CEA in detecting recurrence after intended curative surgery for primary colorectal cancer.

METHODS

Systematic literature searches were performed in PubMed, EMBASE and Cochrane databases, and articles were chosen based on predefined inclusion criteria. Reference lists from included articles were manually searched for additional publications of relevance.

RESULTS

Forty-two original studies with generally representative populations and long follow-up were included. Data were reported on outcomes from 9,834 CEA tests during follow-up. Reporting on the reference standards used was not optimal. Sensitivity of CEA ranged from 17.4 % to 100 %, specificity ranged from 66.1 % to 98.4 %, positive predictive value ranged from 45.8 % to 95.2% and negative predictive value ranged from 74.5 % to 100 %.

CONCLUSION

Results point toward a sensitivity of CEA ranging between 50 % and 80 %, and a specificity and negative predictive value above 80 %. Results on positive predictive value showed low reliability. Overall, CEA did not effectively detect treatable recurrences at an early stage, and a clinically relevant effect on patient mortality remains to be proven.

Blood CEA levels for detecting recurrent colorectal cancer

BACKGROUND

Testing for carcino-embryonic antigen (CEA) in the blood is a recommended part of follow-up to detect recurrence of colorectal cancer following primary curative treatment. There is substantial clinical variation in the cut-off level applied to trigger further investigation.

OBJECTIVES

To determine the diagnostic performance of different blood CEA levels in identifying people with colorectal cancer recurrence in order to inform clinical practice.

SEARCH METHODS

We conducted all searches to January 29 2014. We applied no language limits to the searches, and translated non-English manuscripts. We searched for relevant reviews in the MEDLINE, EMBASE, MEDION and DARE databases. We searched for primary studies (including conference abstracts) in the Cochrane Central Register of Controlled Trials (CENTRAL), in MEDLINE, EMBASE, and the Science Citation Index & Conference Proceedings Citation Index - Science. We identified ongoing studies by searching WHO ICTRP and the ASCO meeting library.

SELECTION CRITERIA

We included cross-sectional diagnostic test accuracy studies, cohort studies, and randomised controlled trials (RCTs) of post-resection colorectal cancer follow-up that compared CEA to a reference standard. We included studies only if we could extract 2 x 2 accuracy data. We excluded case-control studies, as the ratio of cases to controls is determined by the study design, making the data unsuitable for assessing test accuracy.

DATA COLLECTION AND ANALYSIS

Two review authors (BDN, IP) assessed the quality of all articles independently, discussing any disagreements. Where we could not reach consensus, a third author (BS) acted as moderator. We assessed methodological quality against QUADAS-2 criteria. We extracted binary diagnostic accuracy data from all included studies as 2 x 2 tables. We conducted a bivariate meta-analysis. We used the xtmelogit command in Stata to produce the pooled estimates of sensitivity and specificity and we also produced hierarchical summary ROC plots.

MAIN RESULTS

In the 52 included studies, sensitivity ranged from 41% to 97% and specificity from 52% to 100%. In the seven studies reporting the impact of applying a threshold of 2.5 µg/L, pooled sensitivity was 82% (95% confidence interval (CI) 78% to 86%) and pooled specificity 80% (95% CI 59% to 92%). In the 23 studies reporting the impact of applying a threshold of 5 µg/L, pooled sensitivity was 71% (95% CI 64% to 76%) and pooled specificity 88% (95% CI 84% to 92%). In the seven studies reporting the impact of applying a threshold of 10 µg/L, pooled sensitivity was 68% (95% CI 53% to 79%) and pooled specificity 97% (95% CI 90% to 99%).

AUTHORS' CONCLUSIONS

CEA is insufficiently sensitive to be used alone, even with a low threshold. It is therefore essential to augment CEA monitoring with another diagnostic modality in order to avoid missed cases. Trying to improve sensitivity by adopting a low threshold is a poor strategy because of the high numbers of false alarms generated. We therefore recommend monitoring for colorectal cancer recurrence with more than one diagnostic modality but applying the highest CEA cut-off assessed (10 µg/L).

Correlation of CEA but not CA 19-9 as serum biomarkers of disease activity in a case of metastatic rectal adenocarcinoma

We present the case of a 62-year-old-man with moderately differentiated adenocarcinoma of the rectum. This patient underwent neoadjuvant chemoradiation and surgical resection followed by adjuvant chemotherapy. After completing therapy, this patient had 2 instances of CEA elevation, both of which preceded the discovery of recurrent disease. While on treatment for these recurrences, CA 19-9 increased rapidly to 4,405. This CA 19-9 elevation persisted for approximately 4 months in the absence of clinical, radiographic or additional serologic evidence of progressive disease before returning to baseline. Shortly after this tumor marker normalized, a small area of locally recurrent disease was discovered. This case highlights the utility and pitfalls of colorectal cancer disease monitoring with CEA and CA 19-9. The differential diagnosis of CA 19-9 elevation is discussed in this report.

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.

The role of 18F-FDG PET/CT in detecting colorectal cancer recurrence in patients with elevated CEA levels

INTRODUCTION

In this study we aimed to define the success of fluorine-18 (18F) fluorodeoxyglucose (FDG) PET/computed tomography (PET/CT) in detecting recurrent disease in our patient group with colorectal cancer (CRC) and elevated carcinoembryonic antigen (CEA) levels.

MATERIAL AND METHOD

Patients who had a previous diagnosis of CRC were searched retrospectively in our PET center database. Seventy-six 18F-FDG PET/CT studies between October 2006 and December 2010 of 69 patients (25 women, 44 men; mean age: 61.61 ± 4.1 years) with elevated CEA levels were evaluated. 18F-FDG PET/CT findings and concurrent abdominopelvic contrast-enhanced computed tomography (ceCT) findings were compared with histopathological findings and/or clinical follow-up data as the 'gold standard'.

RESULTS

In the patient-based analysis, the sensitivity and specificity of 18F-FDG PET/CT in the detection of disease recurrence were calculated as 97 and 61%, respectively. A statistically significant difference was found in frequencies of positive and negative 18F-FDG PET/CT findings between patients with or without recurrent disease by gold standard (P<0.05). There was no correlation between patients' serum CEA levels and lesions' maximum standardized uptake values (P=0.85). The sensitivity and specificity of ceCT were computed as 51 and 60%, respectively. In the evaluation of separate patient groups, although the sensitivity and specificity of 18F-FDG PET/CT were calculated as 100 and 60% in the group whose CEA level elevation was less than two-fold (5-9.9 ng/ml), these were 100 and 75% in the group with CEA elevation less than three-fold (10-14.9 ng/ml) and 95 and 62% in the group with elevation more than three-fold (≥ 15 ng/ml). The sensitivity and specificity of 18F-FDG PET/CT were computed as 98 and 85% in the lesion-based evaluation. The sensitivity and specificity of ceCT were 73 and 86%, respectively.

CONCLUSION

18F-FDG PET/CT is a safe imaging method that can be used in the determination of CRC recurrence in patients with elevated CEA levels, regardless of the CEA level.

The Role of High Frequency Dynamic Threshold (HiDT) Serum Carcinoembryonic Antigen (CEA) Measurements in Colorectal Cancer Surveillance: A (Revisited) Hypothesis Paper

Following curative treatment for colorectal cancer (CRC), 30% to 50% of patients will develop recurrent disease. For CRC there are several lines of evidence supporting the hypothesis that early detection of metachronous disease offers a second opportunity for cure. This paper revisits the potential role of serum carcinoembryonic antigen (CEA) in follow-up. A comprehensive review of the literature (1978–2008) demonstrates that the initial promise of serum CEA as an effective surveillance tool has been tarnished through perpetuation of poorly designed studies. Specific limitations included: testing CEA as only an ‘add-on’ diagnostic tool; lack of standardization of threshold values; use of static thresholds; too low measurement frequency. Major changes in localizing imaging techniques and treatment of metastatic CRC further cause a decrease of clinical applicability of past trial outcomes. In 1982, Staab hypothesized that the optimal benefit of serum CEA as a surveillance tool is through high-frequency triage using a dynamic threshold (HiDT). Evidence supporting this hypothesis was found in the biochemical characteristics of serum CEA and retrospective studies showing the superior predictive value of a dynamic threshold. A multi-centred randomized phase III study optimizing the usage of HiDT against resectability of recurrent disease is commencing recruitment in the Netherlands.

Ability of 18F-FDG PET/CT to diagnose recurrent colorectal cancer in patients with elevated CEA concentrations

OBJECTIVE

Elevated levels of serum carcinoembryonic antigen (CEA) in patients with colorectal cancer (CRC) during follow-up suggest recurrence, which can be visualized by (18)F-FDG PET/CT. Since the magnitude of CEA elevation reflects cancer volume, the ability of PET/CT to detect recurrence in patients with only mildly elevated CEA might be limited. However, the accuracy of PET/CT in detecting recurrence associated with elevated CEA has not been fully assessed. We retrospectively evaluated the diagnostic performance of (18)F-FDG PET/CT postoperatively relative to CEA levels among patients with CRC.

METHODS

We visually assessed 75 PET/CT evaluations of 57 postoperative patients with CEA >5.0 ng/ml. Tumor volumes were also determined using image analysis software. The final diagnosis was confirmed based on histopathological findings, or at least on 6 months of clinical follow-up.

RESULTS

Two lung cancers were excluded and we finally analyzed data from 73 of the 75 PET/CT evaluations. Recurrences were diagnosed in 54 (prevalence 74%). The sensitivity and specificity of PET/CT to detect recurrence was 50/54 (93%) and 14/19 (74%), respectively. The positive and negative predictive values were 91 and 78%, respectively, and the positive and negative likelihood ratios were 3.52 and 0.10, respectively. Values for the sensitivity of PET/CT were 88 and 95%, and those for specificity were 78 and 70%, at serum CEA concentrations of 5-10 and >10 ng/ml, respectively. Serum CEA (r = 0.500, p < 0.001) significantly correlated with cancer volumes.

CONCLUSIONS

The present findings showed that (18)F-FDG PET/CT could accurately detect recurrent CRC irrespective of the elevated CEA concentration.

Carcinoembryonic Antigen in the Staging and Follow-up of Patients with Colorectal Cancer

CEA is a complex glycoprotein produced by 90% of colorectal cancers and contributes to the malignant characteristics of a tumor. It can be measured in serum quantitatively, and its level in plasma can be useful as a marker of disease. Because of its lack of sensitivity in the early stages of colorectal cancer, CEA measurement is an unsuitable modality for population screening. An elevated preoperative CEA is a poor prognostic sign and correlates with reduced overall survival after surgical resection of colorectal carcinoma. A failure of the CEA to return to normal levels after surgical resection is indicative of inadequate resection of occult systemic disease. Frequent monitoring of CEA postoperatively may allow identification of patients with metastatic disease for whom surgical resection or other localized therapy might be potentially beneficial. To identify this group, serial CEA measurement appears to be more effective than clinical evaluation or any other diagnostic modality, although its sensitivity for detecting recurrent disease is not as high for locoregional or pulmonary metastases as it is for liver metastases. Several studies have shown that a small percentage of patients followed postoperatively with CEA monitoring and who undergo CEA-directed salvage surgery for metastatic disease will be alive and disease-free 5 years after surgery. Furthermore, CEA levels after salvage surgery do appear to predict survival in patients undergoing resection of liver or pulmonary metastases. However, several authors argue that CEA surveillance is not cost-effective in terms of lives saved. In support of this argument, there is no clear difference in survival after resection of metastatic disease with curative intent between patients in whom the second-look surgery was performed on the basis of elevated CEA levels and those with other laboratory or imaging abnormalities. There is also no clear consensus on the frequency or duration of CEA monitoring, although the ASCO guidelines currently recommend every 2-3 months for at least 2 years after diagnosis. In the follow-up of patients undergoing palliative therapy, the CEA level correlates well with response, and CEA is indicative of not only response but may also identify patients with stable disease for whom there is also a demonstrated benefit in survival and symptom relief with combination chemotherapy. More recently, scintigraphic imaging after administration of radiolabeled antibodies afforded an important radionuclide technique that adds clinically significant information in assessing the extent and location of disease in patients with colorectal cancer above and beyond or complementary to conventional imaging modalities. Immunotherapy based on CEA is a rapidly advancing area of clinical research demonstrating antibody and T-cell responses.

How uncommon are isolated lung metastases in colorectal cancer? A review from database of 754 patients over 4 years

BACKGROUND

It is commonly thought that colon cancer metastases to the lungs without involvement of the liver are rare.

METHODS

We performed a retrospective review of all patients with colorectal cancer diagnosed between December 2003 and August 2007 in Singapore. Isolated lung metastases were determined as (1) Definite if there was confirmed histology or cytology of the lung lesion(s) in the absence of liver lesions on CT scan, and (2) Probable if there were only radiological evidence suggestive of lung metastases rather than lung primary also in the absence of liver lesions on CT scan.

RESULTS

There were 196 patients with rectal and 558 patients with colon cancer (369 left-sided and 189 right-sided). There were 13 definite isolated lung metastases, and the remaining 43 were probable. Twenty-three (12%) patients with rectal cancer and 33 (6%) patients with colon cancer had isolated lung metastases (OR 2.11, 95% CI 1.21-3.70). Patients with >or=pT3 lesions (OR 1.92, 95% CI 0.75-4.93) and >or=pN1 (OR 1.56, 95% CI 0.86- 2.83) were more likely to have isolated lung metastases.

CONCLUSION

The true incidence of isolated lung without liver metastases in colorectal cancer is likely to lie between 1.7% and 7.2%. While the incidence of isolated lung metastases is twice as common in patients with rectal cancer, it is still significant in patients with colon cancer. The absence of liver involvement should not preclude a search for lung metastases.

Results of a national survey among Dutch surgeons treating patients with colorectal carcinoma. Current opinion about follow-up, treatment of metastasis, and reasons to revise follow-up practice

OBJECTIVE

Follow-up after curative resection of colorectal carcinoma (CRC) has been subjected to debate concerning its effectiveness to reduce cancer mortality. Current national and international guidelines advise CEA measurements every 3 months during 3 years after surgery. The common clinical practice and opinion about follow-up for colorectal carcinoma, was evaluated by means of a survey among Dutch general surgeons.

METHOD

A web-based survey of follow-up after treatment of CRC was sent to all registered Dutch general surgeons. A reply from 246 surgeons treating patients for colorectal carcinoma in 105 out of 118 hospitals was received (response rate 91%). Questions related to actual follow-up protocol, opinion about serum CEA monitoring, liver and/or lung metastasectomy, and motivation to participate in a new trial concerning follow-up.

RESULTS

For the majority of surgeons the length of follow-up was influenced by age of the patient (62%) and physical condition (76%) prohibiting hepatic metastasectomy. The generally accepted follow-up protocol consisted of CEA measurements every 3 months in the first year and six-monthly thereafter, and ultrasound examination of the liver every 6 months. Nearly all surgeons (92%) were willing to participate in a new study of follow-up protocol.

CONCLUSION

The adherence to national guidelines for the follow-up of colorectal carcinoma is low. The indistinctness about follow-up after curative treatment of colorectal carcinoma also affects clinical practice. Recent advancements in imaging techniques, liver and lung surgery have changed circumstances, which are not yet anticipated upon in current guidelines. Renewal of follow-up based upon scientific evidence is required.

Utility of slot-blot-ELISA as a new, fast, and sensitive immunoassay for detection of carcinoembryonic antigen in the urine samples of patients with various gastrointestinal malignancies

Carcinoembryonic antigen (CEA) is the most widely used clinical tumor marker. CEA immunoassay has found acceptance as a diagnostic adjunct in clinical diagnosis of gastrointestinal tumors (GIT). Several immunoassays have been established for detection of CEA in plasma, serum, tissue, feces, and urine of cancer patients using polyclonal or monoclonal antibodies raised against CEA. Some of these assays display both high sensitivity and specificity for the detection of CEA. However, these assays require special and highly expensive equipment and the procedures require long periods for their completion. In the present study, we established a Slot-Blot Enzyme Linked Immunosorbent Assay (SB-ELISA), based on anti-CEA monoclonal antibody (CEA-mAb), as a new, simple, fast, cheap, and non-invasive immunodiagnostic technique for detection of CEA in the urine of GIT patients. Urine and serum samples were collected from 248 GIT patients (58 with pancreatic cancer, 20 with hepatoma, 23 with ampullary carcinoma, 15 with hilar cholangiocarcinoma, 28 with gastric cancer, 14 with esophageal cancer, and 90 with colorectal cancer). Moreover, urine and serum samples were collected from 50 healthy individuals to serve as negative controls. The traditional ELISA technique was used for determination of CEA in the sera of GIT patients using anti-CEA monoclonal antibody. A comparison between the results of both techniques (ELISA and SB-ELISA) was carried out. The traditional ELISA detected CEA in the sera of 154 out of 248 GIT patients with a sensitivity of 59.8%, 51.7% positive predictive value (PPV) and 75.37% negative predictive value (NPV). In addition, it identified 15 false positive cases out of 50 healthy individuals with a specificity of 70%. The urinary CEA was identified by a Western blotting technique and CEA-mAb at a molecular mass of 180 Kda. The developed SB-ELISA showed higher sensitivity, specificity, PPV, and NPV (70.1%, 78%, 62.4%, and 82.13%, respectively) for detection of CEA in the urine of GIT patients. The semi-quantitative SB-ELISA showed a higher overall efficiency of 72.8% versus 63.4% in the case of the quantitative ELISA, for detection of CEA. In conclusion, SB-ELISA is more efficient for detection of CEA in gastrointestinal tumors. It is a simple, rapid, non-invasive, and sensitive assay. Moreover, all steps of the SB-ELISA are performed at room temperature, without the use of expensive equipment; this may enhance the application of this assay in field studies and mass screening programs.

PET imaging in assessing gastrointestinal tumors

The clinical usefulness of FDG-PET imaging is now firmly established in various situations, such as the preoperative staging of esophageal cancer and recurrent colorectal carcinoma and the detection and staging of recurrent colorectal cancer when there is a clinical or biologic suspicion with inconclusive conventional findings. Encouraging results were obtained in the evaluation of the therapeutic response of various gastrointestinal malignancies, either during the treatment or after its completion. There is no firm consensus regarding its role in pancreatic cancer, either proved or suspected, but it may be valuable in selected clinical situations. Its role seems fairly limited in patients with hepatocellular carcinoma, although PET findings may have prognostic implications. Evaluation of cholangiocarcinoma is an emerging indication, albeit with limited data to date. Finally, PET/CT is very likely to enhance the role of FDG imaging further in the work-up of patients with gastrointestinal tumors.

Follow-up strategies after curative resection of colorectal cancer

Consensus is lacking as to the best strategy for following patients who have undergone definitive surgical medical treatment for colon cancer. The goal of any surveillance program should be detection of recurrent disease at a sufficiently early time to allow subsequent curative therapy. Although periodic clinical examinations, laboratory tests, radiographic imaging, and carcinoembryonic antigen (CEA) testing have been utilized as a form of surveillance, such aggressive and costly intervention has not been validated through clinical studies. Four of the five randomized trials comparing such an intensive surveillance strategy to less frequent testing have not demonstrated the intensive approach to lead to an improvement in overall survival. Furthermore, intensive testing is both costly and has been shown not to improve quality of life. Further research designing appropriate postoperative testing is needed to guide physicians and patients after the curative resection of a colorectal cancer.

Tumor angiogenesis predicts recurrence with normal serum carcinoembryonic antigen in advanced rectal carcinoma patients

Many studies have established the usefulness of serum carcinoembryonic antigen (CEA) oriented serial monitoring for predicting recurrence and prognosis; however, few studies have so far investigated serum CEA-negative recurrence. The aim of this study was to elucidate the nature of CEA-negative recurrence regarding tumor angiogenesis. Fifty-seven patients with T3/T4 rectal cancer were divided into the two groups according to the serum CEA status. Angiogenesis was defined as the intratumoral vessel count by immunohistochemical staining using CD31. The CD31 count was significantly higher in the recurrent patients in both groups and the ratio of nodal involvement was significantly higher in the recurrent patients of the CEA-negative group. Local recurrence mainly developed in the CEA-negative group; however, the CD31 count did not predict the sites of recurrence nor the relapse period in the both groups. A multivariate analysis showed a high CD31 count >26) to be a prognostic factor not only for recurrence but also for survival (P = 0.001, 0.043, respectively). These results suggest that a high degree of tumor angiogenesis in sections of T3/T4 rectal cancer may therefore be an important predictor for CEA-negative recurrence.

Monitoring carcinoembryonic antigen in colorectal cancer: is it still useful?

The results of a study conducted to determine the usefulness of carcinoembryonic antigen (CEA) monitoring in the follow-up of patients with resected colorectal cancer are reported herein. The subjects of this study were 125 patients in whom CEA had been determined preoperatively and 239 patients in whom CEA had been monitored postoperatively. The results revealed increased preoperative CEA in only 24% of the subjects, and that this increment was correlated with subsequent more advanced tumor stage and a higher recurrence rate (P < 0.01). The postoperative CEA level exceeded the threshold in 71% of the patients affected by recurrence, 94.4% of whom developed liver metastases and 50%, nonhepatic recurrence. This marker showed elevated sensitivity for liver metastases (99%), whereas the sensitivity was lower for nonhepatic recurrence of the disease (94%). Thus, we concluded that CEA monitoring can be useful for preoperative colorectal tumor grading, even if its validity in the early diagnosis of recurrence is problematic, especially in terms of radical repeated surgery and survival.

Pre-operative serum levels of CA 242 and CEA predict outcome in colorectal cancer

The prognostic value of the preoperative serum levels of CA 242 and CEA in patients with colorectal cancer was investigated. The serum concentrations of CA 242 and CEA were determined from preoperative serum samples of 259 patients with colorectal cancer (39 Dukes' A, 100 Dukes' B, 59 Dukes' C and 61 Dukes' D). Survival data of these patients were obtained to the end of 1993. There was a significantly longer survival in patients with a CA 242 level below 20 U/ml compared with patients with an elevated serum level. A difference was seen in overall survival (P < 0.0001), and in Dukes' B (P = 0.016) and Dukes' D (P = 0.009) stages. In Dukes' A and C colorectal cancer, the difference was not significant (P = 0.67 and P = 0.07, respectively). When 5 ng/ml was used as cut-off value for CEA, there was a significant difference in overall survival (P < 0.0001), but not within the different Dukes' stages. The prognosis was considerably worse in patients with concomitant elevation of CA 242 and CEA, compared with the prognosis of patients with normal levels or only one marker elevated (P < 0.0001). When analysing according to stage, a significant difference was seen in Dukes' B (P = 0.0004) and Dukes' C (P = 0.0007) stages. In a multivariate analysis, CA 242 was an independent prognostic factor (P < 0.0001). CEA was also an independent prognostic factor (P = 0.03), but only after exclusion of CA 242. Concomitant rise of CA 242 and CEA was found to be a strong independent prognostic factor (P < 0.0001). This study shows that the pre-operative serum CA 242 level is an independent prognostic factor in patients with colorectal cancer and that the prognosis of patients having a concomitant pre-operative elevation of CA 242 and CEA is poor.

The use of prognostic markers in surgery for colorectal cancer

The basis for prognostic prediction after surgery for colorectal cancer remains the various pathological staging systems based on that of Dukes. Serum prognostic markers have not shown significant independent prognostic power compared with these predictive tools. Much energy has been expended in examining the ability of serum markers to predict recurrent tumour prior to the onset of symptoms. Carcinoembryonic antigen (CEA) has been a particular subject of attention, and has been widely, though variably, advocated as a useful predictor in these circumstances. It has been estimated that around half a million Americans are presently undergoing regular postoperative CEA monitoring to this end. Controversy continues regarding the therapeutic utility of such monitoring. This may be resolved when the results of the only randomised trial in the field are published in the near future. No other serum marker, nor any combination of markers, has been shown clearly to be superior to CEA as a predictor of recurrent tumour.

The role of CA-242 and CEA in surveillance following curative resection for colorectal cancer

This study was undertaken to evaluate the role of a new tumour marker, CA-242, alone or in combination with CEA in the practical management of colorectal cancer patients after potentially curative resection. A cohort of 149 patients who had undergone 'curative' surgery was followed up according to an intensive protocol in order to detect recurrent disease. Over a median tumour marker follow-up period of 24 months there were 25 recurrences in 24 patients. Both CEA and CA-242 alone detected half the local recurrences. The sensitivity of CEA was 84% for distant or mixed recurrence compared with 64% for CA-242. An abnormality of either CEA or CA-242 enabled detection of five out of six local recurrences and 17 out of 19 distant or mixed recurrences with a median lead time of 5 months for each marker. Both markers were elevated concurrently in only one local and 11 distant recurrences. While CA-242 alone is not superior to CEA, their combined use (either abnormal) has a high sensitivity (88%), specificity (78%) and negative predictive value (97%); this may be useful in reducing unnecessary investigations in follow-up programmes and as a guide to the initiation of further treatment for recurrent disease.

Optimal follow-up in colorectal cancer patients: what tests and how often?

Patients' benefit from follow-up examinations after curative surgery for colorectal cancer is unproven in spite of numerous different programs' having been designed for that purpose. Unfortunately, no final results from prospective randomized studies have been published yet and no ideal marker for recurrent cancer is available to identify patients in whom new curative treatment may be possible. So far, screening for metachronous neoplasia with intervals of several years may influence survival, whereas benefit from detecting recurrent colorectal cancer may be claimed only by using historical or other inappropriate controls. The tradition of follow-up is expensive and prospective evidence for any cost benefit is needed to justify continuous use of our limited resources in this area of patient care.

Value of carcinoembryonic antigen in the management of colorectal cancer

PURPOSE

The practical value of carcinoembryonic antigen (CEA) assay in the management of colorectal cancer after surgery is controversial. The value of CEA in the management of colorectal cancer was reviewed and discussed to justify the use of CEA assay in the management of colorectal cancer.

METHODS

A retrospective study was performed on 318 patients who underwent resection by one surgeon (JYW) between 1981 and 1986 and who were followed for a minimum of 5 years or until death.

RESULTS

The incidence of preoperative CEA levels > 5 ng/ml in Dukes Stages A, B, C, and D were 0, 32, 48, and 79 percent, respectively. Five-year survival rates for groups with CEA levels < or = 5 ng/ml and > 5 ng/ml were 85 percent and 55 percent (P < 0.05), respectively, in Dukes Stage B patients and 64 percent and 37 percent (P < 0.05) in Stage C patients. The sensitivity and specificity of postoperative CEA monitoring in detecting recurrent diseases were 66 percent and 94 percent, respectively, for patients with a preoperative CEA value < or = 5 ng/ml and 97 percent and 88 percent for patients with a higher preoperative CEA value.

CONCLUSION

CEA is still the best tumor marker available to be used as an independent prognostic factor and as a monitor for recurrence of disease after primary tumor resection.

Serum carcinoembryonic antigen in relation to survival, DNA ploidy pattern, and recurrent disease in 406 colorectal carcinoma patients

Serum carcinoembryonic antigen (CEA) levels in relation to survival, flow cytometric DNA ploidy pattern, Dukes stage, and recurrent disease was prospectively evaluated in 406 patients with colorectal carcinoma. In 246 patients (61%) the carcinomas were DNA aneuploid. Increased preoperative CEA levels (> 5 micrograms/l) were found in 151 of 363 evaluable patients (42%). Dukes stage-B patients with preoperative CEA elevation showed significantly poorer prognosis than those with normal CEA values (p = 0.001). A weak but significant correlation was found between preoperative CEA level and Dukes stage (Kendall's tau = 0.25, p < 0.01). Of 50 evaluable patients with clinical recurrence and postoperative normal or normalized CEA levels, 28 (56%) had a rise in CEA before or at the time of clinical recurrence. The sensitivity of the CEA test for primary and for recurrent disease was not significantly different in the DNA aneuploid and the DNA near-diploid groups.

Role of CEA, TPA, and Ca 19-9 in the early detection of localized and diffuse recurrent rectal cancer

Sixty-six consecutive patients who underwent curative resection for rectal cancer were studied prospectively to evaluate the roles of sequential carcinoembryonic antigen (CEA), tissue plasminogen activator (TPA), and carcinomatous antigen 19-9 (Ca 19-9) determinations in the early diagnosis of resectable recurrences. Thirty-three recurrences were detected between 6 and 42 months. CEA, TPA, and Ca 19-9 showed a sensitivity of 72.7 percent, 78.8 percent, and 60.1 percent, respectively, and a specificity of 60.6 percent, 60.6 percent, and 87.9 percent, respectively. In 23 cases the rise in the value of CEA and/or TPA and/or Ca 19-9 was the first sign of recurrences, and the diagnosis was established later by clinical methods. In this group, the lead time was two months for liver metastases and four months for disseminated metastases. As far as the relationship between localization of recurrence and marker level increase is concerned, of 16 hepatic metastases CEA, TPA, and Ca 19-9 showed a sensitivity of 94 percent (P less than 0.05), 69 percent, and 62 percent, respectively. Of six patients with local recurrences, CEA, TPA, and Ca 19-9 showed a sensitivity of 50 percent, 100 percent (P less than 0.05), and 83.3 percent, respectively. Of three patients with peritoneal carcinomatosis, CEA, TPA (P less than 0.05), and Ca 19-9 showed a sensitivity of 0 percent, 100 percent, and 0 percent, respectively. No significant differences were reported among the three markers according to multiple metastases and metachronous polyps. Fourteen patients (42.4 percent) underwent surgical treatment for recurrent disease, and eight of them (57 percent) showed a resectable disease, for a total resectability rate of 24.2 percent. The findings of our study indicate that a follow-up program based on CEA, TPA, and Ca 19-9 assays is related to an early diagnosis and a good resectability rate for both local and metastatic recurrences from rectal cancer.

Clinical use of tumor markers in oncology

The perfect tumor marker would be one that was produced solely by a tumor and secreted in measurable amounts into body fluids, it should be present only in the presence of cancer, it should identify cancer before it has spread beyond a localized site (i.e., be useful in screening), its quantitative amount in bodily fluids should reflect the bulk of tumor, and the level of the marker should reflect responses to treatment and progressive disease. Unfortunately, no such marker currently exists, although a number of useful but imperfect markers are available. The predominant contemporary markers are discussed here by chemical class, as follows: glycoprotein markers, including carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), beta-human chorionic gonadotropin (beta-hCG), and prostate specific antigen (PSA); mucinous glycoproteins, including CA 15-3, CA 19-9, mucinous-like cancer antigen and associated antigens, and CA 125; enzymes, including prostatic acid phosphatase (PAP), neuron specific enolase (NSE), lactic acid dehydrogenase (LDH), and placental alkaline phosphatase (PLAP); hormones and related endocrine molecules, including calcitonin, thyroglobulin, and catecholamines; and, molecules of the immune system, including immunoglobulins and beta-2-microglobulin. The biologic properties of each group of tumor markers are discussed, along with our assessment of their role in clinical medicine today.

Tumor markers in cancer of the colon and rectum

The primary role that tumor markers for cancer of the colon and rectum have at this time is for postoperative surveillance of those patients resected for cure who are at risk for recurrence of the disease. Carcinoembryonic antigen (CEA) serum levels are followed by most surgeons prospectively after the potentially curative resection. This tumor marker has not been advocated as a screening test for these cancers; however, a preoperative CEA serum level is determined in those patients before the initial surgery for colon or rectal cancer. The serum level of CEA is mainly determined by tumor differentiation and stage of disease. If the CEA serum level begins to increase during the postoperative surveillance period, the recurrence of colon or rectal cancer must be suspected. Further investigations are then performed to identify the location and resectability of the recurrent disease. Monoclonal antibodies labeled with radioisotope are presently being used clinically to identify recurrence of colon and rectal cancer. Used in conjunction with elevated serum CEA levels (or other determinants of recurrent disease) these tumor markers can specifically identify site(s) of cancer recurrence. Theoretically, by attaching cancer-fighting agents (i.e., chemotherapeutic agents) to the monoclonal antibody, the site of tumor recurrence can be potentially treated, too. Hence, these "tumor-seeking missiles" may one day be used to treat cancer recurrence.

Multiple operations for recurrent colorectal cancer

The benefit of an aggressive surgical approach in selective patients with recurrent colorectal cancer has been demonstrated by several investigators. The disease-free 5 year survival is 30%, and in carefully selected series it is as high as 46%. These procedures can be performed safely with minimal morbidity and mortality by surgeons who are experienced in the techniques of radical surgery. It is important and should be our focus to try to identify those patients who will benefit the most from an aggressive surgical approach, by better definition of the biology of the tumor through tumor differentiation and DNA and oncogene analysis.

Hepatic resection for colorectal secondaries

A postal survey of consultant surgeons in England and Wales was carried out to assess current attitudes towards screening for and treatment of hepatic metastases from primary colorectal carcinoma. The results showed that pre-, intra- and postoperative screening were inadequate. There was no consensus as to which patients would benefit from major hepatic resection for colorectal liver secondaries. Fewer than one-third of potentially operable patients underwent liver surgery.

DNA content of rectal scrapings from individuals at low and high risk for the development of colorectal cancer. A feasibility study

Scrapings of superficial rectal mucosa were collected from 31 patients with colorectal carcinoma, 66 patients with sporadic adenoma, and 53 control subjects with no personal or family history of colorectal cancer. The DNA ploidy level and proliferative patterns of each specimen were analyzed by flow cytometry (FCM). A GMS index, calculated as the ratio of G2 + M:S, was found to be significantly lower in control subjects than in any of the high-risk groups studied. Aneuploidy was more prevalent in rectal scrapings from cancer patients and adenoma patients than in those from control subjects. Aneuploid cell populations were detected in apparently normal rectal scrapings from two control subjects. Some high-risk individuals (i.e., cancer patients and patients with adenomas and a family history of cancer) exhibited higher proportions of tetraploid (designated G2/M) cells and a higher G2/M:S phase ratio than control subjects. The results accumulated thus far show that the rectal scraping procedure is safe and easy to perform. Our limited findings give hope that the DNA content analysis of cells obtained by rectal scraping may eventually prove useful in mass screening for colorectal cancer risk. However, definitive evaluation will require further refinement and elaboration of analytic technique and testing on more patients at various levels of predetermined risk.

The value of a follow-up programme after radical surgery for colorectal carcinoma

To evaluate the effectiveness of a follow-up programme after curative surgery for colorectal carcinoma, a 10-year series of 402 patients was surveyed for the detection rate of potentially curative recurrences and metachronous neoplasms. There were 120 recurrences (30%), and 100 of them (83%) were detected at scheduled check ups. Initial suspicion of recurrence was most often based on physical examination, carcinoembryonic antigen assay, or sigmoidoscopy. Reoperation was undertaken in 62 patients, in 26 cases (22%) for cure. The 5-year survival was 48% after curative reoperations. Metachronous adenomas and carcinomas occurred in 38 and 11 patients, respectively, giving corresponding cumulative 5-year incidences of 13% and 3.8%. Altogether, 37 patients (9.2%) had a curative reoperation for recurrent or metachronous carcinoma, and a further 38 patients (9.5%) had adenomas removed by polypectomy. It is concluded that regular follow-up is useful for the patients, and the follow-up schedule must be planned to detect both early recurrences and metachronous neoplasms.

CEA, tumour differentiation and DNA ploidy pattern

The histological growth pattern of large bowel carcinomas is probably of importance for CEA secretion, since it is demonstrated that moderately differentiated carcinomas have the highest plasma CEA levels. Moderately differentiated carcinomas might thus, because of their glandular architecture, secrete a larger proportion of CEA into the gut lumen than poorly differentiated ones. Nevertheless, of the biological variables investigated in relation to plasma CEA, determination of tumour DNA ploidy has turned out to be of the greatest significance in our laboratory. We suggest therefore, that combined evaluation of the preoperative plasma CEA level and tumour DNA ploidy may aid in the selection of patients who should be followed up with repeated plasma CEA measurements after potentially curative large bowel resection.

Isolation and preliminary characterisation of cDNA clones representing mRNAs associated with tumour progression and metastasis in colorectal cancer

We have constructed cDNA libraries from the poly(A)+ RNA of normal colonic mucosa and a liver metastasis from a colonic adenocarcinoma. Differential screening of these libraries using 32P-labelled cDNAs transcribed from poly(A)+ RNAs isolated from specimens of four normal colonic mucosae, five adenocarcinomas, and three liver metastases by Grunstein-Hogness and dot-blot hybridization has identified a number of recombinant cDNA clones homologous to mRNAs that appear to differ significantly in abundance between normal and neoplastic colon and metastases. These cDNA clones, and others identified in the libraries, may be of considerable importance both as diagnostic tools and in defining the phenotypic changes associated with tumour progression and metastasis.

Variation in recognition of recurrent colonic cancer by different CEA assays

Forty-six patients were followed with serial CEA determinations by two CEA assays after curative resection of a primary or recurrent colonic cancer. Thirteen have had a histologically proven recurrence, of which only six (46 percent) were predicted by both assays, while seven (54 percent) were predicted by one assay only. The assays appear complementary in indicating tumor recurrence, and preliminary findings suggest that it may be beneficial to follow patients with more than one CEA assay after resection of a primary or recurrent colonic cancer.

Treatment of local recurrence after primary restorative resection or Hartmann's operation for carcinoma of the colon and the rectum

Between 1970 and 1985, 20 patients underwent laparotomy for local recurrence following a restorative resection or Hartmann's operation for carcinoma of the colon and rectum. Histological confirmation was made in 18 cases and in 2, recurrence not confirmed at surgery became apparent during subsequent follow-up. Of the 16 patients in whom the site of local recurrence could be defined, there was involvement of the previous anastomosis in 13. At laparotomy 7 patients had disseminated disease and in 5 patients without dissemination, local disease was unresectable. Ten recurrences were amenable to resection. Of these 8 patients had a curative operation with a median survival of 26 months and a 5-year actuarial survival rate of 50%. In 10 patients no resection was performed. Median survival in this group was 5 months but 1 patient is still alive at 10 years after radiotherapy. The results emphasise the importance of follow-up given the high salvage rate in patients in whom a curative resection was possible.