Carcinoembryonic antigen and recurrent colorectal cancer

Multiple-matrix metabolomics analysis for the distinct detection of colorectal cancer and adenoma

OBJECTIVES

Although colorectal cancer (CRC) is the leading cause of cancer-related morbidity and mortality, current diagnostic tests for early-stage CRC and colorectal adenoma (CRA) are suboptimal. Therefore, there is an urgent need to explore less invasive screening procedures for CRC and CRA diagnosis.

METHODS

Untargeted gas chromatography-mass spectrometry (GC-MS) metabolic profiling approach was applied to identify candidate metabolites. We performed metabolomics profiling on plasma samples from 412 subjects including 200 CRC patients, 160 CRA patients and 52 normal controls (NC). Among these patients, 45 CRC patients, 152 CRA patients and 50 normal controls had their fecal samples tested simultaneously.

RESULTS

Differential metabolites were screened in the adenoma-carcinoma sequence. Three diagnostic models were further developed to identify cancer group, cancer stage, and cancer microsatellite status using those significant metabolites. The three-metabolite-only classifiers used to distinguish the cancer group always keeps the area under the receiver operating characteristic curve (AUC) greater than 0.7. The AUC performance of the classifiers applied to discriminate CRC stage is generally greater than 0.8, and the classifiers used to distinguish microsatellite status of CRC is greater than 0.9.

CONCLUSION

This finding highlights potential early-driver metabolites in CRA and early-stage CRC. We also find potential metabolic markers for discriminating the microsatellite state of CRC. Our study and diagnostic model have potential applications for non-invasive CRC and CRA detection.

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).

Cancer physicians' attitudes toward colorectal cancer follow-up

BACKGROUND

The optimal follow-up strategy for colorectal cancer is unknown.

MATERIALS AND METHODS

We surveyed all Canadian radiation oncologists, medical oncologists and surgeons specializing in colorectal cancer to assess their recommendations for follow-up after potentially curative treatment, the beliefs and attitudes underlying these practices, and the cost implications of different follow-up strategies.

RESULTS

One hundred and sixty practitioners (58%) returned completed surveys. Most recommended clinical assessments every 3-4 months in the first 2 years including carcino-embryonic antigen testing, gradually decreasing in frequency over 5 years. Ninety per cent recommend a surveillance colonoscopy in the first year. The majority felt that specialist involvement in follow-up was important because of the increased opportunities for patients to contribute to research (76%) and teaching (73%). About half felt that specialists were more efficient at providing follow-up than primary care physicians, but these same physicians recommended significantly longer and more expensive follow-up routines on average than others. Primary care physicians were felt to be important allies, especially in managing the psychosocial concerns of patients.

CONCLUSIONS

Surveillance practices are generally in keeping with published recommendations. Most specialists feel that they should remain involved in follow-up, but this may result in increased resource utilization.

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.

Radioimmunoguided surgery benefits in carcinoembryonic antigen-directed second-look surgery in the asymptomatic patient after curative resection of colorectal cancer

Radioimmunoguided surgery (RIGS) with radiolabeled monoclonal antibodies (MoAbs) has been reported as useful in second-look colorectal cancer procedures to improve surgical decision-making by helping avoid needless extensive surgery and expanding curative resection to sites of recurrence that have been missed previously. Sixteen asymptomatic patients with an history of colorectal cancer surgery underwent second-look surgery using the RIGS system, solely on the basis of rising serum levels of carcinoembryonic antigen (CEA). All patients were injected preoperatively with the anti-tumor-associated glycoprotein (TAG) 125I-labeled MoAb B72.3. Both traditional and RIGS exploration were used to determine the extension of a possible recurrence and its resectability for cure. Recurrent disease was observed in 14 of the 16 patients as the result of this combined exploration. Exploration alone showed the presence of recurrent disease in 9 of 16 patients (56.2%). Thus, RIGS found overlooked tumor in five patients (31.2%). All the additional RIGS-detected tumor sites were locoregional recurrences resectable for cure; conversely, no diagnostic improvements were shown in patients with liver metastases. Resection for cure was obtained by this approach in 9 of 16 patients (56.2%). Two patients without disease at the exploratory laparotomy recurred within 2 months at sites away from the abdomen. RIGS improved the results of colorectal cancer CEA-guided second-look procedures in asymptomatic patients by recruiting one-third of patients to curative resections.

Screening and surveillance for colorectal carcinoma

Screening and surveillance examinations are effective in lowering colorectal cancer risk. Screening tests have been demonstrated to reduce colorectal cancer mortality. Colonoscopic removal of adenomatous polyps has been determined to reduce colorectal cancer incidence. High-risk individuals and their family members should be identified and offered more aggressive recommendations for appropriate screening and surveillance guidelines. Colorectal cancer screening strategies are in an acceptable range of cost effectiveness.

A prospective randomized study of follow-up after radical surgery for colorectal cancer

BACKGROUND

The possible benefit for patients from follow-up examinations after curative surgery for colorectal cancer is unproven. The purpose of this study was to determine whether survival is improved by frequent follow-up examinations.

METHODS

A total of 597 patients less than 76 years old treated with radical surgery for colorectal cancer were included in the study from 1983 to 1994. Patients were randomized to frequent follow-up (group 1) or virtually no follow-up (group 2) with examinations at 5 and 10 years.

RESULTS

Group 1 comprised 290 patients, group 2 contained 307. Recurrence was equally frequent (26 per cent), but the time of diagnosis was 9 months earlier in group 1; also, more recurrences were asymptomatic in group 1 and more patients had new surgery with curative intent (P = 0.02). However, no improvement in overall survival or in cancer-related survival resulted.

CONCLUSION

Patients subjected to intensive follow-up have recurrence diagnosed earlier, and have more operations for recurrence, but the survival results suggest that any major improvement by intensive follow-up is unlikely.

A prospective randomized study of follow-up after radical surgery for colorectal cancer

BACKGROUND

The possible benefit for patients from follow-up examinations after curative surgery for colorectal cancer is unproven. The purpose of this study was to determine whether survival is improved by frequent follow-up examinations.

METHODS

A total of 597 patients less than 76 years old treated with radical surgery for colorectal cancer were included in the study from 1983 to 1994. Patients were randomized to frequent follow-up (group 1) or virtually no follow-up (group 2) with examinations at 5 and 10 years.

RESULTS

Group 1 comprised 290 patients, group 2 contained 307. Recurrence was equally frequent (26 per cent), but the time of diagnosis was 9 months earlier in group 1; also, more recurrences were asymptomatic in group 1 and more patients had new surgery with curative intent (P = 0.02). However, no improvement in overall survival or in cancer-related survival resulted.

CONCLUSION

Patients subjected to intensive follow-up have recurrence diagnosed earlier, and have more operations for recurrence, but the survival results suggest that any major improvement by intensive follow-up is unlikely.

Routine compared with nonscheduled follow-up of patients with "curative" surgery for colorectal cancer

BACKGROUND

The main rationale for follow-up of colorectal cancer patients resected for "cure" is that early detection and treatment of recurrence and metachronous disease should result in improved survival. Our purpose was to assess in a prospective fashion the impact on survival of a follow-up program versus that of undergoing nonscheduled visits.

METHODS

Within the 14-year period from 1975 through 1988, a prospective study was carried out on 800 patients with colorectal adenocarcinoma radically resected with no evidence of synchronous cancers of the colon and rectum or in other organs, of whom 322 patients were to attend a 5-year follow-up, and 478 patients were free to make nonscheduled visits on account of symptoms.

RESULTS

Asymptomatic recurrence was found at follow-up in 92 (28%) of 322 patients, whereas 175 (36%) of 478 patients had a symptomatic recurrence detected at a nonscheduled visit. Diagnosis of resectable recurrence was established within a median time of 21.5 months. Surgical resection of recurrence was performed in 30 (32%) of 92 and in 13 (7%) of 175 patients (32 vs. 7%; p < 0.001). Resection was curative in 13 (14%) of 92 and in two (1%) of 175. Five-year survival of resected recurrence was 10% in 30 of 92 patients and 0.8% in 13 of 175 (10 vs. 0.8%; p < 0.01). Two patients are alive with no evidence of disease or two (2%) of 92. Metachronous colorectal lesions were treated for cure in 63 (19.5%) of 322 patients. The effectiveness of scheduled follow-up was 4% (13 of 322 patients).

CONCLUSIONS

These results underline the rationale for a follow-up program in early detection and surgical treatment of recurrent disease in patients operated on for colorectal cancer.

Prophylaxis against colorectal cancer

Colorectal cancer is diagnosed in more than 3000 people every year in Denmark, with a population of 5 million, and 2000 die from this disease every year. The aetiology of the disease is complex, but an increasing number of cancers have been related to genetics and Denmark is contributing with a well-established register of familial adenomatous polyposis and a recently founded register for hereditary nonpolyposis colorectal cancer, both with major international relationships. The Danish tradition of epidemiology and clinical trials has also been demonstrated in population screening trials for colorectal cancer in average-risk persons as well as high-risk groups with precursors of the disease. The present review places Danish contributions within the prophylaxis of colorectal cancer during the last decade in an international context.

The value of serum carcinoembryonic antigen in predicting recurrent disease following curative resection of colorectal cancer

Carcinoembryonic antigen (CEA) estimations are used to facilitate early diagnosis of recurrent disease after treatment for colorectal cancer.

PURPOSE

This study was designed to determine the natural history of patients with normal and abnormal levels of CEA.

METHODS

Patients undergoing potential curative resection of colorectal tumors (Dukes Stage A-C) entered a prospective, randomized trial comparing two follow-up regimens (to be reported separately) had CEA levels measured every 3 months for two years; then every 6 months for the next three years. In the study protocol, a rise in CEA was not an indication for investigation to determine recurrence unless there was also other evidence of recurrent disease.

RESULTS

Three hundred eleven patients were followed for a median of 4.5 (range, 2-5) years. Recurrent disease developed in 98 (32 percent) patients, 57 of whom had an elevated CEA (sensitivity 58 percent), with a median lead time of six (range, 1-30) months from first abnormal CEA to diagnosis of recurrent disease by other means. The specificity, positive predictive value, and negative predictive value of CEA as an indicator of subsequent recurrent disease was 93 percent, 79 percent, and 83 percent, respectively. The sensitivity of CEA for predicting hepatic metastases was 80 percent, with a median lead time of eight (range, 1-30) months, compared with only 46 percent for sites of recurrent disease other than the liver.

CONCLUSIONS

CEA was the first indicator of recurrent disease in 58 percent of all patients and in 80 percent of patients with liver metastases. The diagnosis of recurrent disease may be made several months earlier by investigating the first abnormal CEA level, although any benefit in terms of survival remains to be proven.

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.

Biochemical markers for colorectal cancer. Diagnostic and therapeutic implications

The development of the understanding of oncogenes, tumor suppressor genes, and signal transduction has provided a significant advance in the concepts of the mechanisms of carcinogenesis in the colon and rectum. The tools provided by the molecular geneticist and the immunobiologist may yield powerful new techniques for screening individuals at risk, for identifying those patients with biologically more aggressive tumors, for developing novel therapies targeted directly at tumor cells, and for providing the means for more sensitive and specific detection of recurrence of disease.

Staging and surgery for colorectal cancer

Staging of colorectal cancer has become increasingly important to select groups of patients for limited or more extensive surgery, and for adjuvant radiotherapy and chemotherapy. The main treatment is still surgery, but subgroups may benefit from adjuvant therapy, even accepting additional side effects. Accurate staging is necessary to define different treatment groups. A critical review is given of the present methods of clinicopathological staging.

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.

Follow-up after radical surgery for colorectal cancer. Design of a randomized study

The value of different follow-up examinations after radical surgery for colorectal cancer has not been proven. The risk of such programmes, including invasive examinations, may invalidate the possible benefit from early diagnosis of recurrent and metachronous cancer. The present trial is a randomized study, evaluating possible benefit from a very detailed programme compared to that of virtually no follow-up. The design is presented, but so far no more than 207 of the 600 patients wanted for trial, have been included. Differences in mortality rates, survival and morbidity will be evaluated and the influence of repeated polypectomy upon risk of metachronous colorectal cancer will also be estimated.