Current status of tumor markers in large bowel cancer

Definition and management of colorectal polyposis not associated with APC/MUTYH germline pathogenic variants: AIFEG consensus statement

An expert consensus panel convened by the Italian Association for Inherited and Familial Gastrointestinal Tumors (Associazione Italiana per lo Studio della Familiarità ed Ereditarietà dei Tumori Gastrointestinali, AIFEG) reviewed the literature and agreed on a number of position statements regarding the definition and management of polyposis coli without an identified pathogenic mutation on the APC or MUTYH genes, defined in the document as NAMP (non-APC/MUTYH polyposis).

The Tumour Marker CA 195 in Colorectal and Pancreatic Cancer

The aim of this study was to measure the serum level of the tumour markers CA 195 and CEA in patients with either colorectal or pancreatic cancer both before and at serial intervals after operation. CA 195 and CEA were measured in 199 patients with colorectal cancer and 52 patients with pancreatic cancer. The median concentrations of CA 195 were 3.0 u/ml (interquartile range 3.0-4.5 u/ml) in patients with a Dukes’ stage A lesion, 5.8 u/ml (3.0-18.2 u/ml) in patients with a Dukes’ stage B lesion, 6.1 u/ml (3.0-24.7 u/ml) in patients with a Dukes’ stage C and 23.8 u/ml (11.1-409.0 u/ml) in patients with metastatic disease (normal range 0-7 u/ml). The median levels of CEA were 2.6 ng/ml (1.7-3.3 ng/ml) for Dukes’ stage A, 3.3 ng/ml (1.7-7.2 ng/ml) for Dukes’ stage B, 3.7 ng/ml (2.2-7.9 ng/ml) for Dukes’ stage C and 34.5 ng/ml (13.3-289.4 ng/ml) for metastatic disease. A rising level of CA 195 or CEA after operation suggested recurrence of the tumour. In none of these patients was the recurrence operable. In patients with pancreatic adenocarcinoma, the level of CA 195 was significantly higher in patients with metastatic disease but it did not discriminate between resectable and unresectable disease. The duration of survival correlated with the initial level of CA 195 (Rs = –0.66, p < 0.001).

The association of preoperative serum tumour markers with Dukes' stage and survival in colorectal cancer

The tumour markers carcinoembryonic antigen (CEA), tissue polypeptide antigen (TPA), TPS, CA 19-9, CA 50 and CA 242 were analysed in serum from 203 potentially curable colorectal cancer patients. The levels of all markers increased with increasing tumour stage, and all markers correlated with survival. Multivariate analyses indicated that the Dukes stage had the best prognostic explanatory power, followed by TPA. In the subset of 166 potentially cured patients, the prognostic information by the markers was substantially reduced. We conclude that preoperative serum tumour marker measurements have the potential to aid therapy selection, but also that their clinical usefulness is not immediately apparent.

Heredity, molecular genetics and colorectal cancer: a review

It is estimated that the hereditary polyposis and non-polyposis colorectal cancer (CRC) syndromes, which have an autosomal dominant pattern of inheritance, represent less than 10% of the total CRC burden. Thus, more than 90% of all cases of CRC have previously been considered to arise 'sporadically', with no identifiable genetic link. However, recent clinical evidence now suggests that a significant proportion of CRC seen in the general population may involve an inherited genetic susceptibility. Therefore, constructing an accurate family tree on all patients with a family history of CRC is an essential part of identifying families with an increased risk for CRC who could then be offered screening. Also, molecular genetic study of colorectal adenomas and carcinomas has led to a proposed genetic model of colorectal tumorigenesis which involves interactions between oncogenes and tumour suppressor genes. This information has important potential implications for screening, determining prognosis and for providing multiple targets for altering the sequence of malignant transformation.

A New Approach to Tumour Marker Assessment by Perioperative Determination in Breast and Colorectal Cancer

Preoperative serum tumour markers are currently classified as positive or negative according to a predetermined cut-off point. In the present study we examined the dynamic variation of marker levels after radical surgery of breast and colorectal cancer. CEA and CA15.3 were measured in 93 patients with breast cancer, CEA and CA19.9 in 97 patients with colorectal carcinoma before and 30 days after radical surgery. Any variation higher than 3-fold the analytical coefficient of variation of the assay was considered significant. In patients with negative preoperative marker levels a significant decrease was noted after surgery in 15.6% of cases for CEA and 27.8% for CA15.3 in breast cancer and in 46.8% for CEA and 25.7% for CA19.9 in colorectal cancer. Using both cut-off-based and dynamic criteria, we found an overall positivity rate of 19.6% for CEA and 33.3% for CA15.3 in breast cancer; 60.0% for CEA and 37.1% for CA19.9 in colorectal cancer.

From the present findings we conclude that the dynamic study of perioperative variations of tumour markers is a sensitive method additional to cut-off-based criteria for the assessment of the phenotypic expression of the marker by the tumour.

Prognostic factors in colorectal cancer

The prognostic power of the extent of tumour invasion is indisputable; Dukes' classification has repeatedly been proven to be strongly correlated with patient survival. Modifications have led only to confusion, resulting in caution being required in the classification of patients with Dukes' A tumours. In the UK, the American tumour node metastasis and Australian clinicopathological systems are frequently considered too complex for routine clinical use. Meanwhile, Jass's classification may be complicated by observer variation between pathologists, and recent evidence suggests that it offers no advantage over that of Dukes. All the conventional staging systems also fail to take the skill of the surgeon into account when determining outcome. Attempts at quantifying tumour structure have not heralded the expected major advance. For instance, the expense and uncertain prognostic value of tumour DNA content assessed by flow cytometry are likely to restrict widespread use of this technique. It may soon be possible, however, to provide optimum treatment for patients based on individual tumour doubling times. Classification using knowledge of how a small number of cells in the tumour have the ability to invade locally, enter blood vessels and metastasize would also provide important prognostic information on which treatment could be based. Until then, the ease of use and high prognostic power of Dukes' classification ensure that, after 60 years, it is still the 'gold standard' against which all other prognostic classifications in colorectal cancer should be assessed.

Comparison of four serum tumour markers in the diagnosis of colorectal carcinoma

The assessment of the diagnostic power of four serum tumour markers, CEA, CA 19-9, CA 50 and CA 195 for colorectal carcinoma is described, according to recently formulated guidelines. Preoperative serum concentrations of the four markers were determined in 198 colorectal cancer patients and 57 patients with a benign colorectal disorder. The cumulative frequency distributions of the malignant and benign group show strong overlap for all markers, which indicates low diagnostic ability. This is confirmed by the Receiver Operating Characteristic curves, which have areas under the curve of 0.65 (95% confidence interval (CI) 0.58-0.73) for CA 19-9, CA 50 and CA 195 and of 0.70 (95%) CI 0.63-0.77) for CEA. The new tumour markers appear to be of slightly less diagnostic value than CEA for the primary diagnosis of colorectal cancer, although the discrepancy is not statistically significant. The low diagnostic power of CA 19-9, CA 50 and CA 195 may be due to a high proportion of colorectal cancer patients having the Lewis(a-b-) phenotype, who cannot synthesise these markers.

Comparative analysis of cancer-associated antigen CA-195, CA 19-9 and carcinoembryonic antigen in diagnosis, follow-up and monitoring of response to chemotherapy in patients with gastrointestinal cancer

To establish further the clinical significance of the CA-195 tandem immunoradiometric assay in gastro-intestinal malignancies, the sera of a total of 222 subjects have been analysed and compared with assays of the "classical gastrointestinal tumour markers", CA19-9 and carcinoembryonic antigen (CEA). CA-195 elevations above normal (greater than 10 U/ml) were noted in 51/72 (70.8%) colorectal, 15/15 (100%) pancreatic, and in 6/12 (50%) gastric cancer patients. Whereas CA19-9 was increased (greater than 37 U/ml) in 65%, 93%, and 42% of cases, only 54% colorectal, 45% pancreatic, and 42% gastric cancer patients had pathologically elevated serum CEA levels (greater than 5 ng/ml). No abnormal increase of both CA-195 and CA19-9 was found in healthy volunteers, whereas 3/20 (smoking) individuals had CEA levels slightly above normal. With a 29% false-positive rate noted among 103 patients with benign gastrointestinal disorders, the specificity of CA-195 was superior to that of CA19-9 (58%) and comparable with that of CEA (31%). A significant correlation between CA-195 levels and the clinical/pathological stage of disease was noted in colorectal (P less than 0.01) and pancreatic cancer patients (P less than 0.007). Preliminary results of serial measurements of CA-195 in colorectal cancer suggest that this new marker protein, which has no cross-reactivity with CEA, may be useful as a non-invasive test for postoperative surveillance of patients to detect disease recurrence, and serve to complement (though certainly not replace) standard clinical measurements of response to chemotherapy.