Distribution of carcinoembryonic antigen and biologic behavior in colorectal carcinoma

Clinical implication of tissue carcinoembryonic antigen expression in association with serum carcinoembryonic antigen in colorectal cancer

This study aimed to evaluate the prognostic significance of carcinoembryonic antigen (CEA) expression in tumor tissues of patients with colorectal cancer (CRC). The cohort included 7,412 patients with CRC from January 2010 to December 2015. Survival outcomes were assessed based on tissue CEA (t-CEA) patterns and intensities. Three-year (76.7% versus 81.3%) and 5-year (71.7% versus 77.6%, p < 0.001) disease-free survival (DFS) rates were significantly (p < 0.001) poorer in patients with a diffuse-cytoplasmic pattern than an apicoluminal pattern. Three-year (79% versus 86.6%) and 5-year (74.6% versus 84.7%) DFS rates were also significantly (p < 0.001) poorer in patients with high than low t-CEA intensity. Three-year (84.6% versus 88.4%) and 5-year (77.3% versus 82.6%) overall survival (OS) rates were significantly (p < 0.001) poorer in patients with diffuse-cytoplasmic than apicoluminal pattern of CEA expression, and both 3-year (86.7% versus 91.2%) and 5-year (80.1% versus 87.7%) OS rates were significantly (p < 0.001) poorer in patients with high than low t-CEA intensity. Multivariate analyses showed that high-intensity t-CEA was independently associated with DFS (p = 0.02; hazard ratio [HR] = 1.233) and OS (p = 0.032; HR = 1.228). Therefore, high-intensity t-CEA is a significant prognostic factor in CRC, independent of serum CEA (s-CEA), and can complement s-CEA in predicting survival outcomes after CRC resection.

Identification of Recurrence-Predictive Indicators in Stage I Colorectal Cancer

BACKGROUND

Patients with stage I colorectal cancer (CRC) rarely experience recurrences; therefore, few risk factors for recurrence are known. This study was designed to evaluate oncologic outcomes of patients with stage I CRC and to identify risk factors for recurrence after curative surgery.

METHODS

A retrospective cohort of 860 patients from a single institution who underwent curative surgery for stage I CRC between July 1995 and June 2010 was enrolled. Patients who were diagnosed with hereditary, synchronous, or metachronous cancer and those who received preoperative chemoradiotherapy were excluded. Patients from whom fewer than 12 lymph nodes were retrieved were also excluded.

RESULTS

The 860 patients included 402 (46.7%) with colon tumors and 458 (53.3%) with rectal tumors. Thirty-five patients (4.1%) experienced recurrences; local and systemic recurrence rates were 1.1 and 3.0%, respectively. The 5-year overall survival and recurrence-free survival (RFS) rates were 93.5 ± 0.8% and 95.7 ± 0.8%, respectively. Multivariate analysis showed that preoperative serum carcinoembryonic antigen (CEA) concentration ≥6 ng/mL (hazard ratio [HR] 3.354, 95% confidence interval [CI] 1.373-8.195, p = 0.008) and lymphovascular invasion (LVI) (HR 2.676, 95% CI 1.097-6.531, p = 0.031) were independent risk factors for RFS.

CONCLUSIONS

The overall recurrence rate among patients with stage I CRC after curative surgery was 4.1%. Elevated serum CEA and LVI were significantly associated with recurrence. Large-scale, multicenter studies are needed to confirm the prognostic value of these risk factors.

Prognostic and Oncologic Significance of Perineural Invasion in Sporadic Colorectal Cancer

BACKGROUND

The presence of perineural invasion (PNI) in colorectal cancer (CRC) indicates a more aggressive phenotype, resulting in a poor prognosis. The aims of this study were to evaluate the oncologic outcome of PNI+ tumors and to investigate whether PNI status affects patient survival.

METHODS

The study retrospectively enrolled 3807 patients from a single institution who underwent surgery for colorectal adenocarcinoma between January 2006 and December 2010. The patients were classified into two groups based on PNI status: PNI+ and PNI-.

RESULTS

The PNI+ group included 565 patients (14.8 %) and had significantly more involved circumferential resection margins (p = 0.001) and a more advanced TNM stage (p = 0.001) than the PNI- group. Compared with the PNI- group, the PNI+ group had worse 5-year overall survival (65 vs. 88 %; p = 0.001) and 5-year disease-free survival (63 vs. 85 %; p = 0.001). Among PNI+ patients with stage IIA disease, those who received adjuvant therapy had significantly greater 5-year overall survival than those who did not (89.3 vs. 50.8 %; p = 0.001). In multivariate analyses, PNI+ was an independent negative prognostic factor for 5-year overall survival (hazard ratio [HR] 1.518, 95 % confidence interval [CI] 1.175-1.961; p = 0.001) and 5-year disease-free survival (HR 1.495, 95 % CI 1.237-1.806; p = 0.001).

CONCLUSIONS

PNI positivity is an independent predictor of aggressive behavior and unfavorable prognosis in CRC. Further evaluation is needed to confirm the impact of PNI status on survival in stage IIA CRC.

Prognostic impact of carcinoembryonic antigen and carbohydrate antigen 19-9 in stage IV colorectal cancer patients after R0 resection

BACKGROUND

Although preoperative carcinoembryonic antigen (pre-CEA) and carbohydrate antigen 19-9 (pre-CA 19-9) are reportedly prognostic indicators for colorectal cancer (CRC), the prognostic roles of postoperative CEA (post-CEA) and CA 19-9 (post-CA 19-9) shortly after surgery have not been clarified in patients with curatively resected stage IV CRC. The aim of this study was to evaluate the predictive abilities of post-CEA and post-CA 19-9.

METHODS

A total of 129 consecutive patients who had stage IV CRC and underwent R0 resection were retrospectively analyzed. Pre-CEA and post-CEA and CA 19-9 levels were measured within 1 mo before and 3 mo after surgery, respectively. Relapse-free survival (RFS) and overall survival were estimated using the Kaplan-Meier method, and multivariate analysis was performed using the Cox proportional hazards model.

RESULTS

Pre-CEA was elevated (≥5.0 ng/mL) in 73.6% of the patients and remained elevated after surgery in 32.7% of the patients. Elevated post-CA 19-9 (≥50 U/mL) was observed in 9.5% of the patients. Neither elevated pre-CEA nor elevated pre-CA 19-9 was significantly associated with RFS but both elevated post-CEA and elevated post-CA 19-9 were associated with markedly reduced RFS (P = 0.0002 and P = 0.0004, respectively). When considered in combination, post-CEA and post-CA 19-9 significantly stratified RFS and was an independent predictive factor for recurrence (P = 0.0035), as was lymphatic invasion (P = 0.0015). Post-CA 19-9 was the only evident independent predictive factor for overall survival (P = 0.0336).

CONCLUSIONS

In patients with stage IV CRC who underwent curative resection, the combination of post-CEA and post-CA 19-9 at 3 mo after surgery was a potent prognostic indicator for recurrence.

Cell surface markers in colorectal cancer prognosis

The classification of colorectal cancers (CRC) is currently based largely on histologically determined tumour characteristics, such as differentiation status and tumour stage, i.e., depth of tumour invasion, involvement of regional lymph nodes and the occurrence of metastatic spread to other organs. These are the conventional prognostic factors for patient survival and often determine the requirement for adjuvant therapy after surgical resection of the primary tumour. However, patients with the same CRC stage can have very different disease-related outcomes. For some, surgical removal of early-stage tumours leads to full recovery, while for others, disease recurrence and metastasis may occur regardless of adjuvant therapy. It is therefore important to understand the molecular processes that lead to disease progression and metastasis and to find more reliable prognostic markers and novel targets for therapy. This review focuses on cell surface proteins that correlate with tumour progression, metastasis and patient outcome, and discusses some of the challenges in finding prognostic protein markers in CRC.

Evaluation of novel histone deacetylase inhibitors as therapeutic agents for colorectal adenocarcinomas compared to established regimens with the histoculture drug response assay

BACKGROUND AND AIMS

This study was to evaluate the efficacy of histone deacetylase (HDAC) inhibitors in colorectal cancer together with other established regimens.

MATERIALS AND METHODS

Chemosensitivities of 114 colorectal cancer patients to established regimens (fluorouracil (5-FU with leucovorin (FL), capecitabine, FL with irinotecan (FLIRI), and FL with oxaliplatin (FLOX)) as well as five hydroxamic acid derivatives (suberoylanilide hydroxamic acid, PXD101, and three novel candidates of CG-1, CG-2, and CG-3) were comparatively evaluated using the histoculture drug response assay.

RESULTS

The chemosensitivity with established regimens was between 34.2% and 52.6%, when the cutoff value of the inhibition ratio was set at 30%, and between 54.5% and 84.1% with HDAC inhibitors. All HDAC inhibitors displayed synergistic effects in combination with established regimens of FLOX and FLIRI (P < or = 0.0001-0.002). Advanced T- and N-category tumors and patients with synchronous adenoma displayed higher chemosensitivity to CG-3, CG-2, and CG-1, respectively, on a multivariate analysis (P = 0.023, 0.044, and 0.045, respectively). Tumors with mismatch repair defects were closely correlated with chemosensitivities to combined regimens of PDX101 with FLOX and FLIRI (P = 0.044 and 0.048, respectively).

CONCLUSIONS

Our findings firstly demonstrated the chemo-responsiveness of colorectal cancers to HDAC inhibitors with therapeutic efficacy comparable to the established regimens. Additionally, tumor growth and heredity were significantly associated with specific regimens, supporting their possible role as chemosensitive predictors.

Synchronous isolated splenic metastasis from colon carcinoma and concomitant splenic abscess: A case report and review of the literature

This study aimed to describe a case in which an isolated splenic metastasis was synchronous with the colonic primary and a concomitant splenic abscess was associated. A wide review of the literature was also performed. A 54-year-old woman with abdominal pain and fever was admitted to our department. Abdominal CT revealed two low-density areas in the spleen and wall-thickening of the left colonic flexure, which was indistinguishable from the spleen parenchyma. The patient underwent emergency celiotomy, with the presumptive diagnosis of obstructing colon carcinoma of the splenic flexure, and concomitant splenic abscess. Subtotal colectomy and splenectomy were performed. Pathological findings were consistent with mucinous colonic carcinoma, synchronous isolated splenic metastasis and concomitant splenic abscess. This paper is also a review of the existing literature on the association between colorectal cancer and splenic metastasis. Only 41 cases of isolated splenic metastasis from colon carcinoma have been reported in the literature. This report is the third described case of synchronous isolated splenic metastasis from colon carcinoma. Only one case with concomitant splenic abscess has been previously reported. When obstructing left-sided colorectal cancer is suspected, careful CT examination can allow early diagnosis of splenic involvement by the tumor. The literature review suggests that there might be a significant improvement in survival following splenectomy for a metachronous isolated splenic metastasis from colon carcinoma. Prognosis for synchronous splenic metastasis seems to be related to the advanced stage of the disease. Nevertheless, no definitive conclusions can be drawn because of the small number of cases.

Correlação entre o padrão de expressão tecidual e os valores séricos do antígeno carcinoembrionário em doentes com câncer colorretal

A correlação entre diferentes padrões de expressão celular do CEA e a quantificação sérica do antígeno é assunto controvertido. OBJETIVO: O objetivo do presente estudo foi verificar se o padrão de distribuição tecidual do CEA no carcinoma colorretal, se correlaciona com seus níveis séricos. MÉTODO: Estudaram-se 24 pacientes portadores de adenocarcinoma colorretal, com média de idade de 62,6 anos. A mensuração sérica foi realizada por quimioluminescência. No estudo do padrão de distribuição tecidual empregou-se método imunoistoquímico com a técnica da estreptavidina-biotina peroxidase, utilizando anticorpos monoclonais anti-CEA. O padrão de expressão tecidual foi classificado em apical, citoplasmático e estromal, segundo a localização predominante do CEA. A intensidade da imunoexpressão foi classificada em leve, moderada e forte. Empregou-se o teste de Mann-Whitney na comparação dos níveis de CEA sérico, segundo o padrão de distribuição tecidual e o grau histológico do tumor, o teste de Kruskal-Wallis para análise de variância e o teste de Spearman para avaliação da correlação entre as variáveis estudadas, adotando-se nível de significância de 5% (p<0,05). RESULTADOS: Dois (8,3%) doentes foram classificados no estádio A de Dukes, 12 (50,0%) no B e 10 (41,6%) no C. Os valores médios do CEA sérico nos doentes com tumores restritos à parede intestinal (A e B de Dukes) foram significativamente menores que os dos doentes com comprometimento linfonodal (p = 0,0139). Nos 14 (58,3%) enfermos com padrão apical de distribuição o valor médio de CEA sérico era de 4,0 ng/ml, enquanto nos 10 (41,6%) em que havia expressão do tipo citoplasmática o valor médio do CEA sérico era de 31,0 ng/ml (p = 0,0002). Independente da graduação histológica, tumores com expressão tecidual do tipo apical apresentavam valores séricos do CEA significativamente menores do que tumores com padrão citoplasmático (p<0.05) Não se encontrou padrão estromal de distribuição. Houve correlação estatisticamente significante entre o padrão de distribuição tecidual, valores séricos do CEA e a classificação de Dukes. CONCLUSÃO: Os resultados do presente estudo permitem concluir que tumores com padrão de distribuição tecidual citoplasmática cursam com valores séricos de CEA significativamente mais elevados que tumores com padrão de distribuição apical. Existe correlação positiva e estatisticamente significante, entre os diferentes padrões de distribuição celular do CEA, seus níveis séricos e o estadiamento da doença.

The significance of tumor markers for proliferation and apoptosis in predicting survival in colorectal cancer

PURPOSE

Clinicopathologic staging is even today the best prognostic factor in both colon and rectal cancers. There is still considerable variation in survival within the stages. To find other prognostic indicators we investigated six biologic markers associated with apoptosis and cell proliferation.

METHODS

Formalin-fixed, paraffin-embedded tissue samples of 363 patients with primary colon or rectal cancer of Dukes Stages A to D were chosen for immunohistochemical staining of five tumor markers: bcl-2, p53, Ki-67, cyclin D1, and carcinoembryonic antigen. Also, the number of apoptotic cells was studied by the terminal deoxynucleotidyl transferase-mediated D: -UTP nick end labeling method in 347 cases. The study was done on specially prepared tissue arrays.

RESULTS

In rectal cancer, patients with a Ki-67 labeling index of 5 percent or higher had a better prognosis than those with a lower index. Also, positive cytoplasmic p53 expression predicted a favorable outcome in rectal cancer. In colon cancer, positive nuclear staining of cyclin D1 reflected better survival. Weak and moderate staining of carcinoembryonic antigen correlated with better prognosis than strong staining, but negative staining predicted poor outcome. High apoptotic index of 100 or higher correlated with poor prognosis in colon cancer. However, in rectal cancer, the trend was the opposite. Bcl-2 staining tended to be more intense in samples of patients living 5 years or longer compared with those with worse prognosis.

CONCLUSIONS

Colon cancer and rectal cancer seem to have different biologic behavior, at least with respect to apoptosis, cytoplasmic p53 expression, and perhaps Ki-67 and carcinoembryonic antigen. Further studies are needed to clarify the significance of these factors.

Genetic and Pathologic Changes associated with Lymphovascular Invasion of Colorectal Adenocarcinoma

Lymphovascular invasion (LVI) is a biological manifestation of aggressive behavior in colorectal cancer. This study sought to identify and examine the association between genetic and pathologic alterations implicated in this invasive tumor progression. We consecutively recruited 81 and 79 colorectal cancer patients with and without LVI, respectively. Biological changes were evaluated by clinicopathological parameters together with CEA and E-cadherin expressions using immune staining. Allelic loss or MSI was examined using 10 microsatellite markers on chromosomes 10, 16, 18, and TGFbetaRII, possibly associated with colorectal cancer. The germline mutation of BMPR1A and SMAD4 was also sought. Tumor stage and lymph node metastasis were significantly greater in patients with LVI tumor than without it (P < 0.001). Decreased CEA expression was closely correlated with allelic loss or MSI at D16S421, D18S46, and D18S474 (P = 0.004-0.047). Allelic loss at D10S14 was specific to LVI tumors (P = 0.007). Using multivariate analysis, allelic loss at D18S46 significantly correlated with histological differentiation (P = 0.02). In addition, allelic loss and MSI at D18S474, histological differentiation, and expression of CEA and E-cadherin were closely associated with the progression of LVI (P = 0.005-0.049). However, no germline mutation in BMPR1A or SMAD4 was detected in all patients regardless of LVI status. In summary, in a subset of colorectal cancers, histological differentiation and expression of CEA or E-cadherin appear to determine aggressive behavior such as LVI. These changes are closely associated with chromosomal alterations at 10q22-23, 16q22 and 18q21, which carry several tumor suppressor genes.

Expression of cellular adhesion proteins and abnormal glycoproteins in human aberrant crypt foci

Aberrant crypt foci (ACFs) may be the earliest recognizable histologic precursor lesion for colon cancer. ACF may develop from a complex of events, including the development of cryptal hyperproliferation, defects in the rate of apoptosis, and abnormalities in cellular adhesion. In this study, we hypothesized that human ACF would exhibit discrete differences in cell adhesion proteins compared with normal mucosa of biologic markers associated with colon cancer. ACFs were isolated from resected colon mucosa from 45 patients undergoing surgery for colon cancer. We evaluated the protein expression of 3 biologic markers that may be related to the progression of aberrant crypt foci to tumors: carcinoembryonic antigen, E-cadherin, and sialyl Tn antigen. In general, ACFs located near cancers in the right colon were more often hyperplastic than dysplastic; this was more noticeable in the left colon. Carcinoembryonic antigen expression was found to be more intense in apical portions of ACF crypts, with sialyl Tn antigen moderately increased, whereas E-cadherin diffusely stained throughout crypts within ACFs. There are significant biologic changes in potential tumor markers that accompany the early transformation of the normal glandular epithelium, some of which are expressed very early in the colon at the stage of appearance of ACF.

Responsiveness of CPT-11 in respect to hMLH1 and hMSH2 protein expression in the primary colorectal cancer

PURPOSE

The aim of this study was to evaluate the responsiveness to CPT-11 with respect to hMLH1 and hMSH2 protein expressions in primary colorectal tumors.

MATERIALS AND METHODS

91 patients with colorectal cancer treated having undergone surgery and postoperative CPT-11-based adjuvant chemotherapy, between 1997 and 2002, were prospectively recruited. Tumor samples were immunohistochemically analyzed for the expressions of hMLH1, hMSH2, p53 and CEA proteins.

RESULTS

Of the 91 tumors, 6 (6.6%) and 4 (4.4%) showed loss of hMLH1 and hMSH2 protein expressions, respectively. The response rate of patients with tumors not expressing either hMLH1 or hMSH2 was higher than that of those expressing either of these proteins (p=0.026). Patients with tumors not expressing hMLH1 showed a significantly better response to CPT-11 (p=0.04). The responsiveness was not associated with the expressions of hMSH2, p53 or CEA. There were no correlations between drug toxicity and the expressions of hMLH1, hMSH2 or p53. The overall survival was better in patients responsive to CPT-11-based chemotherapy compared to non-responders.

CONCLUSION

The immunohistochemical determination of loss of hMLH1 and hMSH2 expressions may be used in determining the responsiveness to CPT-11-based chemotherapy. Our results suggest that hMLH1 protein expression may be a predictor for CPT-11 responsiveness in patients with colorectal cancer.

Coexpression of carcinoembryonic antigen and E-cadherin in colorectal adenocarcinoma with liver metastasis

Carcinoembryonic antigen (CEA) has been suggested as a metastatic activator in colorectal carcinoma, whereas the E-cadherin expression is downregulated in a variety of carcinomas. CEA and E-cadherin expressions were simultaneously assessed with regard to tumor progression in the various sites of colorectal carcinomas with liver metastasis. Twenty-six consecutive patients who had colorectal carcinoma with liver metastasis underwent curative surgery for primary tumor and liver metastasis. CEA and E-cadherin expression were identified on immunohistochemical staining using the labeled streptavidin-biotin method. Their mRNA expression was also detected by RT in situ PCR using one-step reverse transcription-polymerase chain reaction (RT-PCR). CEA and E-cadherin expression scores in the tumor center were greater than those in the tumor margin in both primary tumor and liver metastasis (P<0.001 to 0.006). CEA expression scores were closely associated with E-cadherin expression scores on the corresponding tumor site (P<0.001 to 0.017). CEA and E-cadherin mRNA expression was greatest in the hepatocytes adjacent to liver metastasis, next greatest in the primary tumor, and least in the liver metastasis (P<0.001 to 0.002). CEA mRNA expression was also closely correlated with E-cadherin mRNA expression in the primary tumor (P<0.001) and in the adjacent hepatocytes of the liver metastasis (P=0.018). Patients with a lesser CEA expression score in the liver metastasis margin appeared to have a longer disease-free survival period than did those with a greater CEA expression score. Expression of CEA and E-cadherin was closely correlated with the mRNA levels. Furthermore, these correlations may be implicated in the tumor progression of colorectal carcinoma considering their biological properties.

Expression of CEACAM6 in resectable colorectal cancer: a factor of independent prognostic significance

PURPOSE

CEACAM6, CEACAM1, and human carcinoembryonic antigen (CEA) are coexpressed in normal colorectal epithelia, but show deregulated expression in colorectal cancers (CRC). Upregulation of CEACAM6 expression in hyperplastic polyps and early adenomas represents one of the earliest observable molecular events leading to colorectal tumors. The aim of our study was to evaluate the prognostic relevance of CEACAM6, CEACAM1, and CEA tissue expression in patients with CRC.

PATIENTS AND METHODS

Immunohistochemical analysis was carried out on tissue microarrays from 243 paraffin-embedded biopsies from a randomized controlled clinical trial (Swiss Group for Clinical Cancer Research [SAKK] 40/81) of adjuvant fluorouracil-based chemotherapy with CEACAM-specific monoclonal antibodies. The median follow-up was 8 years. Overall survival (OS) and disease-free survival (DFS) were calculated using Kaplan-Meier estimates and hazard ratios (HRs) estimated using Cox proportional hazards models.

RESULTS

Tissue expression of CEACAM6, CEACAM1, and CEA was enhanced in 55%, 58%, and 94% of patients, respectively. Multivariate Cox analysis including sex, age, tumor site, stage, differentiation grade, treatment, and nodal status as covariates showed that CEACAM6 overexpression independently predicted poor OS (HR, 1.86; P =.0100) and DFS (HR, 2.00; P =.0028), whereas CEACAM1 or CEA were not significantly related to these outcomes. The data did not provide evidence for or against the hypothesis that the CEACAM6 effect on survival differs according to treatment.

CONCLUSION

Expression of the cell adhesion molecule CEACAM6 in CRC is an independent prognostic factor allowing subdivision of patients into low- and high-risk groups. Whether CEACAM6 or CEA and CEACAM1 might be useful as predictive markers of chemotherapy benefit remains unclear.

Immunohistochemical analysis of resected clinical stage I pulmonary adenocarcinomas with high preoperative levels of serum carcinoembryonic antigen

BACKGROUND

Clinical stage I pulmonary adenocarcinoma (AD) patients with persistently high serum carcinoembryonic antigen (CEA) levels after surgery have a poor prognosis. Although CEA staining pattern is reported to be a prognostic indicator for patients with colorectal cancer, the relationship with lung cancer is unclear.

METHODS

One hundred eighteen patients with clinical stage I AD underwent surgery from 1993 to 1997. Of them, 19 (16%) patients with a high preoperative serum level of CEA and 19 randomly selected control patients with preoperatively normal CEA were studied. CEA staining of tumor specimens from each of the 38 patients was performed, and the staining patterns were then classified into two types: apical and diffuse.

RESULTS

Patients with normal postoperative serum CEA levels (group HN, n = 13) had a 5-year survival rate higher than those with persistently high postoperative serum CEA (group HH, n = 6). In a comparison between the two groups, apical patterns (n = 10) were only seen in group HN, and those who demonstrated an apical CEA staining pattern had a 5-year survival rate (5-YSR) of 80% as compared with 13% for those HN patients with only a diffuse pattern (p = 0.01). In the control group, 16 (84%) patients had an apical staining pattern and the other 3 patients showed no staining.

CONCLUSIONS

Patients with normalized serum CEA levels had a high chance of showing an apical staining pattern, which may be a very good prognosis predictor for patients with high preoperative levels of CEA.

Enhancement of colorectal tumor targeting using a novel biparatopic monoclonal antibody against carcinoembryonic antigen in experimental radioimmunoguided surgery

Biparatopic CEA, carcinoembryonic antigen (MAb) was newly designed and tested as to whether it enhanced the accuracy of tumor detection by reducing non-specific binding in experimental radioimmunoguided surgery. Biparatopic MAb was prepared by using cross-linking of reduced Fab' fragments from PR1A3 and T84.66. Fifty-nine tumors from 2 human colorectal carcinoma cell lines with high (KM-12c) and low (Clone A) carcinoembryonic antigen (CEA) expression were successfully implanted subcutaneously on the backs of 42 nude mice. Tumors were localized using 125I-labeled MAbs: IgG, F(ab')(2) and Fab' of PR1A3, and biparatopic MAb of PR1A3 and T84.66. Radioactivity counted on a portable radioisotope detector correlated well with that counted on a gamma counter (p < 0.001). Accumulations of radioactivity in control mice without tumorigenesis were the greatest in PR1A3 IgG-pretreated mice and the least in biparatopic MAb-pretreated mice. Tumors of 2 cell lines did not differ in the distribution of radiolabeled MAbs. Localization indices of the tumor in various organs revealed 1.3 to 4.1 in PR1A3 IgG-pretreated mice, 2.4 to 6.6 in fragment MAbs of PR1A3-pretreated mice and 2 to 4.6 in biparatopic MAb-pretreated mice. Silver grains and immune staining were predominantly distributed in tumor cells of all types of MAb-pretreated mice. Sensitivity and specificity of tumor localization by radioimmunoguided surgery (RIGS) were the highest in the biparatopic MAb-pretreated mice (90.9% and 94.5%, respectively) and the least in the PR1A3 IgG-pretreated mice (50% and 72%). The biparatopic MAb using 2 anti-CEA MAbs against different epitopes achieved a great affinity and avidity with accurate localization of colorectal carcinoma in experimental radioimmunoguided surgery.

The role of carcinoembryonic antigen monitoring in management of colorectal cancer

Carcinoembryonic antigen (CEA) is an important tool in the management of colorectal cancer. Its use as a prognostic indicator in resectable disease remains controversial but may be improved with molecular detection of the antigen. In monitoring patients after resection, CEA can be the first sign of a potentially curable recurrence. It can also be useful in assessing tumor response in patients being treated for metastases without easily measurable disease. CEA alone cannot dictate the type or duration of treatment but may be used in addition to standard monitoring tests.

High preoperative serum carcinoembryonic antigen predicts metastatic recurrence in potentially curative colonic cancer: results of a five-year study

INTRODUCTION

Serum carcinoembryonic antigen is used mainly for tumor follow-up to detect recurrence of colonic cancer. However, raised preoperative carcinoembryonic antigen levels may be helpful for the identification of understaged cases and of patients meriting more intensive preoperative and postoperative diagnostic workup.

METHODS

From a prospectively collected database, the data on 261 patients who had curative colonic carcinoma with a minimal follow-up of five years and who had preoperative carcinoembryonic antigen levels assessed were retrieved and analyzed. Outcome parameters were local and/or distant recurrence and time to recurrence. These parameters were correlated with Dukes staging and preoperative carcinoembryonic antigen levels.

RESULTS

The cumulative disease-free survival of patients with a preoperative carcinoembryonic antigen level within the normal range was significantly better than that of those whose carcinoembryonic antigen was 5 ng/ml or more (P = 0.001). No patient with carcinoembryonic antigen levels less than 1 ng/ml developed metastatic recurrence. Twenty-three percent of all patients with a raised carcinoembryonic antigen above 5 ng/ml compared with 2.1 percent of patients with carcinoembryonic antigen below 5 ng/ml developed a metastasis at two years. At five years, these figures were 37.2 percent and 7.5 percent, respectively. Dukes staging and carcinoembryonic antigen levels were found to be directly correlated (P < 0.001) when all patients were included. Carcinoembryonic antigen of more of 15 ng/ml was found to be a significant adverse prognostic indicator for disease-free survival irrespective of Dukes staging (P < 0.02). Raised carcinoembryonic antigen levels predicted distant metastatic recurrence (P < 0.001) but did not predict local recurrence (P = 0.72).

CONCLUSIONS

High preoperative carcinoembryonic antigen levels above 15 ng/ml predicted an increased risk of metastatic recurrence in potentially curative colonic cancer and may indicate undetectable disseminated disease. Preoperative carcinoembryonic antigen levels predict understaging and the possibility of distant recurrence. Such patients may therefore be selected for adjuvant therapy where indicated. Therefore, carcinoembryonic antigen is complementary to conventional Dukes staging for the prediction of recurrence and survival.