Carcinoembryonic antigen in colorectal practice: report of three cases

Plasma DNA is more reliable than carcinoembryonic antigen for diagnosis of recurrent esophageal cancer

BACKGROUND

Carcinoembryonic antigen (CEA) and plasma DNA are known to be elevated in patients with esophageal cancer and are higher in patients with disseminated disease. The sensitivity and specificity of these markers in the diagnosis of recurrent esophageal cancer have not been compared.

STUDY DESIGN

Plasma DNA was measured using polymerase chain reaction in 45 patients with esophageal cancer and 44 asymptomatic volunteers. The 95(th) percentile (19 ng /mL) in the volunteers was used to define normal. Thirty-nine patients had localized cancer and underwent resection, and six had disseminated disease at operation. Plasma DNA was measured preoperatively in all patients, with serum CEA measured in 31. Plasma DNA was measured sequentially during followup in 21 patients, including 7 who developed recurrence. CEA was measured in 14 of 21 patients who had sequential plasma DNA measured and in 6 of 7 patients with recurrence. CEA levels greater than 5.0 ng/mL were used as cut-off.

RESULTS

Plasma DNA was more sensitive than CEA for detecting unresectable esophageal cancer (100% versus 40%), but it had a lower specificity (22% versus 89%). The positive predictive value (19% versus 40%) and negative predictive value (100% versus 89%) were similar for plasma DNA and serum CEA, respectively. Plasma DNA was also more sensitive than CEA in detecting recurrent esophageal cancer (100% versus 33%). The specificity and positive predictive values were 100% for both tests, but the negative predictive values were higher for plasma DNA. Plasma DNA rose before there was clinical evidence of recurrence in 67% compared with only 17% for CEA.

CONCLUSIONS

Elevated plasma DNA is an extremely reliable indicator of the presence of recurrent disease, and, in the majority of patients, it rises before clinical evidence of recurrence. In contrast, a normal CEA should be interpreted cautiously, because it does not exclude recurrent disease.

Measuring of immunoreactivity of carcinoembryonic antigen (CEA) in colorectal cancer by microdensitometry

In 32 patients with colorectal carcinomas, the immunoreactivity of carcinoembryonic antigen (CEA) was measured on section preparations of the tumours by means of a computer controlled microdensitometric method. By measuring numerous single points, the intensity of the immunohistochemical staining reaction of CEA was evaluated. This method is superior to the commonly used semiquantitative method (+, ++, ) for the assessment of various degrees of staining intensity whenever the antigen to be measured is not homogeneously dispersed in the tissue. The results show that highly differentiated colorectal carcinomas of stage A according to Dukes classification have a lower CEA immunoreactivity than highly differentiated carcinomas of stage B. A correlation between CEA immunoreactivity and degree of malignancy could only be found in patients in stage B. Stage C carcinomas of all degrees of differentiation appeared with a very low CEA immunoreactivity. CEA follow-up controls in our study were of little value for detecting local recurrences; metastases, however, almost always caused an increase in serum CEA titers. Prognostically, a preoperatively increased serum CEA level seems to be as unfavourable as a low CEA immunoreactivity in the tumour.

The laser in surgery. A 23 year perspective

Clinically silent malignant tumor recurrence or metastasis can be treated by laser resection or vaporization as well as by a second-look procedure suggested by an increasing level of carcinoembryonic antigen. Laser resection enables surgeons to resect multiple small metastases that would not normally be resectable. The surgical limitations of each laser unit and each wavelength must be identified. The laser is now used by gynecologists, neurosurgeons, otolaryngologists, ophthalmologists, and oncologic surgeons to rapidly and precisely resect or vaporize tissues and, in some cases, to extend tumor-free survival. Twenty-three years after its first experimental use, the laser has established itself as an important surgical tool.

Results of a 400-patient carcinoembryonic antigen second-look colorectal cancer study

Four hundred patients with resectable colon and rectal cancers were operated on by 37 surgeons at 31 institutions. Patients were monitored with carcinoembryonic antigen (CEA) level determinations and clinical examinations. One hundred thirty patients had recurrences, and 75 were reoperated on, with 43 reoperations CEA-directed and 32 clinically directed. Two of 75 died within 1 month after the second operation. Twenty-two second-look patients remain free of disease 5 years after their second operation. The highest resectability of recurrent cancer occurred in patients with a CEA level below 11 ng/ml in whom the CEA level was determined at intervals of 1 to 2 months.

Usefulness of preoperative CEA levels in the assessment of colorectal cancer patient stage

In order to demonstrate a prognostic value of preoperative CEA levels, we have tried to define a correlation between CEA and histologic stage of tumor in 124 patients with colorectal carcinoma. CEA concentration has been evaluated by radioimmunologic assay and the histologic stage following Dukes' classification. The results show a 25.0% positivity rate for patients in stage A, 48.2% for stage B, 61.1% for stage C, and 85.7% for stage D. The mean CEA values are 7.8 ng/ml in the first group, 30.3 ng/ml in the second, 58.1 ng/ml in the third, and 134.3 ng/ml in the last group. Furthermore, we have tried to relate the histopathologic grade of the tumor (G) with CEA levels in 54 patients of the 124. We conclude that preoperative CEA has a prognostic value, and it is useful in the staging of colorectal cancer patients. A low concentration indicates an early stage of the tumor, while a high concentration indicates a wide spread of disease; on the other hand, there are not significant correlations with cancer grading.

The use of serial CEA determinations to predict recurrence of colon cancer and when to do a second-look operation

The concept of second-look surgery was introduced by Wangensteen 25 years ago, and 17% of patients were reported to be converted to a cancer-free state. Instead of an arbitrary time interval for reoperation, serial CEA values were used as the indicator of colon cancer recurrence and second-look operation. Twenty-two retrospective and 18 prospective patients were evaluable. There was no operative mortality. The CEA Nomogram was used to determine whether the CEA change was significant. All patient-samples were analyzed in duplicate, stored, and compared with the most recent sample; therefore, each patient served as his own control. The prospective results emphasize the importance of minimizing the time delay between a significant change in CEA values and reoperation. Equally important are the frequency of serial determinations (every one or two months), a thorough understanding of the limitations of the CEA radioimmunoassay, and the clinical condition of the patient.