CEA is elevated in all of the following except:March 2007
Ans. D: Prostatic carcinomaAn elevated level of a tumor marker can indicate cancer; however, there can also be other causes of the elevation.Tumor markers can be produced directly by the tumor or by non-tumor cells as a response to the presence of a tumor. As used in oncology, they are as follows:- Screening for common cancers on a population basisExample: elevated prostate specific antigen suggests prostate cancer.- Monitoring of cancer survivors after treatmentExample: elevated AFP in a child previously treated for teratoma suggests relapse with endodermal sinus tumor.- Diagnosis of specific tumor types, paicularly in ceain brain tumors and other instances where biopsy is not feasible.Tumor markers can be classified in two groups: Cancer-specific markers and tissue-specific markers.- Cancer-specific markers:An example of a cancer-specific marker, CEA, or carcinoembryonic antigen, is a blood-borne protein, first noted to be produced by tumors of the gastrointestinal system. Fuher investigation showed that it was produced by the occasional lung and breast cancer case, meaning that an elevated level does not mean a bowel cancer. However, in a patient with a history of a treated bowel cancer, a rising CEA level can be an early sign of bowel cancer return.A sequence of steady low CEA readings can provide much needed reassurance to the post-operative patient. Also, a rising sequence of CEA readings should ale the physician to the need for diagnostic tests such as PET scans.- Tissue-specific markers:Tissue-specific markers are related to specific tissues which have developed cancer.Generally speaking, these substances are not specifically related to the tumor, and may be present at elevated levels when no cancer is present.Examples include PSA, beta-HCG - (Human chorionic gonadotropin), AFP - (Alpha-fetoprotein), AFP-L3 - (a lectin-reactive AFP) and Thyroglobulin.For example, if man has an elevated PSA, a search for prostate cancer will be undeaken.If an individual has an elevated level of beta-HCG, AFP or AFP-L3%, a search for a testicular or liver cancer, respectively, will be made.PSA (Prostate specific antigen) is produced by the normal prostate.It is a protein enzyme called a serine protease that usually acts as an anticoagulant to keep semen liquid. Only small amounts leak into the circulation in normal circumstances.Enlarged prostates leak more substantial amounts, and cancerous prostates also leak substantial amounts. o Beta-hCG: Elevated levels cannot prove the presence of a tumor, and low levels do not rule it out (an exception is in males who do not naturally produce beta-hCG).Neveheless, elevated beta-hCG levels fall after successful treatment (e.g. surgical intervention or chemotherapy) and a recurrence can often be detected by the finding of rising levels.
Alcoholic cirrhosis
Ulcerative colitis
Carcinoma colon
Prostatic carcinoma