Tumour Marker Use in Primary Care

Written by Craig Webster on .

In the last 5 years requests for tumour marker tests from Primary Care have more than doubled. This high use in Primary Care is worrying because the majority of tumour markers (eg. CEA, CA19-9) are neither specific nor sensitive enough for use in the diagnosis of malignancy. See this link for a summary of the main tumour markers, their uses and limitations.

The main use for tumour markers is in monitoring disease progression, treatment or recurrence of a histologically diagnosed cancer. A recent audit of Primary Care requests for tumour markers found that only 9% of CEA and 4% of CA19-9 were requested for these reasons; the rest being for non-specific symptoms.

In contrast to the above, CA125 and PSA do have use in diagnosis of their related cancers, however it should also be noted that these are still only a diagnostic aid and should be used with caution as both can be raised in a number of other benign conditions (see table). Please click the relevant links below of links to guidelines relating to their use in Primary Care.

CA125 link https://pathways.nice.org.uk/pathways/ovarian-cancer

PSA link https://www.gov.uk/guidance/prostate-cancer-risk-management-programme-overview

For symptoms and referral guidelines of other malignancies see the NICE Suspected Cancer Recognition and Referral guidelines. http://pathways.nice.org.uk/pathways/suspected-cancer-recognition-and-referral

You can also use the search bar or test database on this website to find more specific information on the use of each tumour marker.

Tumour marker

Main application

Other tumour elevations

Other limitations

CEA

Monitoring colorectal adenocarcinomas

Breast, lung, gastric, mesotheliomas, oesophageal and pancreatic

Raised in smokers

Raised in other benign renal, liver, lung or GI disease

Poor sensitivity in early disease and may be absent/low in poorly differentiated tumours

CA19-9

Monitoring pancreatic carcinoma

 

Raised in obstructive jaundice, cholestasis, cirrhosis, pancreatic hepatitis and non-malignant GI disease.

Not present in those negative for the Lewis blood group determinant.

CA125

Monitoring ovarian carcinoma

 

Raised in patients with ascites, pleural effusions or free fluid in the pelvis

Raised in patients with congestive heart failure

Raised in benign renal and liver disease and other adenocarcinomas

Mildly raised in menstruation and the first two trimesters of pregnancy

Can be raised in endometriosis

CA15-3

Monitoring breast cancer

Lung, colon, ovary

Raised in benign liver, breast, ovarian disease

AFP

Diagnosis and monitoring of hepatocellular carcinoma and germ cell tumours

Gastric and other GI (oesophageal, pancreatic)

Raised in pregnancy and neonates

Raised in benign liver disease

PSA

Diagnosis and monitoring of prostate carcinoma

 

Also elevated in benign prostatic conditions

Increases with age (as prostate size increases)

Elevated in UTI, catheterisation, prostatitis or other prostate manipulation

hCG

Diagnosis and monitoring of germ cell tumours and gestational trophoblastic neoplasia

Lung

Raised in pregnancy

Transiently elevated with cannabis use

LDH

Diagnosis and monitoring of germ cell tumours

 

Elevated in cardiac disease and benign liver disease

Elevated in some anaemias relating to non-malignant disease

INTERFERON GAMMA RELEASE ASSAYS (IGRA) FOR LATENT TB TESTING.

Written by Stephen Rimmer on .

The QuantiFERON-TB Gold In Tube and the T-SPOT are two in-vitro tests for measuring cell-mediated immune responses to peptide antigens from mycobacteria. These antigens, ESAT-6, CFP-10 and TB7.7 (p4) (which is used only in QFT-G) are absent from all BCG strains and from most non tubercular mycobacterial strains (NTMs) with the exception of M. kansasii, M. szulgai and M. marinum. Individuals infected with M. tuberculosis complex organisms (M. tuberculosis, M. bovis, M. africanum, M. microti, M. canetti) have mononuclear cells in their blood that recognise these mycobacterial antigens. This recognition process leads to the stimulation and secretion of IFN-γfrom sensitized T-cells. The detection and quantification of IFN-γ, measured by enzyme-linked immunoassay (Quantiferon) or enzyme-linked immunospot (T-SPOT), forms the basis of these tests – detectable as early as two weeks after infection with M. tuberculosis.

Both tests are intended for use in conjunction with risk assessment, radiography, and other medical and diagnostic evaluations.  QuantiFERON Gold-IT is the laboratory recommended method for routine screening of patients with a normal lymphocyte count.   T spots are recommended in specific circumstances (see below). 

Clinical Allergy Services

Written by Craig Webster on .

Specific IgE ("RAST")

Measurement of IgE to specified allergens can help to confirm allergies suspected on clinical grounds.  Results must be interpreted in the context of a detailed clinical history, and neither positive or negative results are diagnostic in isolation.  The allergens to be tested must be specified on the request.  This test is not suitable for broad "allergy screening" in the absence of a history suggestive of an allergic reaction.

Skin Prick Testing

In many cases skin prick testing provides a safe and simple alternative to specific IgE measurement, but this does require referral.

Referrals are accepted for the investigation and management of patients who have suffered anaphylaxis and patients with the the following allergic conditions:


Urticaria/Angio-oedema

Clear allergic precipitants can be identified in only a small proportion of cases.  Patients may respond well to regular treatment with antihistamines.

Food Allergy

Skin-prick testing for a range of food allergens is available.  "Screening" is not appropriate, and diet and symptom diaries often help to identify suspected foods for testing.  Patients with life-threatening reactions benefit from detailed advice and individualised management plans.

Allergic Rhinitis and Asthma

Skin prick testing can help to identify significant aeroallergens in these patients, which may held in planning medical management.  Pollen desensitisation may be offered under certain circumstances: patients will only be considered if adequate medical therapy has failed, and certain other suitability criteria are fulfilled. 

Bee/Wasp Venom Allergy

Assessment of patients who have suffered severe reactions to bee or wasp stings is offered.  In some cases desensitisation immunotherapy is indicated to prevent anaphylaxis in individuals at particular risk.

Antibiotic and Anaesthetic Allergies

Suspected antibiotic allergy (especially to penicillin) is common, and can usually be circumvented by the choice of an alternative antibiotic.  In exceptional circumstances allergy testing may be appropriate.  It is often important to exclude or identify allergy to local and general anaesthetic agents, so that future routine or emergency treatment can be given safely.  A detailed history of the suspected anaesthetic reaction and the anaesthetic agents used are vital to successful assessment. Testing of serum tryptase levels immediately after an anaphylactic episode often aids diagnosis (see Laboratory Services).