The low-down on post-treatment blood tests

How many blood tests have you been sent for since your diagnosis? You most probably haven’t been able to keep count. Dr Inge Kriel helps us understand why patients are sent for numerous blood tests.

Treatment is a whirlwind of doctors’ appointments, scans and blood tests. Many patients feel overwhelmed once their treatment is completed and don’t know what to expect going forward. A number of patients feel isolated after they have completed surgery, chemotherapy and radiation, as the safety net of regular appointments gives way to less frequent check-ups.

Patients are often unsure of what signs or symptoms to look out for going forward that may indicate that the cancer has returned. Patients often find comfort in blood tests or scans to verify that the cancer is indeed in remission. Cancer survivors turn to us, their doctors, to advise on what the appropriate tests are going forward.

Over-reliance on blood tests

There is an over-reliance on blood tests and we, as doctors, are probably most to blame. We often order (very expensive and unnecessary) blood tests. 

We are then faced with abnormal results that we don’t necessarily know how to interpret in context of the clinical picture, and results which are of unknown significance. Abnormal results cannot be ignored, and this then often leads to further blood tests and scans (with added cost to the patient).

Further scans are not necessarily innocuous. They may have potential complications, such as radiation risk, and kidney impairment due to contrast administered during the scan. 

Oncology patients also see a number of specialists throughout the course of their treatment. This care is often fragmented in that specialists may not necessarily communicate with each other, regarding what blood tests or scans have already been done. This may lead to duplication of blood tests or other investigations.

So, what are the guidelines for patients entering the survivorship phase of their treatment?

  1. Full history and clinical examination by an oncology care provider every three to six months in the first three years post-treatment, followed by six to 12 monthly follow-up in years four and five, and annual follow-up thereafter.  
  2. Mammogram/breast ultrasound 

a. Not earlier than one year after diagnosis (if patient did not receive radiation).

b. Not earlier than six months after radiation completed.

3. Bone density scan (DEXA scan)

a. Baseline scan to determine baseline bone density (if patient has never had a bone density scan previously).

b. Thereafter bone density scan every two to five years based on findings of initial (baseline) bone density scan.

4. Routine blood tests (including full blood count and cancer markers) are not indicated. 

5. Routine imaging such as: breast MRI, PET scans, bone scans, chest X-ray, and liver ultrasound are not indicated.

Please note, however, that your doctor may request specific post-treatment blood tests and scans depending onyour unique history and follow-up clinical examinations. 

As such, the above guidelines are just that…guidelines. Every patient is different and therefore post-treatment follow-up will differ from patient to patient (based on the discretion of the treating specialist).

Ask why and report symptoms

If you are unsure as to why a specific scan or blood test has been ordered, ask your treating doctor. You are the boss of your own body after all, and you deserve to know the ins and outs of what tests are being done.

No blood test or scan can replace a detailed history and clinical examination. 

Please remember to report any symptoms, such as new lumps in your breasts or armpits; pain in your joints or bones; shortness of breath and chest pain; abdominal pain; and persistent headaches, to your treating clinician. This will assist him/her in doing a full clinical examination, and ordering the appropriate investigations to get to the bottom of your symptoms. This will avoid costly and unnecessary tests being done.

Follow-up is crucial to maintaining your health. Your risk of breast cancer recurrence persists for 15 years after diagnosis. As such, it’s vitally important that you continue regular follow-ups and that the appropriate investigations are done to keep you a fighting-fit cancer survivor.

Dr Inge Kriel is an oncology care physician practicing at Netcare Milpark Hospital.


Dr Inge Kriel is an oncology care physician practicing at Netcare Milpark Hospital.

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