Personalised medicine in cancer care has fewer side effects

If you have a symptom or a screening test result that suggests you have cancer, your doctor will order tests to confirm it is cancer, its type and stage of the disease.

Beyond confirming, laboratory medicine has grown to enable your doctor to offer personalised treatment - and we intend to unpack the impact on cancer care.

Surgery is an important element in cancer treatment. However, not all cancer types are treated using surgery.

In cases where the cancer has spread widely, it may also either not be safe or possible to operate.

Chemotherapy on the other hand, involves a combination of drugs which kill cancer cells and are given before or after surgery or even without surgery.  

Radiotherapy, by contrast, uses high-energy radiation to kill cancer cells.

Surgery, chemotherapy and radiotherapy are often combined.

The use of chemotherapy and radiotherapy may be limited by the fact that normal, non-cancerous cells are usually affected or even killed in the process as ‘collateral damage.’  

Personalised medicine - or precision medicine - involves formulating treatment or prevention plans while considering the differences in individuals, which may be determined by genetics, lifestyles and the abnormal genes that initiate or drive cancer growth in a person.

The aim is to find the best available treatment at the right time for the right individual considering people are not the same and neither are cancers. Treatment also differs for different people even if they have the same type of cancer.

Some of the benefits of personalised medicine include, fewer side effects, greater efficacy and better quality of life.

But is personalised medicine the same as targeted therapy?

Well, targeted therapy falls under personalised medicine. In targeted cancer therapy, uniquely designed drugs, hormones or antibodies are used to block the genes or proteins “molecular targets” that drive cancer growth and spread.

Depending on the type of cancer, stage, recurrence status or failed standard “chemo” or “radio”- therapy, your oncologist may recommend molecular test(s) on the cancer tissue or blood to analyses the status of the “molecular targets” for which targeted therapy, hormones or drugs may be applied.

We generally call these molecules or molecular targets, biomarkers. The biomarkers can be prognostic, meaning they are used to predict the biologic behaviour and aggressiveness of the cancer. They can also be predictive, which has to do with predicting or identifying the best therapy for that type of cancer.

Patients who cannot tolerate “chemo” or “radio” due to underlying conditions like side effects or age, can benefit from personalised therapy — which is available in Kenya including at Aga Khan University Hospital, Nairobi.

Some advanced tests, however, are outsourced to labs outside the country.

Take an example of a patient with colon cancer, which is driven by an abnormal growth pathway called Epidermal Growth Factor Receptor pathway (EGFR).

Blocking this pathway with a specific drug in combination with chemotherapy results in better anti-cancer effect.

Prior to administration of these drugs molecular testing for presence or absence of mutations of key genes, which drive cancer growth, is performed to predict which patients would have maximum benefit or response.

Multiple other cancers, including breast, lung, melanoma, pancreatic and renal cancers are amenable to targeted therapy.

But are there challenges of targeted therapy in cancer?

At the moment, targeted therapies are not widely accessible, and although the cost is dropping with the passage of time, they are expensive. Patients on targeted therapy may also suffer from various side effects, although they are usually less severe than chemotherapy.

Targeted therapies are, therefore, not a magic bullet for cancer, since complete cures are difficult in advanced cancer.  Therefore, even with emerging therapies for cancer, we cannot over-emphasise the importance of screening, early diagnosis and treatment.

Dr Allan Njau and Dr Jonathan Wawire, Molecular Pathologist and Anatomical Pathologist, respectively, at Aga Khan University Hospital, Nairobi

@AKUHNairobi