10 January 2013
Certain cancer patients might benefit from going through periods where they receive no treatment, according to groundbreaking research that could have a sizeable impact to the way this disease is treated.
Researchers in the US and Switzerland have reported in the journal Nature that it is perfectly feasible to interrupt treatment of cancer, whereby a patient effectively "takes a break from medication".
What the team discovered was that it is possible for melanoma, a rare type of cancer that begins in the skin, to develop resistance to vemurafenib, an anti-cancer drug used to fight the disease. In fact, the cancer actually develops an "addiction to the drug".
This finding is hugely significant, as it suggests that vemurafenib loses its ability to heal patients. While in some cases it is rendered ineffective, the drug also becomes a partner of sorts with the cancer, spurring "the growth of rapidly progressing, deadly and drug-resistant tumours".
In coming to this conclusion, the researchers decided to test a new way of prescribing the drug. In experiments, they adjusted the amount mice with the skin cancer received, as well as stopping and starting treatment along a planned schedule.
“Remarkably, intermittent dosing with vemurafenib prolonged the lives of mice with drug-resistant melanoma tumours," commented co-lead researcher Martin McMahon, the Efim Guzik distinguished professor of cancer biology at the UCSF Helen Diller Family Comprehensive Cancer Center.
This implies that if a similar course of treatment were adopted for patients with melanoma, vemurafenib would be much more effective. The next step now is to test this hypothesis in clinical trials.
Researchers chanced upon the idea when they were doing routine tests on mice, whereby they found the cause of resistance. Melanoma, when treated with vemurafenib, responds by producing more BRAF protein – the very thing that the drug is attempting to fight.
"Vemurafenib has revolutionised treatment of a specific subset of melanoma expressing mutated BRAF, but its long-term effectiveness is diminished by the development of drug resistance," explained Prof McMahon.
"By seeking to understand the mechanisms of drug resistance, we have also found a way to enhance the durability of the drug response via intermittent dosing."
In addition to being a rare type of cancer, melanoma is known for being aggressive. It occurs when cells in the skin begin to react abnormally, although the exact cause of this is still not fully understood. The most common type of symptom is the appearance of a new mole or a noticeable change in an existing one.
There are a number of potential factors that increase a person's risk of developing the skin cancer, including the prevalence of moles, having pale skin that is prone to being burnt easily in the sun, and a family history of melanoma.
Every year in the UK, approximately 13,000 people are diagnosed with the disease, and is most common in people aged between 15 and 34. Last year in the US, 76,250 people were diagnosed with melanoma.
Posted by Jeanette Royston
Health News is provided by Adfero in collaboration with Spire Healthcare. Please note that all copy above is ©Adfero Ltd. and does not reflect views or opinions of Spire Healthcare unless explicitly stated. Additional comments on the page from individual Spire consultants do not necessarily reflect the views or opinions of other consultants or Spire Healthcare.