Impact on the heart

One of my tasks in the department is to coordinate our preparation for the UK government’s REF2021 exercise. In 2021 the UK government will assess research (not teaching which is done separately) in UK universities. REF is hugely important, it determines real money, league-table position, and reputation — three things that really matter to universities. Which is why I am in meetings about this four years in advance :(.

One of things that will be assessed in 2021 is “Impact”: defined as being good things in the world outside the ivory towers of universities, that have come from our research. I have to say that I am not enjoying most of the meetings and all of the paperwork on ‘impact’, but they are not all bad.

One of the “Impact” case studies we may submit in 2021 is based on work done by an international team including my colleague Andy Nisbet. The work is on the link between radiotherapy treatment for breast cancer and heart disease. Worldwide about 1 million women a year are diagnosed with breast cancer, but survival rates with modern medicine are high, they can be as high as 90% of women surviving at least 5 years after diagnosis. So many women are living for decades after diagnosis and successful treatment, which is fantastic.

But the treatment for breast cancer can involve radiotherapy. Radiotherapy saves lives but it involves giving very large radiation doses to the breast tissue. The radiation is carefully targeted but inevitably nearby tissue is also irradiated, and this includes the heart, especially if the radiotherapy is of the left breast which is just in front of the heart — our heart is in the left side of our thorax.

Now that we have so many survivors of breast cancer it is a good time to assess their health to see if the radiotherapy that cured their breast cancer is causing long-term health problems, and if so to see how future radiotherapy protocols can be improved to reduce these problems. Nowadays, CAT scans prior to treatment are routine and so we can use the 3D image thsee scans provide to determine the dose the heart gets during radiotherapy, but this was not the case 10 or 20 years ago.

So the team worked out a method to estimate the dose the heart received from medical records, and then armed with this method they looked for a correlation between dose and future heart problems, such as heart attacks. They found one, there is a linear correlation between probability of a heart attack, and dose. The effect is not huge but it is significant, particularly given the very large numbers of women surviving breast cancer. The team estimate that a somewhat larger than typical dose can increase the risk of a serious heart problem from 3.4% to 4.1%, over a 30-year period following radiotherapy.

After the 2013 study, radiotherapy guidelines have been updated around the world to take account of the desirability of minimising the dose to the heart. This impact on medical practice certainly impresses me, I am proud to share a department with one of the people who did this. We will see in 2021/2022 whether it will impress the government-appointed assessors.

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