Non-invasive treatment pinpoints cancer cells more precisely
Writing health articles almost every day, I think Im a bit more aware of health matters than the average person on the Island. We hear a lot about cancer, and I write a lot about it from breast cancer survival stories to more sensitive digital mammography machines, local statistics and two weeks ago, even a cancer treatment breakthrough in the emergence of epigenetics.
Radiation therapy is standard with treating early stage cancers. Most of us know this. And most of us know too, that in radiation therapy cells are targetted and killed. Of course its only the cancer cells anyone really wants the radiation to kill, but invariably that tissue close to the cancer cells will also be killed. This is the danger of the therapy and until recently I thought it was largely still the downside to radiation treatment.
But I was wrong. In a recent Docs for Dinner lecture hosted by the Brown Darrell Clinic, Andrea McKee of the Lahey Clinic in Burlington, Massachusetts, explained that physicians there are able to attack cancer cells better by pinpointing them more precisely.
In stereotactic radiosurgery, the cancer tumour is located on several planes and then a very high dose of radiation is streamed directly on the tumour. Dr McKees lecture was specifically on the success of this treatment on those with early stage lung cancer.
It works because we are able to very precisely map where the tumour is and how it is moving in the lung, she said. We take that movement into consideration when we tell the equipment where to focus.
She said its as detailed as aeronautical navigation. Working in six planes, the equipment doesnt only consider the tumours vertical and horizontal location but also where it is laterally, and its angular orientation its pitch, roll and yaw.
Working in the lung, the shots of radiation are also precisely timed to hit the tumour as the patient breathes normally. Because breathing will cause the tumour to move, the equipment is programmed to fire at specific intervals when the tumour is in range.
Although called stereotactic radiosurgery, the treatment is non-invasive and the patient is not cut in any way. The other advantage is that it typically requires only three treatment sessions compared with the radiation therapy which typically lasts several months.
But stereotactic radiosurgery is not the first option most lung cancer patients are given. Dr McKee said its used with patients who cannot be operated on, or who dont want surgery.
You can refuse surgery and still be a candidate for stereotactic treatment, she said. We would counsel you that we have not studied its use compared to surgery.
But such studies are currently underway and Dr McKee said physicians are hopeful that in the next few years results will show it beneficial over invasive surgery.
She and other physicians at the Lahey Clinic have been using the procedure to treat stage one lung cancer for several years but this year newer more sensitive equipment arrived and has made the procedure even better.
She said the Massachusetts facility is reputed for its treatment of cancer in the upper midsection of the body.
We see a lot of patients from all over the world for lung cancer, she said.
But for decades the treatment has only been used to treat brain tumours because the head could be kept very steady allowing the high dose radiation beam to hit only the tumour. Early versions of stereotactic radiosurgery, where movement could not be factored in, worked for the head which was kept steady in a brace.
Dr McKee said the treatment is especially important when tumours are close to vital organs or structures like the spinal cord. The ability to precisely mark where the beam will hit virtually ensures that nearby organs and tissues can remain safe.
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