Radiation oncologist | ASK THE EXPERT

Associate Professor Susan Pendlebury is Director of Radiation Oncology at North West Cancer Centre, Tamworth. The Beacon asked Susan to tell us about new developments in radiotherapy.

When is radiotherapy treatment recommended for women with breast cancer?
Radiotherapy should be considered for all women diagnosed with early stage breast cancer who have undergone breast conserving surgery (also called lumpectomy or wide local excision). There is also a role for radiotherapy for women who have had a mastectomy and are at intermediate or high risk of experiencing a recurrence of breast cancer, for example if cancer cells are found in a number of lymph nodes in the axilla (armpit) or if the breast cancer is large.

A recent randomised clinical trial has shown that there are benefits also for women when cancer cells are found in only one to three lymph nodes. So radiotherapy should be considered in this situation too, especially if there are other risk factors such as a high-grade cancer, a large tumour or unfavourable biological subtypes such as triple negative cancers.

What does it involve?
Radiotherapy involves delivering small increments of radiation to the breast and/or armpit after breast surgery to kill any remaining cancer cells. It reduces the risk that the cancer will come back in the breast or go on to spread as later-stage disease.

For women who have had a mastectomy and are receiving radiotherapy to their lymph nodes, evidence indicates that radiotherapy should be delivered over a five-week period. For women who have had breast conserving surgery, evidence suggests that radiotherapy can be delivered over a shorter, three- week period. This shorter course is known as hypofractionated radiotherapy.

Evidence also shows benefits if an extra boost of radiotherapy is given to women aged under 60 at the end of their course of radiotherapy. Technology now allows us to incorporate the boost treatment into the three-week or five-week course.

The Cancer Australia Influencing best practice in breast cancer statement states that some women should be offered hypofractionated radiotherapy. Can you explain what that is and who may benefit from it?
For women who have had breast conserving surgery where we are treating just the breast with radiotherapy (i.e. not the lymph nodes in the armpits also), there is evidence to suggest that radiation can be delivered over a three-week period, with a boost treatment delivered during that three weeks. This is called hypofractionated radiotherapy.

There are significant benefits, especially for women in rural areas who may have to travel long distances to and from treatment every day or move to another town or city for their treatment. Hypofractionated radiotherapy offers the same benefit in terms of destroying cancer cells, but with 20 per cent less toxicity, so a reduction in the extent of fatigue, skin redness and peeling women may experience.
At the present time, radiation given over a five-week schedule is standard treatment for women who have undergone mastectomy and for whom radiation treatment includes the lymph node area, such as the axilla. Research is underway to help determine if the hypofractionated course is also suitable for these women.

What is intraoperative radiotherapy, and is it something women should talk to their radiation oncologist about?
Intraoperative radiotherapy involves delivering radiation at the time of surgery through a machine that is inserted into the cavity formed when the cancer is removed. Because radiation is delivered at the time of surgery, it is convenient. On the downside, the clinicians will not yet have the pathology results, so women may require more surgery and possibly more radiotherapy at a later time. There is also an increased risk of infection, though the risk is still low.

Intraoperative radiotherapy requires close interaction between surgeons and radiation oncologists. It also requires a different set-up of the operating theatre, so is not available at all centres. The research suggests it is good, but not better than treatment with an external beam.

What is the deep inspiration breath hold technique?
Deep inspiration breath hold is a technique that lifts the chest wall up and away from the heart. It has been developed to minimise the dose of radiation to the heart, so is primarily for women who have breast cancer in their left breast. There are a number of techniques for achieving this but, essentially, as you breathe in the lungs inflate and the ribs expand upwards and outwards so that the expanded lungs act as a buffer to keep the chest wall away from the heart. As technology advances, it is likely we will have other ways of minimising the dose to the heart.

Where can we find more information about radiotherapy?
The Royal Australian and New Zealand College of Radiologists website targetingcancer.com.au and the Cancer Australia website canceraustralia.gov.au are both good websites.

I also suggest my patients talk to their breast care nurse. Breast care nurses are often very good at answering questions or pointing women in a local direction to have their questions answered.

Issue 79
Winter 2017