Radiation therapy after breast-conserving surgery along with chemotherapy or tamoxifen to treat early breast cancer reduces the risk that the disease will recur in the same breast within 10 years of diagnosis, but still hardly influences that risk from that period of time. Nor does it improve overall survival at 30 years.
Ian KunklerHonorary Professor of Clinical Oncology at the University of Edinburgh (United Kingdom), has assured today (Friday) in the 13th European Congress of Breast Cancer This research, one of the longest and most up-to-date follow-ups of randomized controlled clinical trials of breast-conserving therapies, has been referred to as “probably unique.” She has stressed that it yields important information for long-term breast cancer survivors and their doctors.
“Long-term follow-up is essential in breast cancer trials to understand the full picture,” Kunkler said.
The Scottish breast conservation trial followed 585 patients aged 70 or younger over 30 years. After diagnosis of early breast cancer, they were treated with breast-conserving surgery followed by systemic therapy, such as chemotherapy or the drug tamoxifen, depending on whether or not their cancer was caused by estrogen. They were also randomized to receive or not receive radiation therapy after surgery.
Ten years after radiation therapy, recurrence of disease in the same breast (known as “locoregional recurrence” or “ipsilateral breast tumor recurrence”) was significantly reduced by more than 60% in women who had been randomized to receive radiation therapy compared to those that don’t. However, after the first 10 years, the annual risk of recurrence was very similar in both groups, as was overall survival: 30 years after their treatment, 24% of women who received radiation therapy were still alive compared with 27.5% of those who did not receive it.
Kunkler has assured: «We discovered that there is no long-term improvement on overall survival for those women receiving radiation therapy. This may be because while radiation therapy can help prevent some deaths from breast cancer, it can also cause some more deaths, especially long after radiation therapy, from other causes, such as heart and blood vessel diseases.
“The benefits of receiving radiotherapy in terms of fewer local recurrences only accrue during the first ten years after radiotherapy; thereafter, the local recurrence rate is similar regardless of whether or not patients received radiation therapy.
“Patients with breast cancer can live decades after treatment for the disease. These findings justify comparison with other studies of similar design through careful long-term follow-up.
The benefits of receiving radiation therapy in terms of fewer local recurrences only accrue for the first ten years.
Follow-up of randomized breast cancer clinical trials beyond ten years is often limited by limited resources. Funders should support the collection of long-term outcome data. The results I present today show that such data may challenge traditional concepts of the long-term anti-cancer benefits of radiotherapy,” he added.
“It is important to note that each woman with breast cancer is different and will have different forms of the disease. Decisions about whether or not to undergo radiation therapy after surgery should be made by patients and their doctors after careful discussion, taking into account the individual characteristics of their breast cancer and the likely risks of long-term recurrence, both inside and outside the breast and treatment-related toxicity.
Spanic is co-chair of the European Congress on Breast Cancer, patient advocate and president of Europa Donna, the European Coalition Against Breast Cancer. She did not participate in the research, but when asked about it, she stated: “I was diagnosed with breast cancer when I was only 26 years old. One of the questions I was asking myself, as many women are when they are first diagnosed, is what was the best treatment for me, not only to treat the cancer but also to help me live a long and healthy life.
As this very long-term follow-up of breast cancer patients shows, these are complex issues that patients and their doctors must consider when choosing the best treatments. We need more studies like this one that follow patients for decades to get a true picture of the long-term effects of treatments.”