Researchers found that the use of RT in addition to surgery could reduce the chances of a local recurrence (the cancer coming back in the same breast) by 50%. Results from the trial, which has one of the longest follow-ups of a large group of patients in the world to date, will be reported today (Thursday) to the 8th European Breast Cancer Conference (EBCC-8).
Dr. Mila Donker, a research physician from the Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands, worked with colleagues from thirteen other countries under the auspices of the European Organisation for the Research and Treatment of Cancer (EORTC), based in Brussels, Belgium. They analysed the 15-year follow-up of more than 1000 DCIS patients, 50% of whom had received RT after total surgical excision of a tumour of less than 5cm diameter and 50% who had not. When radiotherapy had not been given, almost one in three women had developed a local recurrence, while the 50% risk reduction in those patients who had had RT held true for both an in-situ and an invasive cancer recurrence, where the cancer had spread outside the duct.
The 15-year cumulative incidence for DCIS recurrence in the surgery group was 14.9%, as opposed to 7.5% in those patients in the combined group (surgery plus radiotherapy), and for an invasive recurrence the rates were 15.5% (surgery only) and 9.8% (combined). Although no survival difference was seen between the surgery alone and the surgery plus RT group, women who had an invasive recurrence had a significantly worse survival compared with those who had a DCIS recurrence or no recurrence at all.
"We found that the majority of the DCIS recurrences occurred within five years of treatment, and that RT seemed to have a continuous protective effect on DCIS recurrence in the long term," says Dr. Donker. "However, the protective effect of radiotherapy on the onset of invasive recurrence seemed to be observed mainly in the first five years after treatment, while the risk of developing a recurrence was more or less continuous over the years."
The number of DCIS cases has increased in the past few decades, and it now accounts for about 25% of all new breast cancer diagnoses. Until the introduction of routine screening it was often overlooked and not diagnosed until it had developed into invasive breast cancer. Because most breast cancers start in the cells that line the ducts and lobules of the breast, the diagnosis of DCIS is an important indication of a woman's risk of developing an invasive cancer.
Detecting an in situ lesion of the breast enables the patient to be treated at an early stage, but it also poses the problem of 'over-treatment' for a lesion that would not have developed into a life-threatening cancer. "That is why it is so important to be able to study the biological behaviour and the malignant potential of these in situ breast cancers in long follow-up trials. Our study provides convincing evidence that early treatment does work, and that it can help to avoid the more severe therapies that might be needed at a later stage," Dr. Donker will say.
"We now intend to analyse prognosis and treatment after recurrence in these patients. We now know that patients who do not receive RT have a higher risk of a local recurrence, but we will have a lot to learn about prognosis and treatment at a later stage. We intend to analyse the data to look at, for example, whether patients who received RT during the initial treatment have a higher risk of having to undergo a mastectomy after a local recurrence," Dr. Donker will say.
The researchers believe that their findings will allow them to better select patients who will benefit from particular treatments and avoid over and under treatment of patients with DCIS. "For example, in the future we will be able to identify patients who will not benefit from RT and spare them a treatment that might induce other tumours later in life. Or we could identify patients who need a more aggressive therapy than only local excision and RT – patients with a high chance of recurrence might benefit from an initial mastectomy, for example. We are hoping that by learning more about the differences in outcome for these patients we will be able to make detailed recommendations for the best treatment to use if the cancer recurs, and hence be able to decrease yet further the local recurrence rate of DCIS patients in the future," Dr. Donker will conclude.
Professor David Cameron, from the University of Edinburgh (Edinburgh, UK) and chair of EBCC-8 said: "This is an important long-term follow-up study. DCIS is a much more common diagnosis now than when this trial was run, so that there are many patients whose care might be influenced by these data. These data also reiterate the importance of long-term follow-up in breast cancer, as patients can, sadly, develop a recurrence of their cancer many years after their initial treatment."
Abstract no: 217, Thursday 15.30 hrs, Clinical Sciences Symposium "The Management of Pre-Invasive Breast Cancer", Hall E.
 DCIS is a kind of 'pre-cancer' where abnormal cells are found in the lining of the milk ducts of the breast. About 80% of invasive breast cancers begin as DCIS.
Mary Rice | EurekAlert!
Team discovers how bacteria exploit a chink in the body's armor
20.01.2017 | University of Illinois at Urbana-Champaign
Rabies viruses reveal wiring in transparent brains
19.01.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences