Marie Jeanne Vrancken Peeters presented the results of the MARI study in a debate at the EBCC. A study in which the axillary staging for chemotherapy takes place with a PET scan and after chemotherapy with the aid of the MARI procedure (a new technique in which one of the affected axillary glands is marked with a radioactive iodine source). After the implementation of this protocol, almost 80% of patients could be spared armpit gland surgery.
It was also an interesting session, chaired by Marie Jeanne Vrancken Peeters, in which Frederieke van Duinhoven presented the MICRA study - a study to determine whether, after chemotherapy, we can see from the breast by means of biopsies if there is any need for a further operation or if there is no tumor in the breast at all. As with the last group of patients, surgery can be spared in this way in the future. More than 10 Dutch hospitals are participating in this study. In this session, Marieke van de Noordaa showed results about not carrying out thyroid surgery with a select group of patients (triple negative and HER2 positive).
Emiel Rutgers presented the loco-regional healing chances of 6693 patients, treated in the Mindact trial. This study was selected as one of the 'best abstracts'. The primary objective of the Mindact trial was to demonstrate the 5-year disease-free survival of patients with a clinical high risk mamma carcinoma (determined by pathological characteristics such as a large tumor, poorer grading and lymph gland metastases), on the basis of which normal chemotherapy is advised, but of which the tumors Mammaprint test was low risk, were NOT given chemotherapy by drawing lots, was around 95%. This primary objective has been achieved: The chance that additional chemotherapy will add something substantial to the disease-free survival of these patients is minimal.
The Mindact scientists have now looked at the probability of a loco-regional relapse (in the breast, in the lymph glands, and amputation in the breast wall), and what the risk factors are for such a relapse. In particular, whether there are differences between high-risk and low-risk Mammaprint tumors. Women who have undergone breast-saving treatmentand who have had a mastectomy, have been considered separately. The results are astonishingly good. Of the more than 5000 patients who received breast-saving treatment, only 2.2% had a local and/or regional relapse, and of the more than 1200 patients who had a mastectomy, 2.9% had a local and/or regional relapse. For the 3000 women above the age of 50 with a tumor smaller than 2cm, the five-year loco-regional relapse probability is less than 1%. These good results raise the question of whether every patient should have irradiation therapy after a breast-saving operation. Investigations into this are under way. The Mammaprint was not an independent predictor for a loco-regional relapse. This is also clear, because the Mammaprint test was created to better predict the process of metastases in the body.
For a number of women with breast cancer, partial breast irradiation (PBI) is a good and internally accepted treatment. The Antoni van Leeuwenhoek hospital has been profiling for years by not giving this partial irradiation after the end of the operation, but instead just prior to it, within the framework of the PAPBI trial (pre-operative accelerated PBI) Because the tumor is is still present in the breast, the irradiated volume can be limited. In addition, a few weeks after the irradiation, it is the very part of the breast that received the highest dose of radiation that is removed. This results in a much better cosmetic outcome, while the chance of recovery remains the same. The follow-up study - PAPBI 2 - started recently which is a lottery as to whether PBI is performed before or after surgery. The focus of the study is on the cosmetic outcome. An important sub-study is the analysis of the genetic profile of the tumors in order to be able to predict the susceptibility of tumors to radiation, with the aim of further customizing the local treatment of women with breast cancer in the future. Several Dutch and foreign institutions are taking part in this study. At EBCC the study was presented to a wider audience by Astrid Scholten, which has been very positively received. In response to this presentation, several other foreign institutes have indicated an interest in taking part in our study.
In recent years, immunotherapy has made breakthroughs in cancer types such as melanoma, lung and bladder cancer, but for breast cancer this treatment is still in its infancy. However, many studies are being carried out into the value of immune checkpoint inhibitors in various types of breast cancer and, at the EBCC, there was a special session on developments in the field of immunotherapy. The Antoni van Leeuwenhoek hospital is at the forefront of this by carrying out innovative studies, where immunotherapy is combined with a small dose of chemotherapy or irradiation. The first translational test data will be presented at the upcoming ASCO 2018 in June in Chicago, USA. At the EBCC Marleen Kok shared what the Antoni van Leeuwenhoek hospital expects to learn from the results for melanoma and other more 'immunogenic' tumor types and how we will be able to recognize immunotherapy-sensitive breast cancers in the coming years. For example, we have shown that a tumor characteristic that is mainly associated with colon and uterinecancer could also be important in identifying breast cancer patients who could benefit from immunotherapy.
Although we assume that recovery is no longer possible when breast cancer has spread to other organs in the body (for example liver, lungs, bones), there is a group of patients who survive many years without any indication that cancerous cells are still present in the body. It appears that patients where only one or a few metastases were have a chance of such long-term remission. As this is quite rare, few studies have been carried out regarding these specific circumstances. The Antoni van Leeuwenhoek hospital is at the forefront of research into oligometastases (oligo means little), among other things, by means of two investigations conducted by Gabe Sonke, one on the value of intensive chemotherapy in this context and one on predicting who will be able to stay alive for a long time despite the spread of breast cancer: Which patient characteristics play a role (age, number and type of metastases, genetic susceptibility, etc.)? Which treatments give a chance of long-term survival? And which genetic characteristics of the tumor play a role? During the EBCC there were several speakers who highlighted these issues; from a surgical, radiotherapy and chemotherapy standpoint, and the importance of cooperation between hospitals and countries was emphasized to take further steps for this small but special group of women with breast cancer that has spread.