Research led by Prof. Vivianne Tjan-Heijnen (Maastricht UMC+) publised in the New England Journal of Medicine.
Until now, it had long been unclear whether the presence of micrometastases or isolated tumour cells in lymph nodes had a negative effect on the chances of recovery; thus, whether this should be a selection criterion for additional treatment. Researchers led by Professor Vivianne Tjan-Heijnen, head of the Internal Medicine Department’s medical oncology section at the Maastricht University Medical Center+, have now shown that the presence of micrometastases or isolated tumour cells indeed lowers the chances of recovery. They have also established that survival chances increase through additional medical treatment. The results of their research have been published today in the authoritative American journal The New England Journal of Medicine.
More than 10 years ago, surgeons in the Netherlands introduced the sentinel node procedure in patients with early stage breast cancer. The sentinel lymph node is the first node that the breast tissue drains into. If this node is clean, no complementary axillary node treatment is necessary. Comprehensive examination of this node is thus a condition to prevent undertreatment of the axillary lymph nodes. This intensified examination by the pathologist has resulted in the increased detection of micrometastases (ranging between 0.2 and 2.0 mm in size) and isolated tumour cells (individual tumour cells or tumour cell groups smaller than 0.2 mm). This raises the question: Are these small anomalies important for long-term outcome? And should we advise additional medical treatment at the time of the primary breast cancer diagnosis?
Results
The results of the MIRROR study (‘Micrometastases and Isolated tumour cells: Relevant and Robust Or Rubbish’) show that micromestastases and isolated tumour cells are associated with an absolute decline in five-year disease-free survival of 10%. For patients who are treated with medication after their operation, the prognosis improves by nearly 10%.
“This study has produced results that we can work with”, says Tjan-Heijnen, emphasising the importance of the research. “It’s the small step forward each time that will ultimately enable us to continuously improve the life expectancy for breast cancer patients. From this research we have learned that isolated tumour cells are important for the prognosis – just as important as micrometastases, in fact. To date these very small anomalies have been classified as lymph node–negative, but now we can show the world that they should be regarded as lymph node–positive.”
Study
For this nationwide study, more than 3000 patients who had undergone a sentinel node procedure before 2006 were identified via the database of the Netherlands Cancer Registry. In total, 2700 patients fulfilled the criteria for the study. The women were then divided into three groups: one group without tumour cells in the nodes and who had not received additional medical treatment, one with isolated tumour cells or micrometastases in the nodes who neither had received additional treatment, and one with isolated tumour cells or micrometastases in the nodes who had received additional treatment. Their diagnosis, treatment and follow-up data were collected with the help of staff from the regional cancer centres, guided by the Comprehensive Cancer Centre East. The steering committee was composed of representatives from the medical centres of all Dutch universities as well as the Netherlands Cancer Institute. The pathology slides of the sentinel lymph nodes were revised centrally in Utrecht and Nijmegen. All hospitals in the Netherlands took part in the research.
Read more: http://content.nejm.org