In patients with metastatic breast cancer, of the HER2-positive subtype, the expression status of hormone receptors, the location of metastases and age have been identified as factors influencing survival, according to the ‘RegistEM study that reveals new data on patients and the evolution of this advanced cancer.
A congresswoman at the 13th European Congress on Breast Cancer held in November 2022 in Barcelona. EFE/ Enric Fontcuberta
The RegistEM study is the most complete registry on metastatic breast cancer available in Spain and is driven by the GEICAM Breast Cancer Research Group which has had the collaboration of 38 hospitals from 14 autonomous communities that collect data of almost 1,900 patients.
And the results of this study have been presented at the recent 45th Breast Cancer Congress in San Antonio (Texas, USA), the world’s leading event in this type of cancer.
The study has focused on the analysis of patients with HER2 and triple negative cancer subtypes and will help increase knowledge about the clinicopathological characteristics of metastatic breast cancer, treatment patterns and the evolution of patients with the different types of cancer, important for therapeutic strategies.
“The prolonged relapse-free interval from the diagnosis of the disease in early stages, the expression of hormone receptors and the anatomical location of tumor lesions at relapse, are clinicopathological factors that have a prognostic impact in HER2 metastatic breast cancer -positive”, says the main author of the poster presented at the Sant Antoni congress, Dr Sara López-Tarruella, member of the Board of Directors and the Scientific Committee of GEICAM and coordinator of the Triple Negative Disease Working Group.
The RegistEM study confirms the trend that cases with metastases of the skin, lymph nodes or soft parts have a better prognosis than those with visceral involvement (including the central nervous system), according to the specialist of the Medical Oncology Service from the Gregorio Marañón General University Hospital in Madrid.
In addition, patients with hormone receptor-expressing tumors (within HER2-positive disease) have better survival in the setting of disseminated disease.
Study of metastatic breast cancer in HER2-0 and HER2-low subtypes
Another of the RegistEM analyzes presented at the American congress analyzes the characteristics of patients with HER2-low breast cancer (who present a certain degree of overexpression of this protein) and whether their behavior and evolution is different from breast cancer HER2-0 breast (without HER2 overexpression) and we can speak of a new clinical entity.
According to the main author of this work, the doctor Isabel Álvarez, from the Gipuzkoa Cancer Management Unit, in San Sebastià, and member of the GEICAM Board of Directors, the main conclusion is that there are no differences in the way you behave because of being HER2-0 or HER2-low. “What continues to mark the evolution of the disease is the presence or absence of hormone receptors,” he emphasizes.
In their opinion, the RegistEM data are relevant in that they include a very large number of patients with metastatic breast cancer with prospectively collected data, which reaffirms data from other series in localized breast cancer that indicate that in level of natural history no differences are objectified between HER2-negative tumors, whether low or 0 in the expression.
“But this differentiation based on the degree of HER2 overexpression is relevant if beneficial therapies appear for the subgroup of patients with HER2-low breast cancer, as it gives us information on the incidence of this subpopulation,” he clarifies.
Triple negative cancer with relapse of initial localized disease
Another of the aspects presented at the Sant Antoni congress was the observation of patients diagnosed with metastatic triple negative breast cancer, either after relapse or with distant metastasis (metastatic de novo).
Among the conclusions, it stands out that three quarters of patients with this biological subtype developed distant metastasis despite having been treated after the diagnosis of the localized primary tumor.
“These data speak of the aggressiveness of triple negative cancer”, according to the main author of this work, the doctor Silvia Antolín, researcher at the University Hospital Complex A Coruña (CHUAC) and member of the Board of Directors of GEICAM.
“Furthermore, one-third of patients with triple-negative breast cancer at the time of advanced disease expressed hormone receptors in the primary tumor, indicating how important it is to be able to obtain a biopsy of the metastasis to select the best treatment for to each patient”, he points out.
The oncologist explains that metastatic breast cancer from a relapse has a worse prognosis and response to treatments because it has already been treated and can acquire resistance.
“However, survival compared to those who debut with initial metastasis is very similar and the presence of visceral disease (traditionally associated with worse evolution) is similar in both groups of patients,” he points out.
This observational study verifies that brain localization is not observed in those patients with de novo metastasis, which may indicate that this localization occurs in patients already treated or with resistant tumors”, points out this expert, for whom these data they help to better establish the prognosis and survival of patients, and further encourage research into this subtype of breast cancer.
In his opinion, the knowledge acquired with the RegistEM “supports the need to biopsy the disease at the time of development of the metastasis and to put into practice less aggressive methods to determine molecular subtypes or resistances acquired by the tumor, as can be the liquid biopsy”.