Analyzing Breast Cancer Metastases Could Improve Outcomes

Tumor biology may differ when cancer recurs.

Along with more advanced therapies, characterizing tumors led to enhanced targeted treatment approaches for breast cancer, which has improved outcomes. A new study published by Nature Communications suggests that also characterizing metastases can improve the understanding of breast cancer progression.

This study is among the first to analyze metastases during autopsies of patients with metastatic breast cancer. The authors believe that their findings may improve care for patients with metastatic disease.

Cancer can metastasize to anywhere in the body, including vital organs, such as the brain and lungs. Despite advances, treating metastatic disease can be challenging. A majority of treatments aim to slow cancer cell growth, but do not cure the disease.

Currently, patients with metastatic cancer are treated based on an analysis of the primary tumor. Meaning that if a patient with breast cancer has metastases in the lungs, they would be treated with breast cancer drugs, rather than exploring the biology of the new tumors. A better understanding of metastatic cancer is crucial for administering the optimal treatment to achieve the best outcomes.

However, studying the spread of breast cancer — from primary tumor to metastatic disease – would require an analysis of all metastases over time. One of the only options to characterize disease progression is to study the metastases of patients after death, according to the study.

In the study, the authors examined the biology of metastases and primary tumors of 10 patients during autopsy to map the cancer’s progression over time.

The authors discovered that most metastases originate in a single metastatic precursor and are not the result of independent multiple dissemination events from the primary tumor, according to the study.

In patients whose cancer recurrences occurred shortly after initial diagnosis, the characteristics of the metastases were similar to the primary tumor, the authors noted. In later recurrences, the molecular characteristics of the metastases and primary tumors differed.

The authors said that the genomic profile of metastases in the same patient could be very different, which could explain the varied response to cancer treatment observed in some patients, according to the study.

These findings suggest that at least 1 metastatic tumor should be biopsied and analyzed upon breast cancer recurrence. Cancers occurring several years after initial diagnosis should be biopsied and analyzed since the genomic profile of the disease may have been modified.

The authors suggest that using high throughput sequencing techniques that target clinically relevant aberrations could be effective at making a treatment decision, especially when it comes to targeted therapies, the study concluded.