"Blood Test Predicts Risk of Metastatic Breast Cancer Spread"

Yonsei Cancer Center Team Identifies ctDNA Instability as a Predictive Marker
Provides a Basis for Selecting Patients Likely to Benefit from Local Treatment

A study has found that the risk of cancer cell spread in patients with metastatic breast cancer can be predicted through a blood test.

The research team led by Professor Jisuk Jang in the Department of Radiation Oncology, and Professors Minhwan Kim and Geonmin Kim in the Department of Medical Oncology at Yonsei Cancer Center, Severance Hospital, announced on June 17 that, based on their analysis of cancer progression patterns in patients with metastatic breast cancer who had received first-line systemic chemotherapy, the genomic instability score (I-score) of circulating tumor DNA (ctDNA) in the blood can serve as a criterion for predicting whether cancer will progress in a multifocal manner in the future.

Professor Jiseok Jang from the Department of Radiation Oncology, Professors Minhwan Kim and Gunmin Kim from the Department of Oncology at Yonsei Cancer Center Research Team. Severance

This study was published in the latest issue of the international journal "International Journal of Radiation Oncology, Biology, Physics (IJROBP)" in the field of radiation oncology.

Metastatic breast cancer refers to a state in which cancer cells have spread beyond the breast to other organs such as the bones, lungs, liver, or brain. For patients with oligometastatic breast cancer, who have only a small number of metastatic lesions, treatment methods that focus high-dose radiation on metastatic sites are used.

However, it has not been clear whether local treatment would be effective in all patients with oligometastatic breast cancer. This is because each patient exhibits different cancer subtypes, metastatic speeds, and systemic spread patterns, making it difficult to determine suitable candidates for treatment based only on the number of metastatic lesions seen on imaging tests.

The research team addressed this issue by focusing on circulating tumor DNA (ctDNA), which is DNA derived from cancer cells floating in the blood. By analyzing data from 207 patients with metastatic breast cancer enrolled in clinical studies from 2017 to 2021, they found that even patients with few metastatic lesions at first could experience widespread metastasis to multiple organs over time.

In particular, patients with higher genomic instability in their circulating tumor DNA were at greater risk of rapid systemic spread of cancer. Those with an I-score, the genomic instability score of ctDNA, exceeding 7.3 had about 3.2 times higher risk of progressing to extensive metastasis compared to those with lower scores.

Therefore, even if a patient appears to have oligometastatic cancer with few lesions on imaging, if genomic instability in circulating tumor DNA is high, there is a possibility of rapid progression to systemic metastasis and a need to adjust the treatment strategy accordingly. Conversely, for patients with low genomic instability in ctDNA, local treatments such as stereotactic radiotherapy can be actively considered.

Professor Jisuk Jang said, "The ongoing controversy over the role of local treatment in oligometastatic breast cancer is because previous approaches did not sufficiently reflect the molecular biological characteristics that determine cancer progression patterns. This study suggests the potential to select patients who can actually benefit from treatment by utilizing circulating tumor DNA."

Professor Minhwan Kim added, "In treating metastatic breast cancer, it is important to predict each patient's risk of systemic spread and to develop strategies that combine drug therapy with local treatment accordingly. We will continue follow-up research to further develop ctDNA-based personalized treatment strategies in the future."

This content was produced with the assistance of AI translation services.