Pathlight Breast Cancer Blood Test

Some of the researchers behind the current study Anthony George, Yilun Chen, Lao Saal and Sergii Gladchuk.
Photo Credit: Ingemar Hultquist

Scientific Frontline: Extended "At a Glance" Summary: Pathlight Blood Test for Breast Cancer Recurrence

The Core Concept: A highly sensitive blood test designed to measure circulating tumor DNA (ctDNA) in patients with early breast cancer. It successfully identifies residual disease and predicts relapse long before clinical symptoms or traditional imaging can detect it.

Key Distinction/Mechanism: Unlike standard clinical imaging that waits for tumors to become physically visible, the Pathlight method tracks microscopic fragments of tumor DNA in the bloodstream. It uses a personalized approach based on the unique genetic fingerprint of a patient's original tumor, offering a faster, more cost-effective, and highly precise liquid biopsy compared to broader genetic screenings.

Major Frameworks/Components:

• Liquid Biopsy Monitoring: Non-invasive, continuous blood sampling to track treatment response from diagnosis through post-surgery recovery.
• Circulating Tumor DNA (ctDNA) Analysis: Detecting specific, early-arising genetic alterations that represent the tumor's unique signature.
• Precision Prognostics: Outperforming standard pathological complete response (pCR) by identifying patients whose ctDNA levels do not decline during therapy, accurately signaling a high recurrence risk.

Branch of Science: Oncology, Molecular Biology, Clinical Genetics, and Precision Medicine.

Future Application: The test aims to revolutionize how breast cancer patients are monitored by enabling personalized treatment adjustments. It offers the potential to initiate earlier, targeted interventions for high-risk patients while sparing lowest-risk patients from unnecessarily intensive, side-effect-heavy therapies.

Why It Matters: In clinical follow-ups, this method detected signs of metastatic disease a median of 13.8 months—and up to four years in some cases—before standard methods recognized the relapse. This provides a critical, expanded time window for potentially life-saving clinical interventions.

Researchers at Lund University have validated a blood-based method for measuring circulating tumor DNA in patients with early-stage breast cancer. The method identified breast cancer patients at high risk for recurrence and detected molecular signs of relapse before the disease became clinically visible using current standard methods.

Researchers at Lund University have developed a blood test capable of detecting signs of breast cancer recurrence long before it becomes visible on imaging or causes symptoms. Previous research demonstrated that this method can detect extremely small amounts of tumor DNA in blood samples with exceptionally high precision and specificity. In the current, much larger study, patients were followed over time to evaluate how accurately the method could predict recurrence and monitor treatment response.

“This study shows that our blood-based method, Pathlight, which reliably measures small fragments of tumor DNA, can provide early information about how breast cancer responds to chemotherapy before surgery, while also indicating whether the disease has returned after surgery,” says Lao Saal, a researcher at Lund University and senior author of the study, which is published in the journal EMBO Molecular Medicine.

Among patients who later developed metastatic disease, the blood test detected signs of recurrence a median of 13.8 months before the relapse became clinically visible—and in some cases, nearly 4 years before current methods detected the disease.

Currently, recurrence is most often detected only after tumors become visible on imaging or begin causing symptoms. The new analytical method instead tracks tiny amounts of tumor DNA in the bloodstream. It is based on comprehensive genetic profiling of the tumor, which allows researchers to identify specific DNA alterations that arise early in cancer development.

“The method is based on the premise that every tumor has a unique genetic fingerprint. By measuring these alterations in a patient’s blood, we can detect extremely small amounts of residual tumor DNA with high precision, even when a recurrence is not yet visible through current imaging methods or has not yet caused symptoms,” says Lao Saal.

Although the technology provides less detailed information than more advanced genetic analyses, it is faster and more cost-effective, while remaining accurate enough to measure treatment response and identify patients who will go on to develop a clinical relapse.

The study included 136 participants treated with chemotherapy and surgery for various types of breast cancer. Blood samples were collected at diagnosis, during treatment, shortly after surgery, and regularly during a follow-up period of up to 6 years.

Key results:

• Tumor DNA was detected in the blood of nearly 90 percent of patients before treatment began.
• In approximately 21 percent of patients, tumor DNA was still detectable after presurgical drug treatment.
• In 13 percent of patients, tumor DNA levels did not show a clear decline during treatment, a finding strongly associated with a high risk of recurrence.
• The method provided more accurate prognostic information than pathological complete response (pCR), the current established measure of presurgical treatment response in breast cancer.

The presence of tumor DNA in the blood after surgery was strongly associated with future recurrence.

“These findings could change how breast cancer patients are monitored and treated in the future. With further research, the technology may provide opportunities to improve treatment for patients at high risk for recurrence. The method may also help us optimize treatment for patients at the lowest risk of recurrence, who may be able to avoid unnecessarily intensive therapy, potentially minimizing side effects,” says Niklas Loman, a senior oncologist at Skåne University Hospital and a coauthor of the study.

Conflict of interest statement: The test evaluated in the study originated from research at Lund University and was developed by SAGA Diagnostics. The method is patented. Several of the study authors own shares in the company, which was co-founded by Lao Saal and others. The company was recently acquired by Roche.

Funding: The study was supported by, among others: the Swedish Cancer Society, the Swedish Research Council, the Mrs. Berta Kamprad Foundation, Vinnova, and FORTE.

Published in journal: EMBO Molecular Medicine

Title: NeoCircle: pre- and post-operative circulating tumor DNA dynamics predicts survival in neoadjuvant-treated early breast cancer

Authors: Anthony M George, Yilun Chen, Sergii Gladchuk, Miguel Alcaide, Hina Dalal, Pei Meng, Christian Brueffer, Hani Saghir, Siker Kimbung, Kristina Aaltonen, Lucia Oton, Christopher Rushton, Sofia Birkeälv, Mats Jönsson, Sophia Zackrisson, Ida Skarping, Daniel Förnvik, Lina Zander, Gabriella Honeth, Samuel Woodhouse, Karen Howarth, Åke Borg, Anna Ehinger, Martin Malmberg, Lisa Rydén, Niklas Loman, and Lao H Saal

Source/Credit: Lund University | Tove Smeds

Edited by: Scientific Frontline

Reference Number: ongy052626_01

Privacy Policy | Terms of Service | Contact Us