How Fast Breast Cancers Grow and Why Timing Matters

Researchers at Fox Chase Cancer Center have developed a novel approach to measure tumor growth, delivering the most detailed analysis yet of breast cancer growth rates in patients (1^✔ ✔Trusted Source
Breast Cancer Upstaging Risk and In Vivo Tumor Growth Rates Associated with Preoperative Delays

Go to source). The study sheds light on how delays in surgery can influence cancer staging—the assessment of how far the disease has spread. These findings provide valuable insight into tumor progression during the interval between diagnosis and surgical treatment.

Surgical Delays and Staging: Unpacking Their Impact on Breast Cancer Progression

“It’s the first study ever to use pathologic tumor sizes to determine how fast tumors of different sizes and traits grow in the patient while they’re waiting for treatment,” said Richard Bleicher, MD, FACS, lead author on the study and Chief of the Division of Breast Surgery at Fox Chase.

Pathologic tumor size refers to the size of a tumor after it is surgically removed from the patient and examined. Clinical size, which is determined by imaging equipment such as X-rays or CT scans before surgery, is typically less accurate.

“Patients who are diagnosed with breast cancer are always worried about how fast breast cancer grows while they wait for their surgery and the likelihood that it will spread from that growth,” Bleicher said. “This study finally gives patients and their physicians that information for tumors of different sizes and types to make the best decisions they can.”

The study, which Bleicher conducted with several colleagues at Fox Chase, found that the upstaging rates associated with delays are still relatively small and consistent with prior data showing that even months-long delays between diagnosis and surgery result in only single-digit mortality risks. Upstaging refers to when a patients localized cancer spreads to other parts of the body.

“Many patients fear that delays in care will allow their cancer to grow and spread beyond the point of cure. This study provides the most comprehensive evaluation of how treatment delays may affect the likelihood that a tumor will be upstaged or be at a more advanced stage at the time of surgery than initially estimated at diagnosis,” Bleicher said.

The research team used the differences between the initial clinical tumor size and the pathologic tumor size to calculate growth and upstaging risk between diagnosis and surgery. Accounting for inaccuracies in clinical staging, this method more accurately demonstrates the associated risks of tumor growth and progression.

The study utilized data from the National Cancer Database for over one million patients treated between 2010 and 2020. These patients had non-metastatic, non-inflammatory breast cancer and were undergoing surgery as their first treatment.

Why Surgical Upstaging Often Reveals Undetected Disease Extent

“Interestingly, a significant proportion of the observed upstaging is not from tumor progression, but from the inaccuracy of clinical staging. In other words, when breast cancers are upstaged at surgery, it’s more likely because we didn’t appreciate the initial extent of disease than because the tumor had time to spread,” said Bleicher.

“The findings in this study expand our knowledge and offer new data to help counsel individuals diagnosed with breast cancer. As we continue to refine our diagnostic tools and clinical assessments, we will reduce the risk of upstaging even further,” he added.

“We may not be able to stop time, but armed with this new knowledge, we can use it more wisely, empowering patients to ensure that they feel urgency and not fear.”

Reference:

1. Breast Cancer Upstaging Risk and In Vivo Tumor Growth Rates Associated with Preoperative Delays - (https://link.springer.com/article/10.1245/s10434-025-17867-9)

Source-Eurekalert