Breast Cancer Growth: Study Reveals Surgery Delays Have Minimal Impact

New analysis indicates inaccuracies in initial scans are more often to blame for staging changes than tumor progression.

Fears that breast cancer may significantly advance while patients await surgery are largely unfounded, according to groundbreaking research. A novel analytical method developed at Fox Chase Cancer Center provides the most detailed look yet at how tumors grow and how pre-operative delays affect cancer staging.

Understanding Tumor Progression

The study, led by **Dr. Richard Bleicher**, Chief of Breast Surgery at Fox Chase Cancer Center, utilized pathologic tumor sizes—the actual dimensions after surgical removal—to understand growth rates. This method offers a more precise view than clinical assessments made via imaging before surgery.

“It is 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.”

—Dr. Richard Bleicher, MD, FACS, Study Lead Author and Chief, Division of Breast Surgery, Fox Chase Cancer Center

“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,” **Dr. Bleicher** explained. “This study finally gives patients and their physicians that information for tumors of different sizes and types to make the best decisions they can.”

Upstaging Linked to Scan Accuracy

The research found that the rates of upstaging—when cancer is found to be more advanced than initially diagnosed—are relatively small and consistent with previous findings. Even prolonged delays between diagnosis and surgery have been linked to only minor increases in mortality risk.

“Many patients fear that delays in care will allow their cancer to grow and spread beyond the point of cure,” **Dr. Bleicher** stated. “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.”

The team’s innovative approach compared initial clinical tumor sizes with post-operative pathologic sizes to calculate growth and upstaging risks. This technique more accurately reflects associated risks by accounting for limitations in clinical staging.

Data from Over One Million Patients

Analyzing data from the National Cancer Database for over one million patients treated between 2010 and 2020, the study focused on individuals with non-metastatic, non-inflammatory breast cancer receiving surgery as their initial treatment.

“Interestingly, a significant proportion of the observed upstaging is not from tumor progression, but from the inaccuracy of clinical staging,” **Dr. Bleicher** noted. “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.”

The findings offer crucial data to help guide conversations with newly diagnosed patients, improving the understanding of treatment timelines. As diagnostic tools advance, the risk of upstaging is expected to decrease further.

A recent report from the American Cancer Society indicates that an estimated 287,590 new cases of invasive breast cancer will be diagnosed in women in the U.S. in 2024 (American Cancer Society, 2024). This study aims to alleviate patient anxiety by providing a clearer picture of the actual impact of waiting periods.

“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,” **Dr. Bleicher** concluded.