Analyses of data from two of the largest datasets of patients with breast cancer in the United States have found that time from diagnosis to surgical treatment makes a difference in patient survival.

A delay in surgery after diagnosis of noninflammatory, nonmetastatic, invasive breast cancer was found to be associated with lower overall and disease-specific survival rates, according to research published in JAMA Oncology.

Lead investigator Richard J. Bleicher, MD, Associate Professor in the Department of Surgical Oncology at Fox Chase Cancer Center – Temple Health, said this research “finally gives clinicians a clear answer to the question of how a longer time to surgery affects a patient’s survival from their breast cancer.”

For the analyses, researchers used patient data from the Surveillance Epidemiology and End Results (SEER)-Medicare-linked database and the National Cancer Database (NCDB).

The SEER-Medicare cohort included 94,544 patients aged 66 years and older who were diagnosed with breast cancer 1992 to 2009.

The National Cancer Database cohort included 115,790 patients aged 18 years and older who were diagnosed 2003 to 2005, had been followed through 2010, and had received their care at Commission on Cancer-accredited facilities.

The analysis of the SEER-Medicare group showed a 9 percent increase in mortality for all patients and from all causes for each 30-day interval increase in the time between diagnosis and surgery.

The time to surgery was statistically significant for overall survival for patients with stage I and stage II breast cancer, but not for patients with stage III disease.

Breast-cancer specific mortality risk increased with each 60-day interval in time from diagnosis to surgery, with the risk significant for stage I patients, but not for stage II or III.

For patients in the second database, the NCDB, the added risk of death from all causes for each 30-day time interval after diagnosis was 10 percent.

Time to surgery was associated with overall survival for patients with both stage I and stage II breast cancer, but not for stage III. Cause-specific mortality data are not available in this cohort.

The analysis of both datasets “represents the most comprehensive study of the subject ever performed, and includes two extraordinarily large groups from two of the largest cancer databases in the United States,” Bleicher said. “The findings from the analysis answer a question that nearly every patient asks: ‘Will my prognosis be affected by the time it takes me to get to surgery?’”

“What’s remarkable about these two large database analyses is that they’re consistent,” he said. “A longer time to surgery means lower survival.”

According to their published report, the researchers noted the similar results “between separate analyses of these two large national datasets, having different characteristics … suggests that the effect of delay on survival is a true phenomenon and not one specific to a particular cohort.”

In particular, the investigators accounted for patient factors such as age, race, urban/rural setting and other demographics, tumour factors such as the histology and characteristics of their cancer, and treatment factors, such as whether particular types of treatment were given. After adjustment for all of these factors, they found that a longer time to surgery was still associated with poorer survival.

Investigators were initially surprised to find that patients with early-stage disease seem to benefit most by shortening the time to surgery, but “this makes sense,” Bleicher said. “Patients who have later stage disease at diagnosis probably have a risk of dying from their disease that outweighs any benefit seen by shortening the delay. In contrast, patients with early stage cancer have outcomes that are so good, that changes in outcome because of a delay in the time to surgery are more easily detectable.”

Only 1.2 percent of patients in the SMDB and 1.5 percent of patients in the NCDB had surgery more than 90 days after their diagnosis. The researchers optimistically noted that “providing these few breast cancer patients the 3-5 percent survival benefit associated with reduced delay …seems achievable.”

Source: Fox Chase Cancer Centre