Timelines Matter in the Treatment of Breast Cancer

Patients who received chemotherapy more than 120 days after being diagnosed with breast cancer had significantly worse overall survival compared with those who received chemotherapy within 120 days, reported a large retrospective analysis in the Annals of Surgical Oncology.

“It’s been known and previously published that delays in chemotherapy are associated with bad outcomes,” said Charles Shapiro, MD, Director of Translational Breast Cancer Research and Director of Cancer Survivorship at the Tisch Cancer Institute at the Icahn School of Medicine at Mount Sinai in New York, during an interview with Cancer Network. Shapiro was not involved in the analysis.

For instance, a study presented at the 2018 San Antonio Breast Cancer Symposium found that patients with triple-negative breast cancer had worse survival outcomes when chemotherapy was initiated more than 30 days after surgery. Though Shapiro described the group of studies as “heterogeneous,” with various cutoffs used to define treatment delay, he said they consistently show delays in chemotherapy impact patient survival.

Researchers in the recent study used the National Cancer Database to identify patients with stage I, II, or III breast cancer who were treated with surgery followed by chemotherapy between 2010 and 2014. The time interval from diagnosis to the receipt of surgery and eventual adjuvant chemotherapy was assessed and compared with survival outcomes.

Patients were also grouped by type of surgery received. Those surgery types included breast conserving surgery, mastectomy with immediate breast reconstruction, and mastectomy without immediate breast reconstruction. Chemotherapy was initiated more than 120 days after diagnosis of breast cancer was considered a treatment delay.

Overall, 172,043 patients were identified from the database. Breast conserving surgery was the most common type of surgery received (90,488 patients), followed by mastectomy without immediate reconstruction (46,253 patients), and mastectomy with immediate reconstruction (35,302 patients). The study population overall had a median age of 55.0 years at the time of diagnosis and 99% of patients were female.

For the entire study population, the median time from diagnosis to surgery was 27 days, with patients who had breast conserving surgery having a 4-day shorter median time to surgery compared with patients who had mastectomy (25 vs 29 days; P<0.001). Patients who had reconstruction had the greatest time interval between diagnosis and surgery (35 days), suggesting a possible area that can be improved to prevent subsequent chemotherapy delays. The time interval between surgery and initiation of chemotherapy was a median of 43 days for the overall study population and was fairly consistent across surgery types, generally ranging between 43 and 44 days.

The median time from diagnosis to initiation of chemotherapy was 74 days, and most patients (89.5%) initiated chemotherapy within the 120-day cutoff. Type of surgery received was associated with delay in chemotherapy initiation, with a lower proportion patients who underwent breast conserving surgery initiating chemotherapy beyond the 120-day cutoff compared with mastectomy (8.3% vs 12.9%; P<0.001).

The analysis showed that regardless of surgery type, patients who started chemotherapy beyond 120 days from the time of diagnosis had worse overall survival compared with patients who started chemotherapy within 120 days (hazard ratio [HR]=1.29; 95% CI, 1.22–1.37; P<0.001).

The association of worse survival and chemotherapy treatment delays was consistent across tumor subtypes evaluated, with HER2-positive disease most affected (HR=1.47; 95% CI, 1.29–1.68), followed by triple-negative breast cancer (HR=1.23; 95% CI, 1.10–1.38) and hormone receptor-positive and HER2-negative disease (HR=1.23; 95% CI, 1.13–1.34).

“The take-home message is try to get your chemotherapy in as early as possible,” Shapiro said.