Comparison of Use of Neoadjuvant Systemic Treatment for Breast Cancer and Short-term Outcomes Before vs During the COVID-19 Era in Ontario, Canada

Abstract

IMPORTANCEIn response to an increase in COVID-19 infection rates in Ontario, several systemic treatment (ST) regimens delivered in the adjuvant setting for breast cancer were temporarily permitted for neoadjuvant-intent to defer nonurgent breast cancer surgical procedures. OBJECTIVE To examine the use and compare short-term outcomes of neoadjuvant-intent vs adjuvant ST in the COVID-19 era compared with the pre-COVID-19 era. DESIGN, SETTING, AND PARTICIPANTS This was a retrospective population-based cohort study inOntario, Canada. Patients with cancer starting selected ST regimens in the COVID-19 era (March 11, 2020, to September 30, 2020 were compared to those in the pre-COVID-19 era (March 11, 2019, to March 10, 2020. Patients were diagnosed with breast cancer within 6 months of starting systemic therapy. MAIN OUTCOMES AND MEASURESEstimates were calculated for the use of neoadjuvant vs adjuvant ST, the likelihood of receiving a surgical procedure, the rate of emergency department visits, hospital admissions, COVID-19 infections, and all-cause mortality between treatment groups over time. RESULTS Among a total of 10 920 patients included, 7990 (73.2%) started treatment in the pre-COVID-19 era and 7344 (67.3%) received adjuvant ST; the mean (SD) age was 61.6 (13.1) years.Neoadjuvant-intent ST was more common in the COVID-19 era (1404 of 2930 patients [47.9%]) than the pre-COVID-19 era (2172 of 7990 patients [27.2%]), with an odds ratio of 2.46 (95% CI, 2.26-2.69; P < .001). This trend was consistent across a range of ST regimens, but differed according to patient age and geography. The likelihood of receiving surgery following neoadjuvant-intent chemotherapy was similar in the COVID-19 era compared with the pre-COVID-19 era (log-rank P = .06). However, patients with breast cancer receiving neoadjuvant-intent hormonal therapy were significantly more likely to receive surgery in the COVID-19 era (log-rank P < .001). After adjustment, there were no significant changes in the rate of emergency department visits over time between patients receiving neoadjuvant ST, adjuvant ST, or ST only during the ST treatment period or postoperative period.Hospital admissions decreased in the COVID-19 era for patients who received neoadjuvant ST compared with adjuvant ST or ST alone (P for interaction = .01 for both) in either setting. CONCLUSIONS AND RELEVANCEIn this cohort study, patients were more likely to start neoadjuvant ST in the COVID-19 era, which varied across the province and by indication. There was limited evidence to suggest any substantial impact on short-term outcomes.

Cancer Patients First Treated with Chemotherapy: Are They More Likely to Receive Surgery in the Pandemic?

“…In line with a recently published report [ 9 ], we found breast cancer patients receiving chemotherapy as the first treatment to have the most significant increase in subsequent surgery use during the pandemic. Incident detection of breast cancer was severely hindered by COVID-19 since cancer screening including mammograms for asymptomatic women was one of the most affected cancer care domains [ 34 ].…”

“…For certain subtypes such as estrogen/progesterone receptor-positive cancers there has been an expanded use of molecular testing (such as Oncotype DX) on diagnostic core biopsies in recent years [ 38 ]. Collectively, these shifts have led to more use of neoadjuvant chemotherapy for breast cancer management during the pandemic [ 9 , 36 ], and, according to our results, more use of breast surgery 9 months after first chemotherapy as well. Further work will be required to demonstrate if 9-months represents a reasonable gap between neoadjuvant chemotherapy initiation and surgery.…”

“…More specifically, whether newly diagnosed patients receiving upfront chemotherapy went on to get surgery for cancer within a clinically reasonable time window is unknown. A literature search on MEDLINE revealed only 5 studies documenting the subsequent receipt of a cancer surgical resection among new cancer patients initially treated non-surgically during the COVID-19 pandemic ( Appendix A ) [ 7 , 8 , 9 , 10 , 11 ]. Notably, newly diagnosed oesophageal cancer patients in Ireland and breast cancer patients in Turkey did not experience a different rate of surgery following neoadjuvant therapy during the pandemic compared to their pre-pandemic counterparts [ 7 , 10 ].…”

“…Likewise, The Netherlands reported significantly prolonged wait times from neoadjuvant radiation or chemoradiation initiation to surgery in colorectal cancer patients in 2020 than in 2018/2019 [ 11 ]. The only real-world results that point to a clearly increased receipt of surgery following neoadjuvant therapy during the pandemic come from Canada; specifically, among newly diagnosed breast cancer patients who had been first treated by hormonal therapy within 6 months of diagnosis, their subsequent receipt of surgery was indeed higher during the pandemic period than before, although such difference was not observed among those initially managed by chemotherapy [ 9 ]. Overall, these conflicting results suggest a lack of clear understanding on how cancer care continuum has been shifted by the pandemic.…”

“…Inequities in healthcare access and outcomes can be accentuated along the continuum of care as patients progress from diagnosis to first and then subsequent treatment modalities, a phenomenon that has been described in low socioeconomic status (SES), rural dwelling, and racialized populations [ 13 ]. As such, cancer patients with low SES may have faced additional barriers during the pandemic in accessing surgery after chemotherapy, a hypothesis yet to be formally assessed [ 6 , 9 , 14 ].…”