More advanced, aggressive breast cancers diagnosed during COVID-19 pandemic
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More patients presented with more advanced-stage and aggressive types of breast cancer during the beginning of the COVID-19 pandemic compared with the same period in 2019 across the Kaiser Permanente Northern California health care system.
The data, presented at the virtual San Antonio Breast Cancer Symposium, also showed that in the 2 months after California instituted its initial stay-at-home order, which reduced screening mammograms and halted elective surgeries, 64% fewer patients were diagnosed than during the year-ago period. Among those who did receive a breast cancer diagnosis, researchers observed reductions in time to surgery and time to chemotherapy.
The results show the ability of a large, integrated system to provide timely care to patients who present with symptomatic disease amid the constraints of the pandemic and highlight the significance of screening in the early detection of breast cancer, according to researchers.
“The COVID-19 pandemic drove operational changes across the Kaiser Permanente Northern California system. After the California shelter-in-place order on March 17, breast cancer guidelines were developed within our large integrated system including 22 hospitals,” Annie Tang, MD, researcher at Kaiser Permanente Northern California’s Permanente Medical Group Breast Research Collaborative, said during a presentation. “All outreach and screening mammography were halted, but women who wished to have screening were still accommodated. Elective surgeries were also stopped, but cancer surgeries continued. On May 17, elective surgeries resumed once COVID-19 cases reached a steady state. There were drastic changes in breast cancer care during this time.”
Tang and colleagues sought to evaluate the presentation and treatment patterns of patients with breast cancer included in the Kaiser Permanente Northern California system who were diagnosed during the shelter-in-place period.
The retrospective double-cohort study included patients newly diagnosed with breast cancer between March 17 and May 18 of this year (n = 703) and patients diagnosed between March 17, 2019, and May 18, 2019 (n = 250).
“If we were to extrapolate the number of patients diagnosed in 2019, we would see that there were potentially 453 [patients with breast cancer] undiagnosed during this time,” Tang said.
Primary outcomes included evaluation of first treatment (surgery, chemotherapy, endocrine therapy or no treatment) and time to treatment, defined as time from biopsy to surgery or time from biopsy to chemotherapy.
The two cohorts had similar characteristics, including age, race and comorbidities, according to Tang.
Results showed that, compared with patients diagnosed in the 2019 period, more patients diagnosed in the 2020 period presented with symptomatic disease (78% vs. 37%; P < .001) and more advanced cancer, with more tumors that were T1c or larger (78% vs. 64%; P < .001).
“Although there was no statistical difference in nodal status, our results did suggest a trend toward nodal positivity, from 18% [in 2019] to 24% in 2020, and more patients presented with metastatic disease in 2020 — an increase from 2% to 7%,” Tang said.
Researchers additionally found that more patients diagnosed in 2019 had hormone receptor-positive, HER2-negative disease (76% vs. 66%), whereas the rate of triple-negative breast cancers increased from 10% in 2019 to 16% in 2020 (P = .04).
More patients diagnosed in 2019 underwent surgery first (83% vs. 71%; P < .001), whereas a greater proportion of patients diagnosed in 2020 underwent neoadjuvant chemotherapy (15% vs. 10%). Five percent of patients underwent neoadjuvant endocrine therapy while awaiting surgery in 2020 vs. no patients in 2019 (P < .001).
Researchers reported a shorter time to treatment during the 2020 period, with a median time to surgery of 26 days in 2019 vs. 19 days in 2020 (P < .001) and median time to chemotherapy of 28 days vs. 24 days (P = .03).
“We hypothesize that this was secondary to operating room availability due to elective surgeries that were stopped, as well as more aggressive breast cancer subtypes,” Tang said.
“Our study suggests that as screening mammography rates return to prepandemic levels, our system must prepare for a likely surge of new breast cancer diagnoses,” she added. “We will continue to monitor screening mammography rates, breast cancer diagnoses and treatment trends for future research.”
Perspective
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Addie Hill, MD
This is an important study that confirms a worry felt by many in the field of breast oncology: Avoiding or delaying screening mammography, although understandable during the COVID-19 pandemic, leads to a large reduction in the number of breast cancers diagnosed. Of the patients diagnosed during the pandemic, a greater proportion were diagnosed with more advanced disease, presenting with larger tumor sizes and metastasis, as well as more aggressive disease, with increased rates of HER2 positivity and triple negativity.
However, it is reassuring that, at least in this study, the COVID-19 pandemic did not necessarily cause delays in care for these patients, although these data only reflect one large integrated health care system in northern California.
I agree with the authors’ conclusion that once screening mammography rates return to prepandemic levels, we will have a surge in new breast cancer cases, and I worry that we may see an increase in advanced disease being diagnosed due to delays in screening mammography. Increasing numbers of cases may stress the parts of the health care system that provide oncologic care. Due to the widespread use of appropriate distancing and personal protective equipment in health care settings, the risks for contracting COVID-19 while obtaining a mammography may be low relative to the benefits of early diagnosis of breast cancer. Therefore, I urge the community to consider screening mammography as essential medical care and to delay screening mammography only if absolutely necessary due to active COVID-19 infection or exposure.
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Chang SB, et al. Abstract SS2-06. Presented at: San Antonio Breast Cancer Symposium (virtual meeting); Dec. 8-11, 2020.
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