May 28, 2020

Breast cancer patients appear to share same risk factors for severe COVID-19 as general population

A prospective registry analysis published in Breast Cancer Research indicates that the mortality rate in breast cancer patients with coronavirus disease 2019 (COVID-19) depends more on comorbidities than prior radiation therapy or current anti-cancer treatment. "Comorbidities, apart from breast cancer, should be the primary focus of attention to define patients at high risk," wrote Perrine Vuagnat, Université Paris-Saclay, Saint Cloud, France, and colleagues.

A COVID-19 registry was set up at Institut Curie hospitals (ICHs) in Paris area, France, for all breast cancer patients with proven or suspected infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Registered data included patient history, tumor characteristics and treatments, COVID-19 symptoms, radiological features and outcome.

The data were extracted on April 25, 2020, for the current analysis.

Seventy-six patients actively treated for breast cancer were included in the ICH COVID-19 registry in the period from March 13, 2020, to April 25, 2020. For comparison, 15,600 breast cancer patients had at least one consultation or treatment for breast cancer at one of the ICHs in the 4 months before lockdown. A total of 59 patients were diagnosed with COVID-19, based on either a positive SARS-CoV-2 RNA test (N = 41; "RNA-positive subgroup") or, in the case of negative or missing RNA test, radiologic findings (N = 18). Among these COVID-19 patients, 63% (37/59) were treated for metastatic breast cancer, and 22% (13/59) were taking corticosteroids daily. Meanwhile, a total of 17 subjects only reported symptoms suggestive of COVID-19 that were not confirmed by RNA test and/or lung CT scan, and none of these had to be hospitalized.

The mean absolute lymphocyte count at diagnosis was normal (1.5/mm3). Among the 28 patients who had a CT scan available for central review, most had no or limited extent of COVID-19 lung disease, with 89% (25/28) having less than a quarter of their lung volume involved. Ground-glass opacities were the most common radiologic feature, seen in half of patients (14/28) with CT scan at diagnosis. The authors said no significant association was observed between these features at diagnosis or the presence of lung metastases, and the extent of COVID-19 lung disease.

Of the 59 patients diagnosed with COVID-19, 47% (28/59) were hospitalized, while 10% (6/59) were transferred to an intensive care unit (ICU). Among the hospitalized patients, 82% (23/28) received antibiotics, and 11% (3/28) received corticosteroids. No patients received hydroxychloroquine, antiviral or immunomodulating drugs as frontline treatment at admission.

At the time of analysis, 76% (45/59) of patients were recovering or had been cured, 17% (10/59) were still followed, and 7% (4/59) had died from COVID-19. Among those who died, two patients were receiving later lines of treatment for metastatic breast cancer, 1 patient had recently started first-line endocrine therapy combined with palbociclib, and 1 patient was receiving neoadjuvant chemotherapy. The authors noted that this last case was treated with an anti-CD80/86 antibody (regulating CTLA-4 signaling).

Specifically, one of the deceased patients was a 69-year-old woman with a history of diabetes, hypertension, hypertrophic cardiomyopathy and rheumatoid arthritis. The second was a 44-year-old patient with no relevant medical history, who was referred to the emergency room within her first month of breast cancer treatment for asthenia, dyspnea, grade IV thrombocytopenia and grade IV neutropenia, and was diagnosed with SARS-CoV-2 lung infection complicated by thrombotic microangiopathy. The third patient was a 78-year-old woman with a history of hypertension, while the fourth was an 80-year-old woman who had been hospitalized for tumor-related symptoms since February 2020.

An exploratory analysis of factors associated with either ICU admission or death in the COVID-19 population showed that being over age 70 years and having hypertension were significantly associated with COVID-19 severity (both p < 0.05). "Age and hypertension remained as prognostic factors in the subgroup of RNA test-positive patients, except that hypertension was of borderline significance. Same statistical conclusions were obtained with the analyses of time to death or ICU admission," the authors reported.

"While our study cannot determine the incidence of COVID-19 infection among breast cancer patients, the small number of diagnosed cases suggests that breast cancer patients do not appear to be at higher risk than the general population," the authors stated, noting this could possibly be due to "much stricter application of social distancing procedures by cancer patients."

They added "our analyses showed that breast cancer patients have similar clinical and radiologic features of COVID-19 to those previously described in other reports on non-cancer COVID-19 patients. Importantly, we found no trend in favor of a relationship between a history of breast and lymph node radiation therapy, radiation therapy sequela, and radiologic extent of disease or outcome. Thrombotic, cardiovascular, microvascular, and dermatological events were not recorded, as their association with COVID-19 was not fully recognized when the registry was set up."

Limitations of the analysis include the small number of patients, a potential under-declaration due to the difficulty in identifying COVID-19 cases in outpatients who may have been referred to other hospitals, the authors added. 

SOURCE: Breast Cancer Research