Pandemic Phase-Adjusted Analysis of COVID-19 Outcomes Reveals Reduced Intrinsic Vulnerability and Substantial Vaccine Protection From Severe Acute Respiratory Syndrome Coronavirus 2 in Patients With Breast Cancer

• Published in: Journal of clinical oncology Vol. 41; no. 15; pp. 2800 - 2814
• Main Authors: Tagliamento, Marco, Gennari, Alessandra, Lambertini, Matteo, Salazar, Ramon, Harbeck, Nadia, Del Mastro, Lucia, Aguilar-Company, Juan, Bower, Mark, Sharkey, Rachel, Dalla Pria, Alessia, Plaja, Andrea, Jackson, Amanda, Handford, Jasmine, Sita-Lumsden, Ailsa, Martinez-Vila, Clara, Matas, Marta, Miguel Rodriguez, Ana, Vincenzi, Bruno, Tonini, Giuseppe, Bertuzzi, Alexia, Brunet, Joan, Pedrazzoli, Paolo, D'Avanzo, Francesca, Biello, Federica, Sinclair, Alasdair, Lee, Alvin J X, Rossi, Sabrina, Rizzo, Gianpiero, Mirallas, Oriol, Pimentel, Isabel, Iglesias, Maria, Sanchez de Torre, Ana, Guida, Annalisa, Berardi, Rossana, Zambelli, Alberto, Tondini, Carlo, Filetti, Marco, Mazzoni, Francesca, Mukherjee, Uma, Diamantis, Nikolaos, Parisi, Alessandro, Aujayeb, Avinash, Prat, Aleix, Libertini, Michela, Grisanti, Salvatore, Rossi, Maura, Zoratto, Federica, Generali, Daniele, Saura, Cristina, Lyman, Gary H, Kuderer, Nicole M, Pinato, David J, Cortellini, Alessio
• Format: Journal Article
• Language: English
• Published: United States Wolters Kluwer Health 20-05-2023
• Subjects: Breast Neoplasms - epidemiology; Breast Neoplasms - therapy; COVID-19 - epidemiology; COVID-19 - prevention & control; COVID-19 Testing; Female; Humans; Middle Aged; ORIGINAL REPORTS; Pandemics; SARS-CoV-2; Vaccines
• ISSN: 0732-183X; 1527-7755
• DOI: 10.1200/JCO.22.01667

Although representing the majority of newly diagnosed cancers, patients with breast cancer appear less vulnerable to COVID-19 mortality compared with other malignancies. In the absence of patients on active cancer therapy included in vaccination trials, a contemporary real-world evaluation of outcomes during the various pandemic phases, as well as of the impact of vaccination, is needed to better inform clinical practice.
We compared COVID-19 morbidity and mortality among patients with breast cancer across prevaccination (February 27, 2020-November 30, 2020), Alpha-Delta (December 1, 2020-December 14, 2021), and Omicron (December 15, 2021-January 31, 2022) phases using OnCovid registry participants (ClinicalTrials.gov identifier: NCT04393974). Twenty-eight-day case fatality rate (CFR
) and COVID-19 severity were compared in unvaccinated versus double-dosed/boosted patients (vaccinated) with inverse probability of treatment weighting models adjusted for country of origin, age, number of comorbidities, tumor stage, and receipt of systemic anticancer therapy within 1 month of COVID-19 diagnosis.
By the data lock of February 4, 2022, the registry counted 613 eligible patients with breast cancer: 60.1% (n = 312) hormone receptor-positive, 25.2% (n = 131) human epidermal growth factor receptor 2-positive, and 14.6% (n = 76) triple-negative. The majority (61%; n = 374) had localized/locally advanced disease. Median age was 62 years (interquartile range, 51-74 years). A total of 193 patients (31.5%) presented ≥ 2 comorbidities and 69% (n = 330) were never smokers. In total, 392 (63.9%), 164 (26.8%), and 57 (9.3%) were diagnosed during the prevaccination, Alpha-Delta, and Omicron phases, respectively. Analysis of CFR
demonstrates comparable estimates of mortality across the three pandemic phases (13.9%, 12.2%, 5.3%, respectively;
= .182). Nevertheless, a significant improvement in outcome measures of COVID-19 severity across the three pandemic time periods was observed. Importantly, when reported separately, unvaccinated patients from the Alpha-Delta and Omicron phases achieved comparable outcomes to those from the prevaccination phase. Of 566 patients eligible for the vaccination analysis, 72 (12.7%) were fully vaccinated and 494 (87.3%) were unvaccinated. We confirmed with inverse probability of treatment weighting multivariable analysis and following a clustered robust correction for participating center that vaccinated patients achieved improved CFR
(odds ratio [OR], 0.19; 95% CI, 0.09 to 0.40), hospitalization (OR, 0.28; 95% CI, 0.11 to 0.69), COVID-19 complications (OR, 0.16; 95% CI, 0.06 to 0.45), and reduced requirement of COVID-19-specific therapy (OR, 0.24; 95% CI, 0.09 to 0.63) and oxygen therapy (OR, 0.24; 95% CI, 0.09 to 0.67) compared with unvaccinated controls.
Our findings highlight a consistent reduction of COVID-19 severity in patients with breast cancer during the Omicron outbreak in Europe. We also demonstrate that even in this population, a complete severe acute respiratory syndrome coronavirus 2 vaccination course is a strong determinant of improved morbidity and mortality from COVID-19.