COVID-19 and Cancer: A Comparison of the Two Important Pandemic Waves in an Indian Cancer Patients' Cohort

Introduction

Coronavirus disease-19 (COVID-19) that is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was declared as a global pandemic in March 2020 by the World Health Organization (WHO).1 Ever since, regional and global efforts have been underway to control this disease using both pharmaceutical and non-pharmaceutical measures.

It is well known that patients with cancer are at an increased risk of severe COVID-19, as evidenced by a retrospective study on 73 million patients in the United States, in which the adjusted odds ratio for COVID-19 infection in known patients of cancer was reported to be 7.2 Although the overall case fatality rate (CFR) in India has been lower than that reported in the rest of the world,3 the same cannot be extrapolated to the group of cancer-affected patients.4 Additionally, the difference in CFR between the first and second pandemic waves differed. There have been studies from India as well as the rest of the world depicting the outcomes and mortality of cancer patients affected with COVID-19.56 Roy et al reported 145 patients of solid organ malignancies, of which 22 (15%) patients succumbed,7 whereas Mehta et al reported a glaringly high CFR of 28% in cancer patients when compared to match noncancer population (14%).8

With the vaccine roll-out drives in full swing across the world, the glaring truth is that this subgroup of patients were excluded from all vaccine trials; hence, the efficacy in the setting of malignancy remained elusive.910 We have previously reported the vaccination status in cancer affected patients from our center in a cohort of 752 cancer patients, of which only 29.1% were vaccinated.11 The knowledge and attitude toward vaccination was reported in a contemporary study by Noronha et al in 435 cancer patients, in which they demonstrated that fear of side effects and fear of effect on cancer therapy were the most common factors leading to vaccine hesitancy in cancer patients.12

Although some studies have reported clinical features as well as molecular mechanisms of increased risk of mortality and morbidity in COVID-infected cancer patients, there are none that depict the differences in outcomes between the two waves of the pandemic.1314

This is a real-world study aimed at characterizing the differences in demographics, clinical features, treatment details, and outcomes in COVID-19-positive cancer (solid organ malignancies) patients between the two pandemic waves. This is relevant as the second wave was associated with higher infectivity and mortality rates, and knowledge of differences between the two waves may help disaster-preparedness programs and policy making, especially for the cancer affected subgroup of patients, who have been excluded from all drug and vaccine trials.

Materials and Methods

Results

A total of 300 patients of solid organ malignancies with proven SARS-CoV-2 infection by either RT-PCR or CBNAAT were encountered, of which 123 were encountered during the first wave of the pandemic and 177 during the second wave. The types of malignancies is depicted in Fig. 1.

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Fig. 1: Bar diagram depicting distribution of cancer types in 1st and 2nd waves.

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Discussion

This was a prospective single-center, single-specialty study characterizing the differences between the first wave of the COVID-19 pandemic and the dreadful second wave in cancer patients. The second wave showed a higher CFR, hospital admission rate, and higher frequency of respiratory complications. Nationwide lockdown and severity of COVID-19 disease reduced the number of patients opting for cancer-targeted therapies. Although guidelines and recommendations were laid for approach toward tumors with curative intent versus palliative; however, reduced patient attendance to the clinic deferred therapy in many.2 In our study, however, for those enrolled, therapy was not deferred except for those with severe COVID-19-related complications.

When compared with other real-world experiences of the COVID-19 disease in cancer patients, our study is unique in comparing the characteristics of both waves. The most common malignancy encountered in our study was of the lungs followed by GIT and breast, which conforms with contemporary studies by Roy et al and CCC-19 literature,716 however differs from the UK Coronavirus Cancer Monitoring Project (UKCCMP) data.17

The case fatality rate in an unselected Indian population was 1.9%8; however, in cancer patients, it was reported to be 6.5% in the first wave from a study in cancer patients in India.18 Another study from India on cancer patients reported a CFR of 14.5%.8 Our study reported a CFR of 9.8% in the first wave and 13% in the second wave. This partly conforms to the contemporary studies from India, as well as that reported by Ma et al (CFR-13.5%),19 whereas the CFR is substantially lower than reported literature from the UK CCMP data (28%) and published literature from the United States (25–28%).2021 The lower CFR may be attributed to exclusion of hematologic malignancies where reported CFR is the maximum,22 racial disparities and majority of the patients had mild disease not requiring hospitalization. Similar to other contemporary reports, and MSKCC20 and UKCCMP data,23 there was no relation of mortality with cancer directed therapy in this study as well.

There have been many reports in the form of reviews and meta-analyses comparing both wave characteristics; however, there was only one real-world study from Reus, Spain, in unselected patients.24 This study reported a higher incidence in babies and pregnant women in the second wave, and cancer patients were not analyzed separately. In our study, the CFR was distinctly higher in the second wave, in concordance with other real-world reported literature of Delta virus outbreak although our study could not analyze severity categories and treatment-related outcomes. The vaccination status of our patients has already been published and hence is not reiterated here.11

Our study is unique in comparing characteristics of the two most important COVID-19 waves and treatment patterns in cancer patients from a single center. However, there are a few limitations. Multivariate analyses and Cox's regression could not be performed owing to non-significant variables in the univariate analysis. The severity scoring of COVID-19 infection and COVID-19 directed therapy could not be performed owing to missing data points for severity scoring and very few numbers in remdesivir and immunological treatment groups (n = 1 each).

The third wave of the pandemic was not analyzed, owing to lesser hospital admissions, and attendance during the same, which would lead to underestimation of the cases. Additionally, this is a single center study with a small sample size, and does not represent a geographical area; therefore conclusions drawn should be interpreted cautiously. However, the information presented here is relevant for the oncology fraternity that despite differences in genomic variants of SARS-CoV-2, cancer-directed therapy had no relation to case fatality or mortality. This is important for treating oncologists to continue cancer-directed treatment even in concurrent COVID-19 infections.