Considering the high infectivity and mortality rates of COVID-19 with malignancies, early diagnosis of the disease is essentially critical. Blood tests and simple scoring systems play an important role in the early diagnosis of the disease, considering the information they provide to physicians regarding the inflammatory process. Several hematological parameter abnormalities were reported for COVID-19 patients, particularly for those who were severe or critically ill [18–22]. Neutrophils, the most abundant white blood cells in the circulation, are one of the major constituents of the immune system. However, their role in viral infections still remains unclear. In addition, the lymphopenia is observed in many virus-related diseases which causes a cytokine storm, thus resulting in a multi-organ failure and death in severe COVID-19 cases [23]. Recent studies indicate that NLR, MLR and PLR can be used as independent prognostic markers for disease severity in COVID-19 [24, 25]. The SII comprehensively summarizes the balance between the immunity and inflammatory status of the host. It has been already suggested as a prognostic biomarker in sepsis patients [26]. In addition, the SII has also been shown to be associated with a worse survival rate in different cancer types [27, 28, 29].
Recently, Alessandro F. et al., showed that the SII was the most significant prognostic biomarker for survival in patients with SARS-CoV2. Their retrospective study, including 119 patients showed that higher SII values were associated with increased mortality rate [14]. Another retrospective study yielded similar results for SII indicating that it was a powerful marker for calling for an invasive ventilator support and preparing for a worse clinical outcome for the COVID-19 patients [13]. In our study, NLR, PLR, MLR and SII did not differ in two groups which were matched according to the age, gender and comorbidities using propensity score matching. Furthermore, SII did not differ in deceased and surviving patients in the malignancy group. These results may lead to a conclusion that COVID-19 may not arouse an adequate inflammatory response in malignancy patients. Therefore, SII as an index defining the instability in the inflammatory response may not be suggested as a prognostic indicator in the follow-up of in COVID-19 patients with malignancies.
Recently, Liang, et al. observed that COVID-19 patients with cancer showed a higher risk and frequency of severity compared with those patients without cancer [3].
Previous studies showed that lower PNI was correlated with a lower survival rate in patients having various malignancies, such as esophageal squamous cancer, colorectal cancer, gastric cancer, and lung cancer [30, 31, 32]. Nowadays, PNI is an important biomarker that can be used to discriminate COVID-19 severity, according to the results of several studies [33–37].
In our study, we found no difference in PNI and ANDC between with malignancy and without malignancy groups in COVID-19 patients. This can be partially accounted for the lack of existence of an adequate inflammatory response and a poor nutritional status for malignancy group. Another factor might be a lower level of albumin in no malignancy group which stands out as an acute phase effect in COVID-19 infection. Although the sample size is small, a significant reduction in PNI scores in deceased patients compared with those of the surviving can be interpreted as an indicative score in predicting the mortality.
In current literature, to our knowledge, there is no information available whether PNI and ANDC have any sort of prognostic capability for predicting in-hospital mortality rates of COVID-19 cases with patients having various cancer types. There is a lack of data on PNI and SII for various malignancies indicated by heterogenous type of tumors. Furthermore, ANDC is a recently developed score for predicting the mortality of COVID-19 patients. This is anticipated to be one of the first studies on ANDC in COVID-19 patients having malignancies. Our results indicate that PNI and ANDC differ significantly in deceased and surviving patients in the malignancy group. As it involves the additional consideration of parameters as d-dimer and age, ANDC seems to be a more reliable measure than SII in predicting the mortality in COVID-19 patients. Even though the cancer types were heterogeneous in our cohort, PNI was also observed to have a predictive quality for predicting the mortality.
Finally, phosphorus is known to have an important role in the metabolism of cells, especially during mitosis. It has been previously reported that the growth of cancer in the body is associated with an increased level of phosphorus in the blood in all cancer patients [38]. In addition, serum albumin levels provide useful prognostic significance in cancer [39]. Hypoalbuminemia is a result of combined effects of inflammation and poor nutritional status in patients with chronic disease and cancer [40]. In our study, we found an increased level of blood phosphorus within reference range, which might be associated with cancer in malignancy group. Also lower albumin levels might be associated with acute phase response and/or poor nutrition.
There are several limitations in our study. First, it is a retrospective design. Second, due to the limited number of cases, some of the conclusions are preliminary, especially those on the prospective impact of PNI and ANDC on COVID-19. These results need to be further validated in a larger population with a longer follow-up period.