DISCUSSION
Chronic diseases are difficult to manage due to the coronavirus pandemic affecting the whole world. Cancer patients constitute the most important part of this group (3). Lung cancer cases, which have been shown to increase frequency, are an important subgroup (4). Each country strives to plan according to the adequacy and possibilities of its own healthcare services for the management of patients receiving cancer treatment. The main issue to focus in this study is symptoms that are overlapping for both lung cancer and new coronavirus. The main symptoms for COVID-19 are fever, cough, fatigue, slight dyspnoea that cause confusion in patients with lung cancer (5). Because many other reasons secondary to tumour or cancer treatments (surgery, chemotherapy, radiotherapy, immunotherapy or targeted therapies) can cause these symptoms to appear. In this pandemic process, it is important to maintain follow-up and treatment process of lung cancer patients by minimizing the risk of covid-19 transmission.
When compared clinical characteristics of our study population to features of COVID-19 patients, it is noteworthy that both of them have the 6th decade and male gender predominance (8). According to some suggestions on diagnosis and treatment strategies of lung cancer patients during outbreak of new coronavirus from China, which started to fight first, for highly suspected or confirmed patient must be transferred to specially prepared isolated department of hospital (5). Five suspected patients of current study had admitted to our outpatient clinic of chemotherapy unite and the differential diagnosis process took place in the isolated service until the covid-19 was ruled out.
Each case should be handled separately, especially in terms of treatments (chemotherapy, targeted therapies, immune-checkpoint inhibitor, radiotherapy etc.) they receive at the time of admission, history of suspected contact, visit to another country are important issues (6). Totally, there were 11 (61.1%) patients (including concurrent chemo-radiotherapy) receiving chemotherapy.
Even ground glass opacities are widely accepted radiological presentation of new coronavirus pneumonia, it can be presented in different manifestations in lung cancer patients (9). There are small number of cases in literature. One of them is a case diagnosed lung adenocarcinoma with simultaneous diagnosis of new coronavirus with RT-PCR. Even she had no covid-19 specific symptoms she had contact with an infected physician. There were no typical CTT findings (showed diffuse, irregular, small, ground-glass opacities with partial consolidation in bilateral lungs) even at the beginning (when she had no symptoms) and after occurring symptoms. Finally, her complaints and radiological findings were dedicated to obstructive pneumonia caused by the tumour (10). Another reported case is a male with age of 73, who had been operated for NSCLC in 2016. Even he had no COVID-19 suspected symptoms, the patient was diagnosed with COVID-19 with positive PCR in the PET-CT taken during re-staging. Bilateral diffuse, peripheral predominant ground-glass opacities suggesting active inflammatory processes on 18F-FDG PET/CT was the suspecting condition for new coronavirus pneumonia (11). The most common radiological findings in our cases were consolidation (44%) and GGOs (44%), even in 5 cases with highly suspicious for covid-19 (Table 2).
There were 5 (27.8%) patients with pleural effusion. However, in none of patients, pleural fluid was considered to be related to COVID. Thus in highly suspected group (Table 2) there were no patients with pleural fluid. Although cancer patients are not included, according to a meta-analyse with 4121 patients, pleural effusion (5.3%) was reported as rarest CTT imaging features in new coronavirus pneumonia (12).
Although complete clinical manifestation is not clear yet; fever, lymphopenia, leukopenia, new pulmonary infiltrates on chest radiography, and no response to antibiotics treatment are the most reliable clues for COVID-19 diagnosis. The diagnosis of COVID-19 must be confirmed by the reverse transcription polymerase chain reaction (RT-PCR) (13). But we already know there is a discrepancy between PCR results and CTT findings. According to data from China, while positive rates of RT-PCR assay was 59% (601/1014), CTT imaging had 88% (888/1014) positivity in suspected patients with COVID-19. Because there were, 308 patients with negative PCR results but having COVİD-19 suggesting radiology. So when evaluated together with clinical findings, CTT findings are quite reliable for diagnosis (14). Considering that RT-PCR is not the gold standard in diagnosis of new coronavirus, clinical and radiological suspicion seems to be sufficient to start treatment early, especially in patients with lung cancer. In our study population there were 2 patients who had negative PCR results along with highly suspected clinical and radiological findings (Table 1, case number 1 and 3). Both of them responded well to COVID-19 specific therapies not requiring intensive care unit (ICU) support (Figure 2).
Another case presentation is a stage IV lung adenocarcinoma patient from Italy. While he was under nivolumab therapy within a multicentre clinical trial almost for 6 months, also having partial response. He had admitted with severe dyspnoea, hypoxia, lymphopenia, increased C-reactive protein, transaminases and lactate deidrogenease. His chest X-ray revealed reticular-interstitial addensative findings and his nasal swab was positive for COVID-19. Due to the rapidly worsening clinical condition, the patient died without receiving any of COVID-19 specific treatment (15). Of course, it is not possible to predict the treatment approach and prognosis in the presence of COVID in cancer cases receiving immunotherapy nowadays. In this sense, we would like to contribute by detailing a case in our study. There was a male receiving immunotherapy following chemo-radiotherapy within the scope of international, multi-centre clinical trial (Table 2, case number 2). On his first admission to outpatient chemotherapy clinic he had severe dyspnoea with oxygen saturation 83% in the room air. His laboratory revealed increased LDH, C reactive protein and lymphopenia. There were bilateral heterogeneous opacities on chest X-ray and bilateral ground glass areas with right hemi thorax predominance on CTT. The patient was quickly taken to isolated service. His nasal swab was negative for new coronavirus for 3 times than transferred to general ward. He had been administrated immunotherapy only for one cycle so it was too early to expect immunotherapy related interstitial pneumonitis. But chemo-radiotherapy was completed almost 4-6 months ago and his radiological features were attempt to appear on radiotherapy side (right hemi thorax). So he had been diagnosed with radiation pneumonia and well-responded to metil-prednisolone therapy (Figure 1).