This study highlights the impact on non-Covid-19 patient care due to the restraints imposed by the Covid-19 pandemic. Recently, this impact has also been assessed in an IR unit in the United States of America , where the elective outpatient procedures were responsible for over 60% of the workload before the pandemic, which reduced to less than 40% during the pandemic. There was a shift to urgent and emergent procedures. Although, there was an intention to maintain interventional oncology, there was also a gradual reduction in volume of procedures as the pandemic progressed. We observed the same findings, with a high reduction in the overall number of procedures performed, and a significant shift from elective to urgent procedures. The oncological IR procedures were the most affected. The “State of Emergency” lasted approximately one and a half month, delaying most oncological IR procedures during this timeframe. This led to a significant delay in treatment response of approximately 2 weeks. As a likely consequence, HCC patients had more decompensated liver cirrhosis. The fact that there was higher tumour burden in the 2020 patients’ group may also be due to the patients’ selection bias. Patients with higher disease burden were prioritized in the post-“State of Emergency” period.
Finally, this had an obvious impact on planned treatments, with many ablation procedures being changed to TACE or even to systemic therapy due to disease progression. This delay in treatment response in IR units has also been described previously . According to the experience from an IR Unit in Milan, Italy , there was a delay of 2 months in the treatment of 26% of the patients due to the pandemic and three patients underwent thermal ablation instead of the pre-planned surgical resection. However, LRTs were encouraged as bridge treatment before liver transplantation, in order to reduce disease progression. LRTs were also preferred over surgical resection to reduce the need of intensive care unit beds and hospitalization time. Palliative treatments (TACE and radioembolization) were maintained, but they were postponed in elderly and in patients with comorbidities. In 2020, the absolute number of liver transplants, surgical resections and TACE was inferior to the same 4-week period in 2019. However, the absolute number of radioembolizations, microwave and radiofrequency ablations was superior , contrary to the present report. In a cross-sectional survey conducted to assess the impact of Covid-19 on hepato-pancreato-biliary surgery , it was shown that chemotherapy and ablation were more utilised for colorectal liver metastases whereas TACE and ablations were more utilised for HCC in Covid-High countries compared to Covid-Low countries.
One study , which analyzed 175 HCCs growth rate showed that total volume doubling time (TVDT) of the tumors increased with increasing tumor size, which meant that HCCs do not grow exponentially. They suggested a sigmoidal growth model, as in other human cancers, and the explanation for this was that only the tumor cells near the tumor boundaries have access to enough nutrients. Another study focusing on liver transplantation for HCC , concluded that the probabilities of waiting list dropout due to disease progression at 6, 12 and 24 months were 7.3%, 25.3% and 43.6%, respectively. The dropout rate increased exponentially in the first 15 months, with the greatest rates between 9 and 15 months. Thus, timing of treatment for patients with HCC matters, with a high probability of disease progression when left untreated for more than 6 months.
On 23rd of March 2020 the Society of Surgical Oncology (SSO)  recommended ablation or stereotactic radiosurgery instead of resection for liver metastases where possible and ablation or embolization over resection for HCC. This emphasises the importance of IR as an alternative option in moments of crisis and resources scarcity. A position paper from the European Association of the Study of the Liver (EASL) and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) , stated that the care of patients with HCC should be maintained according to guidelines, including continuing systemic treatments and evaluation for liver transplant. Thus, it is important and recommended that IR LRTs for oncology patients are kept within reasonable timeframes to avoid treatment delays that could preclude planned procedures due to disease progression.
The limitations in this study were its retrospective analysis, the lack of similar studies for comparison and the relatively small sample size. The difference in HCC size between 2019 and 2010 might also be due to a selection bias. There was prioritization for larger tumours to be treated sooner after the “State of Emergency”. However, we cannot exclude that the Covid-19 pandemic might also have played a role in disease progression. We were not able to measure the time before the diagnostic imaging which could be greater in 2020, delaying the diagnosis and respective treatments. This could also have been influenced with the Covid-19 pandemic with many oncology patients opting to stay home and not performing the standard imaging exams for disease surveillance. The type of activity at this specific IR unit may not represent all IR units as the major activity relies on oncology liver treatments that were analysed. No specific analysis was performed on other frequently performed IR procedures that may be more representative of volume load in other IR units.