Considering just 4 months of delay from March to June, there is a profound impact on additional deaths due to delays, especially in the long term, in Canada. The difference in estimated cases (cases based on the previous trend) and observed cases (expected cases to be seen in real), drive the increase in deaths and eventually the overall cumulative life years lost (19).
A meta-analysis has already established how the hazard ratios increased with a delay of 12 weeks during the pandemic in various cancers(10). Since lung cancer is often associated with a poor prognosis where over half of people diagnosed with lung cancer die within one year of diagnosis and the 5-year survival is less than 18% (20), it becomes even more critical to reduce any kind of delay in its diagnosis and treatment. These delays translate directly into days of life lost, and studies show that lung cancer is associated with the largest burden of cancer mortality measured in potential years of life lost (21).
Our results have presented how the COVID pandemic created healthcare provision limitations that resulted in delays in the diagnosis of lung cancer patients, confirming findings from many other similar studies around the world (12, 22–25). Colorectal cancer and lung cancer are associated with the largest number of years of life lost due to delays in the diagnostic pathways in the UK (22).
Based on these findings, in the future, if any such similar situation arises equal consideration should be taken for patients of other critical diseases (10, 26, 27). Following stringent social distancing and lockdown measures, hospital systems have increasingly transitioned to telemedicine for non-pandemic health care services which have not been easy for oncology patients (26) and the impact of these approaches will continue to be examined.
Models of care aimed at creating solutions to minimize interruptions in diagnosis and treatment of cancer remain a top priority. It has been established that reducing time to treatment for cancer patients will improve survival, particularly for those with manageable disease at diagnosis (28). According to our results 5,004 life-years might be lost over the horizon of 40 months by delays in screening from March to June 2020, which will need to be addressed immediately. The need for expediency essential. Integrating fast tracking approaches to diagnosis and treatment of lung cancer were already being explored in the pre-COVID period in Nordic countries (except Finland) to improve patient outcomes (29). Studies demonstrate that reduced delays result in better survival for lung cancer patients (30) and a fast-track approach to diagnosis and treatment should be accommodated in the Canadian healthcare system as well, particularly given the current constraints presented with the pandemic.
Our study considered only new lung cancer patients in Canada in 2020 and since incidence only reflects a part of the total lung cancer population, the results from this analysis are unable to be extended to the total lung cancer population. Similarly, all cancer patients have undergone a similar or worse situation with their surgeries getting cancelled or delayed (22, 23, 31–34). These were driven by factors such as bed shortages, unavailability of intensive care unit (ICU) beds and or ventilators and the continued human health care resource shortages of hospital personnel due to sickness, quarantine, and the increased demands within the home (31). Similar to the situation in Canada, Corley et al (34) also showed that during the Covid-19 pandemic there was a considerable decrease in lung cancer and other cancer screening rates in the USA.
Our analysis proxies a monthly trend of cancer incidence and impact of COVID restrictions on lung cancer patients’ incidence in Canada from US-based sources (14, 16). Since, the US shares higher similarities in terms of geography, life expectancy and death rate, with Canada, it was deemed fit to use US-based data as a proxy for Canada (35). However, their populations are significantly different as well as their healthcare service model, which can pose a potential barrier for the above justification of using US data. For, Alanen et al (15), a single centre retrospective study, showed the inverse relationship between delay and survival of lung cancer patients. Whereas a systematic review suggested that there was no association between delay to treatment and survival in lung cancer (36).
With the correct input of data, this model can be used for any future similar health related predictions, especially for cancers of all types enabling the predictions of cases and outcomes.