Summary:
During the COVID-19 pandemic, particular countries such as Japan saw a rise in non-COVID-19 related deaths, such as from cancer. This study looked at whether the pandemic had an impact on mortality rates for various types of cancer in Japan spanning from 2020 to 2022. Using nationally reported official statistics, the study compared annual and monthly mortality rates based on pre-pandemic data from 2010 to 2019 with mid and post pandemic data. Notably, the first year of the pandemic (2020) did not exhibit significantly different mortality rates. However, in 2021, following widespread vaccination with initial and booster injections, excessive cancer mortalities were noted. Subsequently, in 2022, significant increases in cancer-related deaths, including ovarian, leukemia, prostate, lip/oral/pharyngeal, pancreatic, and breast cancers, were observed shortly after the widespread administration of the third COVID-19 vaccine doses in Japan. The mortality rate for the most fatal cancers (lung, colorectal, stomach, and liver) was rapidly declining until 2020, but then the decrease rate slowed in 2021 and 2022. Whilst this study is not suggesting causality between the COVID-19 vaccinations and death, it poses interesting links and further areas to explore as to why there was a rise in cancer mortality rates during and post the COVID-19 pandemic.
Abstract:
During the COVID-19 pandemic, excess deaths including cancer have become a concern in Japan, which has a rapidly aging population. Thus, this study aimed to evaluate how age-adjusted mortality rates (AMRs) for different types of cancer in Japan changed during the COVID-19 pandemic (2020-2022). Official statistics from Japan were used to compare observed annual and monthly AMRs with predicted rates based on pre-pandemic (2010-2019) figures using logistic regression analysis. No significant excess mortality was observed during the first year of the pandemic (2020). However, some excess cancer mortalities were observed in 2021 after mass vaccination with the first and second vaccine doses, and significant excess mortalities were observed for all cancers and some specific types of cancer (including ovarian cancer, leukemia, prostate cancer, lip/oral/pharyngeal cancer, pancreatic cancer, and breast cancer) after mass vaccination with the third dose in 2022. AMRs for the four cancers with the most deaths (lung, colorectal, stomach, and liver) showed a decreasing trend until the first year of the pandemic in 2020, but the rate of decrease slowed in 2021 and 2022. This study discusses possible explanations for these increases in age-adjusted cancer mortality rates.
Article Publication Date: 08/04/2024
DOI: 10.7759/cureus.57860
