The COVID-19 pandemic has created challenges in interpreting trends in cancer incidence

According to research published in the Journal of the National Cancer Institute.

The researchers noted that the overall rate of cancer diagnoses in the SEER database decreased by 10% in 2020 compared to 2019. Cancer incidence rates decreased by 9.6% for men and 9 .3% for women.

The greatest decreases in incidence were observed for melanoma (15.8% for men and 14.3% for women) and thyroid cancer (14.0% for men and 17.9% for women). The smallest decrease was observed for pancreatic cancer (4.3% for men and 3.9% for women).

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In addition to calculating changes in cancer incidence in 2020, the researchers demonstrated that including 2020 cancer incidence rates in junction point models can lead to less accurate trend estimates.

The researchers fitted 3 junction point models to age- and lag-adjusted cancer incidence rates using SEER-22 data from the November 2021 submission (2000-2019), the November 2022 submission (2000-2020) and November 2022 submission excluding 2020.

For all cancer sites combined, the model including the 2020 incidence rate suggests that cancer incidence has been decreasing at a constant rate since the year 2000 (annual percent change [APC], 0.60%). Models excluding the 2020 rate suggest that overall cancer incidence was stable from 2013 to 2019.

The model including the 2020 incidence rate suggests that melanoma incidence began to decline by 5.12% per year in 2018. The models excluding 2020 rates suggest that melanoma incidence increased by 1. 15% to 1.16% per year since 2005.

The model including the 2020 incidence rate suggested that the incidence of prostate cancer increased by 2.06% per year during the period 2014-2020. Models excluding the 2020 rate suggested a larger increase in prostate cancer incidence over the 2014-2019 period. The APC was 3.7% for the November 2021 submission and 3.8% for the November 2022 non-2020 submission.

The researchers wrote that these examples “clearly demonstrate that including 2020 incidence rates in junction point models can pose challenges in trend estimates and interpretation, providing a poorer fit to the data. , less accurate and/or less precise long-term trend estimates. ”

Based on these findings, the researchers proposed excluding 2020 cancer incidence rates from trend estimates in the 2023 annual cancer statistics reports.

“The decision to exclude 2020 rates from trend analysis going forward depends on 2021 rates,” the researchers wrote. “If 2021 rates continue to decline, we may reconsider incorporating the 2020 rate. However, if 2021 rates are similar to pre-pandemic levels, we will likely continue to exclude 2020 incidence rates from the junction point analysis.

Reference

Mariotto AB, Feuer EJ, Howlader N, et al. Interpreting Cancer Incidence Trends: Challenges Due to the COVID-19 Pandemic. Lancet Oncol. Published online May 23, 2023. doi:10.1093/jnci/djad086