February 5 (Reuters) - American patients diagnosed with cancer early in the COVID-19 pandemic had a lower chance of surviving the first year after diagnosis compared to patients diagnosed in earlier years, researchers said in the journal JAMA Oncology.

The study included more than one million patients diagnosed with early or late-stage cancer during 2020 and 2021, and concluded that the number of deaths during the first year of diagnosis was about 17,390 higher than expected, when compared to those diagnosed with the disease between 2015 and 2019.

Compared to pre-pandemic trends, the one-year survival rate was 0.44 percentage points lower in 2020 and 0.37 percentage points lower in 2021 for people diagnosed at early stages. For patients diagnosed at later stages, the rate was 0.34 and 0.20 percentage points lower, respectively, in 2020 and 2021.

Survival rates declined across all subpopulation groups, with those aged 65 and over being most affected.

The researchers who prepared the study said the findings indicate "serious harm associated with disruptions to cancer patient care during the first two years of the COVID-19 pandemic."

They added, "Continuous monitoring is needed to assess whether additional changes in survival outcomes extended during and after the pandemic."