The number of patients waiting on an endoscopy in Scotland has increased by 44.5% due to the pressures Covid has placed on the NHS.
Latest Public Health Scotland (PHS) statistics showed 31,637 people were waiting on the procedure in December.
They also revealed the percentage who had been waiting 39 to 52 weeks increased from 6.1% to 18.5%.
An endoscopy is among the key diagnostic tests used to detect serious illnesses, including cancer.
The PHS figures for the final quarter of 2020 also showed 100,913 patients were waiting to be seen for at least one of the eight key diagnostic tests, including MRIs, CT scans and non-obstetric ultrasounds.
This number is down slightly (1.8%) on the previous three months but is 15.3% higher (13,370 patients) than the same period in 2019.
Cancer Research UK in Scotland said early diagnosis was vital to give people access to life-saving treatment.
Kirsty Slack, the charity’s public affairs manager, said: “Overall, the pandemic has led to a worrying drop in the number of people being diagnosed with cancer and starting treatment.
“While services are slowly recovering, we remain deeply concerned about the ongoing backlog of people waiting to receive these crucial tests and get a diagnosis.”
She also urged the Scottish government to address “long-standing staff shortages which exist within cancer services”.
Last year the widow of a cancer patient who died three days after getting the results of a delayed endoscopy told BBC Scotland she believed his life could have been extended if he had been examined sooner.
Billy Hughes was waiting for the procedure at Hairmyres hospital in East Kilbride on 2 April when it was cancelled and he was sent home.
But his condition deteriorated and, a month later, his case was finally classed as an emergency.
He died days after finally getting the results of the examination in May.
In November it emerged the number of people diagnosed with cancer fell by 40% at the start of the the pandemic.
Earlier this month charity, Cancer Support Scotland, said it was starting to see patients who were diagnosed late as a result of Scotland’s first coronavirus lockdown.
They warned the delay in diagnosis would lead to people dying earlier because services had been paused.