New figures show NHS Grampian is the only health board in Scotland to miss a government guideline for cancer treatment times.
The number of people in the north-east who waited longer than recommended 31-day standard for cancer treatment rose in the second quarter of this year.
It was the worst for treatment within the 31-day standard and was the only health board not to meet the 95% target.
Latest statistics released by ISD show it also fell short of the 62-day standard for the maximum time between referral and the start of treatment.
Scottish Government guidelines say 95% of patients should start treatment within 62 days of being referred and within 31 days of a decision to proceed with it.
In the north-east between April and June, treatment began within 31 days in 94.5% of eligible cases – down from 95.2% between January and March.
And 81.9% of eligible referrals began treatment within 62 days, a fall from 83.3% the previous quarter.
North-east Liberal Democrat MSP Mike Rumbles accused the Scottish Government of leaving NHS Grampian under-resourced.
He said: “This is not just a one-off. NHS Grampian went into this pandemic with less resources than any other health board.
“Week after week the figures show that healthcare standards in the north-east are under threat and Scottish Government ministers still refuse to lift a finger to rectify the situation.
“Whether it is sheer incompetence or a lack of political will, Scottish Government underfunding has put our local healthcare services under immense pressure and it is the patients and hardworking staff that are paying the price.
“This is about people’s lives. I have repeatedly asked the Cabinet Secretary to take action to put our local health services on an equal footing with the rest of the country.”
Scottish Government health secretary Jeane Freeman said: “Cancer has remained a top priority throughout the Covid-19 pandemic, with the majority of treatments continuing.
“These statistics reassuringly show that at the height of the Covid pandemic, when NHS Boards were speedily preparing plans to deal with the pandemic, cancer patients in Scotland waited on average two days for treatment, once a decision to treat was made.
“We are continuing to ensure patients are seen and treated as safely and as quickly as possible, and if necessary, changes will be made to treatment plans to minimise risk.
“While the overall aim is to recover cancer waiting times performance, our priority remains ensuring vital services are delivered to patients based on their clinical priority and clinical risk.
“We have invested £10 million to support cancer services during and beyond the Covid-19 pandemic and the new cancer recovery plan will be published in the autumn.”
A spokeswoman for NHS Grampian explained the failure to meet targets was down to shortages of some types of staff.
She said: “With cancer waiting times although we are meeting – or exceeding – the 62-day standard in some individual specialities, across the board our performance is disappointing.
“The reason we are not achieving the standard is due to a shortage of nursing and medical staff within certain specialities. We know waiting for test results or treatment can be very stressful for patients and their families. We would like to assure them that we are doing everything we possibly can to reduce these waits.
“Our performance against the 31-day standard is improving. This is against a backdrop of long-term staffing challenges and it is testament to the very hard work of our teams across cancer services. We are, of course, very grateful to them for their efforts.
“In addition to existing challenges we have had to cope with Covid-19 and this has been extremely complex at times.
“A number of diagnostic services had to be restricted due to the risk to patients, for example endoscopies and colonoscopies. These services are up and running again but there is a large number of patients waiting; all referrals have been reviewed and patients clinically re-prioritised.
“We were very fortunate in that we had access to the independent sector for our patients waiting for cancer surgery and we were able to continue to treat patients throughout the summer.”