Cancer Society Otago-Southland division acting chief executive Bob King said the numbers were sobering and had been getting steadily worse.
"When waiting times get worse that creates enormous anxiety for the clients we are working with, and we have asked for direction from the DHB about what is being done to address these waiting times.
"I think they are well aware of what they are having to deal with and work with, but I think from our interactions that they are doing their best with the resources they have ... but not treating patients in a timely manner is causing levels of complexity and creating this backlog.
"It is quarter on quarter worsening, and while there is extra money and extra resources going in, they don't seem to be making a material impact."
The SDHB was taken by surprise by the 2019 spate of cases, but has long been aware of an upcoming potential issue with cancer treatment this year.
It had made plans for an expected increase in cases as people who had missed or postponed doctor's appointments during the Covid-19 lockdown after they finally received tests and a diagnosis.
However, that expected increase in cases coincided with mechanical issues befalling scanning machinery and a bed block crisis which has seen elective procedures postponed.
A report to last week's SDHB board meeting said the haematology waitlist (77 people) represented approximately 2.75 month's work and the oncology wait list of 77 represented 1.5 month's work.
"At 118, the current radiation oncology wait list is higher than it has historically been."
Extra scanning sessions had been organised and more staff were being recruited, but SDHB chief executive Chris Fleming said if that did not work, sending some patients to Christchurch for treatment would be considered.
King said Cancer Society staff had always taken a holistic approach in supporting cancer patients through both their treatment and also through other associated issues.
However, for some current clients their diagnosis had become almost a secondary concern to ongoing Covid-19-related issues King said, particularly for people whose employment, housing or ability to afford household basics had been affected by the pandemic.
"We are now not only dealing with people who have a cancer diagnosis but may also have other family or societal issues which are compounding the whole process."