It comes after NHS Tayside confirmed vacancies have not yet been filled following the resignation of one oncologist in January and another handing in their six-month notice period, leaving the health board with no breast cancer consultants from June.
Questioned on the issue by Labour MSP Mercedes Villalba on Wednesday, Mr Yousaf said the Government was working with NHS Tayside to recruit oncologists.
The staffing gaps are “not satisfactory”, Mr Yousaf said, and filling them is a priority for the Government.
Ms Villalba labelled the situation “unacceptable” and called for a long-term plan to train and recruit specialists across Scotland.
"Scottish Government officials are currently working closely with the HR director and chief executive of NHS Tayside to support the board to take forward a rebuild plan for recruitment of oncology consultants, specialist nursing, and other support staff to deliver a local service,” said Mr Yousaf.
"This will include options around international recruitment, training schemes, marketing strategies and campaigns, trainee placements and re-examining locum capacity too.”
The staffing problems are felt across Scotland, Mr Yousaf said.
He said: "Although I'm referencing the issues across Scotland, they are, of course, most acutely felt in NHS Tayside, and let me say without any equivocation that the situation in NHS Tayside’s breast cancer service to me is simply not a satisfactory one, and therefore one that is a priority for us to resolve.”
Ms Villalba said: “The health secretary is right to admit that the current situation facing NHS Tayside breast cancer services is not satisfactory as patients face the prospect of travelling up to 80 miles for treatment.
“But his admission comes too late and will do nothing to provide support for the up to eight patients a week who will now be affected by the lack of breast cancer oncology specialists in NHS Tayside.”
It comes as Prof Alastair Munro, emeritus professor of radiation oncology at Dundee University, told the BBC the cancer care crisis at NHS Tayside could have been averted if the health board had publicly supported doctors criticised by an official report.