In the first three months of 2015, 91.8 per cent of patients urgently referred with suspicion of cancer began treatment within 62 days, official figures show.
That compares to 94.2 per cent in the previous three months and is below the Scottish Government goal of having 95 per cent of patients start treatment within two months.
Only four NHS boards – Dumfries and Galloway, Highland, Lanarkshire and Orkney – met the standard, three less than in the previous quarter.
NHS Western Isles had the lowest performance against the treatment goal, with 80 per cent, followed by NHS Grampian with 84.9 per cent.
Every board achieved the target of having 95 per cent of cancer patients start treatment within 31 days of a decision to treat them being taken.
Announcing the funding, health secretary Shona Robison said: “Our cancer targets are rightly rigorous as patients deserve the best cancer care possible but there is no doubt that we must do more – especially on our 62-day target. While this has increased from 84.5 per cent in 2007, we remain fully committed to once again reaching our standard of 95 per cent.
“This is why today’s £4.05m funding, which comes on top of the £8.5m invested over the past three years to improve cancer services, is extremely important.
“This will help improve on diagnostic waits across the country as well as provide local support through the recruitment of a new consultant in the west of Scotland and additional resource for endoscopy services.”
Liberal Democrat health spokesman Jim Hume called on SNP ministers to explain the drop in performance.
He said: “The figures are headed in all the wrong direction for cancer treatment times.
“Sixty-two days will feel like decades to cancer patients and their families as they wait to receive their first treatment. I applaud the hard work of all NHS staff who work tirelessly to provide excellent care.
“With only four out of 14 health boards meeting the treatment-time standard for urgent referral with suspicion of cancer, [we] remain concerned that the SNP government has taken its eye off the ball.”
Janice Preston, head of Macmillan in Scotland, said: “We welcome the investment in cancer care as long as it is targeted in areas that need to demonstrate improvement.
“We have to ensure there is planning across the networks and that good practice is being shared.
“Going through cancer is very stressful and it’s important everyone receives treatment as quickly as possible.”