Wales will become the first UK nation to introduce a new single waiting time target for cancer patients.
It is an effort to speed up diagnosis and improve poor survival rates for the 17,000 patients who get it every year.
The clock will start on cancer treatment for all patients as soon as it is suspected, not just those with clear symptoms.
The two-month target from next June is expected to eventually replace the two-track system.
There are concerns that the current cancer targets do not reflect long delays some patients face waiting for diagnosis or treatment.
Health Secretary Vaughan Gething said the change - making Wales the first UK nation to move towards a single cancer waiting time - was the "right thing to do".
He recognised that existing targets had not been met often enough but said 92% of cancer patients were being treated within target times.
What happens at the moment and why is it changing?
There are currently urgent and non-urgent routes to getting treatment
If you are urgent - and the signs of cancer are obvious - you're referred by your GP to hospital and your treatment is supposed to start within 62 days
But if you symptoms are more unclear, vague or there is a suspicion it could be cancer - you might face months of being sent around different parts of the health service before cancer is diagnosed.
Only when that happens does the clock start - and then you're on a non-urgent 31 day route. It might seem faster but you've been already waiting.
So, treating all suspected cancers at the same - and all getting a 62-day treatment target from the point it is suspected - will aim to see more of these "non-urgent" patients faster too, and enable more to survive.
Not only that, but because the non-urgent pathway does not measure how long people have been bouncing around the NHS system before a decision is taken to start treatment, the experts argue it's impossible to find out where the real delays are.
Mr Gething said health boards would "shadow report" the new target alongside the existing ones.
He said: "Through dual reporting of the single cancer pathway, Wales will be the first UK nation to move towards a single waiting time measure for cancer.
"It is reflective of our aspiration to support early diagnosis of cancer and ensure fast and effective treatment for all patients."
What the experts say
Doctors say there are "considerable challenges" with rising demand, while they aim for earlier diagnosis to push Wales up the league tables for cancer survival in Europe.
Prof Tom Crosby, medical director of the Wales Cancer Network, said he believed the single cancer pathway was ambitious but the aim was to improve patient chances as well as their experience and also be a "platform" for improving access to diagnostic screenings and tests, which would be coming under increasing pressure.
"This has the potential to transform our diagnostic cancer services in Wales and I believe Wales would be leading the way in this regard," he said.
"Scotland are very interested in what we're doing, England are looking at something a little more modest, focusing just on the diagnostic part of the journey. But we think access to treatment after the patient has had the diagnosis is also a really important thing to do."
'That 10 weeks at the start was a death sentence to me'
Dawn Wilson, 36, from Hengoed, Caerphilly county, has terminal breast cancer. She checked herself regularly and found a lump in 2014 and went straight away to her GP, because she thought a breast implant she had fitted three years before might have ruptured. The lump was the size of a small pea and she was told that it was likely to be cyst and was given antibiotics. Dawn returned again to her GP when she felt it was growing and painful and she was referred to hospital.
"In my head an urgent, emergency referral would be instantaneous - but I waited about another three weeks and in the meantime found another lump under my armpit and the original lump even bigger."
Dawn, who has two daughters and a stepdaughter, was finally seen by a specialist and had all the tests and cancer was diagnosed. She had a double mastectomy, chemotherapy and radiotherapy.
Her cancer responded to treatment and she re-married in May 2016.
"It looked like I was going to be one of the lucky ones, it almost felt like a life lesson," she said, but then she felt something and had another scan.
"I was then told it was incurable. I was told I had 11 months and I'm 22 months down the line now. I'll be on chemotherapy for the rest of my life or until I'm too sick to have it.
"I understand cancer is extremely unpredictable but I feel that 10 weeks at the start was a death sentence to me. I just think this waiting game... in my view everyone should be given the best opportunity to be diagnosed immediately."
She said it was too much for one GP to be expected to recognise everything and anyone with symptoms of cancer should be sent to a rapid diagnosis centre.
"Even if it cost £2m to run, I bet myself and the ladies in my support group, we've spent that alone in the chemotherapy treatments we've had."
Catching cancer early - rapid diagnosis centres
Speeding up the process of diagnosing patients - including all the scans they need at a one-stop shop - has been the subject of a pilot in two hospitals over the last year.
At Royal Glamorgan, 259 patients with vague symptoms of cancer were referred by their GPs and given the full range of tests at one time. Altogether 10% were found to have cancer.
At Neath Port Talbot hospital, 45 patients were found to have cancer out of 385 seen. Around half were not diagnosed but were found to have nothing sinister and 40% were found to have a significant issue but nothing cancerous.
Peter Hall, 77, a retired construction worker from Swansea, was given a CT scan. He got results a few hours later and told he was clear of cancer although he had a lung infection.
"It answered a lot of questions, everything was spot on," he said. "It would be good if it could be increased for more patients, it's a marvellous idea."
Richard Pugh, of Macmillan Cancer Support, said the announcement came on the same day that latest cancer waiting times revealed that 120 patients did not start their treatment on time in September.
"What is vitally important now, is how well this new monitoring system helps deliver tangible front-line service improvements which improve care for people with cancer in Wales," he said.