Two years ago, when the Otago and Southland boards were first exploring the possibility of a combined service, he was convinced it "would never happen without at least one or two homicides'', he told this week's hospital advisory committee meeting.
It had not been easy, but the way in which staff on both sides had worked to find a way through deserved "significant congratulations''.
The service is the first joint service of the boards established under their Southern Alliance partnership.
Mr Thomson said Otago and Southland were "so far ahead of the pack'' when it came to collaboration between boards.
Chief operating officer Vivian Blake said the service had been a huge success and challenges in developing it had been enormous - "it's certainly been a learning curve for the next regional clinical service we might wish to embark on with Southland''.
The three-month review of the joint service, which began in December, showed that patient waiting times were virtually eliminated or reduced significantly.
Times vary for each section of the service, but the most dramatic reduction in waiting times has been for Southland people seeking urgent initial haematology assessments. They were waiting an average of more than 100 days last September, but were seen virtually straight away in December.
A single waiting list works across both provinces and patients are expected to have equal access to services wherever they live. So far, Southland patients are waiting a slightly shorter time than their Otago counterparts for treatment for chemotherapy, radiation therapy and haematology.
The waiting times for first assessment by a specialist have been affected by the absence of oncologist Dr Kate Bayston, from Southland, who has been off work after being injured in a crash in January, but still show improvement.
Everyone on the waiting list, along with the doctors involved with their care, is notified about how long the patient could have to wait for an initial assessment.
Anyone who might wait longer for an appointment than nationally recommended is offered an earlier appointment at a a clinic outside their region, if possible. The service also tries to give patients follow-up appointments with specialists and chemotherapy as close to home as possible.
Recommendations proposing extra part-time staff, including a clinical case co-ordinator for the management of complex patients, a social worker, and a clinical psychologist/counsellor, were supported by the committee. These are expected to be financed by the Crown Funding Agency.
The committee agreed to send a formal letter of congratulations to the service.
