Less than one in seven cancer patients started their treatment more than two months after GP referral, with Cambridgeshire and Peterborough Clinical Commissioning Group hitting the NHS target.
During 2017, 2,343 total cancer patients were referred to hospital urgently by their doctors, and 351 did not start their treatment within 62 days, according to NHS figures.
That means 85% were seen within two months, hitting the government's operational target.
The target aims to ensure almost all patients start treatment in two months.
However, it does allow for a minority of patients who choose to delay their course of treatment, which may be chemotherapy, surgery or radiation therapy.
Cambridgeshire and Peterborough CCG's figure is roughly the same as 2016, when 84.5% of patients started treatment two months after referral.
Across England most CCGs are running below the operational target.
The percentage of patients starting treatment within two months nationwide has dropped from 87.1% in 2012-2013, to 82.1% in the first three quarters of the current financial year. Nationally the target hasn't been hit since 2013.
The poorest record in England is in Thurrock CCG, Essex, where only 59% of cancer patients started treatment within two months. The best record is in South Cheshire CCG where it was 93%.
Dr Jeanette Dickson, vice president of clinical oncology at the Royal College of Radiologists, said that while the figures "are a cause for concern" they are a slightly crude measure for judging cancer diagnosis.
"In an ideal world we would want it to be 100%," Dr Dickson said.
However, she explained getting from the GP to treatment is a complicated process requiring many different appointments and staff.
"There is currently a shortage of radiologists (doctors who give X-rays), and to a lesser extent oncologists (doctors specialising in cancer).
"Some people will choose to delay the treatment beyond the two month time period."
Dr Dickson said the time periods required for treating different forms of cancer are vastly different.
"With your average male prostate cancer patient, you will do nothing but examine and watch for ten years.
"However, with tongue cancer or aggressive lung cancer you need to start treatment within three weeks otherwise it's likely the patient will have less chance surviving."
Sara Bainbridge, from Cancer Research UK, said: "We know that local hospitals are making every effort to meet this target, and other cancer waiting times improved from January to February.
"Part of the reason why hospitals are struggling to meet the target is because NHS diagnostic services are short staffed.
"We need the government to make sure there are more staff to deliver the tests and treatment that people need on time.""
An NHS England spokesman said: "Cancer survival is now at its highest ever, and over the past year the NHS treated more patients within the fast-track waiting target than the year before."