Figure falls short of Manx Care's target of 85 percent
Just over half of patients diagnosed with cancer over the last year began receiving treatment within 62 days.
Manx Care's latest figures show a number of its diagnosis and treatment targets for cancer patients are regularly being missed.
The healthcare organisation aims to have 85 percent of patients referred to cancer services begin their treatment within 62 days.
In May, 54.8 percent of cases met that standard, while over the last 12 months 298 out of 604 patients began treatment within that timeframe, or 51.7 percent.
Manx Care also has a 28-day diagnosis target for 80 percent of patients being referred to cancer services to receive a diagnosis.
In May, 56 percent found out whether they had cancer or not within four weeks, which is up from 49 percent in April.
For breast services, which have seen the most referrals over the last year, just 43 percent have received a diagnosis within 28 days; the average wait is currently 32 days.
In urology, 38 percent of referrals met the 28-day standard, while gynaecology patients it was 56 percent, and 65 percent in colorectal.
Skin was the only area to meet the 80 percent target over the last 12 months, with 567 of the 682 referrals receiving a diagnosis within four weeks.
Manx Care says delays in the breast service can be attributed to workforce vacancies, particularly the lack of breast consultant radiologist.
However, it has now appointed a consultant who'll be taking up the role in September, with a locum in place until then.
The healthcare board adds that there are a number of factors affecting colorectal wait times, such as complex pathways, patient frailty and other patient-related delays.
Over the last 12 months, more than 4,000 cases have been referred to cancer services with 618 patients currently awaiting diagnosis or treatment.