One in five people in Northern Ireland receive their cancer diagnosis while attending an emergency department (ED), according to research by the NI Cancer Registry.
The registry confirmed to BBC News NI that, at present, a quarter of bowel cancers are being diagnosed in EDs.
It said mostly older patients are affected.
Its research also found that a third of lung cancers in NI are diagnosed after a patient turns up at an ED.
The problem is a direct result of some people waiting too long on hospital lists and being brought to emergency departments instead.
Survival rate ‘lowest’
The head of services at Macmillan Cancer Support, Heather Monteverde, said the statistics were “shocking and extremely worrying”.
She said emergency departments cannot provide the very specialist care needed by cancer patients and added that only 55% of cancer patients in Northern Ireland are starting treatment within the 62-day target, a figure that was “deteriorating month-by-month”.
The cancer survival rate is lowest for patients who present via emergency than any other route, although it is thought this is because those patients tend to have later-stage cancers than those who present via other medical routes.
Earlier this year, a report by the NI Cancer Registry found that 74% of the 4,316 people who died from cancer in Northern Ireland in 2015 were admitted to emergency departments in the final years of their lives.
Also, one in six (17%) people died within seven days of their last emergency admission and almost all (95%) of these died in hospital.
Breast assessment targets
Meanwhile, the 14-day breast assessment target has not been met again in Northern Ireland.
During March, 1,387 patients were seen by a breast cancer specialist for a first assessment following an urgent referral for suspected breast cancer.
Of these, 85.6 % (1,187) were seen within 14 days compared with 100% in the previous year.
Statistics published by the Department of Health show 69.4% of new referrals for suspected breast cancer were classified as urgent in March 2019.
The department said the waiting times are “unacceptable”.
Previously the permanent health secretary said that it would take £1bn to tackle Northern Ireland’s hospital waiting lists.