Impact of dementia on cancer discovery and pain

Dementia is clinically noted to influence both reporting and experience of cancer pains. However, no systemic evaluation of this aspect has been reported. The aim of the present study was to retrospectively evaluate how dementia modified the cancer discovery process, frequency of cancer pain reports and analgesic-narcotic use at a large psychiatric hospital.

We reviewed all the records of cancer patients with and without dementia treated at the surgical ward of Matsuzawa Hospital from 1993 to 2004. Psychiatric diseases other than dementia, brain metastasis and alcoholism, as well as leukaemia and skin cancer, were excluded. Patients' communicativeness as to pain was ascertained from nursing records.

A total of 134 cancer patients with and without dementia (50 demented and 84 non-demented) were included. Demented patients were accidentally discovered to have cancer (48%) or by an unexpected unfolding of clinical signs (44%), whereas most non-demented patients (63%) voluntarily sought medical evaluation (P= 0.000). Overall, 76% of non-demented patients had cancer pains (stages I and II, 64%; stages III and IV, 84%), whereas just 22% of demented patients had cancer pains (stages I and II, 16%; stages III and IV, 26%; P= 0.000). Non-demented patients showed stage-dependent requirements for both non-narcotic analgesics (stages I and II, 64%; stages III and IV, 84%) and narcotics (stages I and II, 0%; stages III and IV, 41%). Demented patients required much less analgesics (stages I and II, 11%; stages III and IV, 13%), with only one stage IV patient requiring narcotics (P= 0.000).

Dementia greatly modifies the cancer discovery process, reduces prevalence of cancer pain and analgesic requirement.