Thiamine deficiency (TD) presents with various physical and psychiatric symptoms, but no cases with depression-like symptoms have been reported.

We report a patient with cancer who appeared to attempt suicide as a consequence of depressive mood likely related to TD.

The patient was a 58-year-old woman diagnosed with recurrent endometrial cancer, with lung metastasis and pelvic dissemination. The patient apparently attempted suicide was referred to the psycho-oncology department.

At the time of the examination, major depressive disorder was suspected based on her mental symptoms, but when thiamine was administered intravenously in response to her poor dietary intake, her palpitations, dyspnea, anorexia, and insomnia improved, and her suicidal ideation disappeared at her reexamination 1 hour later after thiamine administration.

It is likely that the observed palpitations, dyspnea, anorexia, and insomnia, as well as the severe depression and the attempted suicide, which were thought to be physical symptoms associated with depression, were actually related to TD. Suicidal ideation and attempted suicide are conspicuous as psychiatric symptoms. However, in such cases, rather than simply starting treatment for depression, it is necessary to consider reversible TD as a cause of these symptoms and perform differential diagnosis to confirm the physical illness.

Despite increasing reports of thiamine deficiency (TD) among cancer patients, there remain some patients with borderline thiamine concentrations (BTC). However, it is unclear whether such patients subsequently develop TD.

Here, we report cases of cancer patients progressing to TD within a short time period after presentation with BTC (24–28 ng/ml).

A 49-year-old female with lung cancer. During treatment for depression, the patient showed a decreased appetite, and a blood sample revealed BTC (25 ng/ml). Fourteen days later, she reported a continued loss of appetite, and despite the absence of the 3 classical signs of Wernicke encephalopathy (WE), additional testing showed a thiamine level of 23 ng/ml, leading to a diagnosis of TD.

A 65-year-old female developed depression during chemotherapy for angiosarcoma. Her blood sample revealed BTC (25 ng/ml). Seven days later, despite the absence of the classical signs of WE, a further testing revealed a thiamine level of 20 ng/ml.

A 41-year-old female developed depression during chemotherapy for ovarian cancer. No loss of appetite was observed, but a blood sample revealed BTC (25 ng/ml). Seven days later, despite the absence of the classical signs of WE or decreased appetite, further testing revealed a thiamine level of 19 ng/ml.

Depressed cancer patients with BTC may develop TD within a short time frame. To prevent TD, health-care professionals should maintain an awareness of its potential and the need for regular testing of thiamine level or prophylactic replacement therapy.

It is well known that the burden on the families of cancer patient extends across many aspects, but there have been no reports of family members developing delirium due to the burden of caring for a cancer patient.

We reported a caregiver who developed Wernicke encephalopathy (WE) while caring for a family member with advanced cancer.

The subject was a 71-year-old woman who had been caring for her husband, diagnosed with gastric cancer and liver metastases, for 5 months. She visited the “caregivers’ clinic” after referral by an oncologist who was worried about a deterioration in her mental condition that had appeared several weeks previously. The woman had a history of diabetes mellitus. Some giddiness was observed and, based on her inability to answer questions, her level of consciousness was checked and some disorientation was observed. She was diagnosed with delirium. A blood sample was collected to investigate the cause of the delirium, but the test data showed no hypoglycemia. Her appetite had declined since her husband was diagnosed with cancer. Thiamine deficiency was suspected as thiamine stores in the body are depleted within about 18 days and her loss of appetite had continued for 5 months. On intravenous injection of 100 mg of thiamine, her consciousness level was returned to normal in 1 h. A diagnosis of WE was supported by the patient's abnormally low serum thiamine level.

The family members of cancer patients may develop a loss of appetite due to the burden of caring, resulting in WE. When providing care for signs of distress in family members, it is necessary to pay attention not only to the psychological aspects but also to their level of consciousness and physical aspects, particularly the possibility of serious illness resulting from reduced nutritional status.

Cancer patients often want to spend their final days at home, and it is essential that general practitioners have knowledge of and technical skills related to cancer medicine and symptom relief. Recent clinical studies have revealed that Wernicke encephalopathy (WE) is quite common in cancer patients. However, there have been no reports to date on WE in cancer patients undergoing home medical care.

From a series of cancer patient undergoing home medical care, we reported a patient with lung cancer who developed WE.

An 84-year-old female with lung cancer undergoing home medical care developed an impaired mental state and an attention deficit. Her symptoms fulfilled the diagnostic criteria for delirium. WE was suspected as the patient's food intake had fallen from normal a month previously to somewhere between 50% or just a few mouthfuls. This diagnosis was supported by abnormal serum thiamine and the disappearance of delirium after thiamine administration.

When delirium occurs in cancer patients undergoing home treatment, it is necessary to suspect thiamine deficiency as a potential cause, as appropriate diagnosis and treatment can prevent irreversible brain-related sequelae.

Cognitive dysfunction has a negative effect on cancer treatment; however, in a cancer setting, specific treatments can restore cognitive function. Such conditions are known as reversible dementia, with one of these being vitamin B12 (VB12) deficiency. However, there have been no reports of VB12 deficiency identified by preoperative evaluation in cancer patients.

We studied a patient who was referred to the Department of Psycho-oncology on suspicion of cognitive decline prior to lung cancer surgery. Preoperative evaluation revealed VB12 deficiency.

The patient was an 82-year-old woman diagnosed with lung cancer. She also presented with cognitive decline and, therefore, was referred to the Department of Psycho-oncology for preoperative evaluation. The patient scored 19 points on a Mini-Mental State Examination (MMSE), which is indicative of cognitive decline. As the onset of symptoms occurred several months previously and they were subacute, the possibility of reversible dementia was considered. Extensive examination revealed VB12 deficiency, and VB12 replacement therapy normalized the MMSE score to 25 points before surgery.

When cognitive decline is observed in cancer patients, it is necessary to actively evaluate the serum levels of some B vitamins, including VB12.

In recent years, the use of both molecular targeting agents (MTAs) and immune-checkpoint inhibitors (ICIs) tend to occupy important positions in systemic anticancer therapy (SACT). The objective of this study is to describe the predictors of SACT include both MTAs and ICIs near the end of life (EOL) and the effect on EOL care in patients with advanced cancer.

We analyzed all patients who died of advanced cancer from August 2016 to August 2019, and we analyzed the survival time of patients who underwent anticancer agents excluded due to the loss of information about the last administration of SACT. The primary endpoint of this study was to identify predictors during the last administration of SACT near EOL.

In a multivariate analysis, the Eastern Cooperative Oncology Group performance status (ECOG-PS) (ORs 33.781) was significantly related factors within 14 days of death from the last administration of SACT. Age (ORs 0.412), ECOG-PS (ORs 11.533), primary cancer site of upper GI cancers (ORs 2.205), the number of comorbidities (ORs 0.207), MTAs (ORs 3.139), and ICIs (ORs 3.592) were significantly related factors within 30 days of death. The median survival time (MST) of patients with PS 3–4 was 29 days, while that of patients with both PS 0–2 was 76 days. The prevalence rate of delirium with MTAs was 17.5%, which was significantly lower than that of patients without it (31.8%). The prevalence rate of the mean dose of opioids in patients with ICIs was 97.9 mg/day, which was significantly higher than that of patients without it (44.9 mg/day).

Age, ECOG-PS, primary cancer site, the number of comorbidities, MTAs, and ICIs use were significant associated with SACT near EOL. Information on these factors may aid clinical decision making in referral to palliative care institutes.