Patterns of staging, treatment, and mortality in gastric, colorectal, and lung cancer among older adults with and without preexisting dementia: a Japanese multicentre cohort study

BACKGROUND

Little is known about dementia's impact on patterns of diagnosis, treatment, and outcomes in cancer patients. This study aimed to elucidate the differences in cancer staging, treatment, and mortality in older cancer patients with and without preexisting dementia.

METHODS

Using cancer registry data and administrative data from 30 hospitals in Japan, this multicentre retrospective cohort study examined patients aged 65-99 years who were newly diagnosed with gastric, colorectal, or lung cancer in 2014-2015. Dementia status (none, mild, and moderate-to-severe) at the time of cancer diagnosis was extracted from clinical summaries in administrative data, and set as the exposure of interest. We constructed multivariable logistic regression models to analyse cancer staging and treatment, and multivariable Cox regression models to analyse three-year survival.

RESULTS

Among gastric (n = 6016), colorectal (n = 7257), and lung (n = 4502) cancer patients, 5.1%, 5.8%, and 6.4% had dementia, respectively. Patients with dementia were more likely to receive unstaged and advanced-stage cancer diagnoses; less likely to undergo tumour resection for stage I, II, and III gastric cancer and for stage I and II lung cancer; less likely to receive pharmacotherapy for stage III and IV lung cancer; more likely to undergo tumour resection for all-stage colorectal cancer; and more likely to die within three years of cancer diagnosis. The effects of moderate-to-severe dementia were greater than those of mild dementia, with the exception of tumour resection for colorectal cancer.

CONCLUSION

Older cancer patients with preexisting dementia are less likely to receive standard cancer treatment and more likely to experience poorer outcomes. Clinicians should be aware of these risks, and would benefit from standardised guidelines to aid their decision-making in diagnosing and treating these patients.

Between-hospital variations in 3-year survival among patients with newly diagnosed gastric, colorectal, and lung cancer

Due to increases in cancer survivability, quality assessments of cancer care must include long-term outcomes. This multicenter retrospective cohort study evaluated between-hospital variations in the 3-year survival rates of patients with gastric, colorectal, and lung cancer irrespective of treatment modality. We linked cancer registry data and administrative data from patients aged 18–99 years who were diagnosed with gastric, colorectal, or lung cancer between 2013 and 2015 in Osaka Prefecture, Japan. The 3-year survival rates were adjusted for potential prognostic factors using multilevel logistic regression models. Between-hospital variations were visually evaluated using funnel plots. We analyzed 10,296 gastric cancer patients from 30 hospitals, 9276 colorectal cancer patients from 30 hospitals, and 7978 lung cancer patients from 28 hospitals. The 3-year survival rate was 70.2%, 75.2%, and 45.0% for gastric, colorectal, and lung cancer, respectively. In the funnel plots, the adjusted survival rates of gastric and colorectal cancer for all hospitals lay between the lower and upper control limits of two standard deviations of the average survival rates. However, the adjusted survival rates of lung cancer for four hospitals lay below the lower limit while that for two hospitals lay above the upper limit. Older age, men, advanced cancer stage, comorbidities, functional disability, emergency admission, current/ex-smokers, and underweight were independently associated with poorer survival. In conclusion, there were between-hospital variations in 3-year survival for lung cancer even after adjusting for case mix. Quality improvement initiatives may be needed to raise the consistency of care.