Associations between comorbidities and survival outcomes in older adults with cancer: a scoping review of international and Japanese evidence.
- 1Division of Survivorship Research, National Cancer Center Institute for Cancer Control, Tokyo, Japan.
- 2Department of Cancer Survivorship and Digital Medicine, The Jikei University School of Medicine, Tokyo, Japan.
- 3Division of Survivorship Research, National Cancer Center Institute for Cancer Control, Tokyo, Japan. [email protected].
Abstract
Background
Advances in cancer treatment have improved survival among older adults with cancer, many of whom experience multiple comorbidities. This scoping review synthesized international and Japanese evidence regarding associations between comorbidities and survival outcomes in older adults with cancer.Methods
We conducted a two-stage scoping review using PubMed and Ichushi. In the primary analysis, we searched for large-scale population- or registry-based studies globally to examine whether the pathways through which comorbidities influence survival outcomes in older adults with cancer, previously described for diabetes, are similarly applicable to comorbidities in general. In the secondary analysis, we searched for Japan-based studies to examine whether similar associations and mechanisms were observed in smaller clinical cohort settings in Japan. Data extraction focused on comorbidity measures, survival outcomes, and proposed mechanisms linking comorbidities to prognosis, which were categorized according to six conceptual pathways.Results
Eighteen international studies and 17 Japan-based studies met the eligibility criteria. Across both evidence streams, greater comorbidity burden was consistently associated with poorer overall survival. The Charlson Comorbidity Index was the most frequently used comorbidity measure. International studies more commonly suggested that comorbidities contributed to cancer-related mortality through restricted access to standard treatment (Pathway II). By contrast, Japanese studies more often reported associations with competing non-cancer mortality (Pathway I). Evidence remained limited for mechanisms involving increased malignancy, reduced treatment responsiveness, and delayed cancer detection, highlighting substantial gaps in the literature.Conclusions
Comorbidities were consistently associated with poorer survival outcomes among older adults with cancer. International and Japanese studies appeared to emphasize different mechanisms linking comorbidities to prognosis; however, these differences should be interpreted cautiously owing to heterogeneity in study design, outcome definitions, and data sources. Further large-scale studies incorporating standardized comorbidity assessment are needed to clarify the mechanisms through which comorbidities affect prognosis and to inform survivorship care for aging cancer populations.
Related
- Infectious disease communication for international students: A survey of association-accredited Japanese language schools in Japan
- Ferroptosis-Related GPX4 and CD71 and Immune Checkpoint PD-L1 in Cutaneous Melanoma: Associations with Clinicopathologic Features and Survival Outcomes
- Prognostic associations between patient-reported outcomes and progression-free and overall survival in advanced gastric or gastroesophageal junction adenocarcinoma with PD-L1 TAP score ≥ 5%: results from the RATIONALE-305 trial
- Body mass index at diagnosis, postdiagnosis change, and role of metabolic comorbidities in relation to survival in nonmetastatic renal cell carcinoma patients.
- Fatigue after transient ischemic attack: cross-sectional associations with comorbidities, activities of daily living and social participation
BibTeX
@article{itani2026associations,
title = {{Associations between comorbidities and survival outcomes in older adults with cancer: a scoping review of international and Japanese evidence.}},
author = {Yuki Itani and Ayumu Matsuoka and Kyoko Obama and Maiko Fujimori},
journal = {BMC geriatrics},
year = {2026},
month = jul,
doi = {10.1186/s12877-026-07891-z},
url = {https://europepmc.org/article/MED/42902221},
note = {CC BY},
}
RIS
TY - JOUR
TI - Associations between comorbidities and survival outcomes in older adults with cancer: a scoping review of international and Japanese evidence.
AU - Yuki Itani
AU - Ayumu Matsuoka
AU - Kyoko Obama
AU - Maiko Fujimori
PY - 2026
DA - 2026/07/01
JO - BMC geriatrics
DO - 10.1186/s12877-026-07891-z
UR - https://europepmc.org/article/MED/42902221
AB - Background Advances in cancer treatment have improved survival among older adults with cancer, many of whom experience multiple comorbidities. This scoping review synthesized international and Japanese evidence regarding associations between comorbidities and survival outcomes in older adults with cancer.Methods We conducted a two-stage scoping review using PubMed and Ichushi. In the primary analysis, we searched for large-scale population- or registry-based studies globally to examine whether the pathways through which comorbidities influence survival outcomes in older adults with cancer, previously described for diabetes, are similarly applicable to comorbidities in general. In the secondary analysis, we searched for Japan-based studies to examine whether similar associations and mechanisms were observed in smaller clinical cohort settings in Japan. Data extraction focused on comorbidity measures, survival outcomes, and proposed mechanisms linking comorbidities to prognosis, which were categorized according to six conceptual pathways.Results Eighteen international studies and 17 Japan-based studies met the eligibility criteria. Across both evidence streams, greater comorbidity burden was consistently associated with poorer overall survival. The Charlson Comorbidity Index was the most frequently used comorbidity measure. International studies more commonly suggested that comorbidities contributed to cancer-related mortality through restricted access to standard treatment (Pathway II). By contrast, Japanese studies more often reported associations with competing non-cancer mortality (Pathway I). Evidence remained limited for mechanisms involving increased malignancy, reduced treatment responsiveness, and delayed cancer detection, highlighting substantial gaps in the literature.Conclusions Comorbidities were consistently associated with poorer survival outcomes among older adults with cancer. International and Japanese studies appeared to emphasize different mechanisms linking comorbidities to prognosis; however, these differences should be interpreted cautiously owing to heterogeneity in study design, outcome definitions, and data sources. Further large-scale studies incorporating standardized comorbidity assessment are needed to clarify the mechanisms through which comorbidities affect prognosis and to inform survivorship care for aging cancer populations.
SN - 1471-2318
ER -