Adjuvant chemotherapy patterns and clinicopathological factors associated with survival in patients aged 70 years and older with resected stage II–III colon cancer: a single-center real-world study

Zekeriya Hannarici; Aykut Turhan; Mehmet Emin Büyükbayram; Senar Ebinç; Alperen Akansel Çağlar; Mehmet Bilici; Salim Başol Tekin

Adjuvant chemotherapy patterns and clinicopathological factors associated with survival in patients aged 70 years and older with resected stage II–III colon cancer: a single-center real-world study

Abstract

Aims: Older adults are underrepresented in adjuvant colon cancer trials, leaving uncertainty regarding oxaliplatin benefit and optimal treatment duration. This study evaluated the associations of adjuvant chemotherapy patterns, treatment duration, and clinicopathological factors with overall survival (OS) and disease-free survival (DFS) in patients aged ≥70 years with resected stage II-III colon cancer. Methods: This single-center retrospective study included patients aged ≥70 years with resected stage II-III colon cancer. Survival outcomes were analyzed using Kaplan-Meier methods and Cox regression analyses. Results: Forty-six patients were included; the mean age was 74.39±4.48 years, and 56.5% were male. Overall, 56.5% received oxaliplatin-containing chemotherapy, and 71.7% completed six months of treatment. Disease progression occurred in 41.3% of patients, and 28.3% died. Estimated mean OS and DFS were 100.9 months and 84.2 months, respectively. Although six-month chemotherapy was associated with OS and showed a borderline association with DFS in reduced exploratory Cox models, these associations were attenuated and were no longer statistically significant in the 6-month landmark sensitivity analysis. Oxaliplatin-containing chemotherapy was not significantly associated with OS or DFS in the overall cohort. Conclusion: In this retrospective single-center cohort of patients aged ≥70 years with resected stage II–III colon cancer, sixmonth adjuvant chemotherapy was associated with longer survival in conventional analyses but was no longer statistically significant in the 6-month landmark sensitivity analyses. Therefore, this finding should be interpreted cautiously because of potential immortal time bias, survivor selection, treatment-selection bias, and residual confounding. Oxaliplatin-containing chemotherapy was not significantly associated with OS or DFS in the overall cohort. These findings should be considered hypothesis-generating and should not be interpreted as causal evidence regarding optimal treatment duration or oxaliplatin benefit in older adults.

Keywords

Supporting Institution

no

Project Number

none

Ethical Statement

This study was approved by the clinical research ethics committee of the Atatürk University. Date: 07.09.2023, number: 12.

Thanks

The authors thank the staff of the Oncology Department of Ataturk University for their assistance with data collection and the professional biostatistician for conducting the statistical analyses.

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Details

Primary Language

English

Subjects

Clinical Oncology

Journal Section

Research Article

Authors

Zekeriya Hannarici ^*
0000-0002-6547-0199
Türkiye

Aykut Turhan
0000-0002-2535-9816
Türkiye

Mehmet Emin Büyükbayram
0000-0002-5454-7576
Türkiye

Senar Ebinç
0000-0002-0878-6525
Türkiye

Alperen Akansel Çağlar
0000-0001-8541-3418
Türkiye

Mehmet Bilici
0000-0003-1306-2238
Türkiye

Salim Başol Tekin
0000-0002-0974-3412
Türkiye

Publication Date

August 15, 2026

Submission Date

May 28, 2026

Acceptance Date

June 25, 2026

Published in Issue

Year 2026 Volume: 7 Number: 4

IZ

https://izlik.org/JA97NT72BK

Cite

RIS / Bibtex

APA

Hannarici, Z., Turhan, A., Büyükbayram, M. E., Ebinç, S., Çağlar, A. A., Bilici, M., & Tekin, S. B. (2026). Adjuvant chemotherapy patterns and clinicopathological factors associated with survival in patients aged 70 years and older with resected stage II–III colon cancer: a single-center real-world study. Journal of Medicine and Palliative Care, 7(4), 650-660. https://izlik.org/JA97NT72BK

AMA

1.Hannarici Z, Turhan A, Büyükbayram ME, et al. Adjuvant chemotherapy patterns and clinicopathological factors associated with survival in patients aged 70 years and older with resected stage II–III colon cancer: a single-center real-world study. J Med Palliat Care / JOMPAC / jompac. 2026;7(4):650-660. https://izlik.org/JA97NT72BK

Chicago

Hannarici, Zekeriya, Aykut Turhan, Mehmet Emin Büyükbayram, et al. 2026. “Adjuvant Chemotherapy Patterns and Clinicopathological Factors Associated With Survival in Patients Aged 70 Years and Older With Resected Stage II–III Colon Cancer: A Single-Center Real-World Study”. Journal of Medicine and Palliative Care 7 (4): 650-60. https://izlik.org/JA97NT72BK.

EndNote

Hannarici Z, Turhan A, Büyükbayram ME, Ebinç S, Çağlar AA, Bilici M, Tekin SB (August 1, 2026) Adjuvant chemotherapy patterns and clinicopathological factors associated with survival in patients aged 70 years and older with resected stage II–III colon cancer: a single-center real-world study. Journal of Medicine and Palliative Care 7 4 650–660.

IEEE

[1]Z. Hannarici et al., “Adjuvant chemotherapy patterns and clinicopathological factors associated with survival in patients aged 70 years and older with resected stage II–III colon cancer: a single-center real-world study”, J Med Palliat Care / JOMPAC / jompac, vol. 7, no. 4, pp. 650–660, Aug. 2026, [Online]. Available: https://izlik.org/JA97NT72BK

ISNAD

Hannarici, Zekeriya - Turhan, Aykut - Büyükbayram, Mehmet Emin - Ebinç, Senar - Çağlar, Alperen Akansel - Bilici, Mehmet - Tekin, Salim Başol. “Adjuvant Chemotherapy Patterns and Clinicopathological Factors Associated With Survival in Patients Aged 70 Years and Older With Resected Stage II–III Colon Cancer: A Single-Center Real-World Study”. Journal of Medicine and Palliative Care 7/4 (August 1, 2026): 650-660. https://izlik.org/JA97NT72BK.

JAMA

1.Hannarici Z, Turhan A, Büyükbayram ME, Ebinç S, Çağlar AA, Bilici M, Tekin SB. Adjuvant chemotherapy patterns and clinicopathological factors associated with survival in patients aged 70 years and older with resected stage II–III colon cancer: a single-center real-world study. J Med Palliat Care / JOMPAC / jompac. 2026;7:650–660.

MLA

Hannarici, Zekeriya, et al. “Adjuvant Chemotherapy Patterns and Clinicopathological Factors Associated With Survival in Patients Aged 70 Years and Older With Resected Stage II–III Colon Cancer: A Single-Center Real-World Study”. Journal of Medicine and Palliative Care, vol. 7, no. 4, Aug. 2026, pp. 650-6, https://izlik.org/JA97NT72BK.

Vancouver

1.Zekeriya Hannarici, Aykut Turhan, Mehmet Emin Büyükbayram, Senar Ebinç, Alperen Akansel Çağlar, Mehmet Bilici, Salim Başol Tekin. Adjuvant chemotherapy patterns and clinicopathological factors associated with survival in patients aged 70 years and older with resected stage II–III colon cancer: a single-center real-world study. J Med Palliat Care / JOMPAC / jompac [Internet]. 2026 Aug. 1;7(4):650-6. Available from: https://izlik.org/JA97NT72BK