Review for 10.1186/s12876-025-03882-3 (2025)

Title: Oncologic outcomes of surgically treated colorectal cancer in octogenarians: A
Comparative Study Using Inverse Probability of Treatment Weighting (IPTW)
Version: 1 Date: 19 Feb 2025
Reviewer's report:
The authors investigate the oncologic outcomes of octogenarians with colorectal cancer (CRC).
While understanding the prognosis of octogenarians is clinically important in the context of an
aging society, major revisions to the methodology are necessary. My comments are as follows.
Major:
1. This study includes only patients who underwent surgery for colorectal cancer. Therefore, the
title should explicitly indicate that the study population consists of surgically treated patients
to ensure clarity.
2. This study includes patients across all stages (I–IV) but excludes those who underwent R1 or
R2 resection. This suggests that for stage IV CRC, only patients who underwent radical resection
of the primary tumor along with resection of metastatic tumors were included.
However, survival outcomes in stage IV patients vary significantly depending on the location
and extent of metastasis. Therefore, including all stage IV patients in the analysis may not be
appropriate, as survival outcomes could be strongly influenced by the heterogeneity of metastatic
disease.
3. Unlike colon cancer, rectal cancer patients often undergo neoadjuvant treatment prior to
surgery, and the treatment protocols vary widely, including long-course chemoradiotherapy,
short-course chemoradiotherapy, and total neoadjuvant therapy (TNT).
These treatment variables must be accounted for and adjusted for in the analysis to ensure that
oncologic outcomes are interpreted correctly.
Minor:
4. Providing both 3-year overall survival (OS) and 3-year disease-free survival (DFS) values
for each variable in the univariate analysis of Tables 2 and 3 would be more appropriate for a
comparative analysis between the two groups.
5. The first paragraph of the Methods section contains repetitive sentences, with an identical
sentence appearing in the third paragraph of the Methods section. (The patients were divided
into two groups according to their age: Octogenarian group (OG, aged > 80 years, n=93), and
younger group (YG, aged 60 to 79 years, n=398).).
6. In the first paragraph of the Results section, the number 397 appears to be incorrect. Should
it be 398 instead?
7. In Table 1, check whether the p-value for albumin (p = 0.621) is correct, as stated in the text.
8. Figure 4 appears before Figure 3 in the main text, which should be corrected for sequential
consistency.
9. The p-value (p = 0.120) is mentioned twice in the 'Covariate Adjustment Through IPTW'
section of the Results, and this redundancy should be addressed.
10. Since the primary focus of the study is the comparison between OG and YG, the
figure presenting 'Survival According to Postoperative Complication,' which compares survival
outcomes within OG based on perioperative complications, would be more appropriate as a
supplementary figure rather than a main figure.
11. According to the figures, the values (72.8% vs. 38.8%, p < 0.001) seem to be incorrect. It
appears that the correct values should be (55.2% vs. 26.8%, p = 0.005). Please verify and correct
this discrepancy.