Review for 10.1186/s12876-025-03681-w (2025)

Title: Diagnostic value of peripheral blood inflammatory indices for clinicopathological profile
of colorectal cancer: A retrospective observational study
Version: 1 Date: 09 Jan 2025
Reviewer:  Yinghao Cao
Reviewer's report:
This is an intriguing piece of work in which the authors employed a combination of indicators
from simple, non-invasive and low-cost routine haematological tests to reflect the severity
of systemic inflammation. This was then used to diagnose the clinicopathological features of
colorectal cancer. However, some key issues still need to be clarified.
1. The primary conclusion of the present study was that SIRI possesses considerable diagnostic
value in the identification of metastasis and tumour staging in patients with colorectal cancer.
However, this assertion is not substantiated by the findings of the study. The diagnostic
performance in predicting CRC metastasis was reported to be 61.5% for AUC, 47.4% for
sensitivity, and 33.9% for specificity, indicating that SIRI exhibits a comparatively weak
diagnostic capacity in this domain. The reduced sensitivity of the index may result in the failure
to diagnose metastases in half of patients, while the diminished specificity may lead to an
inaccurate diagnosis in a significant number of non-metastatic patients, consequently increasing
the number of unnecessary follow-up tests and treatments. Due to its intermediate area under the
curve (AUC) value (AUC 0.6-0.7 is often considered to be of intermediate diagnostic value) and
low sensitivity and specificity, SIRI has insufficient diagnostic accuracy if it is used for early
screening or as a metastatic diagnostic tool, and may result in a high false-negative rate, failing
to identify patients at risk of metastasis effectively.
2. In the section dedicated to the methods, the authors incorporated variables with P-values less
than 0.3 in univariate analyses into the multivariate model, a practice that is not commonly
observed. It is recommended that variables with a p-value of less than 0.05 be selected in
multivariate regression analyses rather than 0.3. The rationale for this is that a p-value of less
than 0.05 typically signifies a strong statistical significance, which is in accordance with standard
statistical practice and ensures that the selected variables exhibit a more substantial association
with the outcome. The employment of the more lenient criterion of P < 0.3 as a candidate variable
may result in the introduction of a multitude of variables that are either irrelevant or only weakly
related to the outcomes, thereby diminishing the predictive and explanatory capabilities of the
model. Should there be a desire to explore the impact of the less stringent criteria, the relevant
statistical analyses can be conducted in the paper to compare the differences in the results after
variables with P < 0.05 and P < 0.3 were entered into the model. This would allow for the
validation of the impact of different variable screening strategies on the conclusions.
3. Despite the study's efforts to control for the impact of underlying diseases such as diabetes
and hypertension, there was an omission of consideration of other potential confounders. These
include body mass index (BMI) and lifestyle factors, such as smoking and alcohol consumption.
These factors may influence changes in inflammatory markers in the blood by affecting systemic
levels of inflammation and, in turn, inflammatory markers in the blood. Failure to control for
these variables may result in changes in inflammation indices that do not accurately reflect
the actual state of the tumour. This may lead to increased confounding effects and reduced
independence and clinical accuracy of inflammation indices. Furthermore, the failure to consider
these factors may result in poor reproducibility and generalisation of study results, thereby
limiting their application to different populations.
4. The clinical significance and practical applications of the study were inadequately discussed.
While the study yielded preliminary clinical data, the clinical significance of these findings
remains to be fully explored. Further research is required to elucidate the role of inflammatory
markers such as SIRI and CIPI in clinical decision-making, particularly in the context of early
screening, metastasis prediction and personalised treatment.
5. Despite the study adhering to the STROBE guidelines, the description of the details in terms
of sample selection and case exclusion remains insufficiently clear. It is recommended that the
authors further supplement the study flow chart.