Suggestions
Idioma
Journal Information
Cite
Cite
Share
Download PDF
More article options
Visits
117
Letter to the Editor
Full text access
Available online 30 September 2026

Response to Therán-León, JS, regarding “Critical appraisal of a machine-learning model for predicting right-sided colon cancer recurrence: Toward TRIPOD+AI-compliant reporting and multicenter external validation”

Respuesta a Therán-León, JS, «Análisis crítico del modelo predictivo de recurrencia en cáncer de colon derecho: hacia un reporte conforme a TRIPOD+AI y validación externa multicéntrica»
Visits
117
R. Zayas-Bórquez, J. Canto-Losa, E. Posadas-Trujillo, N. Salgado-Nesme, O. Santes
Corresponding author
oscar.santesj@incmnsz.mx

Corresponding author. Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán. Vasco de Quiroga 15, Belisario Domínguez Sección XVI, Tlalpan, 14080 Mexico City, Mexico. Phone: 55 5487 0900, extension 2133.
Departamento de Cirugía Colorrectal, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
This item has received
Article information
Full Text
Bibliography
Download PDF
Statistics
Full Text
Dear Editors,

We thank Therán-León et al. for their interest in our study and appreciate their constructive comments on aspects of its methodology. We agree that machine learning-based predictive models should be cautiously interpreted, especially when they are developed from retrospective, single-center, small cohorts. Our work was conceived as an exploratory, hypothesis-generating pilot study, whose primary aim was to evaluate the feasibility of integrating routinely obtained clinicopathologic variables into a preliminary model for stratifying the risk of distant recurrence in right-sided colon cancer.1

We share the concerns they expressed about the risk of overfitting and the size of the sample. However, it is worth noting that our analysis was not an empiric comparison of multiple machine-learning algorithms, but rather the development of a simplified random forest model based on 4 clinically interpretable variables readily available in routine practice. Because it was a retrospective pilot study, a previous sample size calculation was not performed, and the size of the sample was determined by the cases that met the eligibility criteria during the study period. We recognize that the contemporary criteria for determining sample size in predictive models, such as those proposed by Riley et al., are essential for planning confirmatory studies and reinforce the exploratory interpretation of our findings.2

To reduce the risk of statistical optimism, the final model was limited to four clinically relevant and easily reproducible predictors: age, sex, lymphovascular invasion, and the number of lymph nodes evaluated. Likewise, internal evaluation strategies were employed, including class balancing through upsampling, 5-fold cross-validation, and learning curve analysis.1 Nevertheless, we realize that such measures reduce, but do not eliminate, the risk of overfitting, particularly in the presence of a limited number of events. Therefore, the results should not be interpreted as definitive evidence of immediate clinical applicability, but rather as an initial approach that requires external confirmation.

We also consider adherence to the TRIPOD+AI statement a relevant observation. In preparing our manuscript, we followed the STROBE guidelines for observational studies, as stated in the Methods section of the original article.1 However, we agree that the TRIPOD+AI provides a more specific and comprehensive framework for describing predictive models developed through regression or machine-learning methods, and clearly, should be adopted in future reports and validation studies on the model.3 This includes a detailed description of data preprocessing, missing data management, a class-balancing strategy, analytic flow reproducibility, and when possible, code availability. In our study, patients with incomplete clinicopathologic data were excluded, but in confirmatory studies, it will be necessary to carefully characterize the missing data pattern and assess its potential repercussions on the performance of the model.

We also agree that discrimination, measured through the area under the ROC curve (AUC), sensitivity, specificity, and F1 score, does not exhaust the assessment of a model’s clinical utility. Evaluation of the calibration, including the calibration intercept and slope, as well as that of the net benefit, measured through the decision curve analysis (DCA), are necessary steps before considering any clinical implementation.4 Because ours was a pilot cohort with a low absolute number of events, and a total of 13 recurrences, those analyses would have resulted in inaccurate and potentially unstable estimates.1 Consequently, they should be central components of methodological evaluation in larger cohorts.

Finally, we fully agree that no predictive model should be transferred to clinical practice without external validation in geographically and temporally independent cohorts, in accordance with the methodological principles described by Ramspek et al.5 This limitation was explicitly acknowledged in our manuscript and we believe that the next logical step is multicenter evaluation, ideally with the participation of various Latin American centers.1 This would enable not only the overall performance of the model, but also its calibration, reproducibility, clinical utility, and performance across different clinical subgroups and populations.

In conclusion, we appreciate the comments by Therán-León et al., which complement and strengthen the interpretation of our study. We reiterate that our model should be regarded as a preliminary, hypothesis-generating tool. Its primary value lies in proposing an approach based on clinically accessible variables for individual risk stratification. The model must be refined and externally validated before its application can be generalizable.

Authorship

All authors participated in the preparation or critical review of the response, approved its final version, and agree to its submission for publication.

Right to privacy and informed consent

No personal data, images, or information that could identify patients appear in this manuscript. Because no new data were used and no new research was conducted, obtaining additional informed consent was not necessary.

Data confidentiality

The response letter does not contain individual patient data or additional clinical information. Consequently, it does not include any information that could directly or indirectly identify any individual.

Funding

No specific grants were received from public sector agencies, the business sector, or non-profit organizations in relation to this article.

Conflict of interest

The authors declare that there is no conflict of interest.

References
[1]
R. Zayas-Bórquez, J. Canto-Losa, E. Posadas-Trujillo, et al.
Desarrollo de un modelo de aprendizaje automático para predecir recurrencia en el cáncer de colon derecho: estudio piloto retrospectivo unicéntrico.
Rev Gastroenterol Mex, 91 (2026), pp. 68-75
[2]
R.D. Riley, J. Ensor, K.I.E. Snell, et al.
Calculating the sample size required for developing a clinical prediction model.
[3]
G.S. Collins, K.G.M. Moons, P. Dhiman, et al.
TRIPOD+AI statement: updated guidance for reporting clinical prediction models that use regression or machine learning methods.
[4]
B. Van Calster, D.J. McLernon, M. van Smeden, et al.
Calibration: the Achilles heel of predictive analytics.
[5]
C.L. Ramspek, K.J. Jager, F.W. Dekker, et al.
External validation of prognostic models: what, why, how, when and where?.
Clin Kidney J, 14 (2021), pp. 49-58
Copyright © 2026. Asociación Mexicana de Gastroenterología
Download PDF
Idiomas
Revista de Gastroenterología de México
Article options
Tools