Illustrative AI review sample — oncology

Key Points

1SEER-based cohort of 3,003 stage IV colorectal cancer patients identifying prognostic factors after metastatectomy; STROBE-relevant gaps in confounding adjustment, competing-risk analysis, and subgroup multiplicity weaken the causal interpretation of key findings.

Major Issues

Methods: SEER lacks data on systemic chemotherapy and targeted agents (e.g., FOLFOX, FOLFIRI, bevacizumab, cetuximab); omission of treatment covariates introduces substantial unmeasured confounding, as treatment selection drives OS independently of surgical resection.

Statistics: Competing-risk analysis for non–cancer-specific death is absent; in older stage IV CRC patients, non-cancer death is non-trivial and the standard Kaplan–Meier estimator over-estimates cancer mortality risk when competing events are common.

Statistics: Proportional hazards assumption is not tested; given the long follow-up (up to 8 years), time-varying effects of stage and site are plausible and should be checked with Schoenfeld residuals or log–log plots.

Results / Discussion: At least eight subgroup comparisons are reported without multiple-testing correction, inflating familywise type-I error; statistically significant subgroup differences should be interpreted as hypothesis-generating only.

Discussion: Causal interpretation language ('liver metastases resection leads to better survival') is applied to an observational SEER dataset without accounting for selection bias, immortal-time effects, or indication bias inherent in who receives surgical resection.

Prognostic Factors in Stage IV Colorectal Cancer Patients With Resection of Liver and/or Pulmonary Metastases: A Population-Based Cohort Study

Key Points

Major Issues