Development and validation of an individualized nomogram to identify occult peritoneal metastasis in patients with advanced gastric cancer
Menée auprès de 554 patients atteints d'un cancer gastrique de stade avancé, cette étude évalue la performance d'un nomogramme, basé notamment sur des données d'imagerie reflétant les caractéristiques de tumeurs primitives et de la région du péritoine, pour identifier des métastases péritonéales occultes
Background : Occult peritoneal metastasis (PM) in advanced gastric cancer (AGC) patients is highly possible to be missed on CT images. Patients with occult PMs are subject to late detection or even improper surgical treatment. We therefore aimed to develop a radiomic nomogram to preoperatively identify occult PMs in AGC patients.
Patients and methods : 554 AGC patients from four centers were divided into one training, one internal validation, and two external validation cohorts. All patients’ PM status was firstly diagnosed as negative by CT, but later confirmed by laparoscopy (PM positive n=122, PM negative n=432). Radiomic signatures reflecting phenotypes of the primary tumor (RS1) and peritoneum region (RS2) were built as predictors of PM from 266 quantitative image features. Individualized nomograms of PM status incorporating RS1, RS2, or clinical factors were developed and evaluated regarding prediction ability.
Results : RS1, RS2, and Lauren type were significant predictors of occult PM (all p<0.05). A nomogram of these three factors demonstrated better diagnostic accuracy than the model with RS1, RS2, or clinical factors alone (all net reclassification improvement p<0.05). The AUC yielded was 0.958 (95% confidence interval [CI]: 0.923-0.993), 0.941 (95% CI: 0.904-0.977), 0.928 (95% CI: 0.886-0.971), and 0.920 (95% CI: 0.862-0.978) for the training, internal, and two external validation cohorts, respectively. Stratification analysis showed that this nomogram had potential generalization ability.
Conclusion : CT phenotypes of both primary tumor and nearby peritoneum are significantly associated with occult PM status. A nomogram of these CT phenotypes and Lauren type has an excellent prediction ability of occult PM, and may have significant clinical implications on early detection of occult PM for AGC.
Annals of Oncology , article en libre accès, 2018