Application of Tumor Burden Score for predicting conversion outcome in patients with initially unresectable colorectal liver metastases after first-line systemic therapy

Abstract

Background: Patients with initially unresectable colorectal liver metastases (CRLM) could achieve survival benefit from successful conversion therapy. Recently, Tumor Burden Score (TBS) was proposed as a valuable index to predict outcome following resection of CRLM. The study is aimed to investigate the association of TBS with conversion outcome. Methods: A total of 234 patients who underwent first-line treatment in our center were enrolled as training cohort. The validation cohort was developed from 89 patients in our previous study. Cut-off value of TBS was calculated to stratify patients into two groups. Significance test and logistic regression model were used to examine the prediction value of TBS for conversion outcome after first-line systemic therapy. Kaplan–Meier method and Cox proportional hazard model were applied to assess the prognostic value of TBS. Results: TBS showed good discriminatory power [area under curve (AUC) 0.726, p < 0.001] with cut-off value defined as 14.3 in training cohort, which was validated in the validation cohort. Increasing TBS was related to adverse chemotherapy response and conversion outcome. Low TBS group had three times higher conversion rate than that in high TBS group (57.3% versus 19.0%, p < 0.001). Multivariate analysis indicated that high TBS [odds ratio (OR) = 3.676, 95% confidence interval (CI) 1.671–8.429, p = 0.002], first-line treatment response as stable disease (SD) or progressive disease (PD) (OR = 9.247; 95% CI 4.736–18.846, p < 0.001), and absence of targeted therapy (OR = 2.453, 95% CI 1.139–5.455, p = 0.024) were three independent risk factors for failure conversion outcome. High TBS was significantly associated with conversion outcome whatever chemotherapy response, addition of targeted therapy, and Kirsten rat sarcoma viral oncogene homolog (KRAS) status. High TBS was also associated with worse overall survival. Conclusion: TBS should be applied in clinical practice to predict conversion outcome in patients with initially unresectable CRLM.

Prognostic factors associated with early recurrence following liver resection for colorectal liver metastases: a systematic review and meta-analysis

“…Tumor size and number were frequently treated as dichotomous variables, with varying cutoff values, leading to heterogeneity across studies. However, these two variables can be used to calculate the tumor burden score (TBS) [TBS 2 = (maximum tumor diameter) 2 + (number of liver lesions) 2 ], and the predictive efficacy of this index has been proved to exhibit higher specificity and sensitivity compared to relying solely on tumor size and number in patients with CRLM [ 54 , 55 ]. Preoperative radiological imaging can provide first indications about the risk of ER, especially gadoxetate disodium-enhanced magnetic resonance imaging (EOB-MRI) can provide greater sensitivity [ 56 ].…”

PIVKA‐II combined with tumor burden score to predict long‐term outcomes of AFP‐negative hepatocellular carcinoma patients after liver resection

“…13 The predictive value of TBS was then further confirmed in many solid tumors as well, including HCC. [37][38][39] Tsilimigras DI et al based on a multicenter retrospective study and demonstrated that TBS could stratify the OS of HCC patients within BCLC 0/A/B and may identify patients in BCLC B who maybe candidates for resection. 14 Some studies also reported that TBS was independently associated with recurrence of HCC patients after liver resection.…”

“…first proposed tumor burden score (TBS, treat tumor size and number as continuous variables) to differentiate the prognosis of colorectal liver metastasis patients after surgery 13 . The predictive value of TBS was then further confirmed in many solid tumors as well, including HCC 37–39 . Tsilimigras DI et al.…”

Multimodal Management of Colorectal Liver Metastases: State of the Art

“…The TBS is based on radiographic features of CRLMs, involving tumor size and number of liver metastasis [ 104 , 105 ]. Of note, the “low-TBS” has a 3-fold higher conversion rate than the “high- TBS”, which tends to have both worse objective response and conversion outcomes [ 106 ]. Different chemotherapy regimens can be used to convert the resectable state ( Table 4 ), including doublet or triplet combinations (oxaliplatin- and/or irinotecan-based regimen) with or without targeted therapy, although the best regimen has not yet been defined.…”