Predictors and outcome of complete removal of colorectal cancer with synchronous lung metastases

A CT-based radiomics approach to predict immediate response of radiofrequency ablation in colorectal cancer lung metastases

Objectives

To objectively and accurately assess the immediate efficacy of radiofrequency ablation (RFA) on colorectal cancer (CRC) lung metastases, the novel multimodal data fusion model based on radiomics features and clinical variables was developed.

Methods

This case-control single-center retrospective study included 479 lung metastases treated with RFA in 198 CRC patients. Clinical and radiological data before and intraoperative computed tomography (CT) scans were retrieved. The relative radiomics features were extracted from pre- and immediate post-RFA CT scans by maximum relevance and minimum redundancy algorithm (MRMRA). The Gaussian mixture model (GMM) was used to divide the data of the training dataset and testing dataset. In the process of modeling in the training set, radiomics model, clinical model and fusion model were built based on a random forest classifier. Finally, verification was carried out on an independent test dataset. The receiver operating characteristic curves (ROC) were drawn based on the obtained predicted scores, and the corresponding area under ROC curve (AUC), accuracy, sensitivity, and specificity were calculated and compared.

Results

Among the 479 pulmonary metastases, 379 had complete response (CR) ablation and 100 had incomplete response ablation. Three hundred eighty-six lesions were selected to construct a training dataset and 93 lesions to construct a testing dataset. The multivariate logistic regression analysis revealed cancer antigen 19-9 (CA19-9, p<0.001) and the location of the metastases (p< 0.05) as independent risk factors. Significant correlations were observed between complete ablation and 9 radiomics features. The best prediction performance was achieved with the proposed multimodal data fusion model integrating radiomic features and clinical variables with the highest accuracy (82.6%), AUC value (0.921), sensitivity (80.3%), and specificity (81.4%).

Conclusion

This novel multimodal data fusion model was demonstrated efficient for immediate efficacy evaluation after RFA for CRC lung metastases, which could benefit necessary complementary treatment.

Preoperative evaluation and indications for pulmonary metastasectomy

Pulmonary metastasectomy (PM) is an established treatment that can provide improved long-term survival for patients with metastatic tumor(s) in the lung. In the current era, where treatment options other than PM such as stereotactic body radiation therapy (SBRT), immunotherapy, and molecular-targeted therapy are available, thoracic surgeons should review the approach to the preoperative evaluation and the indications. Preoperative evaluation consists of history and physical examinations, physiological tests, and radiological examinations. Radiological examinations serve to identify the differential diagnosis of the pulmonary nodules, evaluate their precise number, location, and features, and search for extra thoracic metastases. The indication of PM should be considered from both physiological and oncological points of view. The general criteria for PM are as follows; (I) the patient has a good general condition, (II) the primary malignancy is controlled, (III) there is no other extrapulmonary metastases, and (IV) the pulmonary lesion(s) are thought to be completely resectable. In addition to the general eligibility criteria of PM, prognostic factors of each tumor type should be considered when deciding the indication for PM. When patients have multiple poor prognostic factors and/or a short disease-free interval (DFI), thoracic surgeons should not hesitate to observe the patient for a certain period before deciding on the indication for PM. A multidisciplinary discussion is needed in order to decide the indication for PM.

Prognostic value of KRAS mutation in patients undergoing pulmonary metastasectomy for colorectal cancer: A systematic review and meta-analysis

BACKGROUND

The purpose of the study was to evaluate whether KRAS mutation could be an independent prognostic biomarker in patients undergoing pulmonary metastasectomy (PM) for colorectal cancer (CRC).

METHODS

A systemic review was performed by searching online databases to identify studies reporting overall survival (OS) and recurrence free survival (RFS) of CRC patients undergoing PM. Pooled HRs were calculated for OS and RFS.

RESULTS

A total of 15233 patients from 60 studies were included. Pooled analysis showed that KRAS mutation was associated with worse OS (HR: 1.86, 95 % Cl: 1.35-2.57) and RFS (HR: 1.68, 95 % Cl: 1.38-2.04). A significant effect on OS and/or RFS was also shown by other 18 factors.

CONCLUSIONS

This meta-analysis found that KRAS mutation is an important prognostic predictor for OS and RFS in CRC patients undergoing PM, supporting a comprehensive model including clinicopathological and biological factors for optimal patients selection and prognosis for surgical treatment.

Oncological benefit of complete metastasectomy for simultaneous colorectal liver and lung metastases

BACKGROUND

The oncological benefit of complete metastasectomy for simultaneous colorectal liver and lung metastases (SLLM) have not been fully investigated.

METHODS

Patients undergoing initial hepatectomy for colorectal liver metastases (CLM) from 2005 to 2016 were divided into three groups: patients with isolated CLM undergoing complete resection (Group1, n = 317), SLLM undergoing complete metastasectomy (Group2, n = 33), and SLLM undergoing complete hepatectomy but incomplete lung resection (Group3, n = 20). A staged strategy (hepatectomy followed by lung resection) without interval chemotherapy was mainly applied for SLLM.

RESULTS

The 5-year overall survival rate of Group2 was significantly better than that of Group3 (71.7% vs. 10.2%, P < 0.001) and similar to that of Group1 (63.9%, P = 0.779). The 5-year disease-free survival rate was significantly worse in Group2 than Group1 (15.7% vs. 29.0%, P = 0.035). On multivariable analysis, CEA>200 ng/ml was the sole predictor of incomplete resection of lung metastases (odds ratio, 13.7; 95% confidence interval, 1.30-145; P = 0.011).

CONCLUSIONS

The prognosis in patients with SLLM who achieve complete metastasectomy is acceptable and might be improved by appropriate selection based on operative indications.

Prognostic impact of carcinoembryonic antigen and carbohydrate antigen 19-9 in stage IV colorectal cancer patients after R0 resection

BACKGROUND

Although preoperative carcinoembryonic antigen (pre-CEA) and carbohydrate antigen 19-9 (pre-CA 19-9) are reportedly prognostic indicators for colorectal cancer (CRC), the prognostic roles of postoperative CEA (post-CEA) and CA 19-9 (post-CA 19-9) shortly after surgery have not been clarified in patients with curatively resected stage IV CRC. The aim of this study was to evaluate the predictive abilities of post-CEA and post-CA 19-9.

METHODS

A total of 129 consecutive patients who had stage IV CRC and underwent R0 resection were retrospectively analyzed. Pre-CEA and post-CEA and CA 19-9 levels were measured within 1 mo before and 3 mo after surgery, respectively. Relapse-free survival (RFS) and overall survival were estimated using the Kaplan-Meier method, and multivariate analysis was performed using the Cox proportional hazards model.

RESULTS

Pre-CEA was elevated (≥5.0 ng/mL) in 73.6% of the patients and remained elevated after surgery in 32.7% of the patients. Elevated post-CA 19-9 (≥50 U/mL) was observed in 9.5% of the patients. Neither elevated pre-CEA nor elevated pre-CA 19-9 was significantly associated with RFS but both elevated post-CEA and elevated post-CA 19-9 were associated with markedly reduced RFS (P = 0.0002 and P = 0.0004, respectively). When considered in combination, post-CEA and post-CA 19-9 significantly stratified RFS and was an independent predictive factor for recurrence (P = 0.0035), as was lymphatic invasion (P = 0.0015). Post-CA 19-9 was the only evident independent predictive factor for overall survival (P = 0.0336).

CONCLUSIONS

In patients with stage IV CRC who underwent curative resection, the combination of post-CEA and post-CA 19-9 at 3 mo after surgery was a potent prognostic indicator for recurrence.