Can Surgical Resection of Metastatic Lesions Be Beneficial to Pancreatic Ductal Adenocarcinoma Patients with Isolated Lung Metastasis?

SIMPLE SUMMARY: With the development of chemotherapy, studies have been conducted on the possibility of conversion surgery in metastatic pancreatic ductal adenocarcinoma (PDAC) patients. In addition, studies with large-scale public data have reported that patients with isolated lung metastasis have a good prognosis and can benefit from survival through surgical treatment. Our study aims to evaluate the effect of metastatectomy and prognostic factors in PDAC patients with isolated lung metastasis by analyzing the data from 1342 patients in our institution. We showed that PDAC patients with isolated lung metastasis who underwent metastatectomy seemed to have better survival when compared with patients who underwent only chemotherapy or supportive care. In addition, we performed the analysis using the National Cancer Database for external validation purposes and found consistent results compared to our analysis. Our findings suggest that PDAC patients with isolated lung metastasis should be considered for multimodal therapy with chemotherapy and surgical treatment. ABSTRACT: In the era of effective chemotherapy on pancreatic ductal adenocarcinoma (PDAC) with distant metastasis, data on the effects of metastatectomy are lacking. So, we investigated the effect of metastatectomy on survival after metastasis in PDAC patients with isolated lung metastasis. This retrospective study analyzed 1342 patients who were histologically diagnosed with PDAC with distant metastasis from January 2007 to December 2018, of which 83 patients had isolated pulmonary metastasis. Additionally, 4263 patients were extracted from the National Cancer Database (NCDB) and analyzed. Log-rank test and Kaplan−Meier survival analysis were used to analyze survival after metastasis. The five-year survival rate was significantly higher in patients who underwent pulmonary metastatectomy than in those who received only chemotherapy or supportive treatment (60.6% vs. 6.2% vs. 0.0%, p < 0.001). A similar trend was observed in the NCDB (two-year survival rate, 27.4% vs. 15.8% vs. 4.7%, p < 0.001). In the multivariate analysis, lung lesion multiplicity (hazard ratio (HR) = 2.004, p = 0.017), metastatectomy (HR = 0.278, p = 0.036), chemotherapy (HR = 0.434, p = 0.024), and chemotherapy cycles (HR = 0.300, p < 0.001) had significant effects on survival. Metastatectomy with primary pancreatic lesions is recommended with effective chemotherapy in PDAC patients with isolated lung metastasis.