Meta-analysis of survival after pulmonary resection for isolated metachronous pancreatic cancer metastasis: a promising, albeit infrequent, approach

BACKGROUND

To evaluate survival outcomes of pulmonary resection for isolated metachronous pancreatic cancer metastasis.

METHODS

A systematic search of electronic data sources and reference lists were conducted. Proportion meta-analysis model was constructed to quantify 1- to 5-year survival after pulmonary resection for isolated metachronous pancreatic cancer metastasis. Random-effects modelling was applied to calculate pooled outcome data.

RESULTS

Twenty-four retrospective studies were included reporting a total of 168 patients who underwent pulmonary resection for isolated pancreatic cancer metastasis. The nature of the index pancreatic surgery included 65% pancreaticoduodenectomies, 17.5% distal pancreatectomies, 0.5% total pancreatectomy, and 17% unspecified. Adjuvant chemotherapy was given to 88% of the patients. The median disease-free interval was 35 (8-96) months. The type of pulmonary resection included 54% wedge resections, 26% lobectomies, 4% segmentectomies, 1% pneumonectomies, and 15% unspecified. Pulmonary resection was associated with 1-year survival of 91.1% (95% CI 86.6%-95.5%), 2-year survival of 77.5% (95% CI 68.9%-86.0%), 3-year survival of 65.0% (95% CI 50.7%-79.3%), 4-year survival of 52.0% (95% CI 37.2%-66.9%), and 5-year survival of 37.0% (95% CI 25.0%-49.1%).

CONCLUSION

Pulmonary resection for isolated pancreatic cancer metastasis is associated with acceptable overall patient survival. We recommend selective pulmonary resection for isolated pulmonary metastasis from pancreatic cancer. Our findings may encourage conduction of better-quality studies in this context to help establishment of definitive treatment strategies.

Novel Indications for Surgical Resection of Metachronous Lung Metastases From Pancreatic Cancer After Curative Resection

Few reports exist regarding surgical resection of metachronous lung metastases (MLM) from pancreatic ductal adenocarcinoma (PDA) after curative resection. To elucidate the indications for surgical resection of MLM and long-term survival, we analyzed Japanese case reports of MLM from PDA. Between 1983 and 2014, 17 Japanese case reports concerning surgical resection of MLM from PDA were published. We determined long-term survival in 16 patients (considering the published data of 15 patients and 1 of our own) by using a questionnaire survey and analyzing the relationships between background factors and long-term survival. In 16 patients with long-term survival, 4 patients were still alive without recurrence. The remaining 12 patients died of disease after recurrence. The median survival after the initial lobectomy was 37 months and the 3- and 5-year survival for all patients after lobectomy was 50% and 41%, respectively. Fourteen patients had a disease-free interval after initial resection of the primary pancreatic tumor of >20 months. These patients had a longer median survival period after lobectomy (46 vs. 25.5 mo, P=0.19). Seven patients had MLM of <16 mm. These patients had a statistically longer overall survival after lobectomy (83 vs. 16 mo, P=0.04). Three of 4 patients with primary stage I tumors were still alive without recurrence. We found that the conventional criteria for surgical resection of MLM from PDA (first disease-free interval of >20 mo with no other metastatic lesions) were appropriate. In addition, it is possible that MLM of <16 mm or primary stage I tumors are novel criteria.