Risk Factors for Survival after Lung Metastasectomy in Colorectal Cancer Patients: Systematic Review and Meta-Analysis

Abstract

Despite the lack of randomized trials, lung metastasectomy is currently proposed for colorectal cancer patients under certain conditions. Many retrospective studies have reported different prognostic factors of poorer survival, but eligibility for pulmonary metastasectomy remains determined by the complete resection of all pulmonary metastases. The aim of this review is to clarify which pre-operative risk factors reported in systematic reviews or meta-analysis are determinant for survival in colorectal metastatic patients. Different criteria have been now identified to select which patient will really benefit from lung metastasectomy.

Pulmonary metastasectomy: what is the practice and where is the evidence for effectiveness?: Table 1

“…6 CEA falls after curative resection, and its subsequent elevation is particularly associated with liver metastases. 6 An elevated CEA is associated with poor outcome after pulmonary metastasectomy for patients with CRC, 8 which has led to the paradoxical situation where CEA elevation may trigger investigations that lead to referral for pulmonary metastasectomy while the same blood test is later a reason to decide against metastasectomy. 9 Investigation and surgery triggered by CEA elevation have been shown to not improve survival.…”

Pulmonary metastasectomy in colorectal cancer: a prospective study of demography and clinical characteristics of 543 patients in the Spanish colorectal metastasectomy registry (GECMP-CCR)

“…The red lines demarcate the thresholds (an interval of less than 12 months and 3 or more metastases) beyond which outcomes were always poor in the Duke/MSK-CC experience. 13 The amber lines demarcate the thresholds in most of the meta-analyses by Gonzales et al, 3 again indicating the patients likely to recur above and to the right of the pair of lines. The factors which are favourable for survival (solitary metastasis and long interval) are to the bottom left of the graph where one might anticipate the concentration of patients to be.…”

“…Nevertheless, the authors conclude, 'it seems currently unfair to deny surgery for those patients with two to four lesions'. 3 This value laden statement depends on what is meant by 'unfair'. Some might think it unfair to be put through surgery when benefit is improbable.…”

“…The effect can be seen in figure 12 where surgeons select patients with fewer metastases but evidently are not able to restrict surgery to those with longer intervals. There can be no absolute threshold proposed along the time continuum but indicative intervals, below which long survival cannot be anticipated, are variably suggested at 12 months, 13 in the range of 19-39 months 3 and 36 months 7 in recent pooled analyses. Interpretation is made more difficult Figure 10 Proportion of patients in each centre who had liver metastases at the time of the primary resection (blue), appeared since the primary resection (maroon) or were present at the time of the pulmonary metastasectomy.…”

“…1 2 Belief in its effectiveness in improving survival relies on more than 90 surgical follow-up studies 3 going back to the 1960s 4 (figure 1). Several systematic reviews [3][4][5][6][7] have been published, the most recent in 2013 summing up the available evidence as follows: "There were no prospective randomized study, and most articles reported a single-center experience of fewer than 80 patients operated during a time period of 15-20 years." 3 While surgical removal of lung metastases is widely accepted to be beneficial 'in selected patients', it was argued more than 30 years ago that the perception of benefit may arise from the selection of favourable cases for surgery rather than a real benefit attributable to surgery.…”