eComment. Surgery for isolated adrenal metastasis from non-small-cell lung cancer: the role of preoperative PET/CT scan"

Several studies have reported that a subset of non-small-lung cancer (NSCLC) patients with isolated adrenal metastasis achieves a long survival time through surgical resection of the primary lung cancer and adrenal metastasis [1–2].

In this setting, we have read with interest the recent article by Gao et al. [3] who have performed a systematic review and pooled analysis investigating outcomes and prognostic factors in this peculiar subset of NSCLC patients. The Authors performed a systematic review of the PubMed, Cochrane Library and Embase databases from January 1990 to July 2016. From a total of 440 pertinent studies, they restricted the analysis to 13 studies with a total number of 98 patients [3]. Negative prognostic factors were synchronous adrenal metastasis and lymph node involvement.

We completely agree with the Authors on the assumption that in oligometastatic selected NSCLC patients, an aggressive treatment based on surgical resection of both NSCLC and isolated metastases, combined with chemotherapy could represent a valid therapeutic option. We have reported [4] very rewarding outcomes in a cohort of 53 patients with oligometastatic NSCLC, especially in those cases where a complete resection of the primary tumour and radical control of the distant diseases could be accomplished.

In our study (recruitment period: 1997-2010), we found that a PET-CT scan in the preoperative diagnostic work-up was an independent positive prognostic factor, suggesting the relevance of a proper staging process in oligometastatic NSCLC patients.

In the pooled analysis of Gao et al. [3], the recruitment period of the 13 selected studies ranges from 1986 to 2011, with a small amount of cases in the "PET era". Indeed, as correctly remarked by the Authors themselves, the analysis could not avoid misdiagnosis of other organ metastases because PET/CT was not applied to all patients. In our opinion, this bias remains the main limitation of the analysis. Indeed, as also observed by de Pas and colleagues [5] oligometastatic NSCLC patients need to be screened by 18F-FDG PET/CT scan, because they represent a well-defined population that would indeed benefit from a more aggressive therapeutic strategy than that in the same class of disease but staged without FDG-PET. Therefore, further pooled analyses evaluating the long-term results of an aggressive surgical treatment in NSCLC patients with isolated adrenal gland metastases in the “PET area” are still needed to draft conclusive answers on this topic.

We would greatly appreciate the Authors reflections and reactions of the points raised.

Conflict of interest: none declared.

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