A conservative approach for subsolid lung nodules: is it safe enough?

Abstract

@ERSpublicationsA long-term follow-up strategy may be reasonable for subsolid nodules at low risk of progression based on CT features http://ow.ly/HasGFWith the foreseen dissemination of lung cancer screening with low-dose spiral computed tomography (LDCT), a great number of subjects will come to medical attention harbouring small, indeterminate pulmonary nodules [1]. Subsolid lung nodules (SSNs), also called ground-glass opacities or ground-glass nodules (GGNs), are identified in 2-3% of subjects receiving a screening LDCT [2,3]. Many of them have a benign aetiology and resolve spontaneously over time. However, unlike solid nodules that represent true lung cancer in a tiny fraction of patients, nonresolving SSNs are found to be histologically malignant in 30-70% of the cases [4,5]. For this reason, they are often considered for immediate resection. Nonetheless, recent reports [6,7] suggest that long-term observation of these patients may be appropriate.In this issue of the European Respiratory Journal (ERJ), the clinical course of 108 patients with persistent SSNs detected in the NELSON trial is reported [8], and a long-term follow-up approach is proposed on the grounds that the risk of progression of SSNs towards clinically significant lung cancer is extremely low. In principle, despite the high probability of SSNs being histologically malignant, their clinical behaviour tends to be indolent and surgical resection of all of them would therefore lead to a great number of lung resections with little real benefit, i.e. to overdiagnosis and overtreatment. However, given that progression may actually occur over time, a management plan should be devised and discussed on a case by case basis.Since the mid-1990s, when the association of subsolid nodules with early-stage bronchioloalveolar carcinoma was first reported [9,10], numerous publications have addressed the clinical significance of SSNs and their relationship with the spectrum of lung adenocarcinoma [11]. A good correlation between the aspect of SSNs on computed tomography (CT), their histological features of malignancy and clinical aggressiveness was observed in Japan a long time ago [12,13] and still has practical value today, although the pathology terms have been changed for the spectrum of lung adenocarcinoma.Pure GGNs of <10 mm are most likely benign atypical adenomatous hyperplasia or, more rarely, adenocarcinoma in situ (AIS). Pure GGNs measuring 10-30 mm reflect AIS or minimally invasive lepidic adenocarcinoma. A solid component in a GGN often reflects tumour invasion of the interstitium; the larger the solid part on CT, the larger the area of invasion [14,15]. The relative and absolute sizes of the solid component are also known to correlate with the probability of nodal metastasis, recurrence after surgery and death. Pure GGNs have virtually no probability of nodal involvement, whereas for part-solid nodules, the risk rises to about 15%, and to ∼30% for solid nodules [15,16].In a recent report on 145 patients with resected stage I lung adenocarcinom...

ESR/ERS statement paper on lung cancer screening

“…To date, few radiologists are trained for LCS. Education, training, certification and quality assurance of reading radiologists is warranted, notably to avoid overcalling, which might result in over-investigation of minor findings or overtreatment of findings that can be controlled by active surveillance [66,67]. A LCS certification programme has been prepared by the European Society of Thoracic Imaging, based on e-learning and workshops and validated by a final examination, in order to train radiologists in the specific task of LCS (www.myesti.org).…”

Managing of screening-detected sub-solid nodules—a European perspective

“…Notwithstanding these impressive results, several controversies still exist regarding overdiagnosis, false positives and the cost-effectiveness of a screening program. However, targeting those participants at highest risk of lung cancer using validated risk stratification models, helps to reduce the risk of overdiagnosis and false positives, and improves cost effectiveness (17)(18)(19). The lung nodule is the main target of LDCT during a screening trial: its size, location, multiplicity, density and imaging features at first diagnosis are the parameters that inform the diagnostic algorithm.…”

“…One of the more likely worries is the unnecessary treatment of benign lesions or indolent tumours, as the majority of sub solid nodules are. For this reason, subsolid nodules are one of the leading causes of overdiagnosis, over management, and overtreatment in lung cancer screening (19).…”

Surveillance of subsolid nodules avoids unnecessary resections in lung cancer screening: Long-term results of the prospective BioMILD trial

“…Non-solid nodules (NSNs, also referred to as ground-glass nodules) and part-solid nodules (PSNs), collectively referred to as subsolid nodules (SSNs), may contribute to overdiagnosis and overtreatment in LCS [7,11,12]. Found in approximately 9% of LCS participants [13,14], SSNs are associated with a higher rate of malignancy than solid nodules but, when malignant, tend to demonstrate a slower growth rate and lower risk for recurrence or metastatic disease than solid tumours [15][16][17].…”