Reply: Optimal follow-up duration for nonspecific pleuritis: how long is long enough?

Extract

We welcome your correspondence “Optimal follow-up duration for nonspecific pleuritis: how long is long enough?”, submitted in response to our article “Investigation and outcomes in patients with non-specific pleuritis: results from the International Collaborative Effusion Database” [1].

Shareable abstract

∼8% of patients with nonspecific pleuritis histology at time of thoracoscopy develop a pleural malignancy. 12-month follow-up may not be adequate when there is a risk of pleural mesothelioma. In such cases, follow-up duration should be extended. https://bit.ly/47blcuA

Reply to S. Ozyavuz and colleagues:

We welcome your correspondence “Optimal follow-up duration for nonspecific pleuritis: how long is long enough?”, submitted in response to our article “Investigation and outcomes in patients with non-specific pleuritis: results from the International Collaborative Effusion Database” [1].

We are pleased that our study has helped stimulate further discussion on the important and often challenging clinical finding of nonspecific pleuritis (NSP). By presenting a representative case from your institution you aptly demonstrate the real-world difficulties and uncertainties involved in managing these patients.

Whilst NSP remains a common histological finding at thoracoscopy – reported in up to 40% of cases across several series – its natural history is poorly understood. This uncertainty is particularly relevant when considering the proportion of patients who may ultimately develop pleural malignancy, and how long these individuals should be followed-up.

In our cohort, 6% eventually developed malignancy, which closely aligns with the pooled prevalence reported in the literature (8%) [2]. However, determining the optimal duration of follow-up remains a clinical challenge. While most malignancies in our study were diagnosed within 12 months, we observed cases as late as 32 months. Notably, as in your case, the majority of these delayed diagnoses were pleural mesothelioma (PM), underscoring the need for prolonged surveillance when PM is suspected or considered of particularly high risk. This aligns with current recommendations from the ERS Taskforce on benign pleural effusions and supports your conclusions.

Looking ahead, in tandem with clinical studies, we must do more to understand the natural history and biology underpinning NSP, with a view to clarifying why some patients develop malignancy whilst others do not, and to creating radiomic serum biomarkers which are of clinical use in this population. Recent recognition of mesothelioma in-situ as a pre-cursor to PM by both the World Health Organization and the International Association for the Study of Lung Cancer, identified by specific diagnostic markers, is a step forward [3, 4]. We are hopeful that initiatives such as the PREDICT-Meso project will help address key knowledge gaps, enabling improved risk-stratification and the development of future preventative approaches for patients diagnosed with NSP [5].

We thank the authors for their thoughtful correspondence and for drawing further attention to this often overlooked but clinically significant entity.