To seed or not to seed: the open question of mesothelioma intervention tract metastases

An evaluation of the methodological quality of published guidelines for the surgical treatment of pleural mesothelioma

BACKGROUND

To benchmark their quality, a project was designed to analyze the methodology of previous guidelines and recommendations for malignant pleural mesothelioma projects.

METHODS

A narrative literature search was conducted, and each guideline was evaluated using the Appraisal of Guidelines for Research and Evaluation (AGREE) II tool and rated on a seven-point scale for its many items and domains.

RESULTS

Six guidelines that met the inclusion requirements were evaluated. Due to greater development rigor and editorial independence, the engagement of scientific societies was associated with an improvement in methodological quality.

CONCLUSION

According to the standards of AGREE II, the methodological quality of earlier guidelines was relatively low. Nonetheless, two previously published guidelines could serve as a template for the establishment of the most effective methodological quality guidelines.

Management of Pleural Effusion Secondary to Malignant Mesothelioma

Malignant pleural mesothelioma (MPM) is a highly aggressive pleural tumour which has been epidemiologically linked to occupational exposure to asbestos. MPM is often associated with pleural effusion, which is a common cause of morbidity and whose management remains a clinical challenge. In this review, we analysed the literature regarding the diagnosis and therapeutic options of pleural effusion secondary to mesothelioma. Our aim was to provide a comprehensive view on this subject, and a new algorithm was proposed as a practical aid to clinicians dealing with patients suffering from pleural effusion.

Tract metastasis in patients with long-term pleural catheter-computed tomography diagnosis and longitudinal assessment

OBJECTIVES

Long-term indwelling pleural catheters (IPC), used for the management of malignant pleural mesothelioma (MPM), may lead to catheter tract metastasis (CTM). While computed tomography (CT) is valuable for diagnosis, no studies have assessed CT manifestations of CTM. Our goal is to describe the incidence, CT appearances, and temporal evolution of CTM in MPM.

METHODS

A retrospective review of CT of 90 consecutive patients with MPM and IPC. In patients with CTM, a longitudinal assessment was performed for CT appearance at diagnosis and over time, interval from insertion to diagnosis and rate of progression.

RESULTS

The incidence of CTM was 26% (23/90), in 22 men (54-83 years, mean 73 years). CTM manifested with focal lesion (3 to 60 mm, mean 25 mm) in the subcutaneous tissue at the insertion site. Abnormalities of sub-adjacent skin and fat stranding were present in 16/24 (66%) and 11/24 (46%), respectively, enlargement of chest wall musculature in 11/24 (46%), and dilated subcutaneous vessels in 4/24 (17%) patients. On follow-up, 53% had enlargement of focal lesion. The average rate of progression was 3.5 mm/month, compared to 0.79 mm/month for pleural thickening (p = 0.03). The time between IPC insertion and CTM diagnosis varied from 58 to 1375 days (median 408 days); 83% occurred after IPC removal. Reporting radiologists described focal abnormality at the insertion site in only 9/23 (39%) patients.

CONCLUSIONS

CTM is commonly overlooked and underreported by radiologists. CT invariably demonstrates focal subcutaneous lesion in the procedure tract, most commonly after IPC removal. Ancillary findings, notably serratus or latissimus dorsi muscle enlargement, are novel finding that can assist in CT detection and diagnosis.

KEY POINTS

• Catheter tract metastasis (CTM), resulting from indwelling pleural catheter to manage malignant pleural mesothelioma, invariably manifested on CT as a focal subcutaneous lesion at the site of insertion, more commonly after catheter removal. • Ipsilateral muscle enlargement is a newly described CT finding that can assist in the detection and diagnosis. • Catheter tract metastasis was commonly overlooked by radiologists, reported in only 39% of cases.

Pleural mesothelioma: is the surgeon still there?

Malignant pleural mesothelioma (MPM) is a rare malignancy with some unique characteristics. Tumor biology is aggressive and prognosis is poor. Despite more knowledge on histology, tumor biology and staging, there is still a relevant discrepancy between clinical and pathologic staging resulting in difficult prediction of prognosis and treatment outcome, making treatment allocation more challenging than in most other malignancies. After years of nihilism in the late 80s, a period of activism started evaluating different treatment protocols combined with research driven mainly by academic centers; at the time, selection was based on histology and stage only. This period was important to gain knowledge about the disease. However, the interpretation of data was difficult since selection criteria and definitions varied substantially. Not surprisingly, until now there is no common agreement on best treatment even among specialists. Hence, a review of our current concepts is indicated and personalized treatment should become applicable in the future. Surgery was and still is an issue of debate. In principle, surgery is an effective approach as it allows macroscopic complete elimination of a tumor, which is relatively resistant to medical treatment. It helps to set the clock back and other therapies that have also just a limited effect can be applied sequentially before or after surgery. Furthermore, to date best long-term outcome is reported from surgical series in combination with other modalities. However, part of the community considers surgery associated with too high morbidity and mortality when balanced to the limited life expectancy. This criticism is understandable, since poor results after surgery are reported. The present article will review the indication for surgery and discuss the different procedures available for macroscopic complete resection-such as lung-preserving (extended) pleurectomy/decortication as well as extrapleural pneumonectomy to illustrate that 'The surgeon is still there!'

Video assisted thoracoscopic and open chest surgery in diagnosis and treatment of malignant pleural diseases

Parenchymal cancers of lung, breast, gastrointestinal tract and ovaries as well as lymphomas and mesotheliomas are among the most common cancer types causing malignant effusions, though almost all tumour types have been reported to cause a malignant effusion. The prognosis heavily depends on patients' response to systemic therapy however, regardless of the causing pathology and histopathologic form, malignant pleural disease is normally associated with a poor prognosis. To date, there are not sufficient data to allow accurate predictions of survival that would facilitate decision making for managing patients with malignant pleural diseases. Interventions are directed towards drainage of the effusion and, when appropriate, concurrent or subsequent pleurodesis or establishing long-term drainage to prevent re-accumulation. The rate of re-accumulation of the pleural effusion, the patient's prognosis, and the severity of the patient's symptoms should guide the subsequent choice of therapy. In contemporary medicine, not many cancers have managed to generate as intense debates concerning treatment, as malignant pleural mesothelioma. The relative advantages of surgery, radiation, chemotherapy and any combination of the three are continuously reassessed and reconsidered, even though not always based on scientific evidence. The aim of surgery in mesothelioma may be prolongation of life, in addition to palliation of symptoms. Longer recovery periods from more extensive surgical procedures could be justified, in carefully selected patients. Surgical options include: Video assisted thoracoscopic (VATS) pleurodesis, VATS partial pleurectomy (VATS PP)-both parietal and visceral; open pleurectomy decortication (PD)-with an extended option (EPD) and extrapleural pneumonectomy (EPP). Current evidence implies that EPD can be performed reliably in specialised centres with good results, both in terms of mortality and survival; however, no operation has yet been shown to be beneficial in a prospective randomized controlled clinical trial.

Indwelling Pleural Catheters: A Clinical Option in Trapped Lung

Malignant pleural effusion (MPE) symptoms have a real impact on quality of life. Surgical approach through video-assisted thoracic surgery provides a first step in palliation. In patients unfit for general anesthesia, awake pleuroscopy represents an alternative. Sclerosing agents can be administered at the bedside through a chest tube. Ideal treatment of MPE should include adequate long-term symptom relief, minimize hospitalization, and reduce adverse effects. Indwelling pleural catheter (IPC) allows outpatient management of MPE through periodic ambulatory fluid drainage. IPC offers advantages over pleurodesis in patients with poor functional status who cannot tolerate pleurodesis or in patients with trapped lungs.

Protocol for the surgical and large bore procedures in malignant pleural mesothelioma and radiotherapy trial (SMART Trial): an RCT evaluating whether prophylactic radiotherapy reduces the incidence of procedure tract metastases

INTRODUCTION

Patients with malignant pleural mesothelioma (MPM) may develop painful 'procedure tract metastasis' (PTM) at the site of previous pleural interventions. Prophylactic radiotherapy has been used to minimise this complication; however, three small randomised trials have shown conflicting results regarding its effectiveness. The surgical and large bore procedures in malignant pleural mesothelioma and radiotherapy trial (SMART Trial) is a suitably powered, multicentre, randomised controlled trial, designed to evaluate the efficacy of prophylactic radiotherapy within 42 days of pleural instrumentation in preventing the development of PTM in MPM.

METHODS AND ANALYSIS

203 patients with a histocytologically proven diagnosis of MPM, who have undergone a large bore pleural intervention (thoracic surgery, large bore chest drain, indwelling pleural catheter or local anaesthetic thoracoscopy) in the previous 35 days, will be recruited from UK hospitals. Patients will be randomised (1:1) to receive immediate radiotherapy (21 Gy in 3 fractions over 3 working days within 42 days of the pleural intervention) or deferred radiotherapy (21 Gy in 3 fractions over 3 working days given if a PTM develops). Patients will be followed up for 12 months. The primary outcome measure is the rate of PTM until death or 12 months (whichever is sooner), as defined by the presence of a clinically palpable nodule of at least 1 cm diameter felt within 7 cm of the margins of the procedure site as confirmed by two assessors. Secondary outcome measures include chest pain, quality of life, analgaesic requirements, healthcare utilisation and safety (including radiotherapy toxicity).

ETHICS AND DISSEMINATION

The trial has received ethical approval from the Southampton B Research Ethics Committee (11/SC/0408). There is a Trial Steering Committee, including independent members and a patient and public representative. The trial results will be published in a peer-reviewed journal and presented at international conferences.

TRIAL REGISTRATION NUMBER

ISRCTN72767336.