PET-CT-guided versus CT-guided biopsy in suspected malignant pleural thickening: a randomised trial

BACKGROUND

Pleural biopsy is the gold standard for diagnosis of pleural malignancy but a significant proportion will have an inconclusive biopsy despite ongoing clinical suspicion of malignancy. We investigated whether positron emission tomography-computed tomography (PET-CT) targeted pleural biopsy is superior to standard CT-guided pleural biopsy following an initial non-diagnostic biopsy.

METHODS

The TARGET trial was a multicentre, parallel group randomised trial. Patients with a previous inconclusive pleural biopsy but an ongoing suspicion of pleural malignancy were randomised (1:1) to receive either CT-guided biopsy (standard care) or PET-CT followed by a targeted CT biopsy (intervention). The primary outcome was pleural malignancy correctly identified from the trial biopsy.

RESULTS

Between September 2015 and September 2018, 59 participants were randomised from eight UK hospital sites: 29 to CT-only followed by targeted biopsy and 30 to PET-CT followed by targeted biopsy. The proportion of pleural malignancy correctly identified was similar between the groups (risk ratio 1.03 (95% CI 0.83-1.29); p=0.77). The sensitivity of the trial biopsy to identify pleural malignancy was 79% (95% CI 54-94%) in the CT-only group versus 81% (95% CI 54-96%) in the PET-CT group.

CONCLUSIONS

The results do not support the practice of PET-CT to guide pleural biopsies in patients with a previous non-diagnostic biopsy. The diagnostic sensitivity in the CT-only group was higher than anticipated and supports the practice of repeating a CT-guided biopsy following an inconclusive result if clinical suspicion of malignancy persists.

Is pleural infection associated with longer survival in mesothelioma? A population-based cohort study using data from Hospital Episode Statistics

BACKGROUND

Historically pleural infection was thought to be associated with longer survival in thoracic malignancies. The aim of this population-based cohort study was to investigate this hypothesis in mesothelioma, using national data from a high incidence country.

METHODS

Case records for all patients with mesothelioma seen in English hospitals between 01/01/2005 and 31/12/2014 were extracted from Hospital Episode Statistics using International Classification of Diseases Tenth Edition (ICD-10) codes. Episodes of pleural infection were identified. Linked mortality data was obtained from the Office of National Statistics. The primary outcome was all-cause mortality. The explanatory variable was pleural infection. Cox proportional hazards model was used to analyse survival, with pleural infection, chemotherapy and thoracic surgery handled as time-variable co-factors.

RESULTS

Of 22,215 patients with mesothelioma, 512 (2.3%) developed pleural infection at some point in their illness. Overall median survival was 7.0 months (IQR 2.3-16.4). Pleural infection was associated with shorter survival in the immediate post-infection period (up to 30 days - HR 1.81, 95% CI 1.45-2.22) and longer term (>30 days - HR 1.81, 95% CI 1.63-1.99). Other factors associated with increased mortality were age, male gender and being diagnosed as an inpatient. Receiving chemotherapy and being less economically deprived were associated with longer survival.

CONCLUSION

Pleural infection occurred in 2.3% of people with mesothelioma and was associated with shorter survival. This refutes previous reports suggesting pleural infection may be associated with better outcomes in thoracic malignancy.

Local Anaesthetic (Medical) Thoracoscopy Services in the UK

BACKGROUND

Local anaesthetic thoracoscopy (LAT) is an important procedure in the management pathway of patients with pleural effusions, particularly those with suspected malignancy. The last survey evaluating the use and development of LAT services in the UK was conducted over a decade ago.

OBJECTIVES

We performed a survey of LAT practices in the UK to explore procedural preferences and variations in practice.

METHODS

The online survey was cascaded via regional pleural specialists to sites performing LAT. One response per site was accepted.

RESULTS

Thirty-seven responses were received from England, Scotland and Wales. Most centres have regular access to a dedicated list and a designated area to perform LAT. 97% of the centres have at least 2 trained thoracoscopists. Some variation in practice is seen with patient preparation pre-procedure and medication use. Other procedures, such as insertion of indwelling pleural catheters and adhesiolysis, are not uncommon to be undertaken at the time of LAT.

CONCLUSIONS

Overall, the results are comparable, excepting some minor variations in patient preparation pre-procedure. We hope that this survey functions as an information resource for centres developing a LAT service or for those considering expansion.

Zoledronic acid in the management of mesothelioma - a feasibility study (Zol-A Trial): study protocol for a randomised controlled trial

BACKGROUND

Nitrogen containing bisphosphonates such as zoledronic acid (ZA) are known to contain certain anti-cancer properties. These have been investigated in the past in various cancers such as breast, prostate and colon. ZA in particular has shown promising results in pre-clinical studies. We propose a multicentre double-blind randomised controlled feasibility study to assess the recruitment and acceptability of ZA/placebo alongside chemotherapy in malignant pleural mesothelioma (MPM).

METHODS

Patients will be recruited for a 13-month period from October 2016 to November 2017. Eligible patients will be identified via the regional mesothelioma multidisciplinary team meeting. Those who receive chemotherapy will be randomised to receive either ZA or placebo alongside their chemotherapy. Those who decline chemotherapy will be offered to join the trial on the non-randomised open-labelled arm of the trial. Patients will receive a maximum of six cycles of ZA/placebo, at three-weekly cycles. All patients will be followed up for six months from randomisation. Semi-structured interviews to gather data on acceptability of trial procedures, tolerability of ZA and other relevant information will take place after the participants have completed their six cycles of treatment. For a better understanding about non-participation in mesothelioma trials we also aim to interview those who decline to take part in the trial.

DISCUSSION

The qualitative and quantitative data gathered in this feasibility trial will hopefully pave the way to designing a robust full phase III trial to investigate the potential synergistic effect of ZA and current standard treatment for MPM, cisplatin-pemetrexed combination chemotherapy.

TRIAL REGISTRATION

ISRCTN Registry, ISRCTN45536692 . Registered on 9 August 2016. EudraCT no. 2015-004433-26.

Randomised controlled trial to compare the diagnostic yield of positron emission tomography CT (PET-CT) TARGETed pleural biopsy versus CT-guided pleural biopsy in suspected pleural malignancy (TARGET trial)

Introduction

Pleural malignancy, particularly malignant pleural mesothelioma (MPM) is increasing in incidence due to the long latency period from exposure to asbestos to development of the disease. MPM can be challenging to diagnose. For patients presenting without a pleural effusion, CT-guided biopsy remains the primary choice of biopsy, but the diagnostic sensitivity of this investigation is 70%–75%. Therefore, a proportion of patients will go on to require further biopsies. If the first biopsy is non-diagnostic, the chances of further non-diagnostic biopsies are high in MPM.

Methods

Target is a multicentre randomised controlled trial, aiming to recruit 78 patients over a 30-month period, from 10 centres in the UK. Patients will be randomised to either the standard arm which is a second CT-guided biopsy, or the interventional arm, a positron emission tomography-CT scan followed by a targeted CT-guided biopsy. Patients will be followed up for 12 months (patients recruited in the last 6 months of recruitment will have 6 months of follow-up). MPM biomarker mesothelin will be checked at baseline, 6 month and 12 month follow-up appointments where patients are able to attend these appointments.

Ethics and dissemination

Ethical approval for this trial was granted by the South West—Exeter research and ethics committee (reference number 15/SW/0156). Results of the trial will be published in a peer-reviewed journal and presented at an international conference.

Trial registration number

ISRCTN14024829; Pre-results.

A prospective study to investigate the role of serial serum mesothelin in monitoring mesothelioma

Background

Radiological monitoring of malignant pleural mesothelioma (MPM) using modified RECIST criteria is limited by low sensitivity and inter-observer variability. Serial serum mesothelin measurement has shown utility in the assessment of treatment response during chemotherapy but has never been assessed in the longer term follow up of patients.

Methods

This is a single centre study of consecutive patients diagnosed with MPM who received chemotherapy or best supportive care (BSC). Serum mesothelin measurements with paired 6 monthly CT scans were performed following the completion of chemotherapy, or from baseline in the BSC group. Changes in mesothelin were correlated with radiological progression and overall survival.

Results

Forty-one patients with MPM were recruited and followed up for a minimum of 12 months (range 12–21 months). The majority of patients (n = 23) received chemotherapy with pemetrexed and cisplatin. Across the cohort a 10% rise in serum mesothelin could predict radiological progression with a sensitivity of 96% (IQR; 79–100) and specificity of 74% (IQR; 50–91). Sensitivity fell to 80% in sarcomatoid only disease. Patients with a rising mesothelin at 6 months had significantly worse overall survival (175 days) compared to stable/falling levels (448 days) (p = 0.003).

Conclusions

This is the first study to assess serum mesothelin’s ability to detect progression of MPM following chemotherapy or during BSC. A 10% rise in serum mesothelin level showed excellent sensitivity at predicting progressive disease. Mesothelin measurement has several advantages over serial CT imaging including reducing hospital visits and cost.

BTS guideline for the investigation and management of malignant pleural mesothelioma

The full guideline for the investigation and management of malignant pleural mesothelioma is published in Thorax. The following is a summary of the recommendations and good practice points. The sections referred to in the summary refer to the full guideline.

The physiological consequences of different distributions of diffuse pleural thickening on CT imaging

OBJECTIVE

Diffuse pleural thickening (DPT) refers to extensive visceral pleural fibrosis with adhesion formation to the parietal pleura obliterating the pleural space. The radiological definition of DPT remains controversial with most of the literature requiring the presence of an obliterated costophrenic angle (CPA) for defining DPT. We conducted a study to investigate the variable distributions of DPT and associated lung function deficit.

METHODS

85 patients referred to a pleural clinic with suspected pleural thickening were screened for our study. Data were collected from 37 patients with DPT confirmed on CT by size criteria (≥3 mm thick, ≥5 cm wide and ≥8 cm in length), and 21 controls with pleural plaques but no other pleuroparenchymal pathology. 27 patients were excluded. Groups were matched to age, body mass index and smoking history.

RESULTS

The percentage of predicted forced vital capacity showed a gradual decline from 98.9% for the control group to 83.5% in the DPT without CPA obliteration group (p < 0.05), to 79.5% in the unilateral DPT group (p < 0.001) and 66.7% in the bilateral group (p < 0.001). Similar reductions were seen in the percentage of predicted total lung capacity in the DPT with no CPA obliteration group and the bilateral DPT group.

CONCLUSION

Our study shows an incremental reduction in the forced vital capacity and total lung capacity in DPT without CPA obliteration, unilateral and bilateral DPT when compared with a matched control group. Advances in knowledge: Different distributions of DPT including no CPA obliteration can cause respiratory impairment, with bilateral DPT being the worst affected.

Pleural controversies: image guided biopsy vs. thoracoscopy for undiagnosed pleural effusions?

Undiagnosed pleural effusions present an increasing diagnostic burden upon healthcare providers internationally. The investigation of pleural effusions often requires the acquisition of tissue for histological analysis and diagnosis. Historically there were two options for tissue biopsy: a 'gold standard' surgical biopsy or a "blind" closed pleural biopsy. Over the last decade however, image-guided Tru-cut biopsies and local anaesthetic thoracoscopic (local anaesthetic thoracoscopy) biopsies have become more widespread. Image-guided techniques acquire samples under ultrasound (US) or computed tomography (CT) guidance whereas LAT involves the direct visualisation and biopsy of the pleura with pleuroscopy. Both techniques have been shown to be superior to 'blind' closed pleural biopsy for the diagnosis of pleural or metastatic malignancy. However, closed biopsy remains a viable method of investigation in areas of high incidence of tuberculosis (TB). Beyond this, each investigative technique has its own advantages and disadvantages. Image-guided biopsy is less invasive, usually carried out as an outpatient procedure, and enables tissue biopsy in frail patients and those with pleural thickening but no pleural fluid. Local anaesthetic thoracoscopy (LAT) provides diagnostic and therapeutic capabilities in one procedure. Large volume thoracentesis, multiple pleural biopsies and talc poudrage can be carried out in a single procedure. The overall diagnostic yield is similar for both techniques, although there are no large-scale direct comparisons. Both techniques share low complication rates.