Prevention of malignant seeding at drain sites after invasive procedures (surgery and/or thoracoscopy) by hypofractionated radiotherapy in patients with pleural mesothelioma

Chinese expert consensus on the diagnosis and treatment of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a malignant tumor originating from the pleura, and its incidence has been increasing in recent years. Due to the insidious onset and strong local invasiveness of MPM, most patients are diagnosed in the late stage and early screening and treatment for high-risk populations are crucial. The treatment of MPM mainly includes surgery, chemotherapy, and radiotherapy. Immunotherapy and electric field therapy have also been applied, leading to further improvements in patient survival. The Mesothelioma Group of the Yangtze River Delta Lung Cancer Cooperation Group (East China LUng caNcer Group, ECLUNG; Youth Committee) developed a national consensus on the clinical diagnosis and treatment of MPM based on existing clinical research evidence and the opinions of national experts. This consensus aims to promote the homogenization and standardization of MPM diagnosis and treatment in China, covering epidemiology, diagnosis, treatment, and follow-up.

Incidence and Risk Factors of Chest Wall Metastasis at Biopsy Sites in Patients with Malignant Pleural Mesothelioma

To investigate the incidence and risk factors of chest wall metastasis (CWM) at biopsy sites in patients with malignant pleural mesothelioma (MPM). This retrospective cohort study was conducted in 262 consecutive MPM patients who underwent multimodal treatment in which including neoadjuvant chemotherapy (NAC) and curative-intent surgery, from August 2009 to March 2021. CWM was evaluated radiologically (r-CWM) and pathologically (p-CWM). We also investigated the risk factors of p-CWM and the consistency between r-CWM and p-CWM. Of 262 patients, 25 patients were excluded from analysis due to missing data or impossibility of evaluation. Of the eligible 237 patients, pleural biopsy was performed via video-assisted thoracoscopic surgery in 197 (83.1%) and medical thoracoscopy in 40 (16.9%). Pleurodesis was performed after pleural biopsy in 74 patients (31.2%). All patients received NAC followed by curative-intent surgery. Radiological examination showed r-CWM in 43 patients (18.1%), while pathological examination showed p-CWM in 135 patients (57.0%). The incidence of p-CWM was significantly higher in the patients who received pleurodesis after pleural biopsy (77.0% vs. 47.9%, <0.001). Multivariate logistic regression analysis for p-CWM revealed that pleurodesis is an independent risk factor of p-CWM (adjusted hazard ratio, 3.46; 95% confidence interval, 1.84−6.52, <0.001). CWM at the biopsy site was pathologically proven in more than half of the patients (57.0%) who received NAC followed by curative-intent surgery, which was higher than the numbers diagnosed by radiological examinations (p-CWM: 57.0% vs. r-CWM: 18.1%). Pleurodesis after pleural biopsy is an independent risk factor of p-CWM.

Prophylactic procedure tract radiotherapy for malignant pleural mesothelioma: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Malignant pleural mesothelioma (MPM) is an aggressive cancer with a propensity for seeding procedure tracts, leading to symptomatic metastases. There is conflicting evidence on the value of prophylactic procedure tract radiotherapy in reducing tract metastases. We performed a systematic review and meta-analysis to estimate the benefit of radiotherapy in this setting.

MATERIALS AND METHODS

Electronic databases were searched to January 1, 2018 for prospective randomized control trials with prophylactic procedure tract radiotherapy as the intervention arm. Pooled odds ratios and 95% confidence intervals were calculated using a random effects model. Study heterogeneity was assessed using the I2 statistic, and publication bias was evaluated by funnel plot and Egger's regression model.

RESULTS

Five studies were included for meta-analysis. Prophylactic radiotherapy did not have a statistically significant reduction on the risk of procedure site recurrence, with a pooled relative risk of 0.69 (95% CI 0.33-1.43). There was moderate heterogeneity between trials. All trials were assessed as moderate or high risk of bias overall.

CONCLUSION

This systematic review has confirmed that there is no role for prophylactic procedure tract radiotherapy in MPM. In the absence of effective prophylactic procedures, patients need to be monitored closely, and palliative interventions delivered in a timely manner to reduce morbidity associated with procedure tract metastases.

Prophylactic radiotherapy for procedure tract metastases in mesothelioma: a review

PURPOSE OF REVIEW

Malignant pleural mesothelioma is an aggressive malignancy with a very poor prognosis. The majority of patients require pleural procedures for diagnostic or fluid management purposes. Damage to the pleura during these procedures can lead to procedure tract metastases (PTMs), with increasing risk from larger interventions. Prophylactic radiotherapy to these sites is a controversial topic with conflicting results from trial data. In this review, we summarize the recent evidence.

RECENT FINDINGS

Four RCTs have been published on this topic, with another in follow-up. The earliest, from a cohort of 40 patients, strongly advocated the use of prophylactic radiotherapy. More recent trials, most notably the Surgical and large bore procedures in Malignant pleural mesothelioma And Radiotherapy Trial (SMART) (which randomized over 200 patients) did not demonstrate any benefit, especially when patient report symptoms and cost-effectiveness are considered. Certain subgroups demand further investigation, such as those not receiving systematic chemotherapy or with surgical intervention sites. The soon to be published Prophylactic Irradiation of Tracts (PIT) trial may help to further clarify best practice.

SUMMARY

Recent studies have shown that prophylactic radiotherapy should not be routinely used to prevent PTMs in mesothelioma. Instead patients should undergo careful clinical follow-up to ensure PTMs are identified and treated promptly to minimize symptoms.

Isolated Chest Wall Implantation of Non-Small Cell Lung Cancer after Fine-Needle Aspiration: A Case Report and Review of the Literature

Percutaneous fine-needle aspiration biopsy (FNAB) is a well-established and useful procedure in the diagnosis of lung squamous cell carcinoma (LSCC). Tumor seeding has been shown to be a potential risk. We report the case and management of a 78-year-old patient affected by LSCC who developed a chest wall metastasis in a straight line from the primary lesion along the FNAB needle track. Although tumor seeding after FNAB is a rare but possible complication, we suggest that careful examination for implantation (with periodical CT scans) should be performed for at least three years after FNAB.

[Prophylactic radiotherapy in a single fraction of 10Gy at intervention pleural site in patient with malignant pleural mesothelioma: A retrospective monocentric cohort study]

PURPOSE

Prophylactic radiotherapy to prevent procedure-tracts metastases from malignant pleural mesothelioma remains controversial and clinical practice varies. The purpose was to assess the efficacy of local radiotherapy in a single fraction of 10Gy in preventing malignant seeding at intervention pleural site in patients with malignant pleural mesothelioma.

MATERIAL AND METHODS

This is a retrospective cohort study, including patients with histological confirmed malignant pleural mesothelioma treated by prophylactic irradiation to prevent interventional site metastases with a unique fraction of 10Gy with 6 to 18MeV, from January 1990 to December 2013 in the institut de cancérologie de Lorraine (Nancy, France).

RESULTS

Ninety-one patients were treated by irradiation in intervention site, involving 120 intervention pleural sites, 91 thoracoscopies, 17 thoracotomies with chest drain and 12 CT or ultrasound guided needle biopsies. The median follow-up was 7 months (interquartile between 3 and 15 months). The overall survival was 43.5% at 12 months. The local progression free survival was 43.7% at 12 month. The incidence of local recurrence was 8% at 12 months. The median interval from radiotherapy to local recurrence was 4 months (2; 32). No grade II or higher toxicity was observed.

CONCLUSION

Irradiation of pleural intervention sites with a single fraction of 10Gy is effective, well tolerated, simple, fast and cost effective.

Malignant Mesothelioma Mimicking Invasive Mammary Carcinoma in a Male Breast

Malignant mesothelioma is an uncommon tumor with strong association with asbestos exposure. Few cases of malignant pleural mesothelioma metastatic to the female breast have been reported. Herein, we presented, for the first time, a case of locally infiltrating malignant pleural mesothelioma forming a mass in the breast of a male as the first pathologically confirmed manifestation of the disease. Breast ultrasound revealed an irregular mass in the right breast which involves the pectoralis muscle. Breast core biopsy revealed a proliferation of neoplastic epithelioid cells mimicking an infiltrating pleomorphic lobular carcinoma. IHC studies showed the cells to be positive for calretinin, CK5/6, WT1, and CK7. The cells were negative for MOC-31, BerEp4, ER, and PR. A final diagnosis of malignant mesothelioma, epithelioid type, was rendered. This case demonstrates the importance of considering a broad differential diagnosis in the setting of atypical presentation with application of a panel of IHC markers.

Prophylactic irradiation of intervention sites in malignant pleural mesothelioma

BACKGROUND AND PURPOSE

To assess the effectiveness of prophylactic irradiation of intervention track (PIT) to prevent tumor seeding in patients with malignant pleural mesothelioma.

MATERIALS AND METHODS

A retrospective review was conducted of 171 patients with a histological diagnosis of pleural mesothelioma with some undergoing prophylactic irradiation of intervention sites.

RESULTS

Forty-eight patients (28%) received PIT. A majority of patients were followed until death. Thoracoscopy (88%) was the procedure most often performed. Thirty-three percent of patients received chemotherapy. The median dose of PIT was 21 Gy in 3 fractions with electrons or 6 MV photons. The local progression free survival (LPFS) at the intervention site was significantly higher in the PIT group and was not influenced by chemotherapy. At 6 months, LPFS for the intervention sites was 91% with PIT and 74% without PIT (p=0.002). During the follow-up, 6 patients (13%) in the PIT group had tumor invasion of the subcutaneous tissue compared to 40 patients (33%) in the group without PIT (p=0.008).

CONCLUSIONS

This study suggests that PIT in mesothelioma reduces the incidence of procedure tract metastasis. Finally, chemotherapy does not seem to have an influence on the incidence of tract metastasis.

Should all patients who have mesothelioma diagnosed by video-assisted thoracoscopic surgery have their intervention sites irradiated?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was whether patients diagnosed with mesothelioma by video-assisted thoracoscopic surgery should have their intervention sites irradiated to prevent metastatic seeding. Altogether 334 papers were found using the reported search, of which nine represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. There is no general consensus in the literature. Four studies recommend prophylactic irradiation therapy (PIT), while three studies stated that PIT was unnecessary. A systematic review identified only three suitable randomized controlled trials (RCTs) from the literature. One trial found that 23% of radiotherapy (RT) patients developed tract metastases compared to 10% of control patients (P=0.748) with an estimated hazard ratio (RT to control) of 1.28 (95% CI: 0.29-5.73). Time from procedure to tract metastases was in fact shorter in patients treated with RT (2.4 months RT vs. 6.4 months control, non-significant). Another trial found that seeding of metastatic tumour to the intervention site occurred in 7% of RT sites vs. 10% of control sites (P=0.53). Freedom from tract metastasis survival was also non-significant between RT and control arms (P=0.82). However, the third trial reported a significantly greater incidence of intervention site metastases in control vs. RT patients (40% vs. 0%, respectively, P<0.001). Non-randomised studies found mixed results. One reported that median survival between patients with and without local metastases was not significantly different (P=0.64) while another article described no local metastases in PIT sites. None of the studies reported significant skin or side reactions and treatment was generally well tolerated. Based on the available evidence, we conclude that PIT is not currently justified.

What is the role of radiotherapy in malignant pleural mesothelioma?

OBJECTIVE

A review of the evidence supporting the use of radiotherapy in patients with mesothelioma was performed.

METHODS

Relevant publications were searched for on Medline.

RESULTS

In a Medline search on radiotherapy and mesothelioma, 611 hits were obtained. A limited number of prospective phase II trials of radiotherapy as part of trimodality protocols for early disease and in the palliation of pain were found, along with three small randomized controlled trials of port-site prophylaxis.

CONCLUSION

No randomized data exist to support the use of radiotherapy after radical surgery, although there are a large number of publications describing its use as an integral part of therapy, including seven phase II studies. One ongoing trial is randomizing patients to radiotherapy or not after extrapleural pneumonectomy. None of these studies provided any assessment of radiotherapy independent of the other modalities investigated, nor did any formally assess intensity-modulated radiotherapy. There have been several reports of excessive toxicity with this technique, and its use should be limited to phase I studies until the basis of this toxicity is better understood. Three trials have looked at port-site prophylaxis, one supporting its use and two showing no evidence of benefit. Two studies addressed pain control prospectively, one showing definite but short-lived benefits. Implications. Radiotherapy is widely used in treating mesothelioma with little supporting evidence. More randomized trials are required to justify this use in all three common settings for its use.

Prophylactic radiotherapy to intervention sites in mesothelioma: a systematic review and survey of UK practice

BACKGROUND AND PURPOSE

Patients with malignant pleural mesothelioma (MPM), who undergo chest instrumentation, may develop seeding at the site of intervention, leading to subcutaneous tumour. This is believed to be reduced by the common practice of prophylactic irradiation to intervention tracts (PIT). However, evidence to support PIT is currently inadequate and contentious.

MATERIALS AND METHODS

We carried out a systematic search of published literature for articles relating to the incidence of chest wall intervention tract metastases and the use of PIT in mesothelioma. In addition, a survey of current practice was conducted in 54 UK oncology centres.

RESULTS

Fourteen studies revealed an incidence of chest wall intervention tract metastases of 0-48% with a trend toward a higher rate of metastases for more invasive procedures. Three randomised controlled trials (RCTs), two prospective non-randomised studies and five retrospective series met the eligibility criteria to evaluate the role of PIT in MPM. Of the three RCTs, two did not support the use of PIT. None of the RCTs included patients who had received systemic chemotherapy. Of the oncology centres responding to the survey, 75% practiced PIT, and 80% would be interested in a trial to determine the efficacy of PIT.

CONCLUSIONS

No consensus has been reached to support the use of PIT. However, most centres in the UK still offer PIT. There was widespread interest in a randomised controlled trial to establish PIT efficacy in the era of effective systemic chemotherapy for malignant pleural mesothelioma.