Cormac Thomas Farrelly MD, Presenter: Nothing to Disclose

Conleth Murphy MD, Abstract Co-Author: Nothing to Disclose

Derek Power, Abstract Co-Author: Nothing to Disclose

Ronan Andrew McDermott MBBCh, Abstract Co-Author: Nothing to Disclose

Kenneth O Byrne, Abstract Co-Author: Nothing to Disclose

MPM is a rapidly progressive mailgnancy with a mean survival time of 6-9 months.It is therefore important to establish early if chemotherapy is going to benefit the patient. Studies in non-small cell lung cancer and gastrointestinal stromal tumours suggest that positron emission tomography(PET)using F-18-Fluorodeoxyglucose (FDG) may predict the outcome of chemotherapy at an early stage of treatment. The aim was to assess if early PET scanning could be of similar benefit in Mailgnant Pleural Mesothelioma(MPM), correlating the results with standard computed tomography(CT) assessment. CT was used to measure the tumour thickness perpindicular to the chest wall at three different levels using the modified RECIST (response evaluation criteria in solid tumours) criteria.

Patients referred to a tertiary referral centre with histologically proven MPM, between January 1st 2004 and December 31st 2004 were included in this study. All were treated with pemetrexed 500mg/m2 and cisplatin or carboplatin. Baseline PET and CT scans were performed prior to treatment. Patients then proceeded to a second PET scan within three weeks of commencing the first course of treatment. Early PET response was compared with subsequent CT response during treatment and after six cycles if patients completed treatment. A positive PET scan correlated to a decrease of >20% in standard uptake value(SUV).

Nine patients were evaluated in this study. All nine of the patients had baseline and interval PET scans and baseline and interval CT scans. Four of the patients completed 6 cycles of chemotherapy, with evidence of a partial response on CT scan at the end of their treatment. Of these, 2 patients had a positive interval PET scan and 2 had a negative interval PET scan. Six patients showed either partial response or stable disease on their interval CT scan. Of these 3 had a positive PET response and 3 had a negative PET response.

Based on our data, early PET scanning within 3 weeks of commencing the first course of platin-based combination chemotherapy with pemetrexol, using SUV values for evaluation, does not predict subsequent CT evaluated reponse for patients with MPM.

Farrelly, C, Murphy, C, Power, D, McDermott, R, O Byrne, K, Does Early PET Scanning, within Three Weeks of Commencing Chemotherapy, Predict Later CT-evaluated Response for Patients with Malignant Pleural Mesothelioma?.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4419174.html