PET. Can we afford PET-CT. Positron annihilation. PET-CT scanner. PET detection

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1 PET-CT Can we afford PET-CT John Buscombe New technology Combines functional information-pet anatomical information-ct Machine able to perform both studies in single imaging episode PET imaging depends on positron decay PET Positron annihilation Positron Emission Tomography Positrons positively charged electrons Travel mm 1mm hit electron Annihilate e=mc 2 2 x 511 kev gammas produced travel at 180 degrees Detected by a ring of detectors Mainly used in cancer imaging PET detection PET-CT scanner 1

2 Inside a PET-CT scanner How a PET-CT is used Low dose whole body CT PET imaging in 2-4 blocks 5-8 minutes long Total imaging time about minutes Use of PET in staging FDG in Ca oesophagus What are the costs in PET-CT The machine (US$ 2.6-4million) Cost depends on CT with machine For localisation 2 slice sufficient Even though slower because of time taken with PET imaging will not add much to time of total acquisition For CT perfusion imaging 16 slice better For Cardiac PET-CT 64 slice needed Example of cardiac CT Costs of PET-CT Installation Needs a big room 3 phase power supply Air-con Space for control room, injection room patient waiting area (patients may need to be resting for 2 hours between injection and scan so if scan takes 20 minutes need 6 patient bays (beds not chairs) 2

3 Costs of PET-CT Delivery of isotope in UK Staff Here South Africa costs are low In USA/UK Costs are higher Radiopharmaceutical Most commonly used F-18 F FDG Cyclotron produced 2 hour half life Needs quick delivery Cost US$400-US$800 US$800 Though three cyclotrons would cover much of the main cities of SA in terms of delivery times of F-a8 FDG Many provinces would have little or no cover Delivery of isotope in UK Delivery of isotope in UK Though three cyclotrons would cover most of UK In fact 5 sites would cover over 97% of the population This is the actual situation Delivery of isotope in UK So how much does it cost This is the Plan for 2010 Depends on many factors but price per scan normally rated at between US$1000 and US$3000 South Africa will be closer to US$1000 UK in the middle, US and Germany closer to US$3000 3

4 Can PET-CT be afforbable Depends on how it is used Overall sensitivity and accuracy of PET-CT is normally 10-20% higher than CT or MRI This means that is may find sites of unexpected metastatic cancer Prevents expensive and unnecessary operations Look at example of lung cancer Can we trust PET-CT Prospective comparative study of staging with PET, PET-CT and CT alone Performed in Leuvan Belgium (de Wever et al Eur Radiol 2006) 50 patients with curable NSCLC studied Results compared with pathology at surgery Looked at local and distant nodes Local nodes PET-CT 80% vs 66% with CT Mets outside chest PET-CT 98% vs 88% with CT Correctly staged lung cancer De Wever Eur Radiol 2006 PET imaging in centres without PET service in the management of NSCLC.Is it cost effective? O Rourke E,Gnanasegaran G, Buscombe J R, *Riddleston M, Hilson A J W Dept of Nuclear Medicine and *Oncology Royal Free Hospital, London United Kingdom Material and methods Example 1 Eighteen patients [8 males, 10 females] with histologically proven NSCLC scanned 2004 Mean age: 71 years All the patients underwent whole body PET and CT scans of chest and upper abdomen PET scans were performed at a separate hospital Initial film left upper lobe consolidation Follow up film :Left upper lobe mass 4

5 Example 1 Example 1 CT Spiculated mass left upper lobe. No obvious mediastinal disease 18 FDG 347 MBq FDG-avid lesion LUL; FDG-avid lesion right hilum Lung cancer upstaged -> > inoperable Example 2 Example 2 Mass Left Base Mass left lower lobe, enlarged nodes AP window Example 2 Outcome of 18 patients with potentially curable non-small cell lung cancer 18 patients with curable disease? PET-CT scan 18 FDG PET 350 MBq FDG avid mass left lower lobe Mediastinum normal. Case downstaged 2 PET-CT positive in mediastinum 2 with distant metastasis in 12 months 8 operated on 6 PET-CT negative for metastasis 0 evidence of recurrence at 12 months 10 positive for metastases on PET-CT no operation 2 die in next 12 months 5

6 Conclusion PET was shown to change patient s s operability state in 7/18 (39%) Total saving of approx US$60,000 in this small patient group US$3,300 per patient If systematically used in UK would save US$20 million/year PET is a cost effective method in the management of NSCLC even in units where there is no on site PET service available How does this compare with other centres Using PET to prevent surgery on inoperable patients Sloka et al Newfoundland Canada, Med Sci Monitor 2004 Using F-18 F FDG PET in pre-op assessment of NSCLC Using PET/CT to correctly identify curable patient saves US$1500/patient Results from Australia Yap et al EJNM 2005 Austin Melbourne Looked at 200 patients with potentially operable NSCLC 100 staged with mediastinoscopy 100 with FDG PET and medistinoscopy if PET positive Even though sensitivity of FDG PET was only 3% higher than CT and there was only a 5% reduction on futile medistinoscopies Total saving per patient was still US$2000 Other cancer sites in which PET_CT can be used in staging Oesophagus Stomach Colon Ovary Not useful for Prostate Breast Pancreas, HCC How else to save money with PET-CT Many treatments for cancer are expensive Those that work are more expensive Rituximab US$32,000 per year Gemcitabine US$24,000 per year Also these drugs have marked side effects PET can be used to predict early on in the treatment if it is likely to work If evidence no working treatment should be stopped Has the treatment worked Treatments for haematological malignancies expensive Side effects severe including a deth rate of about 10-15% 15% Need to know was the treatment worth it? Should we continue? CT unhelpful-residual mass 6

7 Residual mass in axilla POST-TREATMENT TREATMENT EVALUATION Jerusalem et al, Blood, patients (NHL + HD) Median follow-up: 23 months Positive predictive value: 100% Negative predictive value: 83% Progression free survival related to PET response Proportion surviving progression-free (%) Negative PET 40 Positive PET 20 P< Duration (months) EARLY TREATMENT EVALUATION PET predicts prognosis after 1 cycle Kostakoglu et al, 1-22 cycles Torizuka 2 cycles Zijlstra et al, 2-33 cycles Jerusalem et al, 2-44 cycles Mikhaeel et al, 3-44 cycles Spaepen et al, J.Nucl.Med.,., 2002 Torizuka et al, EJNMMI, 2003 et al, Br.J.Haematol.,., 2003 Jerusalem et al, Haematologica,, 2000 et al, Leuk.. Lymphoma, 2000 Spaepen et al, Ann. Oncol., 2002 F-18 FDG PET after 1st cycle in ABVD in HD 18 F- FDG PET after 1 cycle vs after completion of chemotherapy Category Relapse Remission Total Median PFS (mo) After 1 cycle 18 F-FDG 18 F-FDG PET+ PET Not reached After completion 18 F-FDG 18 F-FDG PET+ PET Not reached Kostakoglu et al, J Nucl Med

8 Potential savings CR rate in HD about 60-70% Therefore at least 30% chemo wasted Cost per cycle about US$2000 including drugs and administration (not side effects) If chemo not given after 1 st cycle if F-18 F FDG positive saving per patient is US$10000 On average saving in 100 HD patients would be US$100,000 Conclusions PET-CT looks like an expensive test However it high accuracy means it can be relied on to decide management In just 2 diseases lung cancer and lymphoma the correct use of PET-CT saves money Therefore can we afford to live without PET-CT? 8