857P - Interim [18F] fluorodeoxyglucose positron emission tomography (PET) for early metabolic assessment of response to PEB chemotherapy for metastatic s...

Date 27 September 2014
Event ESMO 2014
Session Poster Display session
Topics Anti-Cancer Agents & Biologic Therapy
Germ Cell Tumours
Imaging, Diagnosis and Staging
Presenter Patrizia Giannatempo
Citation Annals of Oncology (2014) 25 (suppl_4): iv280-iv304. 10.1093/annonc/mdu337
Authors P. Giannatempo1, A. Alessi2, D. Raggi1, E. Farè1, S. Tana3, N. Nicolai4, G. Serafini2, M. Marongiu1, B. Padovano2, L. Piva5, D. Biasoni5, T. Torelli5, M. Catanzaro5, S. Stagni5, M. Maffezzini5, A.M. Gianni6, L. Mariani7, R. Salvioni4, F. Crippa8, A. Necchi1
  • 1Medical Oncology/urology Unit, Fondazione IRCCS - Istituto Nazionale dei Tumori, 20133 - Milano/IT
  • 2Nuclear Medicine - Pet Unit, Fondazione IRCCS - Istituto Nazionale dei Tumori, 20133 - Milano/IT
  • 3Radiation Oncology, Fondazione IRCCS - Istituto Nazionale dei Tumori, 20133 - Milano/IT
  • 4Surgery Urology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, 20133 - Milan/IT
  • 5Surgery - Urology Unit, Fondazione IRCCS - Istituto Nazionale dei Tumori, 20133 - Milano/IT
  • 6Medical Oncology, Fondazione IRCCS - Istituto Nazionale dei Tumori, 20133 - milan/IT
  • 7Clinical Epidemiology And Trials Organization Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, 20133 - Milano/IT
  • 8Nuclear Medicine - Pet Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, 20133 - Milano/IT

Abstract

Aim

A risk-adapted strategy for metastatic seminoma may further refine the necessary burden of chemotherapy while sparing futile treatment for early recognized good responders. The objective of this proof-of-principle study was to evaluate the association of an early metabolic response to PEB and the dimensional response at the end of treatment.

Methods

Patients (pts) with newly-diagnosed seminoma and who were candidate to PEB were staged at baseline by computed tomography (CT), PET and serum tumor markers (STM). Then, restaging with PET after 2 cycles of PEB (PET2), and with CT after treatment (3-4 cycles [CT3-4]) were provided. One (greatest) target lesion was chosen to evaluate metabolic/dimensional changes in each case. The primary endpoint was the association between PET2 (EORTC criteria) and CT3-4 response. Secondary endpoints were progression-free survival (PFS) and ability to detect visceral metastases. An analysis after the initial 35 pts was planned.

Results

In the time-frame 06/2010-11/2013, 35 pts have been enrolled in this single-site study. Two pts had CSIIA, 12 CSIIB, 13 CSIIC, and 8 CSIII. 3 had an intermediate prognosis because of liver (1) and bone (2) disease. These two were recognized by PET while having a bone-negative CT scan. 4 had a retroperitoneal and 1 a mediastinal primary. All pts had a PET-positive target disease (retroperitoneal in 33 and mediastinal in 2). After 2 cycles of PEB, 25 pts (71.4%) had a metabolic complete response (CR), 10 a partial response (PR). 10 pts had a CR at CT3-4. PET2-negative pts had a significantly smaller residual disease at CT3-4 scan (median 1.2 cm [IQR: 2.8-6] vs 4 cm [IQR: 1-1.9], p < 0.001 at Mann-Whitney test) as well as a significantly greater shrinkage at CT3-4 compared to baseline (median 6 cm [IQR: 4.4-6.5] vs 2.85 [IQR: 1.5-6], p = 0.026). 6 pts further received RT, 1/10 pt progressed and received II line treatment. After a median follow up of 14.8 months (IQR: 10.9-30.1), all pts are alive.

Conclusions

PET2 early identified pts having the greatest response to chemotherapy and who finally reached the cut off for observation only (<3cm). Also, baseline PET was able to identify bony disease in 2/35 pts otherwise categorized with a good prognosis. These findings warrant further investigation and provide the rationale for an expansion cohort aimed to analyze the association with PFS.

Disclosure

All authors have declared no conflicts of interest.