Effects of radiotherapy planning with a dedicated combined PET-CT-simulator of patients with non-small cell lung cancer on dose limiting normal tissues and radiation dose-escalation: A planning study

doi:10.1016/j.radonc.2005.06.014

Radiotherapy and Oncology

Volume 77, Issue 1, October 2005, Pages 5-10

https://doi.org/10.1016/j.radonc.2005.06.014 Get rights and content

Abstract

Background and purpose

To investigate the effect of radiotherapy planning with a dedicated combined PET-CT simulator of patients with locally advanced non-small cell lung cancer.

Patients and methods

Twenty-one patients underwent a pre-treatment simulation on a dedicated hybrid PET-CT-simulator. For each patient, two 3D conformal treatment plans were made: one with a CT based PTV and one with a PET-CT based PTV, both to deliver 60 Gy in 30 fractions. The maximum tolerable prescribed radiation dose for CT versus PET-CT PTV was calculated based on constraints for the lung, the oesophagus, and the spinal cord, and the Tumour Control Probability (TCP) was estimated.

Results

For the same toxicity levels of the lung, oesophagus and spinal cord, the dose could be increased from 55.2±2.0 Gy with CT planning to 68.9±3.3 Gy with the use of PET-CT (P=0.002), with corresponding TCP's of 6.3±1.5% for CT and 24.0±5.6% for PET-CT planning (P=0.01).

Conclusions

The use of a combined dedicated PET-CT-simulator reduced radiation exposure of the oesophagus and the lung, and thus allowed significant radiation dose escalation whilst respecting all relevant normal tissue constraints.

Introduction

Although the prognosis of patients suffering from stage III non-small cell lung cancer (NSCLC) has improved, local tumour control is still not achieved in the majority of the patients [6], [8], [16], [17]. The latter can probably be achieved by increasing the radiation dose, but this is hampered by unacceptable normal tissue toxicity such as pneumonitis and oesophagitis [6], [8], [14], [16], [17]. An obvious way to lessen the side effects of radiotherapy is to reduce the size of the radiation fields. We previously showed that selective mediastinal irradiation on the basis of the ¹⁸F-Fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) scan, did not result in a high incidence of isolated nodal failures [7]. As the diagnostic accuracy of combined PET-CT scanners is higher than that of each modality alone, we hypothesised that radiotherapy planning using a dedicated combined PET-CT simulator would decrease radiation exposure to dose-limiting normal organs such as the lungs and the oesophagus [1], [13]. This would allow dose escalation and hence increase the tumour control probability (TCP). We therefore compared simulation with a dedicated combined PET-CT simulator with CT planning in 21 consecutive patients with locally advanced NSCLC. For each plan, radiation dose escalation for CT versus PET-CT was calculated based on constraints for lung, oesophagus and spinal cord toxicity. The impact of this dose escalation on TCP was estimated using the dose-response parameters from Martel et al. [14].

Section snippets

Patients

Following the introduction of a dedicated combined PET-CT-simulator in our institution, the first 21 patients suffering from pathologically proven NSCLC that were referred for radical radiotherapy were prospectively studied. Mixed pathologies between non-small cell carcinoma and small cell carcinoma and bronchioloalveolar carcinoma were excluded. All patients had to show a significant FDG uptake in their primary tumour. Mediastinal lymph nodes were considered to be pathological on the CT scan

Patient characteristics and FDG-PET and CT correlations

All but one of the twenty-one patients had N2 or N3 disease on CT scan. CT-stage distribution was stage I: 0 patient, stage II: 1 patient, stage IIIA: 16 patients and stage IIIB: 4 patients. The FDG-PET-CT staging was stage I: 3 patients, stage II: 1 patient, stage IIIA: 13 patients and stage IIIB: 4 patients. None of the patients had atelectasis. The lymph node involvement based on CT vs. PET-CT is given in Table 1.

Oesophageal radiation exposure (Table 2)

Incorporating PET-CT scan information led to a significant decrease of all

Discussion

With the use of conventional radiation techniques, the lungs and the oesophagus are often the dose-limiting organs for radiation dose escalation in NSCLC [6], [8], [14], [16], [17]. Reducing the lung and oesophageal radiation exposure is therefore potentially of great clinical importance. In a previous modelling study, we showed that incorporation of FDG-PET scan data into radiotherapy planning in NSCLC patients with N2/N3 disease allowed a significant reduction of the radiation exposure of the

Acknowledgements

We conclude that the use of a combined dedicated PET-CT-simulator reduced radiation exposure of the oesophagus and the lung, and thus may allow significant radiation dose escalation whilst respecting all relevant normal tissue constraints.

References (20)

J. Bradley et al.
Impact of FDG-PET on radiation therapy volume delineation in non-small-cell lung cancer
Int J Radiat Oncol Biol Phys
(2004)
C.B. Caldwell et al.
provide the 3D extent of tumor motion for individualized internal target volumes? A phantom study of the limitations of CT and the promise of PET
Int J Radiat Oncol Biol Phys
(2003)
I.F. Ciernik et al.
Radiation treatment planning with an integrated positron emission and computer tomography (PET/CT): a feasibility study
Int J Radiat Oncol Biol Phys
(2003)
M.V. Graham et al.
Clinical dose–volume histogram analysis for pneumonitis after 3D treatment for non-small cell lung cancer (NSCLC)
Int J Radiat Oncol Biol Phys
(1999)
S.L. Kwa et al.
Radiation pneumonitis as a function of mean lung dose: an analysis of pooled data from 540 patients
Int J Radiat Oncol Biol Phys
(1998)
M. Martel et al.
Estimation of tumor control probability model parameters from 3-D dose distributions of non-small cell lung cancer patients
Lung Cancer
(1999)
M.I. Saunders et al.
Continuous, hyperfractionated, accelerated radiotherapy (CHART) versus conventional radiotherapy in non-small cell lung cancer: mature data from the randomised multi-center trial
Radiother Oncol
(1999)
W. Sause et al.
Final results of phase III trial in regionally advanced unresectable non-small cell lung cancer: Radiation Therapy Oncology Group Eastern Cooperative Oncology Group, and Southwest Oncology Group
Chest
(2000)
S. Senan et al.
Literature-based recommendations for treatment planning and execution for high-precision radiotherapy in lung cancer
Radiother Oncol
(2004)
G. Antoch et al.
Non-small cell lung cancer: dual-modality PET/CT in preoperative staging
Radiology
(2003)

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^☆: Parts of this study have been presented at the Annual Meeting of the European Society for Therapeutic Radiology and Oncology (ESTRO), Amsterdam, 2004.

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PET-CT based planningEffects of radiotherapy planning with a dedicated combined PET-CT-simulator of patients with non-small cell lung cancer on dose limiting normal tissues and radiation dose-escalation: A planning study☆

Abstract

Background and purpose

Patients and methods

Results

Conclusions

Introduction

Section snippets

Patients

Patient characteristics and FDG-PET and CT correlations

Oesophageal radiation exposure (Table 2)

Discussion

Acknowledgements

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Lung Cancer

Radiother Oncol

Chest

Radiother Oncol

Non-small cell lung cancer: dual-modality PET/CT in preoperative staging

Radiology

PET-CT based planning
Effects of radiotherapy planning with a dedicated combined PET-CT-simulator of patients with non-small cell lung cancer on dose limiting normal tissues and radiation dose-escalation: A planning study☆