Impact of [18F]Fluorodeoxyglucose PET-CT Staging on Treatment Planning in Radiotherapy Incorporating Elective Nodal Irradiation for Non-Small-Cell Lung Cancer: A Prospective Study

Kolodziejczyk, Milena; Kepka, Lucyna; Dziuk, Miroslaw; Zawadzka, Anna; Szalus, Norbert; Gizewska, Agnieszka; Bujko, Krzysztof

doi:10.1016/j.ijrobp.2010.04.018

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Volume 80, Issue 4 , Pages 1008-1014, 15 July 2011

Impact of [¹⁸F]Fluorodeoxyglucose PET-CT Staging on Treatment Planning in Radiotherapy Incorporating Elective Nodal Irradiation for Non-Small-Cell Lung Cancer: A Prospective Study

Milena Kolodziejczyk, M.D.
- Department of Radiation Oncology, M. Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
Lucyna Kepka, M.D., Ph.D.
- Department of Radiation Oncology, M. Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
- Reprint requests to: Lucyna Kepka, M.D., Ph.D., Department of Radiation Oncology, M. Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, ul. Roentgena 5, 02-776 Warsaw, Poland. Tel: 48 22 5462076; Fax: 48 22 6439287
Miroslaw Dziuk, M.D., Ph.D.
- Mazovian PET-CT Center, Military Institute of Health Services, Warsaw, Poland
Anna Zawadzka
- Department of Medical Physics, M. Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
Norbert Szalus, M.D.
- Mazovian PET-CT Center, Military Institute of Health Services, Warsaw, Poland
Agnieszka Gizewska, M.D.
- Mazovian PET-CT Center, Military Institute of Health Services, Warsaw, Poland
Krzysztof Bujko, M.D., Ph.D.
- Department of Radiation Oncology, M. Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland

Received 20 December 2009; received in revised form 23 March 2010; accepted 1 April 2010. published online 26 July 2010.

Purpose

To evaluate prospectively how positron emission tomography (PET) information changes treatment plans for non-small-cell lung cancer (NSCLC) patients receiving or not receiving elective nodal irradiation (ENI).

Methods and Materials

One hundred consecutive patients referred for curative radiotherapy were included in the study. Treatment plans were carried out with CT data sets only. For stage III patients, mediastinal ENI was planned. Then, patients underwent PET-CT for diagnostic/planning purposes. PET/CT was fused with the CT data for final planning. New targets were delineated. For stage III patients with minimal N disease (N0-N1, single N2), the ENI was omitted in the new plans. Patients were treated according to the PET-based volumes and plans. The gross tumor volume (GTV)/planning tumor volume (PTV) and doses for critical structures were compared for both data sets. The doses for areas of potential geographical misses derived with the CT data set alone were compared in patients with and without initially planned ENI.

Results

In the 75 patients for whom the decision about curative radiotherapy was maintained after PET/CT, there would have been 20 cases (27%) with potential geographical misses by using the CT data set alone. Among them, 13 patients would receive ENI; of those patients, only 2 patients had the PET-based PTV covered by 90% isodose by using the plans based on CT alone, and the mean of the minimum dose within the missed GTV was 55% of the prescribed dose, while for 7 patients without ENI, it was 10% (p = 0.006). The lung, heart, and esophageal doses were significantly lower for plans with ENI omission than for plans with ENI use based on CT alone.

Conclusions

PET/CT should be incorporated in the planning of radiotherapy for NSCLC, even in the setting of ENI. However, if PET/CT is unavailable, ENI may to some extent compensate for an inadequate dose coverage resulting from diagnostic uncertainties.

Non-small-cell lung cancer, PET, Radiotherapy, Elective nodal irradiation