AJR: Preradiotherapy FDG PET modifies treatment in NSCLC

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Preradiotherapy FDG PET for non-small cell lung cancer (NSCLC) patients referred for 3D conformal radiotherapy may lead to significant modification of treatment strategy and radiotherapy planning, according to a prospective multicenter study published in the American Journal of Roentgenology.

The purpose of the large multicenter study was to quantify the impact of preradiotherapy 18F-FDG PET when deciding whether radiotherapy should be curative or palliative in intent and defining its detailed planning in patients with NSCLC referred for 3D conformal radical radiotherapy, according to Pascal Pommier, MD from the department of radiation oncology, Lyon University in Lyon, France, and colleagues.

Conventional CT and FDG PET were performed two to three weeks before radiotherapy was scheduled to start by the researchers. As an initial step, the medical team was asked to plan radiotherapy while blinded to the results of FDG PET. In a second step, the FDG PET data were revealed, and the medical team had to decide whether or not to confirm their radical radiotherapy strategy and, if so, whether any modifications were required to the treatment plan.

Of the 134 patients (79 percent with stage III disease) who were included in the analysis, 82 percent had received induction chemotherapy. Prechemotherapy FDG PET also was available for 25 patients.

Knowledge of preradiotherapy FDG PET data caused treatment to be cancelled or changed by the medical team from curative to palliative intent in 11 percent of the patients. “Of the 119 patients in whom radical radiotherapy was confirmed, the treatment plan was modified in 31 percent of the patients,” wrote Pommier and colleagues.

The concordance rate between the treatment strategies with or without preradiotherapy FDG PET was 62 percent. Concordance was improved but was still not complete (80 percent) when the prechemotherapy workup included FDG PET. Thus the addition of preradiotherapy FDG PET probably led to better selection of those patients likely to benefit from conformal radiotherapy, according to Pommier and colleagues.

“Our protocol did not address the question of long-term outcome and did not include the collection of data on the site of recurrence or overall survival. Therefore, whether the resulting modifications in the treatment plan will significantly improve tumor control and quality of life has still to be shown,” noted the authors.

The data from this multicenter study supported the use of preradiotherapy FDG PET when deciding on treatment strategy and planning radiotherapy in NSCLC, even if FDG PET had been performed at the initial workup, and that a prospective evaluation of patient outcome is warranted to assess the clinical relevance of this strategy, concluded Pommier and colleagues.