Pre-op PET/CT predicts stage I NSCLC adjuvant chemotherapy benefit

By Lynda Williams, Senior medwireNews Reporter

Preoperative imaging could help guide the use of postoperative adjuvant chemotherapy in patients with early non-small-cell lung cancer (NSCLC), Japanese researchers believe.

Morihito Okada and co-workers, from Hiroshima University, investigated whether 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) results were significantly associated with the outcomes of patients with stage T1b–2a NSCLC who were free from node and metastatic disease.

The study included 174 patients with completely resected tumours, of whom 90 received adjuvant tegafur–uracil or platinum-based chemotherapy and 84 did not.

Patients given adjuvant chemotherapy were significantly more likely than controls to achieve a 3-year recurrence-free interval (RFI, 90.6 vs 74.8%) and overall survival (OS, 95.4 vs 84.0%) than those who were not, the team reports in TheAnnals of Thoracic Surgery.

In multivariate analysis, a preoperative FDG-PET/CT maximum standardised uptake value (SUVmax) of 2.6 or higher significantly predicted RFI (hazard ratio [HR]=8.03), whereas tumour size greater than 30 mm, and pleural, vascular or lymphatic invasion were not significantly associated with RFI.

Further analysis revealed that among patients with an SUVmax of at least 2.6, those given adjuvant chemotherapy were significantly more likely than controls to achieve 3-year RFI (82.8 vs 44.8%) and OS (93.0 vs 68.6%).

However, for patients with an SUVmax below 2.6, adjuvant chemotherapy was not associated with significantly better survival.

The researchers suggest that tumour size was not a significant predictor of outcome in their study because only participants with tumours with a diameter of 2 cm to 5 cm were included.

Moreover, FDG uptake is associated with tumour growth in lung cancer, they explain.

“We suggest that not only tumor size but also the nature of the tumor defined by FDG-PET/CT imaging could predict the effectiveness of adjuvant chemotherapy”, write Okada et al.

They conclude: “Patients who are likely to derive a greater benefit from adjuvant chemotherapy might be differentiated using SUV_max together with pathologic staging and T status.”

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