Metabolic (FDG-PET) response after radical radiotherapy/chemoradiotherapy for non-small cell lung cancer correlates with patterns of failure.

BACKGROUND

We previously reported that F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) response correlated strongly with survival after radical radiotherapy (RT)/chemoradiotherapy for non-small cell lung cancer (NSCLC). PET-response, survival and patterns of failure data are presented with long-term follow-up.

METHODS

Pre- and post-treatment FDG-PET scans were performed for 88 patients after concurrent platinum-based radical chemo/RT (n = 73) or radical RT alone (n = 15). PET responses were prospectively assessed as either complete metabolic response (CMR), partial metabolic response (PMR), stable metabolic disease (SMD), or progressive metabolic disease (PMD).

RESULTS

RT was 60 Gy in 30 fractions in 6 weeks. Follow-up PET was performed at a median of 70 days after treatment. PET responses were: CMR, n = 40 (45%); PMR, n = 32 (36%); SMD, n = 5 (6%) and PMD 11 (13%). Estimated median survival after follow-up PET was 23 months; median follow-up duration 35 months. One and 2 year survival after follow-up PET was 68% and 45%, respectively. Median survival for CMR and non-CMR patients was 31 and 11 months, respectively (p = 0.0001). One-year survival for CMR and non-CMR patients was 93% and 47%, respectively and 2 years survival was 62% and 30%, respectively. Excluding PMD patients, non-CMR patients had higher rates of local failure (HR 2.15, p = 0.009) and distant metastasis (HR 2.05, p = 0.041) than CMR patients. By last follow-up, 20 of 40 CR patients (50%) had PMD, with local failure (n = 8), distant metastasis (n = 2) or both (n = 10).

CONCLUSIONS

Attainment of CMR after radical RT/chemoRT for NSCLC bestows superior freedom from local and distant relapse; late local relapse is common.