Influence of Surveillance PET/CT on Detection of Early Recurrence After Definitive Radiation in Stage III Non-small-cell Lung Cancer

Abstract

Background: There are few data to support the use of varying imaging modalities in evaluating recurrence in non-small-cell lung cancer (NSCLC). We compared the efficacy of surveillance positron emission tomography (PET)/computed tomography (CT) versus CT scans of the chest in detecting recurrences after definitive radiation for NSCLC.

Materials and methods: We retrospectively analyzed 200 patients treated between 2000 and 2011 who met the inclusion criteria of stage III NSCLC, completion of definitive radiation treatment, and absence of recurrence within the initial 6 months. These patients were then grouped on the basis of the use of PET/CT imaging during postradiation surveillance. Patients who received ≥ 1 PET/CT scans within 6 months of the end of radiation treatment were placed in the PET group whereas all others were placed in the CT group. We compared survival times from the end of treatment to the date of death or last follow-up using log rank tests. Multivariate analysis was conducted to identify factors associated with decreased survival.

Results: In the entire cohort, median event-free survival (EFS) was 26.7 months, and median overall survival (OS) was 41.2 months. The CT group had a median EFS of 21.4 months versus 29.4 months for the PET group (P = .59). There was no difference in OS between the CT and PET groups (median OS of 41.2 and 41.3 months, respectively; P = .59). There was also no difference in local recurrence-free survival or distant metastases-free survival between the CT-only and PET/CT groups (P = .92 and P = .30, respectively). Similarly, in multivariate analysis, stratification into the PET group was not associated with improved EFS (hazard ratio [HR], 0.90; 95% confidence interval [CI], 0.61-1.34; P = .60) or OS (HR, 1.2; 95% CI, 0.83-1.7; P = .34).

Conclusions: In stage III NSCLC patients treated with definitive radiation and without early recurrence, PET/CT scan surveillance did not result in decreased time to detection of locoregional or distant recurrence or improved survival.

Keywords: CT; Lung cancer; PET/CT; Radiation; Recurrence; Surveillance.

Figure 1

A) Study diagram depicting initial patient cohort followed by exclusion criteria. B) Post-treatment CT:PET/CT ratio over time.

Figure 1

A) Study diagram depicting initial patient cohort followed by exclusion criteria. B) Post-treatment CT:PET/CT ratio over time.

Figure 2

A) Overall survival, B) Event-free survival, C) Local recurrence-free survival, and D) Distant metastasis-free survival stratified based on imaging group.

Figure 2

A) Overall survival, B) Event-free survival, C) Local recurrence-free survival, and D) Distant metastasis-free survival stratified based on imaging group.

Figure 2

A) Overall survival, B) Event-free survival, C) Local recurrence-free survival, and D) Distant metastasis-free survival stratified based on imaging group.

Figure 2

A) Overall survival, B) Event-free survival, C) Local recurrence-free survival, and D) Distant metastasis-free survival stratified based on imaging group.