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David Petrov
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P2.16 - Treatment of Early Stage/Localized Disease (Not CME Accredited Session) (ID 965)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall
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P2.16-20 - Prognostic Utility of PET in Non-Small Cell Lung Cancer After Empiric Stereotactic Body Radiotherapy (SBRT) (ID 11292)
16:45 - 18:00 | Author(s): David Petrov
- Abstract
Background
Positron emission tomography (PET-CT) is valuable for diagnosing early stage non-small cell lung cancer (NSCLC) in the absence of biopsy. Here we investigate the diagnostic, prognostic, and treatment response of PET-CT in NSCLC treated with empiric stereotactic body radiotherapy (SBRT).
a9ded1e5ce5d75814730bb4caaf49419 Method
We retrospectively reviewed 78 empiric lung SBRT cases with pre-treatment PET scans treated to biologic equivalent dose>100 Gy10. We correlated pre and post-treatment standard uptake values (SUV) with local, regional, and distant control. Statistical analysis was conducted via SPSS v20.
4c3880bb027f159e801041b1021e88e8 Result
A total of 44 males and 34 females median age 77 were treated to 48 Gy in 4 fractions (n=47) or 50 Gy in 5 fractions (n=31). Lung nodules were 1.6 cm (0.6–4.5 cm) with a median planning target volume of 19.1 cc (3.7-97.4 cc). Median pre-treatment SUV=4.1 (0-20). Of the 43 patients with post-treatment PETs, median SUV = 2.7(0-7.2) or 53%(0-302%) of the pretreatment SUV.
The median follow-up was 18 months with a 3-year survival of 50% for all patients. Local, regional, and distant control rates at 3 years were 91%, 81%, and 78%, respectively. Relative sisease control for pre-treatment SUV <4.0 compared to >4.0 is shown in Table 1:
Pre-treatment
SUV >4 vs < 4
Hazard Ratio (Confidence Interval)
P Value
Local Failure
5.92 (0.74 – 47.15)
0.08
Regional Failure
6.67 (1.86 – 23.98)
<0.01
Distant Failure
3.28 (1.02 – 10.55)
0.04
Overall Progression
3.62 (1.43 – 9.12)
<0.01
There was no difference in tumor size, location, nodule morphology, or prior cancer/smoking history between patients with pre-treatment SUV < 4 (n=40) and > 4 (n=38). Receiver operating characteristic curve analysis identified optimal SUV cutoff values of 6.0, 3.5, and 4.0 to predict local, regional, and distant failure, respectively. Post-SBRT PET scans with SUV reduction >50% demonstrated a 2-year freedom from progression of 89% compared to 57% with SUV reduction <50% (P=0.08).
8eea62084ca7e541d918e823422bd82e Conclusion
Our study demonstrates a strong correlation between initial PET avidity and regional/distant recurrence, and a trend with local recurrence. Perhaps patients with pretreatment SUV>4 warrant a mediastinal evaluation or closer vigilance in follow-up, though this warrants prospective investigation.
6f8b794f3246b0c1e1780bb4d4d5dc53
