The prognostic value of 18F-FDG PET/CT taken immediately after completion of radiotherapy for lung cancer treated with concurrent chemoradiotherapy: A pilot study

PURPOSE

The prognostic value of F-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) taken immediately after completion of radiotherapy in lung cancer patients is not well known. The purpose of this study is to assess the prognostic value of PET/CT taken immediately after completion of radiotherapy in lung cancer patients.

MATERIALS AND METHODS

Patients with primary lung cancer planned to undergo concurrent chemoradiotherapy were enrolled. Patients underwent PET/CT scans at 3 time points: before radiotherapy, within 24hours of completing radiotherapy (im-PET/CT), and 2-9 months after radiotherapy (post-PET/CT). Maximum standardized uptake value (SUV_max) was obtained. A post-PET/CT-SUV_max cut-off of 2.5 was determined as radiotherapy success.

RESULTS

Nineteen patients were enrolled. im-PET/CT-SUV_max for patients in the high post-PET/CT-SUV_max group was significantly higher than that of the low group (P=0.004). Receiver operator curve analysis indicated that im-PET/CT-SUV_max of 4.35 was an optimal cut-off value to discriminate between the two groups. Multivariable analysis showed that a high im-PET/CT-SUV_max was significantly associated with a high post-PET/CT-SUV_max (P=0.003).

CONCLUSION

PET/CT-SUV_max taken immediately following radiotherapy was associated with that evaluated 2-9 months after radiotherapy.

Is the Berg axillary lymph node categorization useful in the 3D Era

10643

Background: The Berg muscle-based categorization of axillary lymph node location has been used extensively by pathologists and surgeons to describe the extent of axillary node dissection in breast cancer patients, but its reproducibility with different arm positions and its utility in 3-D radiation treatment planning have not been tested. Methods: CT scans were obtained in 16 patients in 2 positions: historic position (HP), arms 90 degrees to the body axis; standard position (SP), arms above head. The volume, contents, and location of each Berg lymph node level (LNL) and the location of lymph nodes, surgical clips, pectoral muscles, and vascular structures relative to reference points were compared between the two scans. Results: Relative to T3, the LNL positions in SP were shifted from HP as follows: Level I, 23.1 mm anteriorly, p < 0.01; Level II, 7.5 mm medially, p = 0.04; Level III, 18.8 mm medially, p = 0.05. The pectoralis major and minor muscles were displaced medially (23.9 mm, p < 0.01 and 7.5 mm, p = 0.09) and anteriorly (18.2 mm, p < 0.01 and 11.2 mm, p < 0.01). At Level I, the axillary vessels (18.0 mm, p < 0.01), subscapular artery (25.4mm, p < 0.01) and lateral thoracic artery (8.4 mm, p < 0.01) were displaced anteriorly. With arm position change, lymph node position moved with vessel position rather than muscle position. Discrepancies were also observed in the number and location of lymph nodes (60%) and clips (66%) in given LNL’s between arm positions. Conclusions: Surgeons, radiologists, and radiation oncologists alike should be aware that lymph node position relative to muscle boundaries will vary significantly with arm position changes, making objective comparisons of information collected in different arm positions unreliable. This has significant implications for radiation treatment planning.

No significant financial relationships to disclose.