Monitoring and management of lung cancer patients following curative-intent treatment: clinical utility of 2-deoxy-2-[fluorine-18]fluoro-d-glucose positron emission tomography/computed tomography

Clinical Value of Surveillance 18F-fluorodeoxyglucose PET/CT for Detecting Unsuspected Recurrence or Second Primary Cancer in Non-Small Cell Lung Cancer after Curative Therapy

Simple Summary

Non-small cell lung cancer (NSCLC) patients are at considerable risk of recurrence or second primary cancer (SPC) after curative therapy. The utility of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) surveillance to detect recurrent lesions in NSCLC patients without suspicion of recurrence has not been established. The aim of our retrospective study was to evaluate the diagnostic value of surveillance FDG PET/CT for detecting clinically unsuspected recurrence or SPC in patients with NSCLC after curative therapy. In a cohort of 2684 NSCLC patients after curative therapy, surveillance FDG PET/CT showed good diagnostic efficacy for detecting clinically unexpected recurrence or SPC. Furthermore, the diagnostic performance was improved in subgroups of patients with advanced stage prior to curative therapy, PET/CT scans performed within 3 years after curative-intent therapy, and curative surgery. Surveillance PET/CT can be more useful when performed soon after therapy in curative surgery recipients and those with an advanced disease stage considering its diagnostic efficacy and yield.

Abstract

We evaluated the diagnostic value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT surveillance for detecting clinically unsuspected recurrence or second primary cancer (SPC) in patients with non-small cell lung cancer (NSCLC) after curative therapy. A total of 4478 surveillance FDG PET/CT scans from 2864 NSCLC patients without suspicion of recurrence after curative therapy were reviewed retrospectively. In 274 of 2864 (9.6%) patients, recurrent NSCLC or SPC was found by surveillance PET/CT during clinical follow-up. Surveillance PET/CT scans showed sensitivity of 98.9% (274/277), specificity of 98.1% (4122/4201), accuracy of 98.2% (4396/4478), positive predictive value (PPV) of 77.6% (274/353), and negative predictive value of 99.9% (4122/4125). The specificity and accuracy in the curative surgery group were significantly higher than those in the curative radiotherapy group. PPV was significantly improved in subgroups of patients with advanced stage prior to curative therapy, PET/CT scans performed within 3 years after curative-intent therapy, and curative surgery. FDG PET/CT surveillance showed good diagnostic efficacy for detecting clinically unexpected recurrence or SPC in NSCLC patients after curative therapy. It can be more useful when performed soon after therapy in curative surgery recipients and those with an advanced disease stage considering its diagnostic efficacy and yield.

The usefulness of 18F-FDG PET/CT in follow-up and recurrence detection for patients with lung carcinoma and its impact on the survival outcome

Background

We assess the usefulness of 18F-FDG PET/CT for detection of recurrent or residual tumor in post treatment patients with NSCLC and comparing the results with CECT, and we evaluate its impact to the clinical assessment and overall survival of lung cancer patients.

Results

A prospective study of 63 patients with potentially resectable NSCLC, were divided into 2 groups according to the initial staging of the disease and the early response to treatment.

Group A (n=29) patients were treated by curative treatment, and group B (n=34) patients were treated by palliative treatment.

Evaluation of patients was done during the follow-up period clinically every 3 months and by 18F-FDG PET/CT and CECT imaging at 6 months intervals.

In group A, 18F-FDG PET/CT correctly diagnosed all recurrent or residual tumors (n=7) whereas CECT diagnosed only 5 with 2 false negative cases.

In group B, 18F-FDG PET/CT correctly diagnosed all recurrent or residual tumors (n=23) whereas CECT diagnosed 16 patients with 7 false negative cases.

By comparison of 18F-FDG PET/CT and CECT in detection of residual or recurrent lung cancer (n=30), the sensitivity, specificity, PPV, NPV, and accuracy of 18F-FDG PET/CT were 100%, 92%, 92%, 100%, and 96% respectively, while of CECT were 72%, 95%, 94%, 79%, and 84% respectively in correlation with reference standard data. The calculated SUV max ranged from 2.1 to 4.9.

There was a significant difference in overall survival between patients in routine scan who had positive 18F FDG PET/CT result (median survival 18 months) and those who had negative result (median survival 45 months) (P<0.0001).

Conclusion

18 F-FDG PET/CT plays an important role in distinguishing post treatment changes from tumor recurrence in patients with lung cancer. Follow-up or surveillance 18 F-FDG PET/CT is a prognostic indicator for overall survival of patients.

The Effect of Carbogen Breathing on 18F-FDG Uptake in Non-Small-Cell Lung Cancer

It has been reported that ¹⁸F-FDG uptake is higher in hypoxic cancer cells than in well-oxygenated cells. We demonstrated that ¹⁸F-FDG uptake in lung cancer would be affected by high concentration oxygen breathing. Methods. Overnight fasted non-small-cell lung cancer A549 subcutaneous (s.c.) xenografts bearing mice (n = 10) underwent ¹⁸F-FDG micro-PET scans, animals breathed room air on day 1, and same animals breathed carbogen (95% O₂ + 5% CO₂) on the subsequent day. In separated studies, autoradiography and immunohistochemical staining visualization of frozen section of A549 s.c. tumors were applied, and to compare between carbogen-breathing mice and those with air breathing, a combination of ¹⁸F-FDG and hypoxia marker pimonidazole was injected 1 h before animal sacrifice, and ¹⁸F-FDG accumulation was compared with pimonidazole binding and glucose transporter 1 (GLUT-1) expression. Results. PET studies revealed that tumor ¹⁸F-FDG uptake was significantly decreased in carbogen-breathing mice than those with air breathing (P < 0.05). Ex vivo studies confirmed that carbogen breathing significantly decreased hypoxic fraction detected by pimonidazole staining, referring to GLUT-1 expression, and significantly decreased ¹⁸F-FDG accumulation in tumors. Conclusions. High concentration of O₂ breathing during ¹⁸F-FDG uptake phase significantly decreases ¹⁸F-FDG uptake in non-small-cell lung cancer A549 xenografts growing in mice.

Is open surgery necessary for metastatic pulmonary tumors evaluated with thorax tomography?

Background

This study aims to compare the tomographic evaluations and intraoperative findings of patients treated surgically for primary tumors and who had pulmonary metastasis.

Methods

The study included 160 patients (102 males, 58 females; mean age 34.6±14.3 years; range, 11 to 64 years) who underwent pulmonary metastasectomy. The primary focus was surgically excised and no metastases other than pulmonary were detected on scans. Preoperative tomographic images together with the findings of the open surgical intervention were evaluated and compared.

Results

A total of 296 surgical resection were performed and 345 metastatic lesions were excised in 166 open surgical procedures. In 35 patients (21.9%), 71 (20.6%) metastatic lesions were detected in tomographic evaluations although no lesions had been detected on direct radiographs. In 29 patients (18.1%), 33 (9.6%) metastatic lesions, which had not been detected radiologically, were found intraoperatively.

Conclusion

Tomographic evaluation is used in the follow-up of patients with malignancy but as for pulmonary metastasis it is not efficient and adequate. Therefore, open surgery should be the preferred approach for intraoperative detection of metastases that cannot be detected radiologically. Open surgical resection for pulmonary metastasis can be performed safely with low rates of perioperative morbidity and mortality.

[Quantitative Imaging Assessment of Tumor Response to Chemoradiation in Lung Cancer]

精准医疗的实施要求及时准确地对治疗疗效进行评估，以便于治疗方案的调整和优化，从而进一步提高疗效，改善预后。以定量评估为基础的影像组学以其无创、直观和可重复的特点在临床疗效评估方面具有不可替代的作用。本文将综述定量影像学在肺癌放化疗疗效评估中的应用现状及其相关进展。