Clinical Applications of FDG PET and PET/CT in Head and Neck Cancer

18F-FDG PET plays an increasing role in diagnosis and management planning of head and neck cancer. Hybrid PET/CT has promoted the field of molecular imaging in head and neck cancer. This modality is particular relevant in the head and neck region, given the complex anatomy and variable physiologic FDG uptake patterns. The vast majority of 18F-FDG PET and PET/CT applications in head and neck cancer related to head and neck squamous cell carcinoma. Clinical applications of 18F-FDG PET and PET/CT in head and neck cancer include diagnosis of distant metastases, identification of synchronous 2nd primaries, detection of carcinoma of unknown primary and detection of residual or recurrent disease. Emerging applications are precise delineation of the tumor volume for radiation treatment planning, monitoring treatment, and providing prognostic information. The clinical role of 18F-FDG PET/CT in N0 disease is limited which is in line with findings of other imaging modalities. MRI is usually used for T staging with an intense discussion concerning the preferable imaging modality for regional lymph node staging as PET/CT, MRI, and multi-slice spiral CT are all improving rapidly. Is this review, we summarize recent literature on 18F-FDG PET and PET/CT imaging of head and neck cancer

Personalized High-Dose-Rate Brachytherapy with Non-Sealed Rhenium-188 in Non-Melanoma Skin Cancer

Objectives: Most non-melanoma skin tumors are treated with conventional methods, being the most common surgery. However, satisfactory surgical treatment can be very challenging for patients with large or multiple lesions. In cases where the tumor is located on the face, hands or genital areas, the results may be suboptimal in terms of aesthetics and/or function. A high dose-rate brachytherapy using non-sealed Rhenium-188 was developed to offer a personalized solution for these cases as well as cases where a surgical approach was not preferred. Here we show a retrospective analysis of 43 patients treated with this technique.Methods: The technique, called dermatological high-dose-rate beta-brachytherapy (DBBR), is a brachytherapy based on a non-sealed beta-emitter embedded in a complex specially-designed acrylic matrix. We use Rhenium-188 as the beta-emitter. This matrix is applied over the tumor, which is protected by a special thin plastic foil avoiding any direct physical contact of the radioisotope with the skin. After the calculated required amount of time, the protective foil with the applied radioactive acrylic matrix is removed. 43 patients (basal/squamous cell carcinomas, BCCs and SCCs) were treated with this technique after histological confirmation of the non-melanoma skin tumor. Patients were then followed up, to evaluate wound healing as well as potential side-effects and recurrences.Results: 29 BCC and 14 SCC patients were treated with DBBR. 36/42 achieved complete clinical remission with only 1 application (24 BCC, 12 SCC) and 6/42 with 2 applications (4 BCC, 2 SCC); 1 BCC patient was lost to follow-up before wound closing. In 4 of the 6 patients (3 BCC, 1 SCC) treated twice the second treatment was planned due to the thickness of the tumor; in the remaining 2 patients (1 BCC, 1 SCC) the second treatment was needed to treat a recurrence at the border of the previously treated area. No side effects were reported. Wound healing was complete in 34-180 days (average 65 days, median 53) for all 42 patients that were followed-up. An average follow-up of 288 days (after one or two treatments) showed no single recurrence (42 patients).Conclusions: DBBR is a very promising alternative for treatment of BCCs and SCCs for all cases in which a surgical approach is not recommended or accepted by the patient

Predictive value of clinical and 18F-FDG-PET/CT derived imaging parameters in patients undergoing neoadjuvant chemoradiation for esophageal squamous cell carcinoma.

Aim of this study was to validate the prognostic impact of clinical parameters and baseline 18F-FDG-PET/CT derived textural features to predict histopathologic response and survival in patients with esophageal squamous cell carcinoma undergoing neoadjuvant chemoradiation (nCRT) and surgery. Between 2005 and 2014, 38 ESCC were treated with nCRT and surgery. For all patients, the 18F-FDG-PET-derived parameters metabolic tumor volume (MTV), SUVmax, contrast and busyness were calculated for the primary tumor using a SUV-threshold of 3. The parameter uniformity was calculated using contrast-enhanced computed tomography. Based on histopathological response to nCRT, patients were classified as good responders (< 10% residual tumor) (R) or non-responders (≥ 10% residual tumor) (NR). Regression analyses were used to analyse the association of clinical parameters and imaging parameters with treatment response and overall survival (OS). Good response to nCRT was seen in 27 patients (71.1%) and non-response was seen in 11 patients (28.9%). Grading was the only parameter predicting response to nCRT (Odds Ratio (OR) = 0.188, 95% CI: 0.040-0.883; p = 0.034). No association with histopathologic treatment response was seen for any of the evaluated imaging parameters including SUVmax, MTV, busyness, contrast and uniformity. Using multivariate Cox-regression analysis, the heterogeneity parameters busyness (Hazard Ratio (HR) = 1.424, 95% CI: 1.044-1.943; p = 0.026) and contrast (HR = 6.678, 95% CI: 1.969-22.643; p = 0.002) were independently associated with OS, while no independent association with OS was seen for SUVmax and MTV. In patients with ESCC undergoing nCRT and surgery, baseline 18F-FDG-PET/CT derived parameters could not predict histopathologic response to nCRT. However, the PET/CT derived features busyness and contrast were independently associated with OS and should be further investigated