The role of changes in maximum standardized uptake value of FDG PET-CT for post-treatment surveillance in patients with head and neck squamous cell carcinoma treated with chemoradiotherapy: preliminary findings.

OBJECTIVE: No clear consensus exists regarding the optimal interval and frequency of follow-up positron emission tomography (PET)-CT in patients with head and neck squamous cell carcinoma (HNSCC) treated with chemoradiotherapy (CRT). Here, we sought to clarify whether the changes in the maximum standardized uptake value (ΔSUVmax) may be a valid parameter to help decision-making for surveillance management after CRT. METHODS: 40 patients underwent PET-CT at pre-treatment and 3 months after CRT. Patients were followed by sequential PET-CT for 2 years after CRT. The ΔSUVmax of the primary tumour and the metastatic nodes were calculated between pre-treatment and 3 months after the CRT, and we evaluated the associations between ΔSUVmax and the manifestation of recurrence, time to recurrence and the patient survival. RESULTS: The ΔSUVmax of the primary tumour was significantly lower for the lesions with recurrence than that for those with non-recurrence for both the primary site and the nodal site (p = 0.007, 0.02). A significant correlation was found between the time to recurrence and the ΔSUVmax of the primary tumour (r = 0.63, p < 0.05). The threshold ΔSUVmax of the primary tumour of 1.04 revealed 76.9% sensitivity and 86.4% specificity for distinguishing recurrence from non-recurrence. The progression-free survival and overall survival of the two patient groups divided by the ΔSUVmax of the primary tumour at 1.04 showed a significant difference (p = 0.003, 0.02). The ΔSUVmax of the metastatic nodes did not show a significant association with recurrence or patient survival. CONCLUSION: The ΔSUVmax of the primary tumour showed a significant association with recurrence and patient survival. Advances in knowledge: The ΔSUVmax of the primary tumour may be a valid clinical parameter to help decision-making for the surveillance management of patients with HNSCC after CRT.

Lesion regression rate based on RECIST: prediction of treatment outcome in patients with head and neck cancer treated with chemoradiotherapy compared with FDG PET-CT.

The aim of this study was to evaluate whether the lesion regression rate (ΔLR) based on the Response Evaluation Criteria in Solid Tumors (RECIST) criteria could be used for the prediction of treatment outcome in head and neck squamous cell carcinoma (HNSCC) patients treated with chemoradiotherapy (CRT) compared with FDG PET-CT. A total of 33 patients underwent MRI and PET-CT at pretreatment and at 8 weeks after CRT. We assessed the treatment outcome by analyzing the following parameters: the RECIST criteria, ΔLR, the European Organization for Research and Treatment of Cancer (EORTC) criteria, and pretreatment SUVmax of the primary tumor and node. The correlation between the analysis of the parameters and the results of the long-term follow-up of the patients was determined. The RECIST did not significantly correlate with locoregional control (LRC) or survival. The ΔLR was significantly lower for the lesions with locoregional failure (LRF) than for those with LRC. A threshold ΔLR of 48% revealed a sensitivity of 72.7% and specificity of 77.3% for the prediction of LRF. Progression-free survival (PFS) of patients with ΔLR ≥ 48% was significantly better than that of patients with ΔLR < 48% (P = 0.001), but not overall survival. There was a significant correlation between LRC and the EORTC (P = 0.02). The patients who achieved a complete response by the EORTC criteria showed significantly better PFS and overall survival (P = 0.01 and 0.04, respectively). The ΔLR was inferior to FDG PET-CT with respect to the prediction of patient survival; however, it may be useful for selecting patients in need of more aggressive monitoring after CRT.

Usefulness of 4D-CT for radiation treatment planning of gastric MZBCL/MALT.

It is well known that significant variations in stomach size, shape, and respiratory motion lead to uncertainties in target localization during treatment for gastric lymphoma. In this study, the usefulness of 4D-CT for radiation planning of gastric MZBCL/MALT was evaluated. Treatment planning using 4DCT (plan A) and conventional planning with a uniform margin (plan B) were compared using dose volume histograms (DVH) of the planning target volume (PTV) and the organ at risk, as well as the dose coverage of the clinical target volume (CTV) assessed by weekly online cone beam CT (CBCT) during the treatment course. In addition, regarding the image quality of CBCT , the interobserver agreement for the delineated volume of the CTV on CBCT was analyzed. The mean PTV of plan A was significantly smaller than that of plan B (p = 0.008). The mean doses to the liver and heart in plan A were significantly lower than those in plan B (p = 0.02 and 0.03, respectively). The reductions of V(20) of each kidney in plan A compared with those in plan B were 4.8 ± 2.4% in the right kidney and 16.3 ± 10.4% in the left. There was no significant difference in the dose coverage of the CTV between the plans during the treatment course. The interobserver agreement for the volume of the CTV was moderate correlation. Treatment planning using 4DCT for gastric MZBCL/MALT was useful for effective and safe irradiation with minimizing exposure of the organ at risk.

Noninvasive monitoring of radiation-induced early therapeutic response using high-resolution MR imaging and proton MR spectroscopy in VX2 carcinoma.

The purpose of this study was to evaluate the usefulness of high-resolution MRI (HR-MRI) and proton MR spectroscopy ((1)H-MRS) for monitoring the early therapeutic response to radiotherapy. Twenty rabbits with VX2 carcinoma were divided into control (n = 8) and irradiation (n = 12) groups. The irradiation group underwent HR-MRI and (1)H-MRS using a microscopy coil at 1, 3, 7 or 14 days after irradiation. Rabbits in the control group were subjected to HR-MRI and (1)H-MRS at the same time intervals. All rabbits were killed after imaging and subjected to histopathologic examinations. The diameter of necrosis by HR-MRI was then compared to that on the gross specimens. The ratios of choline/creatine (Cho/Cr) and lactate/creatine (Lac/Cr) on the tumor and necrotic area detected by in vivo (1)H-MRS were compared between the control and irradiation groups, respectively. In addition, the ratios of Cho/Cr and Lac/Cr were compared between the tumor and necrotic area in each irradiation group. A significant correlation was found between the diameter of necrosis in each sequence of HR-MRI and that in the gross specimens (r = 0.84-0.91, p = 0.03- < 0.003). The ratios of Lac/Cr in the tumors of the irradiation groups were significantly higher than those in the control groups after 1 day and 3 days of irradiation (p = 0.04, and p = 0.02). Histological analysis showed necrosis and swelling of the endothelia of capillaries and arterioles at 1 day and 3 days after irradiation. It was suggested that HR-MRI and (1)H-MRS are useful methods for monitoring the early therapeutic response to radiotherapy.

Palliative radiotherapy with 1 x 8 Gy using conformal radiotherapy for chemotherapy-refractory, recurrent, aggressive lymphomas.

We performed palliative radiotherapy with a single-fraction of 8 Gy using a three-dimensional conformal radiotherapy (3D-CRT) technique for patients with dyspnea due to a bulky nasooropharyngeal lesion who had chemotherapy-refractory, recurrent, aggressive lymphoma. After palliative radiotherapy, a complete response with acceptable toxicity was achieved at the irradiated sites of two patients, and the symptoms resolved completely. These results indicated that a single fraction of 8 Gy using 3D-CRT is an effective palliative treatment for chemotherapy-refractory, recurrent, aggressive lymphoma.