Diagnostic efficacy of sentinel node biopsy in oral squamous cell carcinoma : cohort study and meta-analysis

Objectives: To evaluate the efficacy of sentinel node biopsy (SNB) in oral squamous cell carcinoma (OSCC). Design: A prospective study of a cohort of 25 consecutive patients with OSCC anatomopathological confirmation through biopsy, without oncological pre-treatment, in clinical stage T1-T4N0, of these 25 patients 14 were T1-T2N0. The absence of regional disease (N0) was determined by means of clinical exploration and cervical tomography (CT). To establish the overall sensitivity of the technique, a meta-analysis was carried out of 10 series published to February 2005 where SNB had been applied to head and neck cancer, adding our 14 T1-T2N0 cases, thus making a total of 260 patients. Results: Identification by SNB was accurate in 96% of the 25 cases, with a sensitivity of 66.7%. Analyzing only the T1-T2N0 cases (n=14), the accuracy was 100% with a sensitivity of 1 (CI 95%, 0.29-1.00). The overall sensitivity was 93%. The accuracy in identifying the sentinel node varied between 66% and 100%. The SN was identified in 251 of 260 cases, of those, 71 were true positive, 5 false negative and 175 true negative. The overall sensitivity was 93.4% (CI 95%, 85.3-97.8), with a specificity of 100% (CI 95%, 0.98-100). The weighted negative probability quotient was 0.176 (CI 0.103-0.301) and that of positive probability 24.75 (CI 95%, 10.8-56.71). The weighted diagnostic odds ratio was 183.71 (CI 95%, 59.36-568.56). If we accept that the prevalence of hidden regional disease is 30%, a negative sentinel node has 5% possibility of having hidden disease. Conclusions: Our data provide a certain degree of evidence that, due to its high sensitivity, the SNB procedure can be applied to the initial stages of OSCC

Whole-remnant and maximum-voxel SPECT/CT dosimetry in ¹³¹I-NaI treatments of differentiated thyroid cancer.

Purpose To investigate the possible differences between SPECT/CT based whole-remnant and maximum-voxel dosimetry in patients receiving radio-iodine ablation treatment of differentiated thyroid cancer (DTC).Methods Eighteen DTC patients were administered 1.11 GBq of 131I-NaI after near-total thyroidectomy and rhTSH stimulation. Two patients had two remnants, so in total dosimetry was performed for 20 sites. Three SPECT/CT scans were performed for each patient at 1, 2, and 3-7 days after administration. The activity, the remnant mass, and the maximum-voxel activity were determined from these images and from a recovery-coefficient curve derived from experimental phantom measurements. The cumulated activity was estimated using trapezoidal-exponential integration. Finally, the absorbed dose was calculated using S-values for unit-density spheres in whole-remnant dosimetry and S-values for voxels in maximum-voxel dosimetry.Results The mean absorbed dose obtained from whole-remnant dosimetry was 40 Gy (range 2-176 Gy) and from maximum-voxel dosimetry 34 Gy (range 2-145 Gy). For any given patient, the activity concentrations for each of the three time-points were approximately the same for the two methods. The effective half-lives varied (R = 0.865), mainly due to discrepancies in estimation of the longer effective half-lives. On average, absorbed doses obtained from whole-remnant dosimetry were 1.2 ± 0.2 (1 SD) higher than for maximum-voxel dosimetry, mainly due to differences in the S-values. The method-related differences were however small in comparison to the wide range of absorbed doses obtained in patients.Conclusions Simple and consistent procedures for SPECT/CT based whole-volume and maximum-voxel dosimetry have been described, both based on experimentally determined recovery coefficients. Generally the results from the two approaches are consistent, although there is a small, systematic difference in the absorbed dose due to differences in the S-values, and some variability due to differences in the estimated effective half-lives, especially when the effective half-life is long. Irrespective of the method used, the patient absorbed doses obtained span over two orders of magnitude

Analysis of activity uptake, effective half-life and time-integrated activity for low- and high-risk papillary thyroid cancer patients treated with 1.11 GBq and 3.7 GBq of 131I-NaI respectively

Purpose: To analyse the activity uptakes, effective half-lives and time-integrated activities, of relevance for remnant dosimetry, for patients treated for papillary thyroid cancer (PTC) with a different amount of activity of 131I-NaI. Methods: Fifty patients were included. Of those, 18 patients had low-risk PTC and were treated with 1.11 GBq of 131I-NaI (Group 1), and 32 patients had high-risk PTC and were treated with 3.7 GBq (Group 2). Radioiodine was administered after total thyroidectomy and rhTSH stimulation. Two SPECT/CT scans were performed for each patient to determine the remnant activities and effective half-lives. Results: Significantly higher values (p 0.05). Conclusions: We found a significant difference in the remnant activity per administered activity, the rate of washout from thyroid remnants, and the time-integrated activity coefficient between low-risk PTC patients treated with 1.11 GBq and high-risk PTC patients treated with 3.7 GBq. On the contrary, there was no such difference in the time-integrated activity. If remnant masses were also not statistically different (reasonable assumption for this monocentric study) no difference in time-integrated activity would imply no difference in remnant absorbed dose, of relevance for treatment efficacy and the risks of stochastic effects

Dosimetric results in treatments of neuroblastoma and neuroendocrine tumors with (131)I-metaiodobenzylguanidine with implications for the activity to administer.

The aim was to investigate whole-body and red marrow absorbed doses in treatments of neuroblastoma (NB) and adult neuroendocrine tumors (NETs) with (131)I-metaiodobenzylguanidine and to propose a simple method for determining the activity to administer when dosimetric data for the individual patient are not available