[Role of [18]-FDG PET/CT in the initial staging of head and neck cancers]. / Apport de la [18F]-FDG TEP/TDM dans la stadification initiale des cancers de la tête et du cou.

OBJECTIVE: To evaluate the impact of fusion of positron emission tomography with computed tomography (FDG-PET/CT) in the initial staging of head and neck carcinomas. METHODS: This retrospective study included 44 patients with squamous cell carcinoma of the upper aerodigestive tract. Patients underwent a standard workup and a PET/CT image fusion during the initial staging. The standard workup included CT scan of the head, neck and chest, panendoscopy under general anaesthesia, oesophageal endoscopy and abdominal echography. Potential additional diagnostic value of PET/CT was evaluated. RESULTS: Findings between PET/CT and standard workup were concordant in 41/44 cases for primary tumour in 79/88 cases for lymph node staging, in 36/44 cases for distant metastases (or distant second primary) and in 41/44 cases for synchronous second primaries of the upper aero-digestive tract. PET/CT leads to a change of treatment for 6.8% of patients (1 for lymph node staging and 2 for distant metastases). 17.2% of pathological FDG uptake foci found by PET/CT were false-positives results. CONCLUSION: PET/CT enables to realise a whole body check-up in a single time. However, it cannot be used alone, due to its lack of spatial resolution: It must be used in complement of the standard workup. This high rate of false-positive findings, asking for further expensive diagnostic procedures, limits its usefulness.

Evolution of DNA strand-breaks in cultured spermatocytes: the Comet Assay reveals differences in normal and gamma-irradiated germ cells.

In reproductive toxicity assessment, in vitro systems can be used to determine mechanisms of action of toxicants. However, they generally investigate the immediate effects of toxicants, on isolated germ cells or spermatozoa. We report here the usefulness of in vitro cultures of rat spermatocytes and Sertoli cells, in conjunction with the Comet Assay to analyze the evolution of DNA strand-breaks and thus to determine DNA damage in germ cells. We compared cultures of normal and gamma-irradiated germ cells. In non-irradiated spermatocytes, the Comet Assay revealed the presence of DNA strand-breaks, which numbers decreased with the duration of the culture, suggesting the involvement of DNA repair mechanisms related to the meiotic recombination. In irradiated cells, the evolution of DNA strand-breaks was strongly modified. Thus our model is able to detect genotoxic lesions and/or DNA repair impairment in cultured spermatocytes. We propose this model as an in vitro tool for the study of genotoxic injuries on spermatocytes.

Early sequential changes in serum thyroglobulin after radioiodine ablation for thyroid cancer: possible clinical implications for recombinant human thyrotropin-aided therapy.

TNM status and posttherapy whole-body scan findings aid in risk stratification of patients with thyroid cancer during initial therapy. Recently, the thyroglobulin (Tg) value measured during hypothyroidism just before 131I therapy (preablation Tg) has proved to be effective for predicting persistent/recurrent disease. In this study, we assessed the changes in serum Tg 48 hours after radioiodine ablative therapy performed in the hypothyroid state in order to evaluate if this parameter could be used in recombinant human thyrotropin (rhTSH)-treated patients. Because rhTSH-stimulated TG is traditionally measured 72 hours after the second injection of rhTSH corresponding to 48 hours post-131I therapy, the time course of serum Tg after radioiodine administration is an important clinical issue. To address this issue, we performed a prospective evaluation of 26 consecutive patients with low-risk differentiated thyroid cancer hypothyroidism for radioiodine ablation (3.7 GBq of 131I). Baseline Tg values were compared to posttherapy Tg values (at 24 and 48 hours). We found that Tg increased after 131I therapy because of the acute radiation effects on residual thyroid cells. Median values at each of the three time points were 1.8 ng/mL (baseline), 3 ng/mL (Tg-24), and 11.3 ng/mL (Tg-48) (Brahms Tg Kryptor assay, Brahms AG, Berlin, Germany). Tg-48 values were not statistically correlated with initial Tg values. Tg-48 remained below 15 ng/mL in 14 of 26 patients. In conclusion, the increase in Tg during the early post-131I therapy period means that first rhTSH-stimulated Tg cannot be used as a corresponding value for preablative hypo-Tg. We discussed whether rhTSH-stimulated Tg value might be useful in a subset of patients. In our opinion, this drawback does not outweight the expected benefits of rhTSH-aided therapy on quality of life of patients and overall cost of the therapy.

Incidental diagnosis of struma ovarii after thyroidectomy for thyroid cancer: functional imaging studies and follow-up.

BACKGROUND: Struma ovarii is a rare ovarian germ-cell tumor containing thyroid tissue. We report an unusual case of incidental diagnosis of struma ovarii after thyroidectomy for thyroid cancer. CASE: A 24-year-old woman presented with a papillary thyroid carcinoma (pT3N1). After (131)I administration for thyroid remnant ablation, whole-body scan showed a thyroid bed uptake and a right pelvic uptake corresponding to an ovarian cyst on ultrasonography. Preablation thyroglobulin was more elevated than usually found after total thyroidectomy. (18)F-FDG PET was normal. Histopathological analysis revealed a benign struma ovarii. At 6 months, after oophorectomy, serum-stimulated Tg returned to undetectable value and diagnostic WBS was negative. CONCLUSION: Only few cases of incidental scintigraphic diagnosis of struma ovarii have been described. To our knowledge, it is the first case revealed after remnant ablation for thyroid carcinoma. The distinction with ovarian metastasis is discussed.

Subcutaneous administration of recombinant human thyrotropin as an alternative to thyroid hormone withdrawal in patients with anticoagulated thyroid cancer: preliminary results.

For patients with thyroid cancer taking anticoagulants, because of hematoma risk at the injection site, intramuscular injections (IM) of recombinant human thyrotropin (rhTSH) are usually avoided and patients remain hypothyroid. The aim of the present study was to evaluate if subcutaneous injections (SC) of rhTSH are an alternative to IM. Five consecutive patients receiving anticoagulants were evaluated. The dose regimen was similar to the traditional follow-up protocol (2 x 0.9 mg, SC route). rhTSH administration elicited a sharp and prompt increase in serum TSH that peaked at day 3 (24 hours after the second rhTSH injection), with mean values of 246 +/- 68 mU/L. In one patient with a large thyroid remnant, thyroglobulin (Tg) rose from 18 ng/mL to 450 ng/mL. No adverse effects were observed. We conclude that SC injection of rhTSH represents a safe and efficient procedure in the monitoring of patients with thyroid cancer taking anticoagulants.