Primary squamous cell carcinoma of the thyroid. Initial assessment and follow-up using 18F-FDG PET/CT

Squamous cell carcinoma of thyroid is an uncommon, very aggressive neoplasm, having a poor prognosis and poor response to chemotherapy and radiotherapy. Surgery is the initial treatment of choice, although it often presents as a widespread disease at the time of diagnosis, usually with cervical swelling that causes most of the symptoms due to local infiltration or metastasis. Local infiltration from adjacent tumour and metastatic disease needs to be excluded from other primary epidermoid carcinomas, in order to make a correct diagnosis. This also requires the typical cytokeratin pattern seen in histological studies. The case is presented of a 53 year-old man with a medical history of hepatocarcinoma, with a cervical hypermetabolic lesion detected in an ¹⁸F-FDG PET/CT performed to exclude widespread disease. The follow-up of this lesion with this technique and its usefulness is also described.

Sentinel lymph node biopsy in paediatric melanoma. A case series

The incidence of melanoma in children is uncommon, being particularly rare in children under 10 years-old. However, this disease is increasing by a mean of 2% per year. As in adults, the lymph node status is the most important prognostic factor, crucial to performing the selective sentinel lymph node biopsy (SLNB). We report 3 cases of paediatric patients of 3, 4 and 8 years-old, in which SLNB was performed for malignant melanoma. Paediatric age implies greater technical difficulty to the scintigraphy scan due to poor patient cooperation, with mild sedation required in some cases, and only being able to acquire planar images in other cases. SPECT/CT was only performed in the oldest patient. In our cases, SLNB was useful for selecting the least invasive surgery in order to reduce morbidity.

[Effectivity and clinical impact of (18)F-FDG-PET in the diagnosis of unsuspected second primary tumors]

OBJECTIVE

This study has aimed to determine the capacity and clinical impact of the (18)F-FDG-PET to detect previously unsuspected second primary tumors.

MATERIAL AND METHODS

This is a retrospective cross-sectional study of 1984 consecutive scans performed between March 2004 and March 2005, identifying those studies that had reported the presence of hypermetabolic lesions, that had not been previously suspected or detected and that could be suggestive of second primary tumors. Diagnosis was made histopathologically or by clinical and radiological follow-up for a period exceeding one year.

RESULTS

62 findings suggestive of second primary tumors were detected in 58 patients (3.1%). The reasons for the study for this group of patients were diverse, the most common being the differential diagnosis of solitary pulmonary nodules. A total of 43.5% of lesions were not followed-up. We confirmed the existence of 35 lesions, either by pathology study (21 lesions, 13 second primary tumors, the incidence in our population was 0.65%) or clinical and radiological follow-up (14 lesions, none of which corresponded to second primary tumors). The total clinical impact was the discovery of unexpected 14 lesions in 12 patients.

CONCLUSION

The presence of second primary tumors on (18)F-FDG-PET is relatively common. These lesions should be monitored clinically for accurate diagnosis. In a high percentage, they correspond to unexpected second primary tumors in an early stage and therefore amenable to curative treatment or for which tumor treatment planning may be modified.

[Clinical impact of FDG-PET in patients with suspected recurrent ovarian cancer]

AIM

To evaluate the efficacy and clinical impact of FDG-PET in patients with suspected recurrent ovarian cancer.

METHODS

Between October 2001 and October 2006, we retrospectively studied 49 FDG-PET performed in 40 women (age: 52.4 +/- 12.2 years) with ovarian cancer, who had suspicion of recurrent disease by positive morphologic imaging tests (MIT) or increased tumour markers and negative MIT. All patients underwent whole body FDG-PET after the injection of 370-434 MBq of (18)FDG. The results were confirmed by histology in 31 cases, and by clinical-radiological follow-up in 18.

RESULTS

Prevalence of disease was 79.6 %. We obtained a global sensitivity and positive predictive value of 87.2 % and 87.2 %, and an accuracy of 79.6 %. Results led to a change in the patient's management in 25 cases (51 %). Subgroup results were: Sensitivity of 81.8 % in patients with increased tumour markers and negative MIT, and 89.3 % in patients with operable malignant lesions.

CONCLUSIONS

FDG-PET has high sensitivity and clinical impact in patients with suspicion of recurrent ovarian cancer. Better results were obtained in patients with increased tumour markers and negative MIT.

[Evaluation of efficacy and clinical impact of FDG-PET on patients with potentially resectable non-small cell lung cancer]

AIMS

We have evaluated the efficacy and clinical impact of FDG-PET for staging patients with potentially resectable non-small cell lung cancer (NSCL) in CT.

MATERIALS AND METHODS

We have prospectively studied 115 patients (104 M/11 F and mean age: 59 years old) with diagnosis of potentially resectable NSCL, (resectable criteria: Stage <IIIB in CT), including cases with equivocal lesions in mediastinum or in extrathoracic sites. In all patients we have done a whole body scan with FDG-PET, after intravenous injection of 370-440 MBq of 18F-FDG, in normoglucemia conditions. A qualitative and semiquantitative (SUV) analysis of images was carried out.

RESULTS

Prevalence of mediastine lymphatic metastasis was 46.6 %, and CT was false negative (FN) in 21 cases and FDG-PET only in 9. Overall sensitivity, specificity, negative predictive value, positive predictive value and accuracy were of 83.3, 73.7, 75, 81.8 % and 78.3 % in FDG-PET, and 61.1, 68.8, 64.7, 65.6 % and 65.2 % in CT, respectively. All contralateral or supraclavicular lymph metastasis (N3) were detected in FDG-PET, whereas CT had 7 FN cases. In distant metastasis, FDG-PET had 1 FN and 4 FP, whereas CT had 6 cases FN and 10 FP. Clinical Impact of FDG-PET was 26 % of patients, avoiding surgery in 11 cases, allowing in 8, indicating neoadjuvant chemotherapy in 8 and surgery of synchronic incidentaloma in 3 cases.

CONCLUSION

PET-FDG had better efficacy than CT in resectable NSCL, and should be incorporated in diagnosis protocols of NSCL before surgery decision making.

[Bone metastases from unknown primary. FDG-PET detection of two synchronous tumors]

A 60-year-old woman presented with noncardiac chest pain over months and negative laboratory findings. Conventional imaging methods and bone scintigraphy detected bone lesions suggesting metastatic disease from an unknown primary tumor. An 18FDG-PET scan performed to orient the search for the primary tumor found focal lesions suggesting lymphoma and identified a focal thyroid lesion and a cervical lymph node accessible for biopsy. The biopsy of this lymph node incidentally detected a papillary differentiated thyroid cancer (DTC), since the existence of a non-Hodgkin's lymphoma was confirmed after a new biopsy. After confirming the presence of a lymphoma, 18FDG-PET enabled the initial staging of the tumor, the evaluation of the response to treatment, and follow-up for detection of recurrence. On the other hand, 18FDG-PET incidentally detected a DTC.

[Patients treated for differentiated thyroid cancer with negative 131I whole-body scans and elevated thyroglobulin levels: a possible course]

OBJECTIVE

To verify the existence of patients with treated differentiated thyroid cancer (DTC) with negative 131I whole-body scanning (WBS) and high serum thyroglobulin (Tg) in the follow-up who evolve towards normalization without other therapy interventions.

MATERIAL AND METHODS

Retrospective revision of the periodic examinations established in the protocol for patients with DTC, analyzing the levels of Tg found with IRMA annually in those with hormonal treatment and every 1-5 years in absence of previous hormonal treatment to WBS. Minimum surveillance of 2 years. Those who had elevated levels of Tg and WBS and other negative imaging tests in their course were selected. The characteristics of the patients selected were analysed in those whose Tg levels evolved to normalization without specific medical or surgical treatment (Group I) and those who did not reach normalization of Tg (Group II).

RESULTS

A total of 130 patients (17.93 %) with high levels of Tg and negative WBS were detected. Group I: 31 patients (4.28 %), 11 men and 20 women; average age at the moment of the diagnosis of 33.4 years (rank: 5-60); average surveillance: 12.4 years (+/- 7.4).

HISTOLOGY

27 papillary and 4 follicular carcinoma. Average ablation dose: 3.260 GBq (88,1 mCi); average total I131 dose: 6.850 GBq (185.13 mCi). Tg normalization average time: 8.2 years. Group II: 99 patients (13.65 %), 27 men and 72 women. Average age of 40.4 years (rank: 7-76). Average surveillance: 9.8 years.

HISTOLOGY

86 papillary and 13 follicular carcinoma. Average ablation dose: 3.266 GBq (88.28 mCi); average total 131I dose: 9.363 GBq (253,06 mCi). Two of the patients in group I had negative PET-FDG. There were 13 patients in whom progressive reduction of the levels of thyroglobulin without reaching normalization with negative PET-FDG was detected.

CONCLUSIONS

In patients with radiated DTC, deferred normalization of the levels of the serum thyroglobulin is possible. Empirical treatments cannot be considered the only factor that contributes to this result, which can occur without the administration of high-doses of 131I.

[Evaluation of efficacy and clinical impact of FDG-PET on patients with suspicion of recurrent cutaneous melanoma]

AIMS

To evaluate the efficacy and clinical impact of positron emission tomography with 18F-FDG (FDG-PET) in patients with suspected recurrent melanoma.

MATERIALS AND METHODS

We studied 105 patients with melanoma and suspicion of recurrent melanoma by clinical symptoms in 38 cases or equivocal/positives morphological tests (TC, MR, US) in 77 cases. In all patients a whole body scan was performed with FDG-PET (ECAT HR +) after an intravenous injection of 444-518 MBq of 18F-FDG, in normoglucemia conditions, and previous administration of muscular relaxant, hydration and diuretic. Images were evaluated by 2 dxpert nuclear physicians and were analysed qualitatively and semiquantitatively. In 48 cases the results were confirmed by histology and clinical evolution (follow-up period >12 months) and imaging tests in 57 cases.

RESULTS

Prevalence of recurrent melanoma was 63.8 %. Sensitivity, specificity, PPV, NPV and accuracy of FDG-PET was 97 %, 97.2 %, 98.5 %, 82 % y 94.7 % respectively. FDG-PET had led to a management change in 48 cases (38 %).

CONCLUSIONS

FDG-PET has high clinical impact in patients with suspicion of recurrent melanoma, and should be incorporated in the diagnosis protocols, before making therapeutic decision.

[Evaluation of efficacy and clinical impact of positron emission tomography with 18F fluoro-deoxyglucose in patients with suspicion of recurrent head and neck cancer or distant metastases]

AIMS

To evaluate the efficacy and clinical impact of Positron Emission Tomography with FDG (FDG-PET) in patients with suspected recurrent head and neck cancer or distant metastases.

MATERIALS AND METHODS

Sixty patients (12 women and 48 men) with suspicion of recurrent head and neck cancer and ambiguous conventional imaging modalities. In all patients a whole body scan was performed with FDG-PET in fasting patients following i.v. administration of 370-444 MBq FDG. The results were confirmed by histology and clinical evolution (follow-up period > 12 months) and imaging test.

RESULTS

Prevalence of recurrence was 66.6 %. FDG-PET was positive in 40/60 patients, with confirmation in 39 cases, and 18 were true negative (TN). We have found 2 false positive and 1 false negative. Overall sensitivity, specificity, PPV, NPV and accuracy were 97.5 %, 90 %, 95.12 %, 94.7 % and 95 %, respectively. FDG-PET changed the modality of treatment in 34 patients (clinical impact 56.6 %)

CONCLUSIONS

FDG-PET has high clinical impact in patients with suspicion of recurrent head and neck cancer, and should be incorporated in the diagnostic protocols before making a therapy decision.

[Evaluation of efficacy and clinical impact of positron emission tomography with 18F fluoro-deoxyglucose (FDG) in patients with suspicion of recurrent laryngeal carcinoma]

AIMS

To evaluate the efficacy and clinical impact of FDG-PET in patients with suspected recurrent laryngeal carcinoma.

MATERIALS AND METHODS

15 patients, with suspicion of recurrent laryngeal carcinoma and ambiguous conventional imaging modalities. In all patients a whole body scan was performed with FDG-PET in fasting patients following i.v. administration of 370-444 MBq FDG. The results were confirmed by histology and clinical evolution (follow-up period > 12 months).

RESULTS

Prevalence of recurrence was 86.6%. FDG-PET was positive in 13 patients, with confirmation in all cases, and 2 were true negative (TN). Overall sensitivity, specificity, PPV, NPV and accuracy were 100%. FDG-PET changed the modality of treatment in 10 patients (clinical impact 63.3%).

CONCLUSIONS

FDG-PET has high clinical impact in patients with a suspicion of recurrent laryngeal carcinoma, and should be incorporated to the diagnostic protocols before making a therapy decision.

PET con 18FDG en pacientes con cáncer diferenciado de tiroides que presentan niveles elevados de tiroglobulina sérica y rastreos con 131I negativos

This study aimed to evaluate the role of Fluorine-18-fluorodeoxyglucose positron emission tomography (PET-FDG) in patients with elevated serum thyroglobulin (hTg) levels where thyroid cancer tissue does not concentrate radioiodine, rendering false-negative results on I-131 scanning.

MATERIAL AND METHODS

Whole-body PET imaging using FDG was performed in 54 patients (37 female, 17 male) aged 17-88 years: 45 with papillary tumors and 9 with follicular tumors who were suspected of having recurrent thyroid carcinoma due to elevated thyroglobulin levels (hTg > 2 ng/ml) under thyroid-stimulating hormone (TSH > or = 30 microIU/ml) in whom the iodine scan was negative. All whole body scans were obtained with diagnostic doses (185 MBq). Whole body PET imaging was performed in fasting patients following i.v. administration of 370 MBq FDG while the patients were receiving full thyroid hormone replacement. Before PET, 99mTc methoxyisobutylisonitrile scintigraphy (99mTc-MIBI) was done in 14 patients and morphologic imaging in 26 by CT scan.

RESULTS

Positive PET results confirmed the presence of hypermetabolic foci in 25/54 patients (46.29 %). Positive findings were found for PET-FDG in patients with hTg levels higher than 10 ng/ml receiving full thyroid hormone replacement. 99mTc-MIBI demonstrated lesions in 7/14 patients (50 %). PET-FDG and 99mTc-MIBI had congruent positive results in 4/7 patients. All the lesions found by CT were detected by PET-FDG, while recurrent disease was found in 12/21 patients with previous negative CT.

CONCLUSIONS

These results suggest that PET-FDG seems to be a promising tool in the follow-up of thyroid cancer and should be considered in patients suffering from differentiated thyroid cancer with suspected recurrence and/or metastases by elevated thyroglobulin levels, and negative I-131 whole body scans. PET-FDG might be more useful at hTg levels > 10 ng/ml.

Evaluación de la eficacia y del impacto clínico de la PET-FDG en pacientes con sospecha de recurrencia de cáncer colorrectal

AIMS

To evaluate the utility and clinical impact of Positron Emission Tomography with FDG (FDG-PET) in patients with suspected recurrent colorectal cancer (RCR).

MATERIALS AND METHODS

Eighty five (85) patients with suspicion of RCR (Group A: 35 for increased tumor markers and negative imaging tests, Group B: 25 operable malignant lesions and Group C: 25 with non-conclusive morphological tests) were studied retrospectively. In all patients a whole body scan was performed with FDG-PET. In 29 cases the results were confirmed by histology and clinical evolution (follow-up period > 12 months) and imaging test in 56.

RESULTS

Prevalence of RCR was 89.4 %. FDG-PET was positive in 30/35 patients in Group A, with confirmation in 29 cases (PPV: 96.6 %) and 4/5 were true negative (TN) (NPV: 80 %). FDG-PET enabled surgery for 6 patients. In Group B, PET was positive in 22/25, and all of them had confirmation (PPV: 100 %) but surgery was performed in only 7 patients. NPV was 66.6 %. Out of the 25 cases of Group C, FDG-PET obtained 21 TP, 1 FP case, 1 TN, 2 FN, and was able to avoid surgery in 8 patients (PPV: 95.4 % and NPV: 33.3 %). Overall sensitivity, specificity, PPV, NPV and accuracy were 94.7 %, 77.7 %, 97.2 %, 63.3 % and 92.9 %, respectively.

CONCLUSIONS

FDG-PET has high clinical impact in patients with suspicion of recurrent colorectal cancer, and should be incorporated in the diagnostic protocols before making a surgery decision.

[A proposal for the rational use of the PET in oncology]

OBJECTIVE

This study aims to develop a Clinical Practice Guide for the rational use of the Positron Emission Tomography (PET) in Oncology, that makes it possible to approach the real existence of demand in the public health care service of Andalucía, by limiting the clinical indications, using criteria based on the existence of sufficient scientific evidence on the effectiveness and clinical impact of PET.

METHOD

The consensus technique was used to elaborate the Guide, gathering a group of nuclear medicine experts. Prior to this a systematic research of the scientific literature was carried out, using strict criteria for the selection of the articles, such as the evaluation of the epidemiological data, work methodology, clinical and pathological diagnosis, gold standard references and statistical analysis. In each pathology group, the existence of alternative non-invasive diagnostic techniques was assessed, comparing its effectiveness and clinical impact with the PET, and the existence of useful treatments correlated with the results of the examination was also evaluated. When it was possible, we evaluated the cost-effectiveness of the PET. Finally, the cost-effectivity of the technique was assessed and the limitation of present and future resources and the economical costs arising from the PET costs and introduction were evaluated.

RESULTS AND CONCLUSIONS

It was considered that the PET was indicated in the following clinical conditions: 1: Assessment of Colorectal Cancer recurrence in patients with increased levels of tumor markers and negative morphological imaging techniques. Suspicion of isolated resectable recurrence. 2: Restaging in patients with high risk melanoma. 3: Differential diagnosis of solitary pulmonary nodules. 4: Staging of non-small cell bronchial carcinoma. 5: Staging and detection of recurrences of lymphomas. 6: Restaging of head and neck cancer with possibilities of curative treatment. 7: Diagnosis of recurrences in differentiated thyroid cancer in patients with increased plasma levels of thyroglobulin and negative radioiodine scintiscan. 8: Staging and follow-up of medullary thyroid carcinoma. 9: Differential diagnosis between recurrent tumor and scar or radionecrosis in brain tumors.