Andrea Mutvar

Reliability of sentinel node assay in vulvar cancer: The first Croatian validation trial

OBJECTIVE To evaluate the reliability of sentinel node assay in early stage vulvar cancer patients by using preoperative lymphoscintigraphy. METHODS Technetium-99m colloid albumin was injected intradermally around the tumor for lymphoscintigraphic mapping and intraoperative hand-held gamma probe detection of sentinel nodes. For all patients, sentinel node biopsy was followed by inguinofemoral lymphadenectomy, regardless of the sentinel lymph node status. RESULTS From December 2008 until May 2011, 25 consecutive patients with T1 or T2 stage of vulvar squamous cell cancer were enrolled. The median age of patients was 69 years (range, 48-79). The detection of sentinel lymph node was successful in all 25 patients. A total of 36 sentinel lymph nodes were harvested and metastatic carcinoma was identified in 12 sentinel nodes from 8 patients. There was 1 patient with metastatic non-sentinel lymph node despite the negative sentinel node. Two patients with negative sentinel nodes proven by routine histopathological examination were positive by immunohistochemical staining. The sensitivity, specificity and negative predictive value of sentinel node assay with immunohistochemistry included were 89%, 100%, and 94%, respectively. CONCLUSIONS Lymphoscintigraphy and sentinel lymph node biopsy under gamma-detecting probe guidance proved to be an easy and reliable method for the detection of sentinel node in early vulvar cancer. Immunohistochemical analysis improves the sensitivity for the detection of regional micrometastases. The sentinel node assay is highly accurate in predicting the status of the remaining inguinofemoral lymph nodes. Our results indicate that patients best suited to SLN assay have had a simple punch biopsy to confirm the diagnosis rather than a previous tumor excision. This technique represents a true advance in the selection of patients for less radical surgery.

The nonspecific lymph node uptake of 18F-choline in patients with prostate cancer--a prospective observational study.

BACKGROUND The aim of this study was to observe and characterize the nonspecific ¹⁸F-choline lymph node uptake in patients with prostate cancer. MATERIAL AND METHODS In this single center, prospective observational study which was done in University Hospital Center Zagreb between December 2012 and October 2014, 69 patients (median age 71 years; range 50-92) with prostate cancer were included. Patients underwent ¹⁸F-choline PET/CT for staging or restaging of prostate cancer. The mean follow-up period was 11.5 months. Kruskal-Wallis test was used to find out if the differences between SUV values of specific and nonspecific accumulation of the tracer are statistically significant. RESULTS Nonspecific accumulation of ¹⁸F-choline in lymph nodes was found in 36 patients (52.7%). Most of these findings (n = 24) were nonspecific accumulation of the tracer in mediastinal lymph nodes. Other sites of nonspecific tracer uptake were pulmonary hila (n = 20), inguinal lymph nodes (n = 15), and axillary lymph nodes (n = 10). Mean SUV values for mediastinal lymph nodes, pulmonary hila, axillary and inguinal lymph nodes were 4.8, 4.3, 3.1 and 4.1, respectively. Mean SUV value of nonspecific sites of tracer accumulation was lower (not significantly; (p = 0.2) than tracer uptake values measured in metastases sites (bone metastases mean SUVmax value - 13.2, metastatic lymph nodes mean SUVmax value - 9.2). CONCLUSIONS ¹⁸F-choline PET/CT is a valuable and an established functional diagnostic imaging method for staging and restaging prostate cancer. However, nonspecific uptake of the tracer can often be seen in lymph nodes not related to primary disease. Patient history, clinical examination, laboratory tests and correlation with other imaging methods, must be taken into consideration when interpreting ¹⁸F-choline PET/CT findings.

The value of 18F-DOPA PET/CT in patients with medullary thyroid carcinoma and increased calcitonin values

Aim The aim of this prospective observational study was to examine the benefit of a fluorine-18-L-dihydroxyphenylalanine (18F-DOPA) PET/computed tomography (CT) scan in patients with medullary thyroid carcinoma (MTC) in terms of increased calcitonin levels. Patients and methods Twenty-eight MTC patients after initial total thyreoidectomy with increasing follow-up calcitonin levels suggestive for active disease after negative conventional imaging findings (neck ultrasound or thorax, abdomen, pelvis multislice computed tomography as standard imaging) were scanned using 18F-DOPA PET/CT from November 2012 to April 2016. The mean calcitonin level was 108.5 (range: 6.7–290) pmol/l and the mean carcinoembryonic antigen level was 15.7 (range: 1.1–221.9) &mgr;g/l. The mean follow-up period was 19.7 months. Results 18F-DOPA PET/CT was positive in 16 out of 28 (57%) patients, mostly because of metabolically active neck and mediastinal lymph nodes metastases. Previously unknown bone metastases were found in six patients. A positive scan was reported in four patients (25% of positive scans) with a very low calcitonin value of less than 49.9 pmol/l. PET/CT findings led to a change of management and therapy in 16 out of 28 patients, with surgical procedure performed in eight patients, radiotherapy in five patients, and chemotherapy in two patients. Conclusion 18F-DOPA PET/CT is a clinically useful modality in MTC whenever the calcitonin level is increased. There is a clear trend toward more positive scans with the higher calcitonin values, but patients with moderately elevated calcitonin values should also be taken into consideration for molecular imaging with 18F-DOPA PET/CT as the tumor burden in these patients is probably low, enabling further therapy to be individualized and consequently more efficient.