Point mutations and a large intragenic deletion in SPG11 in complicated spastic paraplegia without thin corpus callosum

BACKGROUND

Hereditary spastic paraplegia (HSP) with thin corpus callosum (HSP-TCC) is a frequent subtype of complicated HSP clinically characterised by slowly progressive spastic paraparesis with cognitive impairment and thin corpus callosum (TCC). SPG11, the gene associated with the major locus involved, encodes spatacsin, a protein of unknown function.

METHODS

Different types of mutations were identified in patients with the complex form of HSP (cHSP) including TCC. We screened a series of 45 index patients with different types of cHSP with (n = 10) and without (n = 35) TCC.

RESULTS

Ten mutations, of which five are novel, were detected in seven patients. Of importance, three out of seven mutated patients present with cHSP without TCC. Among the novel mutations identified, we characterised a large intragenic rearrangement deleting 2.6 kb of the SPG11 gene. The rearrangement is due to non-allelic homologous recombination between Alu sequences flanking the breakpoints.

CONCLUSIONS

These findings expand the mutation spectrum of SPG11 and suggest that SPG11 mutations may occur more frequently in familial than sporadic forms of cHSP without TCC. This helps to define further clinical and molecular criteria for a correct diagnosis of the SPG11 related form of cHSP. In addition, the intragenic deletion detected here, and the mechanism involved, both provide clues to address the issue of SPG11 missing mutant alleles previously reported.

Imatinib mesylate in advanced chordoma: A multicenter phase II study

10003

Background: The antitumor activity of Imatinib in chordoma was preliminarily shown in a compassionate series of 18 pts. This prospective Phase II collaborative study was planned thereafter. Methods: From November 2004 to April 2006, 55 pts with progressing advanced chordoma were enrolled in this Phase II study. Cases were provided by 13 Italian centers and one Swiss. Imatinib was given at the planned dose of 800 mg/day (for a received dose intensity in excess of 600 mg/day), until evidence of progression. Mean age was 59 yrs, (range 24–86); PS 0–3 (=2 in 22%); site of origin was the sacrum in 60%, spine in 25%, skull base in 15%; the disease was metastatic in 43% and localized advanced in 57%. All tumors were positive for PDGFRB/PDGFB. Results: In 44 pts evaluable for antitumor response, 37 (84%) had stable disease as their best RECIST response, which was maintained for more than 6 months in 32, for a clinical benefit rate (CR+PR+SD=6mos) of 73%. In 7 of these SD pts (16%), a degree of objective tumor shrinkage was reported. Centralized radiological review is underway, focusing on non-dimensional, “tissue” response, and results thereof will be presented. In 39 pts who were symptomatic at baseline, subjective improvement of symptoms was claimed by 25 (64%). On ITT analysis, median PFS was 32 wks, with 38% of pts free from progression at one year, and 16% on treatment at 18 months. Most frequent drug-related adverse events were nausea (35%) and vomiting (30%), edema (30%), skin rash (28%), G1–3 anemia (24%), asthenia (17%), G1–3 leucopenia (13%). Conclusions: Preliminary evidence of Imatinib efficacy in chordoma was provided in a single-institution, compassionate setting, and is now confirmed by this multicenter Phase II study. On the basis of these data, an international effort on molecular-targeted therapy with Imatinib in advanced chordoma is warranted.

No significant financial relationships to disclose.

Adding cisplatin (CDDP) to imatinib (IM) re-establishes tumor response following secondary resistance to IM in advanced chordoma

10038

Background: IM is active in advanced chordoma, possibly by targeting PDGFRB. Secondary progressions following response have been observed. The case of a pt with sacral chordoma and lung adenocarcinoma responding to CDDP soon after stopping IM prompted us to combine the two drugs in IM-resistant advanced chordoma. Methods: Since February 2006, 6 advanced chordoma pts (F=4, M=2; mean age 56 yrs; PS 0–2) with a secondary resistance to IM following previous response, have started IM 400 mg/day + low-dose CDDP (25 mg/sqm/wk) on an individual use basis. Results: One pt completed her treatment (after 7 mos, reaching a total dose of CDDP = 525 mg/sqm), and, following ablation of the residual lesion, is now continuing on IM alone. The remaining pts are on combination therapy (4 for <2 mos). After 4–6 weeks, 4 pts had a PET response (SUV max decrease ≥25%), with subjective improvement and stable disease on CT/MRI, while 2 were metabolically stable. In the 2 pts treated for >12 weeks, a minor dimensional response was observed after 3 mos. The single pt who completed combination therapy had a continuous PET scan improvement throughout treatment, and pre-ablation biopsy of residual tumor showed histological signs of tumor response (marked cellular depletion and sclerohyalinosis in most of the sample, with residual tumor cells intermingled with inflammatory ones). Conclusions: In 4 out of 6 advanced chordoma pts progressing on IM, a tumor response was re-established by adding CDDP, and 2 pts treated for a relatively longer interval showed dimensional tumor shrinkage. Four more pts are starting therapy, and results will be updated. An independent cytotoxic effect of CDDP cannot be ruled out, but sensitivity of chordoma to CDDP is at best occasional. The combination of IM and CDDP may have synergic activity in chordoma.

[Table: see text]

Cetuximab (C225) in recurrent and/or metastatic salivary gland carcinomas (RMSGCs): A monoinstitutional phase II study

5547

Background: EGFR is expressed in 70% of salivary gland carcinomas (SGC). Investigations of anti EGFR treatment seems rational. Aim: To assess activity of C225 in patients with RMSGCs in terms of clinical benefit (CB), defined as occurrence of objective response (CR or PR) or stable disease (SD) for at least 6 months. To correlate treatment outcome with skin toxicity degree and EGFR analysis. Methods: One prior chemotherapy regimen was allowed, except for pts with adenoid cystic carcinoma (ACC) and acinic cell carcinoma for whom 2 lines were allowed. Prior exposure to targeted treatment was not allowed. C225 (Erbitux) was administered iv weekly at 400 mg/mq followed by 250 mg/mq until disease progression, major toxicity or voluntary discontinuation. MRI or CT and PET scan were performed every 6 weeks q4, and q12 thereafter. RECIST response criteria and CTC 3.0. were adopted. Results: From April to December 2005, 30 RMSGCs pts (20 F/10 M; median age 50 yrs), 50% with major SGC, were enrolled. Histotypes were: 23 ACC; 2 mucoepidermoid; 3 myoephitelial; 1 cystadenocarcinoma and 1 acinic cell carcinoma. Thirteen pts (43%) received prior chemotherapy. Localregional (LR) and metastatic (M) disease was present in 13 cases, M in 12, and LR in 5. A median number of 11 drug administration (range 2–31) was given. G2 skin toxicity was recorded in 24 cases. G2 fatigue in 2. At a median FU of 6 months (range 0–8), 2 pts died of PD. Of 22 pts evaluable for response with ≥ 3 months of potential FU, there were 11 SD, 9 PD, while 2 pts refused to continue after 1 months. Currently, 7 of these pts are progression-free at ≥ than 6 months, qualifying for CB definition according to study protocol. Preliminary EGFR analysis showed a high or intermediate expression score in 5 (3 ACC, 1 acinic cell, 1 cistoadenocarcinoma) out of 7 cases, no gene amplification nor chromosome 7 polisomy were found in 3 of 3 analysed ACC. PET results are under evaluation. Conclusions: Hints of activity of C225 in RMSGCs were observed. The early analysis for the CB rate in 23 pts is planned for April 2006, when all of them will have a potential follow-up of ≥ 6 months, and results thereof will be reported.

[Table: see text]

Ganciclovir is associated with low or undetectable Epstein-Barr virus DNA load in cerebrospinal fluid of patients with HIV-related primary central nervous system lymphoma

BACKGROUND

Epstein-Barr virus (EBV) is pathogenically linked to human immunodeficiency virus (HIV)-related primary central nervous system lymphoma (PCNSL) and is found in virtually all HIV-related PCNSL cases. The objective of this study was to assess the effect of ganciclovir on EBV DNA replication in patients with HIV-related PCNSL.

PATIENTS AND METHODS

EBV DNA was measured by real-time polymerase chain reaction in cerebrospinal fluid and plasma samples from 25 patients with HIV-related PCNSL. Eight of these patients were receiving ganciclovir for concurrent cytomegalovirus infections.

RESULTS

EBV DNA was detected in cerebrospinal fluid samples obtained from 15 (88%) of 17 ganciclovir-untreated patients and 4 (50%) of 8 ganciclovir-treated patients (P = .028). EBV DNA load was significantly lower for treated patients, compared with untreated patients (median value, 2.15 vs. 4.16 log copies/mL; P = .001). Analysis of sequential cerebrospinal fluid samples from 7 patients showed that EBV DNA decreased in samples obtained from 2 patients following the start of ganciclovir administration but did not decrease in samples obtained from the 5 untreated patients. In addition, patients who received ganciclovir survived longer than the untreated patients (median duration of survival, 181 vs. 72 days; P = .006).

CONCLUSION

The effect of ganciclovir on EBV DNA load in cerebrospinal fluid supports the hypothesis that EBV is replicating in patients with PCNSL. This observation, together with the effect of ganciclovir therapy on patient survival, suggests that this drug might be useful for the management of PCNSL.

Itraconazole versus fluconazole for prevention of fungal infections in patients receiving allogeneic stem cell transplants

Prophylactic fluconazole prevents candidiasis; however, this drug has no activity against molds. We performed a randomized trial to determine whether prophylactic itraconazole prevents invasive mold infections (IMIs). A total of 304 patients receiving allogeneic stem cell transplants (SCT) were randomized to receive fluconazole (400 mg/d) or itraconazole (oral solution 2.5 mg/kg 3 times daily, or intravenous 200 mg daily) for 180 days after SC transplantation, or until 4 weeks after discontinuation of graft-versus-host disease (GVHD) therapy. Proven or probable invasive fungal infections (IFI) were evaluated by intent-to-treat and "on-treatment" analyses. More patients in the itraconazole arm developed hepatotoxicities, and more patients were discontinued from itraconazole because of toxicities or gastrointestinal (GI) intolerance (36% versus 16%, P <.001). Intent-to-treat analysis demonstrated no difference in the incidence of IFI during the intended study period (fluconazole 16% versus itraconazole 13%, P =.46); however, fewer patients in the itraconazole arm developed IFI on treatment (fluconazole 15% versus itraconazole 7%, P =.03). Itraconazole provided better protection against IMI (fluconazole 12% versus itraconazole 5%, P =.03), but similar protection against candidiasis (3% versus 2%, P =.69). There was no difference in overall or fungal-free survival. Itraconazole appears to prevent IMI in the subset of patients who tolerate the drug; however, toxicities and poor tolerability limit its success as prophylactic therapy.

Cyclophosphamide metabolism is affected by azole antifungals

We performed a randomized trial to compare the safety and efficacy of itraconazole with fluconazole in preventing fungal infections in patients undergoing allogeneic stem cell transplantation (SCT). Itraconazole (intravenous 200 mg daily, or oral solution 2.5 mg/kg 3 times daily) and fluconazole (intravenous or oral, 400 mg daily) were administered with the start of conditioning therapy, until at least 120 days after SCT. After enrollment of the first 197 patients, a data and safety monitoring board reviewed potential drug-related toxicities. Patients who received itraconazole developed higher serum bilirubin and creatinine values in the first 20 days after SCT, with highest values in patients who received itraconazole concurrent with cyclophosphamide (CY) conditioning. Analysis of CY metabolism in a subset of patients demonstrated higher exposure to toxic metabolites among recipients of itraconazole compared with fluconazole. These data suggest that azole antifungals, through differential inhibition of hepatic cytochrome P-450 isoenzymes, affect CY metabolism and conditioning-related toxicities.

Infectious complications after autologous CD34-selected peripheral blood stem cell transplantation

CD34 selection of peripheral hematopoietic blood stem cell products has been applied to reduce the risk of relapse after an autologous transplantation. However, CD34 selection is also associated with a significant reduction in T-cells, natural killer cells, and monocytes, and these reductions may influence immune reconstitution and thus increase the risk for infections. An increased incidence of cytomegalovirus (CMV) disease in patients receiving CD34-selected transplants has been reported. In this study, the incidence rate of infections other than CMV is reported in 32 patients who underwent myeloablative therapy followed by the infusion of CD34-selected autologous peripheral blood stem cells (PBSC) and compared to the rate in a contemporaneous group of 273 patients who received unselected autologous PBSC during the same time period. Infection surveillance and prevention strategies were identical between the 2 groups. More non-CMV infections occurred in the recipients of CD34-selected PBSC than in recipients of unselected PBSC (78% versus 30%, P < .0001). The differences in the rates of viral infections were mainly due to dermatomal and disseminated varicella-zoster virus (VZV) (any VZV, 26% versus 4%, P = .002; disseminated VZV, 11% versus 0.3%, P = .03) and parainfluenza 3 virus infections (13% versus 3%, P = .04). Bacterial infections were also more common among CD34-selected PBSC transplant recipients (34% versus 16%, P = .01), whereas fungal infections were not significantly different between the groups. In multivariable logistic regression models, the effect of CD34 selection on infection risk remained significant for viral infections and overall non-CMV infections. Infection-related mortality was not significantly different between the groups. In conclusion, the incidence of viral and bacterial infections appears to be increased in recipients of CD34-selected autologous PBSC transplants. Because the risk for infections approaches that seen in allogeneic transplant recipients, infection surveillance, diagnostic work-up, and prevention strategies similar to those used in allogeneic recipients are warranted.

Circulating tumor markers and nuclear medicine imaging modalities: breast, prostate and ovarian cancer

Clinical oncologists have always shown great interest in circulating tumor markers. There are several markers that in the clinical routine are a signal of particular tumor types; some of them are strictly tissue-specific such as prostatic specific antigen (PSA) for prostatic cancer, AFP and HCG for germ cell tumors of the testis and ovary, others such as CA 15.3, CA125, CEA or cytokeratins are less specific since their elevations can be found in different varieties of cancers even if they are preferentially associated to a certain tumor type, thus are considered markers for breast, ovarian cancer and colon adenocarcinoma. The most useful clinical applications of these parameters is their determination during the follow-up of the treated patients, in order to detect the tumor recurrence early, and also to evaluate the evolution of the disease by monitoring the treatment responses. During follow-up, increasing levels of tumor markers can be observed even several months before the clinical demonstration of cancer recurrence. The association of tumor marker tests with imaging modalities can lead to several advantages: the first is to confirm the diagnosis of relapses, possibly before the appearence of the related clinical symptoms due to tumor growth; the second is to localize the sites of lesions, while tumor markers provide only a general indication of the existence of metastases; the third is to make possible a correct whole body restaging. In the assessment of cancer response tumor markers are often very reliable and their changes are faster than the morphological ones. Among all the imaging modalities, nuclear medicine plays an important role in detecting recurrences and metastatic localizations as it is able to investigate functional rather than morphological aspects of tumors, and provide different information in comparison to morphologic imaging. In addition, the scintigraphic techniques offer the possibility to evaluate treatment responses, confirming or not the information from biochemical changes. This review aims to show some examples (breast, prostate and ovarian cancer) in which the combination of nuclear medicine imaging modalities and tumor marker tests is proposed for clinical practice. The advantages and some critical aspects are discussed on the basis of the clinical findings and the most important clinical indications are described.

Epidemiology and outcome of mould infections in hematopoietic stem cell transplant recipients

Reports have focused on the emergence of moulds as pathogens in recipients of hematopoietic stem cell transplants. To review the incidence of and risks for mould infections, we examined the records of 5589 patients who underwent hematopoietic stem cell transplantation at the Fred Hutchinson Cancer Research Center (Seattle) from 1985 through 1999. After 1992, the incidence of invasive aspergillosis increased in allograft recipients and remained high through the 1990s. Infections with non-fumigatus Aspergillus species, Fusarium species, and Zygomycetes increased during the late 1990s, especially in patients who received multiple transplants. Although infection caused by Scedosporium species was common in patients who had neutropenia, infection caused by Zygomycetes typically occurred later after transplantation, when patients had graft-versus-host disease. The overall 1-year survival rate was equally poor (similar20%) for all patients with mould infections. The results of the present study demonstrate the changing epidemiology of mould infections, emphasizing the increasing importance of amphotericin B--resistant organisms and the differences in risks and outcome of infection with different filamentous fungi.

PET imaging in breast cancer

The basis of tumour imaging with PET is a specific uptake mechanism of positron emitting radiopharmaceuticals. Among the potential tracers for breast cancer (fluorodeoxyglucose, methionine, tyrosine, fluoro-estradiol, nor-progesterone), 2-deoxy-2-fluoro-D-glucose labelled with fluorine (FDG) is the most widely used radiopharmaceutical because breast cancer is particularly avid of FDG and 18F has the advantages of a relatively long physical half-life. Mammography is the first choice examination in studying breast masses, due to its very good performances, an excellent compliance and the best value regarding the cost/effectiveness aspects. However FDG-PET revealed to be effective in the study of patients with ambiguous mammographies. The FDG uptake in tissue correlates with the histological grade and potential aggressiveness of breast cancer and this may have prognostic consequences. Besides the evaluation of breast lesions, FDG-PET shows a great efficacy in staging lymph node involvement prior surgery and this could have a great value in loco-regional staging. Whole body PET provides also information with regard to metastasis localizations both in soft tissue and bone, and plays an important clinical role mainly in detecting recurrent metastatic disease. In fact for its metabolic characteristics PET visualizes regions of enhanced metabolic activity and can complements other imaging modalities based on structural anatomic changes. Even though CT and MRI show superior resolution characteristics, it has been demonstrated that PET provides more accurate information in discriminating between viable tumour, fibrotic scar or necrosis. Several clinical evidences demonstrated that FDG-PET is also able to predict wether cancer will respond to the therapy, or, when applied at the end of the treatment, it can assess the response to the therapy. These statements are coming from the examination of more than 2000 breast cancer patients included in 88 articles or abstracts on studies in which FDG-PET was used for breast cancer detection.

Axillary lymph node staging in breast cancer by 2-fluoro-2-deoxy-D-glucose-positron emission tomography: clinical evaluation and alternative management

BACKGROUND

Surgical removal of axillary lymph node and histologic examination for metastases are used to determine whether adjuvant treatment is necessary for patients with breast cancer. Axillary lymph node dissection (ALND) is a costly procedure associated with various side effects, and 80% or more of patients with tumors of 20 mm or less are lymph node negative and might avoid ALND. In this study, we evaluated whether an alternative, noninvasive method--i.e., positron emission tomography (PET) with 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG)-- could be used to determine axillary lymph node status in patients with breast cancer.

METHODS

One hundred sixty-seven consecutive patients with breast cancers of 50 mm or less (range = 5-50 mm; mean = 21 mm) scheduled for complete ALND were studied preoperatively with FDG-PET, and then PET and pathology results from ALND were compared. All statistical tests were two-sided.

RESULTS

The overall sensitivity, specificity, and accuracy of lymph node staging with PET were 94.4% (PET detected 68 of 72 patients with axillary involvement; 95% confidence interval [CI] = 86.0% to 98.2%), 86.3% (82 of 95 patients without axillary involvement; 95% CI = 77.8% to 91.9%), and 89.8% (150 of 167 patients with breast cancer; 95% CI = 84.2% to 93.6%), respectively. Positive- and negative-predictive values were 84.0% (68 patients with histologically positive lymph nodes of 81 patients with positive FDG-PET scan; 95% CI = 74.2% to 90.5%) and 95.3% (82 patients with histologically negative lymph nodes of 86 patients with negative FDG-PET scan; 95% CI = 88.2% to 98.5%), respectively. When PET results for axillary metastasis were analyzed by tumor size, the diagnostic accuracy was similar for all groups (86.0%-94.2%), with higher sensitivity for tumors of 21-50 mm (98.0%) and higher specificity for tumors of 10 mm or less (87.8%), and the range was 93.5%-97.3% for negative-predictive values and 54.5%-94.1% for positive-predictive values. Among the 72 patients with axillary involvement, PET detected three or fewer metastatic lymph nodes in 27 (37.5%) patients, about 80% of whom had no clinically palpable axillary lymph nodes.

CONCLUSIONS

Noninvasive FDG-PET appears to be an accurate technique to predict axillary status in patients with breast cancer and thus to identify patients who might avoid ALND. These results should be confirmed in large multicenter studies.

Uptake of tritiated thymidine, deoxyglucose and methionine in three lung cancer cell lines: deoxyglucose uptake mirrors tritiated thymidine uptake

[(18)F]-fluorodeoxyglucose and [(11)C]-methionine are tracers which are widely used in oncological positron emission tomography. This study has been designed to assess the deoxyglucose and methionine uptake behaviour in three cell lines from different lung cancer histotypes. Tracer uptake was compared with proliferative activity as determined by growth curves and tritiated thymidine uptake. Deoxyglucose paralleled thymidine in all cell lines, peaking in the lag phase, decreasing throughout the exponential phase, and reaching its minimum in the plateau phase. The correlation was statistically verified and Spearman's rho ranged from 0.79 to 0.99. The absolute methionine uptake was always highest and always peaked on day 2, followed by a quite rapid decrease. However, besides the delay in maximum uptake, methionine incorporation was also related to proliferation, although the statistical correlations were weaker. These results show for the first time a clear correlation between deoxyglucose uptake and cell proliferation in a model comparing tracer uptake in different growth phases. Although delayed, methionine uptake was also related to cell growth and its greater intensity could be of interest for clinical use.

Positron emission tomography (PET) and other nuclear medicine modalities in staging gastrointestinal cancer

Gastrointestinal (GI) cancers account for the second highest number of new tumor cases and deaths per year in the United States and Western Europe. The most frequently involved sites are, in descending order, the colorectum, stomach, pancreas, liver, bile duct, and esophagus. The most common tumor type is adenocarcinoma. Among the epithelial cancers, great attention has recently been given to the tumors of neuroendocrine origin. These concepts are relevant because nuclear medicine imaging is based on visualization by means of a particular uptake of radiolabelled tracers in cancer cells that concentrate the radioactive signal. This signal is detected and reconstructed in planar or tomographic images. Different radiopharmaceuticals have been proposed for diagnostic application in oncology (such as radiolabelled monoclonal antibodies (MAbs), receptor tracers, and positron-emitting radiopharmaceuticals), and they are currently used as tracers for tumor detection with different modalities and techniques. Most of these techniques demonstrate their clinical usefulness in the diagnosis of GI cancer. This work is not intended to be a comprehensive review of all the extensive experience and possibilities of nuclear medicine for the diagnosis of GI tumors; rather, it aims to summarize the current status of the most important approaches and their main indications in staging GI cancers.

Virological, clinical, and ophthalmologic features of cytomegalovirus retinitis after hematopoietic stem cell transplantation

We identified 10 patients who developed cytomegalovirus (CMV) retinitis after HSCT during a 14-year period. The median day of diagnosis of CMV retinitis after transplantation was day 251 (range, days 106--365). CMV retinitis was associated with CMV serostatus of donor or recipient (P=0.01), CMV reactivation before day 100 (P=0.007), delayed lymphocyte engraftment (P<0.05), and chronic graft versus host disease (GVHD; P<0.001). In allogeneic recipients of HSCT who were alive at day 100 after transplantation and had chronic clinical extensive GVHD, the incidence of GVHD was 1.4% (8 of 577). Five of 10 patients had other manifestation of CMV disease before retinitis occurred (4 with gastrointestinal disease and 1 with interstitial pneumonia; median time, 70 days before onset of CMV retinitis; range, 58--279 days), and 4 others had CMV excretion. CMV retinitis was bilateral in 4 patients; 9 of 10 patients had ocular symptoms (i.e., decreased vision and floaters). Six of 7 patients responded well to ganciclovir or foscarnet systemic treatment, 1 improved only after switching to cidofovir, and 1 patient who received a transplant in 1983 did not respond to acyclovir treatment. In conclusion, CMV retinitis is an uncommon late complication after HSCT that occurs mainly in seropositive allograft recipients with previous CMV reactivation and chronic GVHD, and with delayed engraftment of lymphocytes.

Which kinds of lymph node metastases can FDG PET detect? A clinical study in melanoma

The purposes of this study were to establish the diagnostic accuracy of FDG PET for lymph node metastases and to determine the smallest detectable volume of disease.

METHODS

Using FDG PET, we preoperatively studied 56 lymph node basins in 38 patients with a clinical or instrumental diagnosis of lymph node metastases from melanoma. All lymph node basins underwent node dissection. The FDG PET results were compared with the postoperative histopathology results. PET images were obtained using a GE 4096 WB scanner, after injection of a mean activity of 496 MBq (range, 366-699 MBq) of FDG.

RESULTS

The efficacy of FDG PET in the diagnosis of involved lymph node basins was good. Sensitivity was 95% (35/37); specificity, 84% (16/19); accuracy, 91% (51/56); positive predictive value, 92% (35/38); and negative predicative value, 89% (16/18). Metastases were shown histologically in 114 of 647 surgically removed lymph nodes. FDG PET detected 100% of metastases > or = 10 mm, 83% of metastases 6-10 mm, and 23% of metastases < or = 5 mm. Moreover, FDG PET had high sensitivity (> or = 93%) only for metastases with more than 50% lymph node involvement or with capsular infiltration.

CONCLUSION

Our study shows that FDG PET has a reasonable sensitivity and specificity for detecting the presence or absence of lymph node metastases in patients with melanoma. However, even if able to detect small volumes of subclinical macroscopic disease, FDG PET cannot detect subclinical microscopic disease with acceptable sensitivity. The specificity of FDG PET is good, but some false-positive results may occur.