The use of standardized uptake values for assessing FDG uptake with PET in oncology: a clinical perspective

Among clinicians who use positron emission tomography (PET), the standardized uptake value (SUV) is a popular semi-quantitative value that can be easily assessed whenever a PET study is performed under physiological and pathological conditions. It provides an index of regional tracer uptake normalized to the administered dose of tracer. The simplicity of SUV assessment contrasts with the complexity of full quantitative procedures requiring blood sampling and possibly dynamic scanning, which limits patient throughput and significantly increases the workload of a PET centre. Two main clinical conditions/variables affect the significance and usefulness of the SUV: the type and stage of the disease being assessed. Diagnosis, prognosis and therapy monitoring represent the possible uses of SUV. In the above clinical conditions an SUV may provide information about the single lesion in which it is assessed, but the utility of such information depends largely on its integration with all the available clinical and instrumental data.

Thyroid disease in northern Italian children born around the time of the Chernobyl nuclear accident

BACKGROUND

The Chernobyl nuclear accident of 1986 caused a dramatic increase in the incidence of thyroid cancers in exposed children in Belarus. Airborne radioactivity from the reactor spread over northern Italy, where rainout gave rise to low levels of radioactivity at ground level.

PATIENTS AND METHODS

As the latency between exposure to ionising radiation and development of thyroid cancer is thought to be about 10 years, in 1996/1997 all children born in 1985 and 1986 and attending school in an area of Milan, Italy were examined for thyroid nodules. A total of 3949 children were examined by two physicians blinded to the examination and diagnosis of the other. The children were to be reassessed in 2001/2002.

RESULTS

In total, 1% had palpable nodules. The nodule diagnoses were: Hurtle cell adenoma (one), thyroglossal duct cyst (one), thyroid cyst (four) and thyroiditis (four). The prevalence of thyroid disease in the cohort was indistinguishable from that of populations not exposed to radioactive pollution. Only 10 children re-presented for examination 5 years later; all were negative. The direct costs of the study were estimated at 21,200 Euros.

CONCLUSION

The high cost of the study in relation to reassuring lack of increase in thyroid nodule prevalence suggests that further studies are not justified.

Combined treatment of glioblastoma patients with locoregional pre-targeted 90Y-biotin radioimmunotherapy and temozolomide

AIM

In a previous phase I-II study, the safety profile and anti-tumor efficacy of pre-targeting locoregional radioimmunotherapy (LR-RIT), based on the ''3 step'' method, was assessed in 24 high-grade glioma patients. The encouraging results in terms of low toxicity and objective response rate (25%) prompted us to continue our study.

METHODS

An analysis of 73 patients with hystologically confirmed glioblastoma multiforme (GBM), treated with the ''3 step'' (90)Y-biotin based LR-RIT, is herein reported. All patients had a catheter implanted at 2(nd) surgery and underwent at least 2 cycles of LR-RIT (range 2-7) with 2 months interval. Thirty-five out of 73 patients were also treated with Temozolomide (TMZ). Two cycles of TMZ (200 mg/m(2)/day, for 5/28 days) were administered in between each course of LR-RIT. Overall survival (OS) and progression free survival (PFS) were retrospectively calculated.

RESULTS

Stabilization of disease was achieved in 75% of patients, while 25% progressed. In the 38 patients treated with LR-RIT alone, median OS and PFS were respectively 17.5 months (95%CI=[17-20]) and 5 months (95%CI=[4-8]), while in the 35 treated with the combined treatment (LR-RIT+TMZ) respective values were 25 months (95%CI=[23-30]) and 10 months (95%CI=[9-18] (p<0.01). The addition of TMZ to LR-RIT did not increase neurological toxicity, and no major hematological toxicity was observed.

CONCLUSION

These results confirm the safety and the efficacy of (90)Y LR-RIT in recurrent GBM patients; the addition of TMZ significantly improved the overall outcomes; a further controlled prospective, randomized study is fully justified.

Safety of sentinel node biopsy in pregnant patients with breast cancer

BACKGROUND

Lymphoscintigraphy (LS) and sentinel lymph node biopsy (SLNB) have typically been contraindicated for pregnant patients diagnosed with breast cancer because they are considered unsafe.

PATIENTS AND METHODS

Twenty-six premenopausal non-pregnant patients who were candidates for LS underwent peritumoral injection of approximately 12 MBq of 99mTc-HSA nanocolloids. Static [15 min and 16 h post-injection (p.i.)] and whole-body (16 h p.i.) scintigraphic images were acquired. Activity concentration in the urine (0-2, 2-4, 4-8, 8-16 h p.i.) was evaluated by a gamma-counter. Activity in the bloodstream was measured at 4 and 16 h p.i. Thermoluminescent dosimeters (TLD) were placed, before tracer injection, on the injection site, between injection site and epigastrium (two points), and on the epigastrium, umbilicus and hypogastrium, and were removed before surgery.

RESULTS

Scintigraphic images showed no radiotracer concentration except in the injection site and in the sentinel node. In all patients, the total activity excreted within the first 16 h was <2% of the injected activity. Activity in the blood pool was, at each time point, <1% of the injected activity. In 23 of 26 patients, all absorbed dose measurements were lower than the sensitivity of the TLD (<10 microGy); in the remaining three patients, the absorbed doses at the level of epigastrium, umbilicus and hypogastrium were in the following ranges: 40-320, 120-250 and 30-140 microGy, respectively.

CONCLUSIONS

According to our standard technique (12 MBq of 99mTc-HAS), LS and SLNB can be performed safely during pregnancy, since the very low prenatal doses from this diagnostic procedure, when properly performed, do not significantly increase the risk of prenatal death, malformation or mental impairment.

Optimised nuclear medicine method for tumour marking and sentinel node detection in occult primary breast lesions

The aim of this study was to evaluate the feasibility of sentinel node (SN) biopsy in occult breast lesions with different radiopharmaceuticals and to establish the optimal lymphoscintigraphic method to detect both occult lesions and SNs (SNOLL: sentinel node and occult lesion localisation). Two hundred and twenty-seven consecutive patients suspected to have clinically occult breast carcinoma were enrolled in the study. In addition to the radioguided occult lesion localisation (ROLL) procedure, using macroaggregates of technetium-99m labelled human serum albumin (MAA) injected directly into the lesion, lymphoscintigraphy was performed with nanocolloids (NC) injected in a peritumoral (group I) or a subdermal site (group II). In group III, a sole injection of NC was done into the lesion in order to perform both ROLL and SNOLL. Overall, axillary SNs were identified in 205 of the 227 patients (90.3%). In 12/62 (19.4%) patients of group I and 9/79 (11.4%) patients of group III, radioactive nodes were not visualised, whereas SNs were successfully localised in 85 of 86 patients of group II ( P<0.001). Pathological findings revealed breast carcinoma in 148/227 patients (65.2%) and benign lesions in 79 (34.8%). A total of 131 axillary SNs were removed in 118 patients with breast carcinoma; intraoperative examination of the SNs revealed metastatic involvement in 16 out of 96 cases of invasive carcinoma (16.7%). It is concluded that the combination of the ROLL procedure with direct injection of MAA into the lesion and lymphoscintigraphy performed with subdermal injection of radiocolloids represents the method of choice for accurate localisation of both non-palpable lesions and SNs.

Improved radiotracing of oxytocin receptor-expressing tumours using the new [111In]-DOTA-Lys8-deamino-vasotocin analogue

Oxytocin receptors (OTR) have been described in a number of tumours of different origin, and represent a new target for specific radiolabelled oxytocin (OT) analogues in cancer diagnosis and therapy. By linking the DOTA chelating agent to position 8 of the deamino derivative of Lys(8)-vasotocin (dLVT), we obtained a new compound (DOTA-dLVT) with the following characteristics: (1) it forms a monomeric and stable compound that binds to OTR with an affinity comparable to that of the endogenous OT ligand; (2) it is characterised by a very good selectivity profile for the human OTR, with a low affinity binding to the closely related V1a, V1b and V2 vasopressin receptor subtypes; (3) it induces rapid and persistent receptor internalisation and (4) when radiolabelled, [(111)In]-DOTA-dLVT is efficiently and selectively taken up by OTR-positive tumours grown in mice. These features makes radiolabelled DOTA-dLVT a very good candidate for the radiotargeting of OTR-expressing tumours.

90Y-DOTA-D-Phe1-Try3-octreotide in therapy of neuroendocrine malignancies

Somatostatin receptors type 2 (sst(2)) are expressed in high concentration on numerous neudoendocrine tumors. The successful use of radiolabeled somatostatin analogs in imaging promoted further studies in utilizing them in radiopeptide therapy. The somatostatin analog [(90)Y-DOTA-D-Phe(1)-Try3]octreotide (DOTATOC) (DOTA: 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid) possesses favorable characteristic for its therapeutic use; shows high affinity for sst(2), moderately high affinity for sst(5), and intermediate affinity for sst(3); high hydrophilicity; stable and facile labeling with (111) In and (90) Y. In this article we report our experience with (90)Y-DOTATOC in neuroendocrine tumors. Eighty-seven patients with neuroendocrine tumors were treated with a cumulated activity ranging from 7.4 to 20.2 GBq. Most patients responded with stabilization of disease (48%); however, objective responses were observed in 28% of patients (5% complete response). No major acute reactions were observed up to the activity of 5.55 GBq per cycle. The dose limiting was bone marrow toxicity and the maximal tolerated dose was defined as 5.18 GBq.

Novel antitenascin antibody with increased tumour localisation for Pretargeted Antibody-Guided RadioImmunoTherapy (PAGRIT)

The Pretargeted Antibody-Guided RadioImmunoTherapy (PAGRIT) method is based on intravenous, sequential administration of a biotinylated antibody, avidin/streptavidin and (90)Y-labelled biotin. The hybridoma clone producing the monoclonal antitenascin antibody BC4, previously used for clinical applications, was found not suitable for further development because of the production of an additional, nonfunctional light chain. In order to solve this problem, the new cST2146 hybridoma clone was generated. The monoclonal antibody ST2146, produced by this hybridoma, having the same specificity as BC4 but lacking the nonfunctional light chain, was characterised. ST2146 was found able to bind human tenascin at an epitope strictly related, if not identical, to the antigenic epitope of BC4. It showed, compared to BC4, higher affinity and immunoreactivity and similar selectivity by immunohistochemistry. Biodistribution studies of biotinylated ST2146 and three other monoclonal antitenascin antibodies showed for ST2146 the highest and more specific tumour localisation in HT29-grafted nude mice. On the overall, ST2146 appears to be a good alternative to BC4 for further clinical development of PAGRIT.

Peptide receptor radiotherapy: a new option for the management of aggressive fibromatosis on behalf of the Italian Sarcoma Group

The management of aggressive fibromatosis (AF) is problematic, and few options are available to patients unsuitable for surgery and resistant to external-beam radiation therapy (EBRT). We report on two patients with fast-growing recurrences of AF resistant to EBRT who obtained protracted clinical benefits with (90)Y-DOTATOC. (90)Y-DOTATOC should be further investigated in this setting.

Innovation in early breast cancer surgery: radio-guided occult lesion localization and sentinel node biopsy

The surgical management of non-palpable breast lesions remains controversial. At the European Institute of Oncology we have introduced a new technique, radio-guided occult lesion localization (ROLL) to replace standard methods and overcome their disadvantages. Regarding axillary dissection, probe-guided biopsy of the sentinel node (SN) is easy to apply, and the whole procedure is associated to a low risk of false negatives. We suggest that the SN technique should be widely adopted to stage the axilla in patients with breast cancer with clinically negative lymph nodes. Large-scale implementation of the sentinel node technique will reduce the cost of treatment as a result of shorter hospitalization times.

Internal mammary node lymphoscintigraphy and biopsy in breast cancer

BACKGROUND

In patients with breast cancer, sentinel nodes (SNs) are detected outside the axilla in 1-2% of cases after superficial injection of radiocolloid in the breast. We investigated whether deep injection of tracer visualized internal mammary chain lymph (IMC) nodes more often, and assessed the impact of IMC status on disease staging.

METHODS

A total of 400 patients were enrolled in this trial. The study group included 200 patients with T1-T2 N0 breast cancer in an inner quadrant. Radio tracer was injected superficially in 100 (group A), and deeply under the tumor in the others (group B). If an IMC took up tracer in group B patients it was biopsied. An additional 200 patients with outer quadrant lesions were also studied lymphoscintigraphically following superficial (100 patients) or deep (100 patients) injection, but IMC nodes were not biopsied as this would have required an additional surgical excision.

RESULTS

An SN was visualized in the IMC in 65.6% of inner quadrant patients after deep injection and in 2.1% after superficial injection. In outer quadrant patients, deep injection visualized an SN in the IMC in 10% of cases. The IMC SN was located mainly in the 2nd and 3rd intercostal spaces. Radioguided IMC biopsy was performed in 62 patients. Node removal proved simple and risks insignificant. Stage migration occurred in 8% of cases.

CONCLUSIONS

Deep injection allows SN localization in the IMC in 65% of inner quadrant breast lesions. Biopsy of the axillary plus IMC resulted in stage migration in 8% of patients. It is unclear whether this additional information can lead to better survival.

Radioguided occult lesion localisation (ROLL) and surgical biopsy in breast cancer. Technical aspects

BACKGROUND

The surgical management of non-palpable breast lesions remains controversial. At our Institute we have introduced a new technique, radioguided occult lesion localisation (ROLL) to replace standard methods and overcome their disadvantages. In this paper technical aspects of ROLL and results on a large series of patients are reported.

METHODS

We analysed 812 consecutive patients with 816 non-palpable breast lesions detected mammographically or ultrasonically. (99m)Tc-labelled particles of human serum albumin (7-10 MBq) in 0.2 ml saline were injected into the lesion under stereotactic mammographic or ultrasonic guidance. Mammography and scintigraphy were then performed. With ultrasound guidance only scintigraphic control was necessary. The excision biopsy was carried out with the aid of a hand-held gamma-detecting probe, and entire removal of the lesion was verified by X-ray of the specimen.

RESULTS

The tracer was correctly positioned initially in 772/816 (94.6%) cases and at second attempt in another 2. In 42/816 (5.1%) cases, lesion localisation had to be repeated using a traditional approach. X-ray demonstrated the lesion was entirely removed in 770/774 (99.5%) cases. Pathological examination revealed 367 (47.4%) benign lesions and 407 (52.6%) cancers. The cancers were treated by conservative breast surgery in 99.5% of cases.

CONCLUSIONS

We concluded that ROLL enables the surgeon to remove occult breast lesions easily and reliably.

Pretargeted adjuvant radioimmunotherapy with yttrium-90-biotin in malignant glioma patients: a pilot study

In a previous study we applied a three-step avidin-biotin pretargeting approach to target 90Y-biotin to the tumour in patients with recurrent high grade glioma. The encouraging results obtained in this phase I-II study prompted us to apply the same approach in an adjuvant setting, to evaluate (i) time to relapse and (ii) overall survival. We enrolled 37 high grade glioma patients, 17 with grade III glioma and 20 with glioblastoma, in a controlled open non-randomized study. All patients received surgery and radiotherapy and were disease-free by neuroradiological examinations. Nineteen patients (treated) received adjuvant treatment with radioimmunotherapy. In the treated glioblastoma patients, median disease-free interval was 28 months (range=9-59); median survival was 33.5 months and one patient is still without evidence of disease. All 12 control glioblastoma patients died after a median survival from diagnosis of 8 months. In the treated grade III glioma patients median disease-free interval was 56 months (range=15-60) and survival cannot be calculated as only two, within this group, died. Three-step radioimmunotherapy promises to have an important role as adjuvant treatment in high grade gliomas, particularly in glioblastoma where it impedes progression, prolonging time to relapse and overall survival. A further randomized trial is justified.

Receptor-mediated radiotherapy with 90Y-DOTA-D-Phe1-Tyr3-octreotide

A newly developed somatostatin radioligand, DOTA-[D-Phe1-Tyr3]-octreotide (DOTATOC), has been synthesised for therapeutic purposes, because of its stable and easy labelling with yttrium-90. The aim of this study was to determine the dosage, safety profile and therapeutic efficacy of 90Y-DOTATOC in patients with cancers expressing somatostatin receptors. We recruited 30 patients with histologically confirmed cancer. The main inclusion criterion was the presence of somatostatin receptors as documented by 111In-DOTATOC scintigraphy. 90Y-DOTATOC was injected intravenously using a horizontal protocol: patients received equivalent-activity doses in each of three cycles over 6 months. The first six patients received 1.11 GBq per cycle and the four successive groups of six patients received doses increasing in 0.37-GBq steps. Toxicity was evaluated according to WHO criteria. No patient had acute or delayed adverse reactions up to 2.59 GBq 90Y-DOTATOC per cycle (total 7.77 GBq). After a total dose of 3.33 GBq, one patient developed grade II renal toxicity 6 months later. The maximum tolerated dose per cycle has not yet been reached, although transient lymphocytopenia has been observed. Total injectable activity is limited by the fact that the maximum dose tolerated by the kidneys has been estimated at 20-25 Gy. Complete or partial tumour mass reduction occurred in 23% of patients; 64% had stable and 13% progressive disease. It is concluded that high activities of 90Y-DOTATOC can be administered with a low risk of myelotoxicity, although the cumulative radiation dose to the kidneys is a limiting factor and requires careful evaluation. Objective therapeutic responses have been observed.

The humoral immune response to macrocyclic chelating agent DOTA depends on the carrier molecule

The chelating agent 1,4,7,10-tetraazacyclododecane-N,N', N",N"'-tetraacetic acid (DOTA) is used to label monoclonal antibodies (mAbs) and peptides with (90)Y. DOTA allows the generation of clinically useful stable metallic radioconjugates for the treatment of a variety of tumors, but its immunogenicity has remained controversial. In this study, we evaluated the immune response to DOTA in a preclinical mouse model and in patients entered in a clinical trial.

METHODS

Sera were obtained from BALB/c mice injected intraperitoneally or subcutaneously with different doses and formulations of syngeneic and xenogeneic mAbs or peptide (murine mAb Mov19 [mM19]; its chimeric version; murine V/human C ChiMov19 [cM19]; or Tyr(3)-octreotide)-DOTA conjugates. Sera from patients with neuroendocrine tumors, enrolled in a protocol for somatostatin receptor-mediated radionuclide therapy with (90)Y-DOTA-D-Phe(1)-Tyr(3)-octreotide (DOTATOC), were also collected before and after each treatment. Levels and specificity of antibody response to relevant (Mov19, ChiMov19, or Tyr(3)-octreotide) and nonrelevant (human serum albumin) DOTA targets were tested by enzyme-linked immunosorbent assay and competition assays. An anti-DOTA mAb (IgG1) derived from a ChiMov19-DOTA immunized mouse was used, in a competitive radioimmunoassay, to determine the efficiency of DOTA presentation on the different carriers.

RESULTS

Depending on the immunogenicity and dosage of the mAb, a specific anti-DOTA response was revealed in the preclinical system. However, DOTA-peptide conjugate induced no immune-detectable response against either chelator or carrier. DOTA was poorly presented on small peptides, as determined using the anti-DOTA mAb.

CONCLUSION

A humoral response against DOTA is possible, but only as a consequence of the response elicited against the carrier. Octreotide was not immunogenic. Thus, (90)Y-DOTATOC can be considered a safe and useful tool for receptor-mediated radionuclide therapy of somatostatin receptor-overexpressing tumors.

Sentinel node biopsy in head and neck cancer

The purpose of this study was to assess the value of sentinel node (SN) biopsy in oral cancer by means of a lymphoscintigraphic technique and intraoperative detection by blue-dye combined with gamma-ray probe to facilitate identification of the SN. Forty-one T1-T2N0 patients underwent lymphoscintigraphy, SN biopsy, and modified radical neck dissection. An SN was identified in 39 of 41 patients by the combined use of intraoperative blue dye and the probe and was removed. Complete neck dissections were performed and the histological evaluation compared. Thirty-eight SNs in 35 patients were negative at final pathology and correctly predicted the pathological status of the specimens from the full-neck dissections. Five SNs in four patients had micrometastases and were the only metastatic nodes identified. The results of this study on a homogenous series of patients show that SN biopsy is a valuable staging technique in T1 and T2 oral cancer with uninvolved neck, provided that no previous surgery or radiotherapy has altered lymphatic drainage in the oral cavity or in the neck. In a large number of patients, SN biopsy can avoid unnecessary neck dissection and its relevant morphofunctional sequelae.