Efficacy of 90Y ibritumomab-tiuxetan treatment in a case of resistant gastric MALT non-Hodgkin's lymphoma

Treatment modalities for resistant/relapsing gastric mucosa associated lymphoid tissue (MALT) non-Hodgkin's lymphoma (NHL) are not yet well standardized. In the past, most patients were treated surgically with a gastrectomy, while, more recently, radiotherapy and systemic approaches (chemotherapy and immunotherapy) have been used with improving results.Here, we report the case of a patient affected by MALT NHL resistant to antibiotics, chemotherapy and immunotherapy, who achieved a durable complete remission after radio-immunotherapy treatment with Zevalin ((90)Y ibritumomab-tiuxetan), administered in a single-standard dose. This observation must be confirmed on a larger series but suggests that radio-immunotherapy may be a valid approach in treating relapsing MALT NHL patients, or those resistant to conventional therapies, so avoiding more aggressive and toxic approaches.

Algorithmic reproduction of asymmetry and border cut-off parameters according to the ABCD rule for dermoscopy

BACKGROUND

Semiquantitative algorithms were applied to dermoscopic images to improve the clinical diagnosis for melanoma.

OBJECTIVE

The aim of the study was to develop a computerized method for automated quantification of the 'A' (asymmetry) and 'B' (border cut-off) parameters, according to the ABCD rule for dermoscopy, thus reproducing human evaluation.

METHODS

Three hundred and thirty-one melanocytic lesion images, referring to 113 melanomas and 218 melanocytic nevi, acquired by means of a digital videodermatoscope, were considered. Images were evaluated by two experienced observers and by using computer algorithms developed by us. Clinical evaluation of asymmetry was performed by attributing scores to shape asymmetry and asymmetry of pigment distribution and structures, whereas computer evaluation of shape and pigment distribution asymmetries were based on the assessment of differences in area and lightness in the two halves of the image, respectively. Borders were evaluated both by clinicians and by the computer, by attributing a score to each border segment ending abruptly. Differences between nevus and melanoma values were evaluated using the chi-square test, while Cohen's Kappa index for agreement was employed for the evaluation of the concordance between human and computer.

RESULTS

Pigment distribution asymmetry appears the most striking parameter for melanoma diagnosis both for human and for automated diagnosis. A good concordance between clinicians and computer evaluation was achieved for all asymmetry parameters, and was excellent for border cut-off evaluation.

CONCLUSIONS

These algorithms enable a good reproduction of the 'A' and 'B' parameters of the ABCD rule for dermoscopy, and appear useful for diagnostic and learning purposes.

High dose 90Yttrium ibritumomab tiuxetan with PBSC support in refractory-resistant NHL patients: Preliminary results of a phase I/II study

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Background: Therapeutic options are limited in the treatment of relapsing NHL pts not suitable to HDCT. 90Yttrium ibritumomab tiuxetan (Zevalin) is active in DLBCL at 0.4 mCi/kg, but duration of response is usually short. We present feasibility and toxicity results of a phase I/II study of HD-Zevalin with PBSC support in resistant-refractory NHL pts. From 04/04 to 11/05, 14 pts were enrolled. Median age was 68ys. 13/14 pts had advanced stage disease (III/IV) at diagnosis. 8 DLBCL, 4 MCL, 1 FL G3, 1 transformed MZL. Median number of prior therapies were 3, including rituximab, RT and HD-CT. Methods: 3 dose levels were fixed: 0.8, 1.2, 1.5 mCi/kg. 4 pts received 0.8, 4 pts 1.2 and 6 pts 1.5 mCi/kg. 1wk prior to Zevalin all pts underwent dosimetry: if no abnormal uptake was observed they received the planned dose. On d13 pts received PBSC previously harvested. On d28 from reinfusion (+41 from Zevalin) engraftment was considered to be delayed if ANC <1.0×109/L or PLT<20.0×109/L. Results: Dosimetry showed acceptable radiation-absorbed doses to uninvolved organs, reaching max 20Gy. Only 1pt received 30Gy to the liver without developing toxicity. The median radiation-activity delivered was 90 mCi (range 57–150): 8 pts received a dose within 80 and 100 and 6 pts >100 mCi. Mean dose to red marrow: 0.8±0.2 mGy/MBq. All pts but 1 engrafted promptly. PLT/ANC count nadirs were observed 21/17 days after Zevalin (median values: 11×109/L and 0.01×109/L). No statistically significant difference in terms of hematological toxicity exists in PLT-recovering for pts receiving 1.5 mCi/kg and it is probably influenced by PLT count at baseline and by the several treatment previously received. Non-haematologic toxicity: 1 febrile neutropenia and 1HZV at 2nd level; 1 febrile neutropenia, 1 G3 liver toxicity, 1 bacterial pneumonia, 1HZV, 1HCV reactivation (pt died 4 months after treatment) at the 3rd level. 13/14pts are evaluable for response: 6CR, 2PR, 5PD. Conclusions: Zevalin at myeloablative activity with PBSC is feasible. It could be safely delivered in elderly and heavily pretreated pts, including those who previously received HDCT. Efficacy and mild toxicities suggest further investigation. We are continuing enrollment, including pts who previously received no more than 2 lines of CT.

No significant financial relationships to disclose.

Practical color calibration for dermoscopy, applied to a digital epiluminescence microscope

BACKGROUND/PURPOSE

The assessment of colors is essential for melanoma (MM) diagnosis, both for pattern analysis on dermoscopic images, and when using semiquantitative methods. Our aim was to provide a simple, precise characterization and reproducible calibration of the color response for dermoscopic instruments.

METHODS

Three processes were used to correct the non-uniform illumination pattern of the instrument, to easily estimate the camera gamma settings and to describe the color space conversion matrices required to produce standard images, in any color space. A specific color space was also developed to optimize the representation of dermatoscopic colors. The calibration technique was tested both on synthetic reference surfaces and on real images by comparing the difference between the images colors obtained with two different equipments.

RESULTS

The differences between the images acquired by means of the two instruments, calculated on the reference patterns after calibration, were up to 10 times lower then before, while comparison of histograms referring to real images provided an improvement of about seven times on average.

CONCLUSIONS

A complete workflow for dermatologic image calibration, which allows the user to continue using his own software and algorithms, but with a much higher informative content, is presented. The technique is simple and may improve cooperation between different research centers, in teleconsulting contexts or for result comparisons.

Pigment distribution in melanocytic lesion images: a digital parameter to be employed for computer-aided diagnosis

BACKGROUND/PURPOSE

Since in early melanoma (MM) and especially in in situ MM differential structures, which are diagnostic for MM may be lacking, pigment distribution asymmetry represents an important diagnostic feature. Our aim was to automatically assess pigment distribution in images referring to MMs, atypical nevi (AN) and clearly benign nevi (BN), and to evaluate the diagnostic capability of numerical parameters describing a non homogeneous distribution of pigmentation.

METHODS

An image analysis program enabling the numerical assessment of pigment distribution in melanocytic lesions (ML), based on evaluation and comparison of red, green, blue (RGB) colour components inside image colour blocks, was employed on 459 videomicroscopic digital images, referring to 95 MMs, 76 AN and 288 BN.

RESULTS

Significant differences in pigment distribution parameters (mean RGB distance, variance and maximum distance) between the three ML populations were observed, permitting a good discrimination of MMs. On the test set comprising 230 lesion images, the area under the curve value of the receiver operating characteristic curve was 0.933. For a D score equal to 0, corresponding to the best diagnostic accuracy (86.6%), a sensitivity of 87.5% and a specificity of 85.7% were obtained.

CONCLUSION

This original evaluation method for digital pigment distribution, based on mathematical description and comparison of colours in different image blocks, provides numerical parameters to be implemented in image analysis programs for computer-aided MM diagnosis.

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.

Computer description of colours in dermoscopic melanocytic lesion images reproducing clinical assessment

BACKGROUND

The assessment of colours is essential for the diagnosis of malignant melanoma (MM), both for pattern analysis on dermoscopic images, and when employing semiquantitative methods.

OBJECTIVES

To develop a computer program for colour assessment in MM images mimicking the human perception of lesion colours, and to compare the automatic colour evaluation with one performed by human observers.

METHODS

A colour palette comprising six colour groups (black, dark brown, light brown, blue-grey, red and white) was created by selecting single colour components inside melanocytic lesion images acquired by means of a digital videomicroscope, and was implemented in the image analysis program. Subsequently, colours were assessed by the computer program on 331 melanocytic lesion images composing our image database, and the results were compared with the evaluation of lesion colours performed by the clinician.

RESULTS

The black, white and blue-grey colours were more frequently found in MMs than in naevi, both by the clinicians and by the computer. In MM images we observed 4.27 +/- 1.14 colours (mean + or - SD) per lesion, as opposed to 3.22 +/- 0.68 in naevi. The correlation between clinical and computer evaluation of the colours was very good, with a value of 0.781 for overall assessment.

CONCLUSIONS

This innovative method for automatic colour evaluation, reproducing clinical assessment of melanocytic lesion colours, may provide numerical parameters to be employed for computer-aided diagnosis of MM.

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.

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.

Pre-targeted locoregional radioimmunotherapy with 90Y-biotin in glioma patients: phase I study and preliminary therapeutic results

The aim of this study was to determine the maximum-tolerated dose, of a pre-targeting three-step (3-S) method employing 90Y-biotin in the locoregional radioimmunotherapy (RIT) of recurrent high grade glioma, and to investigate the antitumor efficacy of this new treatment. Twenty-four patients with recurrent glioma underwent second surgical debulking and implantation of a catheter into the surgical resection cavity (SRC), in order to introduce the radioimmunotherapeutic agents [biotinylated monoclonal antibody (MoAb), avidin and 90Y-biotin]. Eight patients with anaplastic astrocytoma (AA) and 16 patients with glioblastoma (GBM) were injected with biotinylated anti-tenascin MoAb (2 mg), then with avidin (10 mg; 24 h later) and finally 90Y-biotin (18 h later). Each patient received two of these treatments 8-10 weeks apart. The injected activity ranged from 0.555 to 1.110 GBq (15-30 mCi). Dosage was escalated by 0.185 GBq (5 mCi) in four consecutive groups. The treatment was well tolerated without acute side effects up to 0.740 GBq (20 mCi). The maximum tolerated activity was 1.110 GBq (30 mCi) limited by neurological toxicity. None of the patients developed hematologic toxicity. In three patients infection occurred around the catheter. The average absorbed dose to the normal brain was minimal compared with that received at the SRC interface. At first control (after 2 months), partial (PR) and minor (MR) responses were observed in three GBM (1 PR; 2 MR) and three AA patients (1 PR; 2 MR) with an overall objective response rate of 25%. Stable disease (SD) was achieved in seven GBM and five AA patients (50%). There was disease progression in six GBM patients (25%), but in none of the AA patients. At the dosage of 0.7-0.9 GBq per cycle, locoregional 3-S-RIT was safe and produced an objective response in 25% of patients. Based on these encouraging results, phase II studies employing 3-S-RIT soon after first debulking are justified.

Is there a role for sentinel node biopsy in early N0 tongue tumors?

BACKGROUND

Detecting metastases to the cervical lymph nodes is the main problem in the management of squamous cell carcinoma of the tongue. We investigated the ability of sentinel node (SN) biopsy to predict neck status in 11 patients with lateral T1-T2, N0, and M0 squamous cell carcinoma of the tongue who underwent ipsilateral neck dissection 30 to 40 days after primary surgery.

METHODS

In 5 patients, technetium 99m-labeled particles were injected close to the operation scar on the day before neck dissection, and the labeled neck nodes were revealed by lymphoscintigraphy. The next 6 patients underwent lymphoscintigraphy both before surgery and before neck dissection. During neck dissection, the ipsilateral SNs were identified by using a hand-held probe and removed separately.

RESULTS

Three patients (27%) had metastatic neck nodes. In all cases, labeled nodes were revealed by scintigraphy. Ipsilateral SNs were removed from 8 patients and correctly predicted the state of the neck (6 negatives and 2 positives). Lymphoscintigraphy before and after surgery revealed that drainage was modified after surgery in 5 of 6 patients; the pre-surgery drainage pattern varied markedly among the 5 pN0 patients.

CONCLUSIONS

The technique allows easy and safe identification of SNs and shows promise in guiding selective neck dissection. Surgery on the primary tumor often modifies lymphatic drainage, so that SN biopsy may only be useful if the primary operation and neck dissection are performed at the same time.

Diagnosis of persistent ovarian carcinoma with three-step immunoscintigraphy

The diagnosis of recurrent ovarian carcinoma is usually determined at surgical re-exploration since the main non-invasive diagnostic tests have low accuracy. It would be desirable to have a high accuracy non-invasive diagnostic procedure. With this aim, we have assessed the utility of three-step immunoscintigraphy. Thirty patients were intravenously injected with biotinylated monoclonal antibodies MOv18 and B72.3, followed by avidin-streptavidin injection and finally by 111In-biotin. Tumour recurrences were imaged 2 h post radioactivity injection. All patients underwent surgical re-exploration 3-4 days after immunoscintigraphy; the presence of tumour in the area of immunoscintigraphic uptake was evaluated in the biopsied material. Twenty-one patients studied were true-positive, five were true-negative, four were false-positive and none was false-negative. The diagnostic accuracy, positive predictive value and negative predictive value were 87%, 84% and 100% respectively. If these findings are confirmed in a larger number of patients, we expect immunoscintigraphy to be introduced as a cost-effective procedure in the follow-up of patients who have received surgery for ovarian carcinoma, since it promises to reliably identify patients who do not require surgical re-exploration, and guide biopsies when they are indicated.

Sentinel node biopsy in early vulvar cancer

Lymph node pathologic status is the most important prognostic factor in vulvar cancer; however, complete inguinofemoral node dissection is associated with significant morbidity. Lymphoscintigraphy associated with gamma-probe guided surgery reliably detects sentinel nodes in melanoma and breast cancer patients. This study evaluates the feasibility of the surgical identification of sentinel groin nodes using lymphoscintigraphy and a gamma-detecting probe in patients with early vulvar cancer. Technetium-99m-labelled colloid human albumin was administered perilesionally in 37 patients with invasive epidermoid vulvar cancer (T1-T2) and lymphoscintigraphy performed the day before surgery. An intraoperative gamma-detecting probe was used to identify sentinel nodes during surgery. A complete inguinofemoral node dissection was then performed. Sentinel nodes were submitted separately to pathologic evaluation. A total of 55 groins were dissected in 37 patients. Localization of the SN was successful in all cases. Eight cases had positive nodes: in all the sentinel node was positive; the sentinel node was the only positive node in five cases. Twenty-nine patients showed negative sentinel nodes: all of them were negative for lymph node metastases. Lymphoscintigraphy and sentinel-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. This technique may represent a true advance in the direction of less aggressive treatments in patients with vulvar cancer.

Sentinel node localization in primary melanoma: learning curve and results

Ninety primary melanoma patients were studied to investigate the importance of adopting the simultaneous use of patent blue dye (PBD) and lymphoscintigraphy plus gamma detection probe to locate the sentinel node (SN). In total 135 SNs in 105 basins were visualized preoperatively under a gamma camera after lymphoscintigraphy. When a SN was identified intraoperatively, its radioactivity level and colour were verified and documented. Two of the SNs seen on lymphoscintigraphy were not found. Using PBD 78.52% of the SNs were identified; 95.5% were identified using the gamma detection probe. Using both methods together 98.5% of the SNs were detected. Twenty-two patients (24.4%) had pathologically positive SNs. The surgical learning curve was assessed for the two techniques. The learning curve associated with the methodology was important in finding the SN when using PBD associated with lymphoscintigraphy, but not when the gamma detection probe was used; we found a statistically significant reduction in the percentage of stained SNs found using PBD in the initial 14 SNs biopsied compared with the subsequent 121 nodes. This is important as not all institutions have access to a gamma probe. The time required to identify each SN was documented and analysed. The duration of the procedure was significantly shorter for stained SNs than for non-stained SNs, which support the use of both PBD and the gamma probe. In conclusion, SN biopsy should be performed by surgeons and nuclear medicine doctors in co-operation, both methods being adopted simultaneously to reduce the percentage of procedure failures.

Antibody-guided three-step therapy for high grade glioma with yttrium-90 biotin

While the incidence of brain tumours seems to be increasing, median survival in patients with glioblastoma remains less than 1 year, despite improved diagnostic imaging and neurosurgical techniques, and innovations in treatment. We have developed an avidin-biotin pre-targeting approach for delivering therapeutic radionuclides to gliomas, using anti-tenascin monoclonal antibodies, which seems potentially effective for treating these tumours. We treated 48 eligible patients with histologically confirmed grade III or IV glioma and documented residual disease or recurrence after conventional treatment. Three-step radionuclide therapy was performed by intravenous administration of 35 mg/m2 of biotinylated anti-tenascin monoclonal antibody (1st step), followed 36 h later by 30 mg of avidin and 50 mg of streptavidin (2nd step), and 18-24 h later by 1-2 mg of yttrium-90-labelled biotin (3rd step). 90Y doses of 2.22-2.96 GBq/m2 were administered; maximum tolerated dose (MTD) was determined at 2.96 GBq/m2. Tumour mass reduction (>25%-100%), documented by computed tomography or magnetic resonance imaging, occurred in 12/48 patients (25%), with 8/48 having a duration of response of at least 12 months. At present, 12 patients are still in remission, comprising four with a complete response, two with a parital response, two with a minor response and four with stable disease. Median survival from 90Y treatment is 11 months for grade IV glioblastoma and 19 months for grade III anaplastic gliomas. Avidin-biotin based three-step radionuclide therapy is well tolerated at the dose of 2.2 GBq/m2, allowing the injection of 90Y-biotin without bone marrow transplantation. This new approach interferes with the progression of high-grade glioma and may produce tumour regression in patients no longer responsive to other therapies.

Three-step radioimmunotherapy with yttrium-90 biotin: dosimetry and pharmacokinetics in cancer patients

A three-step avidin-biotin approach has been applied as a pretargeting system in radioimmunotherapy (RIT) as an alternative to conventional RIT with directly labelled monoclonal antibodies (MoAbs). Although dosimetric and toxicity studies following conventional RIT have been reported, these aspects have not previously been evaluated in a three-step RIT protocol. This report presents the results of pharmacokinetic and dosimetric studies performed in 24 patients with different tumours. Special consideration was given to the dose delivered to the red marrow and to the haematological toxicity. The possible additive dose to red marrow due to the release of unbound yttrium-90 was investigated. The protocol consisted in the injection of biotinylated MoAbs (first step) followed 1 day later by the combined administration of avidin and streptavidin (second step). After 24 h, biotin radiolabelled with 1.85-2.97 GBq/m2 of 90Y was injected (third step). Two different chelating agents, DTPA and DOTA, coupled to biotin, were used in these studies. Indium-111 biotin was used as a tracer of 90Y to follow the biodistribution during therapy. Serial blood samples and complete urine collection were obtained over 3 days. Whole-body and single-photon emission tomography images were acquired at 1, 16, 24 and 40 h after injection. The sequence of images was used to extrapolate 90Y-biotin time-activity curves. Numerical fitting and compartmental modelling were used to calculate the residence time values (tau) for critical organs and tumour, and results were compared; the absorbed doses were estimated using the MIRDOSE3.1 software. The residence times obtained by the numerical and compartmental models showed no relevant differences (<10%); the compartmental model seemed to be more appropriate, giving a more accurate representation of the exchange between organs. The mean value for the tau in blood was 2.0+/-1.1 h; the mean urinary excretion in the first 24 h was 82.5%+/-10.8%. Without considering any contribution of free 90Y, kidneys, liver, bladder and red marrow mean absorbed doses were 1.62+/-1.14, 0.27+/-0.23, 3.61+/-0.70 and 0. 11+/-0.05 mGy/MBq, respectively; the effective dose was 0.32+/-0.06 mSv/MBq, while the dose to the tumour ranged from 0.62 to 15.05 mGy/MBq. The amount of free 90Y released after the injection proved to be negligible in the case of 90Y-DOTA-biotin, but noteworthy in the case of 90Y-DTPA-biotin (mean value: 5.6%+/-2.5% of injected dose), giving an additive dose to red marrow of 0.18+/-0.08 mGy per MBq of injected 90Y-DTPA-biotin. Small fractions of free 90Y originating from incomplete radiolabelling can contribute significantly to the red marrow dose (3.26 mGy per MBq of free 90Y) and may explain some of the high levels of haematological toxicity observed. These results indicate that pretargeted three-step RIT allows the administraton of high 90Y activities capable of delivering a high dose to the tumour and sparing red marrow and other normal organs. Although 90Y-biotin clears rapidly from circulation, the use of DOTA-biotin conjugate for a stable chelation of 90Y is strongly recommended, considering that small amounts of free 90Y contribute significantly in increasing the red marrow dose.

Lymphoscintigraphy and radioguided biopsy of the sentinel axillary node in breast cancer

Lymphoscintigraphy associated with radioguided biopsy of the sentinel node (SN) is well established in clinical practice for melanoma. In breast cancer, the SN concept is similarly valid, and lymphoscintigraphy is a useful method for localizing the axillary SN. The aim of this study was to optimize the lymphoscintigraphy technique in association with a gamma ray detecting probe (GDP) for identifying and removing the SN in breast cancer patients.

METHODS

Two-hundred fifty patients with operable breast tumor underwent lymphoscintigraphy before surgery. Three different size ranges of 99mTc-labeled colloid particles (<50, <80 and 200-1000 nm) were used, with either subdermal (above tumor) or peritumoral injection. Early and late scintigraphic images were obtained in anterior and oblique projections, and the skin projection of the detected SN was marked. Sentinel nodes were identified and removed with the aid of the GDP during breast surgery; they were tagged separately. Complete axillary dissection followed. In 40 patients, a blue dye was also administered in addition to subdermal radiolabeled colloid to compare blue dye mapping with lymphoscintigraphy localization.

RESULTS

Lymphoscintigraphy successfully revealed lymphatic drainage in 245 of 250 patients (98%). The axillary SN was identified in 240 patients (96%). SN biopsy correctly predicted axillary node status in 234 of 240 patients (97.5%). Lymphoscintigraphy and GDP detected the SN most easily and consistently when 200-1000 nm colloid was administered subdermally in an injection volume of 0.4 ml. Blue dye mapping was successful in 30 of 40 patients (75%). In 26 of these patients, the dye and lymphoscintigraphy identified the same node; in 4 cases different nodes were identified. None of these four patients had axillary disease.

CONCLUSION

Lymphoscintigraphy is a simple procedure that is well tolerated by patients. Sentinel node identification is more reliable when large-size radiolabeled colloids are injected in a relatively small injection volume (0.4 ml). Use of a GDP greatly facilitates precise pinpointing and rapid removal of the SN.

Combined treatment of advanced oropharyngeal cancer with external radiotherapy and three-step radioimmunotherapy

The prognosis of patients with locally advanced head and neck cancer remains grim due to poor locoregional tumour control. In the attempt to eradicate residual disease, various novel modalities have been tested, among which radioimmunotherapy (RIT) has shown some potential. We present a case of locally advanced oropharyngeal carcinoma successfully treated with a combination of various treatments including surgery, radio-chemotherapy and three-step RIT, with the avidin-biotin pretargeting system. A partial tumour response was achieved after surgery and radio-chemotherapy; persistent disease was documented at computed tomography (CT), ultrasound (US) and immunoscintigraphy (ISG) 10 weeks after the end of chemo-radiotherapy. The good correlation between the tracer localization in the scintigraphic images and residual mass visualized at CT suggested the application of three-step RIT using systemic administration of yttrium-90 (py) biotin. At present, 17 months after RIT, the patient is alive with no evidence of disease as documented by magnetic resonance imaging (MRI) and US. This is the first case of complete clinical remission of a head and neck carcinoma induced by combined treatment including pretargeted RIT with 90Y-biotin.

Double-blind stereo-EEG and FDG PET study in severe partial epilepsies: are the electric and metabolic findings related?

The aim of this study was to evaluate, in 16 patients with drug-resistant partial epilepsy who were waiting to undergo surgical treatment, the relation between positron emission tomography (PET) findings with fluorine-18 fluorodeoxyglucose ([18F]FDG) in the interictal state and the different stereo-electroencephalography (SEEG) patterns that characterize: (a) the epileptogenic zone (low-voltage fast-activity discharge before or concurrent with ictal clinical symptoms), (b) the irritative zone (spikes, spikes and waves, isolated or grouped in short bursts) and (c) the lesional zone (continuous, sometimes polyrhythmic slow waves or continuous delta waves or very important voltage depression). SEEG was performed following an individually defined electrode implantation strategy. Whereas at least one area of hypometabolism was detected by visual interpretation of PET/[18F]FDG images in all the subjects in the study, there was poor agreement between PET/[18F]FDG quantitative measures of regional metabolism and SEEG findings. Normal metabolic rates were found in up to 62% of the areas with abnormal SEEG activity, independent of the type of electrical activity, i.e. epileptogenic, irritative, or lesional, while abnormal metabolic rates were found in up to 23% of the areas with normal SEEG activity. In conclusion, whereas the visual interpretation of interictal studies of glucose utilization in our series of drug-resistant epileptic patients consistently allowed the localization of an area of temporal hypometabolism, the quantitative and regional metabolic analysis demonstrated that such a finding is not specifically related to any of the three very different SEEG patterns (epileptogenic, irritative, lesional) or combinations thereof. These results complement those of previous interictal and ictal single-photon emission tomographic studies and of receptor studies in epileptics, suggesting functional and biochemical heterogeneity within the interictal hypoperfused/hypometabolic area in epileptic patients, and contribute to the debate on the use and interpretation of interictal PET/[18F]FDG studies in patients with medically refractory partial seizures.

Increased interictal cerebral glucose metabolism in a cortical-subcortical network in drug naive patients with cryptogenic temporal lobe epilepsy

Positron emission tomography with [18F]-2-fluoro-2-deoxy-D-glucose ([18F]FDG) has been used to assess the pattern of cerebral metabolism in different types of epilepsies. However, PET with [18F]FDG has never been used to evaluate drug naive patients with cryptogenic temporal lobe epilepsy, in whom the mechanism of origin and diffusion of the epileptic discharge may differ from that underlying other epilepsies. In a group of patients with cryptogenic temporal lobe epilepsy, never treated with antiepileptic drugs, evidence has been found of significant interictal glucose hypermetabolism in a bilateral neural network including the temporal lobes, thalami, basal ganglia, and cingular cortices. The metabolism in these areas and frontal lateral cortex enables the correct classification of all patients with temporal lobe epilepsy and controls by discriminant function analysis. Other cortical areas--namely, frontal basal and lateral, temporal mesial, and cerebellar cortices--had bilateral increases of glucose metabolism ranging from 10 to 15% of normal controls, although lacking stringent statistical significance. This metabolic pattern could represent a pathophysiological state of hyperactivity predisposing to epileptic discharge generation or diffusion, or else a network of inhibitory circuits activated to prevent the diffusion of the epileptic discharge.

Regional cerebral metabolism of glucose in comatose and vegetative state patients

Regional cerebral metabolism of glucose (rCMRglu) was evaluated in patients who were in a coma and vegetative state to determine the level of brain function during these conditions. rCMRglu was measured in 17 discrete brain regions with (/-) [18F] -fluoro-2-deoxy-D-glucose (FDG) and positrn emission tomography (PET) in 15 patients with ;brain pathology subsequent to cardiorespiratory arrest (CA), head trauma (HT), or brain ischemia (BI) resulting from cerebrovascular accident or brain surgery. Five comatose patients (Coma group, n = 5), and 10 vegetative state patients (VS, patients awake but not aware) were studied. The VA patients were subdivided, according to the length of their VS condition, into a VS group (n = 6, < 3 months if CA or BI patients, or < 12 months if HT patients) and a persistent vegetative state group (PVS, n = 4, > 3 months if CA or BI patients of > 12 months if HT patients.) Ten normal age-matched subjects served as control. Global CMRglu was 6.72 +/- 0.93 (+/-SD) mg/100 g/min in control subjects. It was significantly (p < - 0.001) reduced to 3.70 +/- 61 in coma, to 3.45 +/- in VS, and to 2.33 +/- 0.34 mg/100 g/min in PVS patients. rCMRglu was significantly reduced (p < - 01001) from control values in all the 17 structures surveyed in every patient. In the Coma and VS groups, there was an overlapping of rCMRglu in the majority of the brain structures. (ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral glucose metabolism in neurofibromatosis type 1 assessed with [18F]-2-fluoro-2-deoxy-D-glucose and PET

Cerebral PET with [18F]-2-fluoro-2-deoxy-D-glucose has been performed in four patients with neurofibromatosis type 1 (NF1) to assess the relation between cerebral metabolic activity, MRI, and the presence of neurological symptoms, including seizures, as well as mental and language retardation. Widespread hypometabolism occurred in three of the patients. The lesions on MRI, which were localised in the subcortical white matter and grey structures, had normal rates of glucose metabolism. This finding suggests that the abnormalities seen on MRI are not due to defective blood supply, localised oedema, or grey matter heterotopic foci as previously hypothesised. The presence of the hypometabolic areas seems to be inconsistently related to the occurrence of seizures and is not proportional to the degree of mental impairment. This study provides evidence of a widespread cerebral hypometabolism that is not related to the presence of MRI abnormalities; conversely normal metabolism was present in the areas with an abnormal MRI signal.