3D dosimetry in patients with early breast cancer undergoing Intraoperative Avidination for Radionuclide Therapy (IART) combined with external beam radiation therapy.

PURPOSE: Intraoperative Avidination for Radionuclide Therapy (IART) is a novel targeted radionuclide therapy recently used in patients with early breast cancer. It is a radionuclide approach with (90)Y-biotin combined with external beam radiotherapy (EBRT) to release a boost of radiation in the tumour bed. Two previous clinical trials using dosimetry based on the calculation of mean absorbed dose values with the hypothesis of uniform activity distribution (MIRD 16 method) assessed the feasibility and safety of IART. In the present retrospective study, a voxel dosimetry analysis was performed to investigate heterogeneity in distribution of the absorbed dose. The aim of this work was to compare dosimetric and radiobiological evaluations derived from average absorbed dose vs. voxel absorbed dose approaches. METHODS: We evaluated 14 patients who were injected with avidin into the tumour bed after conservative surgery and 1 day later received an intravenous injection of 3.7 GBq of (90)Y-biotin (together with 185 MBq (111)In-biotin for imaging). Sequential images were used to estimate the absorbed dose in the target region according to the standard dosimetry method (SDM) and the voxel dosimetry method (VDM). The biologically effective dose (BED) distribution was also evaluated. Dose/volume and BED volume histograms were generated to derive equivalent uniform BED (EUBED) and equivalent uniform dose (EUD) values. RESULTS: No "cold spots" were highlighted by voxel dosimetry. The median absorbed-dose in the target region was 20 Gy (range 15-27 Gy) by SDM, and the median EUD was 20.4 Gy (range 16.5-29.4 Gy) by the VDM; SDM and VDM estimates differed by about 6 %. The EUD/mean voxel absorbed dose ratio was >0.9 in all patients, indicative of acceptable uniformity in the target. The median BED and EUBED values were 21.8 Gy (range 15.9-29.3 Gy) and 22.8 Gy (range 17.3-31.8 Gy), respectively. CONCLUSION: VDM highlighted the absence of significant heterogeneity in absorbed dose in the target. The EUD/mean absorbed dose ratio indicated a biological efficacy comparable to that of uniform distribution of absorbed dose. The VDM is recommended for improving accuracy, taking into account actual activity distribution in the target region. The radiobiological model applied allowed us to compare the effects of IART® with those of EBRT and to match the two irradiation modalities.

Sentinel lymph node biopsy in breast cancer: ten-year results of a randomized controlled study.

OBJECTIVE: Sentinel node biopsy (SNB) is widely used to stage the axilla in breast cancer. We present 10-year follow-up of our single-institute trial designed to compare outcomes in patients who received no axillary dissection if the sentinel node was negative, with patients who received complete axillary dissection. METHODS: From March 1998 to December 1999, 516 patients with primary breast cancer up to 2 cm in pathologic diameter were randomized either to SNB plus complete axillary dissection (AD arm) or to SNB with axillary dissection only if the sentinel node contained metastases (SN arm). RESULTS: The 2 arms were well-balanced for number of sentinel nodes found, proportion of positive sentinel nodes, and all other tumor and patient characteristics. About 8 patients in the AD arm had false-negative SNs on histologic analysis: a similar number (8, 95% CI: 3-15) of patients with axillary involvement was expected in SN arm patients who did not receive axillary dissection; but only 2 cases of overt axillary metastasis occurred. There were 23 breast cancer-related events in the SN arm and 26 in the AD arm (log-rank, P = 0.52), while overall survival was greater in the SN arm (log-rank, P = 0.15). CONCLUSIONS: Preservation of healthy lymph nodes may have beneficial consequences. Axillary dissection should not be performed in breast cancer patients without first examining the sentinel node.

Investigation of 18F-FDG PET in the selection of patients with breast cancer as candidates for sentinel node biopsy after neoadjuvant therapy.

PURPOSE: The main objective of this study was to determine the role of [(18)F]-2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) in the selection of patients with breast cancer as candidates for sentinel node biopsy (SNB) after neoadjuvant therapy. METHODS: Forty-four patients with primary breast cancer clinically classified as cT2, cT3 or cT4(a-c) cN0-N2 or cN3 M0 and with a baseline FDG PET scan positive both in the site of primary tumour and axillary lymph nodes underwent neoadjuvant therapy and then a second FDG PET scan. In the case of axillary FDG PET uptake, patients underwent axillary lymph node dissection (ALND). If the second FDG PET scan was negative for axillary involvement, SNB was performed in order to evaluate axillary lymph node status. Only in the case of SN positivity did total ALND follow. RESULTS: Specificity and positive predictive value of FDG PET for detection of axillary lymph node metastases after neoadjuvant therapy were as high as 83% (95% confidence interval: 51-97%) and 85% (95% confidence interval: 54-97%), respectively, whereas sensitivity, negative predictive value and diagnostic accuracy were inadequate for a correct staging (34, 32 and 48%, respectively). CONCLUSION: The poor sensitivity of FDG PET in detecting axillary lymph node metastases makes SNB mandatory in cases of a negative scan. The relatively high positive predictive value seems to suggest a role of FDG PET in selecting patients who, after neoadjuvant therapy, are candidates for ALND, avoiding SNB. However, this issue requires confirmation in a larger series of patients.

Intraoperative avidination for radionuclide treatment as a radiotherapy boost in breast cancer: results of a phase II study with (90)Y-labeled biotin.

PURPOSE: External beam radiotherapy (EBRT) after conservative surgery for early breast cancer requires 5-7 weeks. For elderly patients and those distant from an RT center, attending for EBRT may be difficult or impossible. We investigated local toxicity, cosmetic outcomes, and quality of life in a new breast irradiation technique-intraoperative avidination for radionuclide therapy (IART)-in which avidin is administered to the tumor bed and (90)Y-labelled biotin later administered intravenously to bind the avidin and provide irradiation. Reduced duration EBRT (40 Gy) is given subsequently. METHODS: After surgery, 50 (ten patients), 100 (15 patients) or 150 mg (ten patients) of avidin was injected into the tumor bed. After 12-24 h, 3.7 GBq (90)Y-biotin (beta source for therapeutic effect) plus 185 MBq (111)In-biotin (gamma source for imaging and dosimetry) was infused slowly. Whole-body scintigraphy and SPECT/CT images were taken for up to 30 h. Shortened EBRT started 4 weeks later. Local toxicity was assessed by RTOG scale; quality of life was assessed by EORTC QOL-30. RESULTS: Of 35 patients recruited (mean age 63 years; range 42-74) 32 received IART plus EBRT. 100 mg avidin provided 19.5 +/- 4.0 Gy to the tumor bed and was considered the optimum dose. No side-effects of avidin or (90)Y-biotin occurred, with no hematological or local toxicity. Local G3 toxicity occurred in 3/32 patients during EBRT. IART plus EBRT was well accepted, with good cosmetic outcomes and maintained quality of life. CONCLUSIONS: IART plus reduced EBRT can accelerate irradiation after conservative breast surgery.

Peptide receptor radionuclide therapy with (90)Y-DOTATOC in recurrent meningioma.

PURPOSE: Meningiomas are generally benign and in most cases surgery is curative. However, for high-grade histotypes or partially resected tumours, recurrence is fairly common. External beam radiation therapy (EBRT) is usually given in such cases but is not always effective. We assessed peptide receptor radionuclide therapy (PRRT) using (90)Y-DOTATOC in a group of patients with meningioma recurring after standard treatments in all of whom somatostatin receptors were strongly expressed on meningioma cell surfaces. METHODS: Twenty-nine patients with scintigraphically proven somatostatin subtype 2 receptor-positive meningiomas were enrolled: 14 had benign (grade I), 9 had atypical (grade II) and 6 had malignant (grade III) disease. Patients received intravenous (90)Y-DOTATOC for 2-6 cycles for a cumulative dose in the range of 5-15 GBq. Clinical and neuroradiological evaluations were performed at baseline, during and after PRRT. RESULTS: The treatment was well tolerated in all patients. MRI 3 months after treatment completion showed disease stabilization in 19 of 29 patients (66%) and progressive disease in the remaining 10 (34%). Better results were obtained in patients with grade I meningioma than in those with grade II-III, with median time to progression (from beginning PRRT) of 61 months in the low-grade group and 13 months in the high-grade group. CONCLUSION: PRRT with (90)Y-DOTATOC can interfere with the growth of meningiomas. The adjuvant role of this treatment, soon after surgery, especially in atypical and malignant histotypes, deserves further investigation.

Radioembolisation with 90Y-microspheres: dosimetric and radiobiological investigation for multi-cycle treatment.

INTRODUCTION: Radioembolisation with (90)Y-microspheres is a new locoregional treatment of hepatic lesions, usually applied as single cycle. Multi-cycle treatments might be considered as a strategy to improve the risk-benefit balance. With the aim to derive suitable information for patient tailored therapy, available patients' dosimetric data were reviewed according to the linear-quadratic model and converted into biological effective dose (BED) values. Single vs. multi-cycle approaches were compared through radiobiological perspective. MATERIALS AND METHODS: Twenty patients with metastatic lesions underwent radioembolisation. The (90)Y-administered activity (AA) was established in order to respect a precautionary limit dose (40 Gy) for the non-tumoral liver (NTL). BED was calculated setting alpha/beta = 2.5 Gy (NTL), 10 Gy (tumours); T (1/2,eff) = T (1/2,phys) = 64.2 h; T (1/2,rep) = 2.5 h (NTL), 1.5 h (tumours). The BED to NTL was considered as a constraint for multi-cycle approach. The AA for two cycles and the percent variations of AA, tumour dose, BED were estimated. RESULTS: In one-cycle, for a prescribed BED to NTL of 64 Gy (NTL dose = 40 Gy), AA was 1.7 (0.9-3.2) GBq, tumour dose was 130 (65-235) Gy, and tumour BED was 170 (75-360) Gy. Considering two cycles, approximately 15% increase was found for AA and dose to NTL, with unvaried BED for NTL. Tumour dose increase was 20 (10-35) Gy; tumour BED increase was 10 (3-11) Gy. In different protocols allowing 80 Gy to NTL, the BED sparing estimated was approximately 50 Gy (two cycles) and 65 Gy (three cycles). CONCLUSIONS: From a radiobiological perspective, multi-cycle treatments would allow administering higher activities with increased tumour irradiation and preserved radiation effects on NTL. Trials comparing single vs. multiple cycles are suggested.

Intraoperative avidination for radionuclide therapy: a prospective new development to accelerate radiotherapy in breast cancer.

PURPOSE: In a continuous effort to seek for anticancer treatments with minimal side effects, we aim at proving the feasibility of the Intraoperative Avidination for Radionuclide Therapy, a new procedure for partial breast irradiation. EXPERIMENTAL DESIGN: To assess doses of 90Y-DOTA-biotin to target (i.e., breast tumor bed) and nontarget organs, we did simulation studies with 111In-DOTA-biotin in 10 candidates for conservative breast surgery. Immediately after quadrantectomy, patients were injected with 100-mg avidin in the tumor bed. On the following day, patients were given 111In-DOTA-biotin (approximately 111 MBq) i.v. after appropriate chase of biotinylated albumin (20 mg) to remove circulating avidin. Biokinetic studies were done by measuring radioactivity in scheduled blood samples, 48-h urine collection, and through scintigraphic images. The medical internal radiation dose formalism (OLINDA code) enabled dosimetry assessment in target and nontarget organs. RESULTS: Images showed early and long-lasting radioactive biotin uptake in the operated breast. Rapid blood clearance (<1% at 12 h) and urine excretion (>75% at 24 h) were observed. Absorbed doses, expressed as mean+/-SD in Gy/GBq, were as low as 0.15+/-0.05 in lungs, 0.10+/-0.02 in heart, 0.06+/-0.02 in red marrow, 1.30+/-0.50 in kidneys, 1.50+/-0.30 in urinary bladder, and 0.06+/-0.02 in total body, whereas in the targeted area, they increased to 5.5+/-1.1 Gy/GBq (50% ISOROI) and 4.8+/-1.0 Gy/GBq (30% ISOROI). CONCLUSION: Our preliminary results suggest that Intraoperative Avidination for Radionuclide Therapy is a simple and feasible procedure that may improve breast cancer patients' postsurgical management by shortening radiotherapy duration.

A randomized comparison of sentinel-node biopsy with routine axillary dissection in breast cancer.

BACKGROUND: Although numerous studies have shown that the status of the sentinel node is an accurate predictor of the status of the axillary nodes in breast cancer, the efficacy and safety of sentinel-node biopsy require validation. METHODS: From March 1998 to December 1999, we randomly assigned 516 patients with primary breast cancer in whom the tumor was less than or equal to 2 cm in diameter either to sentinel-node biopsy and total axillary dissection (the axillary-dissection group) or to sentinel-node biopsy followed by axillary dissection only if the sentinel node contained metastases (the sentinel-node group). RESULTS: The number of sentinel nodes found was the same in the two groups. A sentinel node was positive in 83 of the 257 patients in the axillary-dissection group (32.3 percent), and in 92 of the 259 patients in the sentinel-node group (35.5 percent). In the axillary-dissection group, the overall accuracy of the sentinel-node status was 96.9 percent, the sensitivity 91.2 percent, and the specificity 100 percent. There was less pain and better arm mobility in the patients who underwent sentinel-node biopsy only than in those who also underwent axillary dissection. There were 15 events associated with breast cancer in the axillary-dissection group and 10 such events in the sentinel-node group. Among the 167 patients who did not undergo axillary dissection, there were no cases of overt axillary metastasis during follow-up. CONCLUSIONS: Sentinel-node biopsy is a safe and accurate method of screening the axillary nodes for metastasis in women with a small breast cancer.

Unnecessary axillary node dissections in the sentinel lymph node era.

In the sentinel lymph node era, axillary lymph node dissection (ALND) for uninvolved axillary lymph nodes should be considered unnecessary and inappropriate. Between January 2000 and August 2005, 3487 out of 10,031 invasive breast cancer patients consecutively operated at the European Institute of Oncology were considered not suitable for sentinel lymph node biopsy (SNB) and were directly submitted to ALND ('direct ALND'). In 2875 cases (82%) a variable grade of axillary involvement was shown, while in 612 patients (18%) no evidence of metastatic spreading was documented in the axilla. In particular, the presence of suspicious nodes at pre-operative clinical evaluation of the axilla (191 patients), neoadjuvant treatment (188 patients), large tumour >2 cm (88 patients), multifocality of disease (76 patients), previous excisional biopsy (49 patients), were considered the most frequent contraindications to SNB and led to an 'unnecessary ALND'. According to the wider extension of the indications for SNB over the time, the number of 'unnecessary ALNDs' progressively decreased from 26% (in 2000) to 9% of the 'direct ALNDs' (in 2005). As the clinical indications to SNB are progressively extending to encompass most breast cancer patients with non-metastatic disease who were previously excluded, great effort should be made to avoid 'unnecessary ALNDs'.

IART: intraoperative avidination for radionuclide treatment. A new way of partial breast irradiation.

A new procedure, known as Intraoperative Avidination for Radionuclide Therapy (IART), is described in breast cancer patients. In this paper, we provide proof of the principle that intraoperative injection of avidin in the tumour bed after quadrantectomy allows homing in of intravenously (IV) administered radioactive biotin to the target site. This approach of targeted therapy consists of two steps: (i) "avidination" of the anatomical area of the tumour with avidin injected by the surgeon, into and around the tumour bed; (ii) targeting the anatomical area of the tumour by IV injection of radiolabelled biotin. The scintigraphic images demonstrated fast and stable uptake of labelled biotin at the site of operated breast. The radiation dose released to the index quadrant was more than 5 Gy/GBq, consistent with a boost of 20 Gy for an activity of 3.7 GBq 90Y-biotin (100mCi). A further large clinical trial facing IART in combination with reduced external-beam radiotherapy is, in our opinion, fully justified.

Neoadjuvant therapy in locally advanced breast cancer: 99mTc-MIBI mammoscintigraphy is not a reliable technique to predict therapy response.

Mammoscintigraphy (MMS) has been indicated as a useful tool in predicting response to therapy in cancer. However, contrasting results have been reported in the literature for breast cancer patients. The aim of this study was to explore the role of MMS in locally advanced breast cancer (LABC) patients. Fifty-one patients affected by LABC and scheduled for neoadjuvant therapy were enrolled. Breast tumor status was evaluated at baseline, during therapy and at the completion of therapy by radiological techniques and by MMS. Pre-therapy (MMS1) and post-therapy MIBI (2-methoxyisobutilysonitrile) images (MMS2-3) were analyzed. MMS1 was performed in all pts, 41 carried out MMS2 and 27 had MMS3. Tumor uptake and washout in MMS1 did not show any correlation with the therapy response. The absence of any association between tumor uptake and washout with respect to therapy response suggests that MMS is not a reliable technique to predict therapy response in LABC.

Clinical application of spectral electromagnetic interaction in breast cancer: diagnostic results of a pilot study.

AIMS AND BACKGROUND: There is a need for a cost-effective method to safely reduce the number of diagnostic procedures women undergo for breast cancer. We tested a new procedure for breast cancer diagnosis based on breast tissue response to low level electromagnetic incident waves. METHODS: We tested 101 patients with suspicious palpable breast lesions detected by mammography or ultrasonography, who were scheduled to undergo an open biopsy. Using an electromagnetic field generator (tissue resonance interaction method probe [TRIMprob]), we passed the TRIMprob over the breast area and recorded the signal variation of one or more spectral lines (dB1, dB2, dB3). The results were compared with those of a control group as well as with pathology data obtained from excisional biopsy. RESULTS: No adverse effects of the test were observed. Pathology revealed 86 malignant breast cancers (72 invasive, 14 in situ) and 15 benign conditions. We achieved the best discrimination between normal breasts and lesions using dB1 (dB1 AUC-ROC = 0.8; dB2 AUC-ROC = 0.61; dB3 AUC-ROC = 0.76). With a specificity of 75% to 95%, the sensitivity ranged from 49% to 84%. Tumor or patient variables did not influence the results. CONCLUSIONS: The TRIMprob test was able to provide some degree of discrimination between normal breast tissue and lesions but not between benign and malignant lesions. The lack of influence of patient age and tumor size on test results might be advantageous in terms of early diagnosis in young women. These preliminary results need to be verified and extended in a preclinical-stage disease setting before clinical applicability can be envisaged.

Sentinel node detection and radioguided occult lesion localization in breast cancer.

Sentinel lymph node biopsy might replace complete axillary dissection for staging of the axilla in clinically N0 breast cancer patients and represent a significant advantage as a minimally invasive procedure, considering that about 70% of patients are found to be free from metastatic disease, yet axillary node dissection can lead to significant morbidity. In our Institute, Radioguided Occult Lesion Localization is the standard method to locate non-palpable breast lesions and the gamma probes is very effective in assisting intra-operative localization and removal, as in sentinel node biopsy. The rapid spread of sentinel lymph node biopsy has led to its use in clinical settings previously considered contraindications to sentinel lymph node biopsy. In this contest, we evaluated in a large group of patients possible factors affecting sentinel node detection and the reliability of sentinel lymph node biopsy carried out after large excisional breast biopsy. Our data confirm that a previous breast surgery does not prohibit efficient sentinel lymph node localization and sentinel lymph node biopsy can correctly stage the axialla in these patients.

Sentinel lymph node biopsy performed with local anesthesia in patients with early-stage breast carcinoma.

HYPOTHESIS: Sentinel lymph node (SN) biopsy performed with local anesthesia has a positive effect on patients' quality of life and on treatment management for early-stage breast carcinoma. This method represents an interesting development in breast-conserving surgery. DESIGN: We performed SN biopsy with local anesthesia in selected patients to test the feasibility of the technique and its impact on our organization and on patients' quality of life. PATIENTS AND METHODS: From September 2000 to December 2001, we studied 115 patients with a palpable breast tumor (maximum diameter, 2.5 cm). The axilla was clinically negative for metastasis in all cases. RESULTS: Forty-eight patients (41.7%) had SNs that were positive for metastasis. In 20 cases (17.4%), the SN was macrometastatic and in 28 cases (24.3%), it was micrometastatic (diameter <2 mm). The SN was negative for metastasis in 66 cases (57.4%). In 1 case, the histologic examination revealed the presence of a non-Hodgkin B-cell lymphoma. The complete axillary dissection performed in the subgroup of patients with macrometastatic SNs showed that in 9 cases (45%), the SN was the only positive node. In another 9 cases (45%), patients had fewer than 4 positive axillary lymph nodes; more than 4 axillary nodes were metastatic in 2 cases (10%). Among the 28 patients with SN micrometastasis, 21 received complete axillary dissection: 15 patients (53.6%) had no other metastasis to the axillary nodes and 6 patients (21.4%) had cancer cells in other axillary nodes. In case of micrometastasis, we suggested that patients enter the International Breast Cancer Study Group 2301 trial (15 of them accepted and signed the informed consent), which compared completion of axillary dissection with no further surgical treatment of the axilla. Based on randomization, 7 patients (25%) in the group with micrometastasis to the SN received no axillary dissection. Patients' tolerance to this kind of treatment was excellent. CONCLUSION: Our experience indicates that SN biopsy performed with local anesthesia can be a suitable alternative to standard intraoperative evaluation with general anesthesia in patients with unifocal, early-stage breast carcinoma.

Clinical utility of 99mTc-Sestamibi scintimammography in the management of equivocal breast lesions.

The aim of this study was to assess the utility of 99mTc-sestamibi scintimammography (SM) in patients with suspected primary or recurrent breast cancer. Forty-four (44) breast lesions (17 with suspected recurrence of disease) in 40 patients were included into the study. In these patients, the results of conventional diagnostic methods were equivocal or inconclusive. Twenty-one (21) lesions were palpable and 23 lesions were not. Histological examinations performed during the follow-up revealed malignancy in 24 specimens. SM correctly identified 21 of them, as well as 12 true negatives. There were 8 false-positive studies; therefore, the sensitivity of SM was 87.5%, specificity was 60%, positive predictive value (PPV) was 72.4%, and the negative predictive value (NPV) was 80%. The sensitivity in palpable lesions was 100%; three (3) false negatives, 1 recurrence, and 2 cancers, all of them nonpalpable. In conclusion, SM is useful in equivocal palpable lesions for resolving diagnostic uncertainty after conventional examination, and can limit the number of surgical interventions for benign disease. However, its use in nonpalpable tumors is not recommended.

Sentinel node biopsy in male breast cancer.

OBJECTIVE: Male breast cancer is a rare disease and axillary status is the most important prognostic indicator. Lymphoscintigraphy associated with gamma-probe guided surgery has been proved to reliably detect sentinel nodes in female patients with breast cancer. This study evaluates the feasibility of the surgical identification of sentinel node by using lymphoscintigraphy and a gamma-detecting probe in male patients, in order to select subjects who would be suitable for complete axillary lymphadenectomy. METHODS: Colloid human albumin labelled with 99Tc was administered to 18 male patients with breast cancer and clinically negative axillary lymph nodes. Lymphoscintigraphy was performed the day before surgery. An intraoperative gamma-detecting probe was used to identify sentinel nodes during surgery. RESULTS: Lymphoscintigraphy and biopsy of the sentinel node were successful in all cases. A total of 20 sentinel nodes were removed. Pathological examinations showed 11 infiltrating ductal carcinomas, two intraductal carcinomas and five intracystic papillary carcinomas. Six patients (33%) had positive sentinel node (micrometastases were found in three patients). These patients underwent axillary dissection; in five of them (83%) the sentinel node was the only positive node. Twelve patients (67%) showed negative sentinel nodes; in all of them no further surgical treatments were planned. CONCLUSIONS: As in women, lymphoscintigraphy and sentinel node biopsy under the guidance of a gamma-detecting probe proved to be an easy method for the detection of sentinel nodes in male breast carcinoma. In male patients with early stage cancer, sentinel node biopsy might represent the standard surgical procedure in order to avoid unnecessary morbidity after surgery, preserving accurate staging of the disease in the axilla.

Sentinel Node Biopsy Interpretation: The Milan Experience.

From March 1996 to December 1999 we performed 1,266 sentinel node biopsies (SNBs) in patients with small breast cancers. The technique is to inject technetium 99m-labeled albumin particles close to the tumor, locate the sentinel node (SN) scintigraphically, and use a handheld gamma-detecting probe to guide its removal via a small incision during breast surgery. Our experience was divided into three phases. In the first phase, complete axillary dissection was performed to assess the accuracy of SNB in predicting axillary status. We also assessed safety, perfected tracer injection technique, determined optimal particle size and radioactivity levels, optimized lymphoscintigraphic scanning, and perfected the surgical technique. The SN was identified and removed in 98.7% of cases. Comparison with complete axillary dissection showed that the SN predicted axillary status in 96.8% of cases. However, use of an intraoperative frozen section method predicted axillary status in only 86.5% of cases. In the second phase we developed a new method for intraoperative histologic analysis. Extensive sampling (up to 60 sections/SN) and an experienced pathologist proved more important than use of antikeratin immunostaining in identifying tumor cells, and the new method has the accuracy of a definitive histologic examination. The third phase, a randomized trial, closed at the end of 1999. Trial objectives were to confirm that the SN predicts axillary status, to determine the number of axillary relapses, and to assess overall and disease-free survival. Patients were randomized in the operating room to complete axillary dissection or SNB. If the SN was positive, complete axillary dissection was performed; if the SN was negative, no further axillary treatment was given. We expect the trial to confirm our clinical experience that SNB is a safe and accurate procedure for staging patients with early breast cancer and a clinically negative axilla.

Planning combined treatments of external beam radiation therapy and molecular radiotherapy.

Molecular radiotherapy (MRT) with radiolabeled molecules has being constantly evolving, leading to notable results in cancer treatment. In some cases, the absorbed doses delivered to tumors by MRT are sufficient to obtain complete responses; in other cases, instead, to be effective, MRT needs to be combined with other therapeutic approaches. Recently, several studies proposed the combination of MRT with external beam radiation therapy (EBRT). Some describe the theoretical basis within radiobiological models, others report the results of clinical phase I-II studies aimed to assess the feasibility and tolerability. The latter includes the treatment of various tumors, such as meningiomas, paragangliomas, non-Hodgkin's lymphomas, bone, brain, hepatic, and breast lesions. The underlying principle of combined MRT and EBRT is the possibility of exploiting the full potential of each modality, given the different organs at risk. Target tissues can indeed receive a higher irradiation, while respecting the threshold limits of more than one critical tissue. Nevertheless, clinical trials are empirical and optimization is still a theoretical issue. This article describes the state of the art of combined MRT and EBRT regarding the rationale and the results of clinical studies, with special focus on the possibility of treatment improvement.