Adjuvant oral clodronate improves the overall survival of primary breast cancer patients with micrometastases to the bone marrow: a long-term follow-up.

BACKGROUND: Adding oral clodronate to postoperative adjuvant breast cancer therapy significantly improves disease-free survival (DFS) and overall survival (OS). Long-term follow-up data from the prospective, randomized, controlled study are reported. PATIENTS AND METHODS: Patients with primary breast cancer received clodronate 1600 mg/day for 2 years or no treatment along with standard adjuvant breast cancer treatment. RESULTS: Analysis of 290 of 302 patients demonstrated that a significant improvement in OS was maintained in the clodronate group at a median follow-up of 103 +/- 12 months; 20.4% of patients in the clodronate group versus 40.7% of control group patients (P = 0.04) died during the 8.5 years following primary surgical therapy. Significant reductions in the incidence of bony and visceral metastases and improvement in duration of DFS at 36- and 55-month follow-up periods were no longer seen with clodronate. CONCLUSION: These long-term survival data extend the survival advantage reported in previous studies with oral clodronate in breast cancer.

Gemcitabine, epirubicin and docetaxel as primary systemic therapy in patients with early breast cancer: results of a multicentre phase I/II study.

Developing primary systemic chemotherapy (PST) regimens that induce higher pathological complete response (pCR) rates remains a challenge in operable breast cancer. We recruited 77 eligible patients into a multicentre phase I/II study to evaluate the maximum tolerated dose (MTD), toxicity and efficacy of preoperative gemcitabine day 1 and 8 (800 mg/m(2) fixed dose), epirubicin and docetaxel on day 1 (doses escalated from 60 mg/m(2)) (GEDoc), repeated 3-weekly for 6 cycles with filgrastim support. MTD for epirubicin was 90 mg/m(2) and for docetaxel 75 mg/m(2). Dose-limiting toxicities (DLTs) included febrile neutropenia and grade 3 diarrhoea. Clinical response rate was 92%, pCR rate was 26%. 79% of patients had breast-conserving surgery. Grade 3/4 leucopenia was the main toxicity, occurring in 55 (87%) of 63 patients treated at the MTD. Non-haematological toxicity caused no serious clinical problems. In conclusion, GEDoc is highly active as PST. Efficacy and toxicity compare favourably with other effective combinations.

Micrometastatic bone marrow cells at diagnosis have no impact on survival of primary breast cancer patients with extensive axillary lymph node involvement treated with stem cell-supported high-dose chemotherapy.

BACKGROUND: To determine the impact of micrometastatic bone marrow cells (MMC) on survival in high-risk primary breast cancer (HRPBC) patients treated with high-dose chemotherapy (HDCT) and autologous stem cell transplantation (ASCT). PATIENTS AND METHODS: Ninety-one HRPBC patients (73 patients with > or =10 involved axillary lymph nodes (ALN), 18 premenopausal women with > or =4 involved ALN) received one cycle (eight patients) or two cycles of HDCT and ASCT. Bone marrow aspiration was performed before systemic treatment to search for MMC using a cocktail of four monoclonal epithelial-specific antibodies (5D3, HEA125, BM7 and BM8). The influence of MMC and other prognostic factors on disease-free survival (DFS), distant DFS (DDFS), and overall survival (OS) was analysed. RESULTS: In 23 of 91 patients (25%) we detected a median of three MMC (range, 1-43) among 10(6) mononuclear cells. With a median follow-up of 62 months (range, 10-117), the detection of MMC was not associated with DFS (P=0.929), DDFS (P=0.664) or OS (P=0.642). In multivariate analysis the strongest predictor was nodal ratio for DFS (P=0.012) and expression of p53 for OS (P <0.001). CONCLUSION: The detection of MMC at diagnosis has no impact on survival in HRPBC patients treated with HDCT and ASCT.

Risk factors in alcohol associated breast cancer: alcohol dehydrogenase polymorphism and estrogens.

Chronic alcohol consumption is associated with an increased risk for breast cancer, even if consumed in moderate doses. Since acetaldehyde is a carcinogenic factor associated with chronic alcohol consumption, individuals with the alcohol dehydrogenase 1C*1 allele (ADH1C*1 allele) seem to be at particular risk, since this allele encodes for a rapidly ethanol metabolizing enzyme leading to increased acetaldehyde levels. Since recent epidemiological studies demonstrated an increased risk for breast cancer for individuals with the ADH1C*1 allele, we have investigated here ADH1C genotypes in moderate alcohol consumers. Furthermore, estradiols are also known risk factors for breast cancer and acute alcohol ingestion in high doses results in increased serum estradiol concentrations. Thus, in the present study, we tested the effect of low ethanol doses on estrogen serum concentrations. We analyzed the ADH1C genotype in 117 moderate alcohol consumers with breast cancer and in 111 age-matched women with alcohol associated diseases without cancer (74 cirrhotics, 22 patients with pancreatitis and 15 alcohol dependent patients). In addition, 107 healthy controls were studied. Genotyping of the ADH1C-locus was performed using polymerase chain reaction-based restriction fragment length polymorphism methods on leukocyte DNA. To study the effects of ethanol on estradiol levels, ethanol in a dose of 0.225 g/kg body weight was given orally to 8 premenopausal women at various time points of their menstrual cycle. Thereafter estradiol serum concentrations were measured over time. The allele frequency of the ADH1C*1 allele was found to be significantly increased in moderate alcohol consumers with breast cancer as compared to age-matched alcoholic controls without cancer (62% vs. 41.9%, p=0.0035). Women with the ADH1C*1,1 genotype were found to be 1.8 times more at risk for breast cancer than those with another genotype (95% CI 1.431-2.330, p<0.001). Oral ethanol increased serum estradiol levels significantly by 27-38%. The data demonstrate that moderate alcohol consumers with the ADH1C*1 allele have an increased risk to develop breast cancer and even small amounts of alcohol increase serum estradiol levels significantly in premenopausal women especially in the midphase of the menstrual cycle.

[Diagnosis of uterine vascular malformation using Doppler ultrasound]. / Diagnostik uteriner Gefässfehlbildung mittels Dopplersonographie.

We present the case of a 56-year-old woman, who was admitted to our clinic for diagnostic laparoscopy because of a cystic uterine tumour of uncertain dignity. In the patient's history three curettages due to recurrent acyclic premenopausal vaginal bleeding were reported without specific histological findings. The preceding MRI described the structure as a myoma. During preoperative diagnostics an arteriovenous malformation was suspected by transvaginal Doppler sonography. Consequently the procedure was changed and a laparotomy performed. The sonographic findings were confirmed during surgery and by histological examination. This case points out the important role of transvaginal sonography combined with colour-flow-mapping. By confirming the diagnosis preoperatively and changing the management a low-risk procedure could be ensured.

[Prognostic factors in carcinoma of the breast. Thereupon depends success of the treatment]. / Prognosefaktoren beim Mammakarzinom. Davon hängt der Therapieerfolg ab.

To enable individualized risk-oriented adjuvant treatment of breast cancer, validated parameters are needed to help evaluate the individual relapse risk. The clinical significance of these factors is assessed by published evidence (level of evidence) and its utility in the clinical setting (utility score). The traditional prognostic factors (age, TNM stage, grading, and steroid hormone receptor status are of established clinical relevance, and their determination should be obligatory. Of the "new" tumor-biologic parameters, only the measurement of the urokinase-type plasminogen activator (uPA) and its inhibitor (PAI-1) in the primary tumor of node-negative patients has been adequately validated and can therefore be recommended for clinical application. Promising recent prognostic markers are the expression of Her2/neu, detection of disseminated tumor cells in bone marrow aspirates, various different surrogates for proliferative activity, and tumor-specific gene expression profiles. Currently, however, the data available are insufficient to allow recommendation of the parameters for routine clinical use at this time.

Continuous infusion of ceftazidime for patients with breast cancer and multiple myeloma receiving high-dose chemotherapy and peripheral blood stem cell transplantation.

This prospective study was performed to examine the safety and efficacy of a continuous infusion of ceftazidime in patients who developed febrile neutropenia after high-dose chemotherapy (HDCT) and autologous peripheral blood stem cell transplantation (PBSCT) and to determine if the underlying disease represents a risk factor for infectious complications. From September 1995 to May 2000, 55 patients with breast cancer (BC, group I, 54 females, one male) and 32 patients with multiple myeloma (MM, group II, 10 female, 22 male) were included in this study. The febrile patients received a 2 g intravenous bolus of ceftazidime, followed by a 4 g continuous infusion over 24 h using a portable infusion pump. If the fever persisted for 72 h a glycopeptide antibiotic was added. The median age was 42 years (range 22-59) in group I and 52 years (range 35-63) in group II. Thirty-five BC patients (64%) and 20 MM patients (63%) responded to the monotherapy with ceftazidime. After addition of a glycopeptide antibiotic, an additional 11 BC patients vs 10 MM patients became afebrile. The causes of fever in group I were fever of unknown origin (FUO) in 49 patients, microbiologically documented infection (MDI) in five patients, and clinically documented infection (CDI) in one patient. The causes of fever in group II were FUO in 22 patients, MDI in eight patients and CDI in two patients. Forty-one febrile episodes in BC patients (75%) and 22 episodes in the MM patients (69%) were successfully managed by out-patient treatment, resulting in a saving of an average of 20 days of inpatient care. Significantly more episodes of MDI and CDI occurred in patients with MM (P = 0.05). The results indicate that BC and MM patients with febrile neutropenia after HDCT and PBSCT can be treated as outpatients with close monitoring to ensure safety. This approach represents a better use of health care resources.

Characteristics associated with long-term progression-free survival following high-dose chemotherapy in metastatic breast cancer and influence of chemotherapy dose.

BACKGROUND: The purpose of this study was to characterize long-term progression-free survivors (LTPFS) of metastatic breast cancer (MBC) following high-dose chemotherapy (HDCT) with autologous stem cell transplantation (ASCT) and to assess the influence of chemotherapy dose in order to identify patients who derive major benefit from this approach. PATIENTS AND METHODS: We compared patient and tumor characteristics of 16 LTPFS with the characteristics of 118 MBC patients who received HDCT with ASCT at our institution between 1992 and 2000. To estimate the cumulative dose of chemotherapy received, the summation dose intensity product (SDIP) of the different chemotherapy regimens was calculated as recently described by Hryniuk et al. The SDIP of the induction regimens was added to that of the HDCT regimens to yield the total SDIP of the chemotherapy received. Multivariate analysis was performed to describe the influence of the total SDIP and other prognostic factors on progression-free survival (PFS). RESULTS: LTPFS were mostly < or = 50 years of age and had limited, chemotherapy-sensitive, hormone-responsive MBC. Due to an apparent dose-survival relationship, an increase by 10 units (U) in the SDIP increased the PFS time by 3 months. Independent predictors of an improved PFS were positive estrogen receptors (P = 0.001), positive combined hormone receptors (P = 0.020), and a complete remission/no evidence of disease status after HDCT (P < 0.001). In patients who had a disease-free interval (DFI) >24 months after primary surgery, an SDIP of >55 U was independently associated with a longer PFS [hazard ratio (HR) = 2.73; 95% confidence interval 1.29-5.81; P = 0.009]. CONCLUSION: HDCT can achieve long-term PFS in young MBC patients with limited, hormone-responsive and chemotherapy-sensitive disease. After a DFI >24 months, a longer PFS is associated with a higher chemotherapy dose as measured by SDIP. These retrospective analyses suggest SDIP might be a tool for studying cumulative dose as a determinant of outcome of MBC chemotherapy. Thus far, however, we cannot clearly identify any subgroup of MBC patients in whom HDCT with ASCT is of particular benefit.

Duration of adjuvant chemotherapy for breast cancer: a joint analysis of two randomised trials investigating three versus six courses of CMF.

Cyclophosphamide, methotrexate and fluorouracil adjuvant combination chemotherapy for breast cancer is currently used for the duration of six monthly courses. We performed a joint analysis of two studies on the duration of adjuvant cyclophosphamide, methotrexate and fluorouracil in patients with node-positive breast cancer to investigate whether three courses of cyclophosphamide, methotrexate and fluorouracil might suffice. The International Breast Cancer Study Group Trial VI randomly assigned 735 pre- and perimenopausal patients to receive 'classical' cyclophosphamide, methotrexate and fluorouracil for three consecutive cycles, or the same chemotherapy for six consecutive cycles. The German Breast Cancer Study Group randomised 289 patients to receive either three or six cycles of i.v. cyclophosphamide, methotrexate and fluorouracil day 1, 8. Treatment effects were estimated using Cox regression analysis stratified by clinical trial without further adjustment for covariates. The 5-year disease-free survival per cents (+/-s.e.) were 54+/-2% for three cycles and 55+/-2% for six cycles (n=1024; risk ratio (risk ratio: CMFx3/CMFx6), 1.00; 95% confidence interval, 0.85 to 1.18; P=0.99). Use of three rather than six cycles was demonstrated to be adequate in both studies for patients at least 40-years-old with oestrogen-receptor-positive tumours (n=594; risk ratio, 0.86; 95% confidence interval, 0.68 to 1.08; P=0.19). In fact, results slightly favoured three cycles over six for this subgroup, and the 95% confidence interval excluded an adverse effect of more than 2% with respect to absolute 5-year survival. In contrast, three cycles appeared to be possibly inferior to six cycles for women less than 40-years-old (n=190; risk ratio, 1.25; 95% confidence interval, 0.87 to 1.80; P=0.22) and for women with oestrogen-receptor-negative tumours (n=302; risk ratio, 1.15; 95% confidence interval, 0.85 to 1.57; P=0.37). Thus, three initial cycles of adjuvant cyclophosphamide, methotrexate and fluorouracil chemotherapy were as effective as six cycles for older patients (40-years-old) with oestrogen-receptor-positive tumours, while six cycles of adjuvant cyclophosphamide, methotrexate and fluorouracil might still be required for other cohorts. Because endocrine therapy with tamoxifen and GnRH analogues is now available for younger women with oestrogen-receptor-positive tumours, the need for six cycles of cyclophosphamide, methotrexate and fluorouracil is unclear and requires further investigation.

Treosulfan in the treatment of advanced ovarian cancer: a randomised co-operative multicentre phase III-study.

BACKGROUND: In August 1988 a randomised phase III multicenter trial was started in order to compare cisplatinum/treosulfan (PT) with standard cisplatinum/cyclophosphamide (PC) in advanced ovarian carcinoma, aiming at lower toxicity and maintained efficiency. PATIENTS AND METHODS: Five hundred and nineteen patients were enrolled into the protocol. Final evaluation after a median observation time of more than five years was made in July 1996 and included 398 eligible patients, of whom 366 were evaluable regarding efficiency and 290 in respect of toxicity. The tumour stages were classified as FIGO II in 53, FIGO III in 244 and FIGO IV in 68 patients. The patients were stratified regarding post-operative tumour burden. RESULTS: Hematological and gastrointestinal toxicity WHO > = 3 were comparable between the two study arms though a significant difference could be demonstrated regarding alopecia (PT 8% vs. PC 47% after six cycles). The median time to progression as the main efficiency item was in favour of the study schedule (PT 20.6 vs. PC 15.1 months) while significant differences were neither observed in the whole study group nor in the analysed subgroups (R0, < 2 cm, > = 2 cm). The same held true for overall survival. CONCLUSION: PT may be recommended as a less toxic substitute for the former standard PC. After the acceptance of paclitaxel/cisplatin as a new standard, the role of treosulfan should be investigated regarding adjuvant therapy in patients without residual tumor, as a potential partner in triple or sequential treatment and in second-line treatment.

Time independence of the prognostic impact of tumor cell detection in the bone marrow of primary breast cancer patients.

PURPOSE: Tumor cell detection (TCD) in bone marrow is an outstanding prognostic factor in breast cancer. There is only one other study that has investigated more than 300 patients with a median follow-up of more than 5 years (J. L. Mansi et al., Lancet, 354:197-202, 1999). We report data from 727 patients with a median follow-up period of 6.5 years. EXPERIMENTAL DESIGN: In a prospective study, intraoperatively aspirated bone marrow was screened for micrometastatic cancer cells. We used an immunocytological method (monoclonal mucin antibody 2E11; the avidin-biotin complex method). RESULTS: Forty-three percent of the patients were TCD positive. Sixty percent of the patients with distant metastases were tumor cell positive (155 of 258 patients). Forty-nine percent of the patients with positive TCD developed distant metastases (155 of 315 patients). TCD was an independent prognostic factor for clinical outcome after a median follow-up time of 6.5 years. The prognostic impact of TCD and tumor size remains constant with the time, whereas the impact of grading and progesterone receptor on risk seems to decrease with longer follow-up time. CONCLUSIONS: TCD remains an independent prognostic factor The impact of TCD does not change with longer follow-up time. TCD is a reliable prognostic factor and provides important information about the process of metastasis.

[Taxane-based palliative chemotherapy for metastatic breast cancer: matched pair analysis to compare the efficacy and safety of docetaxel and paclitaxel]. / Die palliative Behandlung des metastasierten Mammakarzinoms mit Taxanen: Ein Wirkungsvergleich zwischen Docetaxel und Paclitaxel mittels Matched-Pair-Analyse.

OBJECTIVE: A retrospective comparison of the efficacy and toxicity of docetaxel and paclitaxel in the treatment of metastatic breast cancer (MBC) was conducted based on our institution's experience since 1992. METHODS: Two groups of 43 patients who received a similar chemotherapy regimen containing either docetaxel or paclitaxel were matched for the number of prior treatments. RESULTS: Toxicity was mild in both groups. Tumour growth control, defined as either objective response or stable disease for at least 6 months, was obtained in a significantly higher proportion of patients treated with docetaxel compared with paclitaxel (67 % vs. 44 %, p = 0.001). Moreover, fewer patients progressed during treatment with docetaxel (28 % vs. 53 %, p < 0.001). At a median follow-up of 17 months there was no significant difference between the groups in median progression-free survival (7 vs. 5 months, p = 0.123) or median overall survival (OS) (12 vs. 11 months, p = 0.211). According to the method of Kaplan and Meier estimated OS rates at 1 year (74 % vs. 62 %) and 2 years (50 % vs. 26 %), however, were in favour of docetaxel. In a multivariate analysis only a positive hormone receptor status was significantly associated with improved OS. CONCLUSION: These results suggest that docetaxel may be superior to paclitaxel in the treatment of MBC.

Prospective clinical study comparing DNA flow cytometry and HPV typing as predictive tests for persistence and progression of CIN I/II.

A cohort of 70 consecutive women at a university hospital colposcopy clinic with untreated CIN I and CIN II (CIN I/II) confirmed by cytology and histology was followed for 1 year in the setting of a prospective trial. In the lesions, the presence of DNA from HPV types was examined by restriction fragment length polymorphism (RFLP) analysis. Aneuploid cell lines were demonstrated by aneuploid histograms generated by high-resolution DNA flow cytometry. HPV type 16 infection and the existence of aneuploid cell lines proved to be significant risk factors for CIN I/II lesions to persist or progress to CIN III in the 1-year follow-up period in the same cohort of patients. The relative risks and 95% confidence intervals (CI) were 1.81 (1.44-2.76) for aneuploid cell lines and 1.74 (1.10-2.76) for HPV type 16 infection in CIN I/II lesions. As a predictive diagnostic test for CIN I/II lesions to persist or progress, the specificity and positive predictive value (PPV) for aneuploid histograms were 100% (CI, 73.5-100%) and 100% (CI, 86.8-100%), respectively. The low sensitivity of 27.3% (CI, 14.9-42.8%) restricted the clinical application of the test, leaving 32 of 44 women with persisting or progressing CINI/II with diploid histograms. HPV type 16 positivity by FRLP had a PPV of 68.4% (CI, 43.5-87.4%) as a prognostic test. Six of 19 HPV 16 infected women showed complete remission of their CIN lesion. A combination of the two tests did not provide any additional information.

Tandem high-dose chemotherapy in high-risk primary breast cancer: a multivariate analysis and a matched-pair comparison with standard-dose chemotherapy.

Stem cell-supported high-dose chemotherapy (HDCT) is currently being evaluated in patients with high-risk primary breast cancer (HRPBC), as defined by extensive axillary lymph node involvement. Conclusive results from randomized studies with sufficient patient numbers and follow-up are pending. We retrospectively analyzed 144 HRPBC patients enrolled in a single-arm trial of tandem HDCT at the University of Heidelberg to evaluate the prognostic value of nodal ratio, HER2/neu status, and cytokeratin-positive bone marrow cells and to compare the outcomes of these patients with those of a conventionally treated control group of 91 patients matched by nodal ratio, tumor size, combined hormone-receptor status, and HER2/neu status. The tandem HDCT regimen consisted of 2 cycles of induction chemotherapy followed by 2 cycles of blood stem cell-supported high-dose ifosfamide, 12 g/m2; carboplatin, 900 mg/M2; and epirubicin, 180 mg/m2. Conventionally treated patients received a regimen containing anthracycline without taxanes (52 patients) or CMF (cyclophosphamide, methotrexate, and 5-flurouracil; 39 patients). With a median follow-up of 3.8 years, disease-free, distant disease-free, and overall survival rates were 62%, 65%, and 84%, respectively. In univariate analysis, besides the hormone receptor status (P = .007), HER2/neu overexpression was the strongest predictor of earlier death (P = .017). In multivariate analysis, a nodal ratio of > or =0.8 was found to be the only independent predictor of relapse (relative risk [RR] = 2.09; 95% confidence interval [CI], 1.21-3.60; P = .008) and only the absence of hormone receptors was associated with earlier death (RR = 3.59; 95% CI, 1.45-8.86; P = .006). Despite a trend toward later distant relapse after HDCT compared with standard-dose chemotherapy with a median follow-up of 3 years (P = .059), thus far, matched-pair analysis has not demonstrated significantly better survival rates after HDCT in all matched patients (P = .786) or in the subgroups of anthracycline-treated patients and patients with and without overexpression of HER2/neu. So far, the follow-up time has been too short to draw definite conclusions; however, patients with a nodal ratio of > or =0.8, receptor-negative tumors, or HER2/neu overexpression are at high risk for relapse and death, irrespective of the kind of adjuvant chemotherapy.

Long-term prognosis of breast cancer patients with 10 or more positive lymph nodes treated with CMF.

The purpose of this investigation was to study the long-term prognosis of breast cancer patients with 10 or more positive lymph nodes after conventional chemotherapy treatment with cyclophosphamide, methotrexate and 5-fluorouracil (CMF). Between 1984 and 1989, 1048 node-positive patients were treated with CMF in two separate trials conducted by the German Breast Cancer Study Group (GBSG). Subgroups either received radiotherapy or tamoxifen in addition. In this study, long-term prognosis in the subgroup of 141 patients with 10 or more positive lymph nodes was investigated. Univariate and multivariate Cox models were used to evaluate the effect of prognostic factors on event-free survival (EFS) and overall survival (OS). Both univariate and multivariate analyses revealed the progesterone receptor (PR) status as the dominating prognostic factor for both EFS and OS, resulting in a strongly increased risk of more than 2-fold for receptor-negative patients. A large number of positive lymph nodes also affected the prognosis for EFS. In univariate analysis, the degree of lymph node involvement (i.e. percentage of positive nodes out of all examined nodes), oestrogen status (ER) status, and tumour grade also showed significant effects. To conclude, the prognosis in the subgroup of patients with 10 or more positive lymph nodes is heterogeneous. Some surprisingly high survival rates have been observed in case series of breast cancer patients treated with high-dose chemotherapy which may be explained by patient selection. From the usual factors investigated in this study, the PR status showed the strongest effect, and, at least this factor should be taken into account in the design and analysis of trials for breast cancer patients with a poor prognosis.

Technical results of falloposcopy for infertility diagnosis in a large multicentre study.

Despite increasing evidence of its potential clinical value, falloposcopy has not yet found widespread use. In a large prospective international multicentre study we investigated the hypothesis that limited technical reproducibility may be of crucial significance in this regard. From 1994 to 1998, data on 367 patients with 639 tubes were recorded from 18 centres (median number of falloposcopies 22). Falloposcopy was performed using hysteroscopic ostium access, coaxial tubal cannulation and retrograde visualization under laparoscopic control. The procedure was successful in 69.6% of the tubes. Failures occurred in 6.1% during hysteroscopy, in 10.6% during the cannulation step and in 16.4% during visualization. While predominantly intracavitary pathology or thick endometrium were found to interfere with hysteroscopic ostium access, technical insufficiencies resulting in catheter damage or vision disturbing light reflexions were identified to be responsible for most cannulation and visualization failures, confirming the importance of these factors. The number of patients who received a complete falloposcopic evaluation did not exceed 57%. Additionally, 23.7% of patients may have profited from unilateral success depending on the individual indication. As a consequence of these technically limited results it was concluded that the method currently qualifies for selected indications rather than for routine clinical application.

Immunoscintigraphy with positron emission tomography: gallium-68 chelate imaging of breast cancer pretargeted with bispecific anti-MUC1/anti-Ga chelate antibodies.

Pretargeting techniques that are based on the sequential administrations of bispecific antitumor/antimetal chelate antibodies (BS-MAbs), a blocker to saturate the anti-chelate binding sites of the BS-MAb still present in the circulation, and the radiolabeled chelate are suitable to increase tumor-to-normal tissue contrasts and enable positron emission tomography (PET) as an imaging method. As demonstrated in the nude mouse model, a combination of pretargeted immunoscintigraphy and PET markedly improved the detection of tumor xenografts. With the presented preliminary clinical trial, we attempted to assess the efficacy of pretargeting and PET for breast cancer localization in patients. The BS-MAb used for pretargeting was synthesized from the F(ab')(2) fragments of the anti-MUC1 MAb 12H12, which reacts with the vast majority of breast tumors, and the F(ab') fragments of an anti-gallium (Ga) chelate MAb via a mixed functional chemical linker. For labeling of the Ga-chelate, we used the short-lived positron emitter Ga-68 (t(1/2), 68 min; beta(+), 88%). The dose and time schedule of pretargeting was deduced from previous animal experiments. Ten patients with biopsy-proven, primary breast carcinoma were infused with 10 mg of the BS-MAB: Eighteen h later, they received i.v. injections of 10.7 mg of a blocker and, 15 min later, 9.6 microg of the Ga chelate labeled with 230-300 MBq of (68)GA: PET imaging was started 60-90 min after injection of the (68)Ga chelate. Average tumor-to-blood and tumor:normal breast tissue ratios were 0.9 and 3.0 at 1 h postinjection. Tumor uptake amounted to approximately 0.003% iD/g corresponding to a standard uptake value of approximately 2. Blood clearance of the (68)Ga chelate showed a t(1/2) beta of approximately 100 min. Fourteen of 17 known lesions, averaging 25 +/- 16 mm in size, were clearly visualized as foci of increased activity with PET. No false-positive but three false-negative readings were obtained. An enhanced, bilateral activity uptake in the whole breast parenchyma, found in 4 of the 10 patients, compromised the recognition of these tumor sites. Although the shedding of the MUC1 antigen and the comparatively low tumor affinity of the BS-MAb, common to all anti-mucin MAbs, proved not to be optimal for increasing tumor:tissue ratios with a pretargeting technique, PET imaging offered better sensitivity for the detection of breast cancer at low tumor contrasts than conventional immunoscintigraphy. This could be demonstrated by the clear visualization of tumor sites 10 mm in size, which contrasted only by a factor of 2 from surrounding normal breast tissue.