Hans Peterse

Gene expression profiling predicts clinical outcome of breast cancer.

Breast cancer patients with the same stage of disease can have markedly different treatment responses and overall outcome. The strongest predictors for metastases (for example, lymph node status and histological grade) fail to classify accurately breast tumours according to their clinical behaviour. Chemotherapy or hormonal therapy reduces the risk of distant metastases by approximately one-third; however, 70–80% of patients receiving this treatment would have survived without it. None of the signatures of breast cancer gene expression reported to date allow for patient-tailored therapy strategies. Here we used DNA microarray analysis on primary breast tumours of 117 young patients, and applied supervised classification to identify a gene expression signature strongly predictive of a short interval to distant metastases (‘poor prognosis’ signature) in patients without tumour cells in local lymph nodes at diagnosis (lymph node negative). In addition, we established a signature that identifies tumours of BRCA1 carriers. The poor prognosis signature consists of genes regulating cell cycle, invasion, metastasis and angiogenesis. This gene expression profile will outperform all currently used clinical parameters in predicting disease outcome. Our findings provide a strategy to select patients who would benefit from adjuvant therapy.

Synergistic tumor suppressor activity of BRCA2 and p53 in a conditional mouse model for breast cancer.

Inheritance of one defective BRCA2 allele predisposes humans to breast cancer. To establish a mouse model for BRCA2-associated breast cancer, we generated mouse conditional mutants with BRCA2 and/or p53 inactivated in various epithelial tissues, including mammary-gland epithelium. Although no tumors arose in mice carrying conditional Brca2 alleles, mammary and skin tumors developed frequently in females carrying conditional Brca2 and Trp53 alleles. The presence of one wildtype Brca2 allele resulted in a markedly delayed tumor formation; loss of the wildtype Brca2 allele occurred in a subset of these tumors. Our results show that inactivation of BRCA2 and of p53 combine to mediate mammary tumorigenesis, and indicate that disruption of the p53 pathway is pivotal in BRCA2-associated breast cancer.

Risk factors in breast-conservation therapy.

PURPOSE To identify clinical and pathologic factors associated with an increased risk of local recurrence following breast-conservation therapy (BCT) to assess the safety of this procedure for all subgroups of patients. PATIENTS AND METHODS The study population consisted of 1,026 patients with clinical stage I and II breast cancer treated between 1979 and 1988 at the Netherlands Cancer Institute. The BCT regimen consisted of local excision and axillary lymph node dissection (ALND) followed by whole-breast irradiation to a total dose of 50 Gy in 2-Gy fractions and boost irradiation (mostly by iridium implant) of 15 to 25 Gy. RESULTS With a median follow-up duration of 66 months, the actuarial breast recurrence rate was 4% at 5 years, counting all breast recurrences. Univariate analysis showed seven factors to be associated with an increased risk of local recurrence; age, residual tumor at reexcision, histologic tumor type, presence of any carcinoma-in-situ component, vascular invasion, microscopic margin involvement, and whole-breast radiation dose. Three factors remained independently significant after proportional hazard regression analysis: age, margin involvement, and the presence of vascular invasion. When the analysis was repeated, but counting only those breast recurrences that occurred before regional or distant failures, only young age and vascular invasion were independent predictive factors. In the third analysis, factors predicting the necessity of local salvage treatment were analyzed. In this analysis, the possible bias in the former analysis caused by censoring actuarial methods was avoided. The results were the same as in the second analysis, showing young age and vascular invasion as the only independent predictive factors. Breast recurrence rates were 6% for patients less than 40 years of age and 8% for patients with tumors showing vascular invasion. In the absence of risk factors, the breast recurrence rate is only 1% at 5 years. CONCLUSION Slightly higher recurrence rates were found in patients less than 40 years of age and in patients with tumors showing vascular invasion. The role of margin involvement is uncertain.

Angiosarcoma of the breast after conservation therapy for invasive cancer, the incidence and outcome. An unforeseen sequela

Purpose. In the past 15 years breast conserving therapy (BCT) has become an important treatment option for primary breast cancer. Thirty three angiosarcomas (AS) after BCT have been described in a total of 20 published reports. Limited follow-up data and the lack of information on incidence of AS prompted the authors to review the comprehensive experience in the Netherlands. Methods. Between 1987 and 1995 twenty-one patients with BCT-associated AS were diagnosed in the Netherlands. Follow-up after diagnosis of AS ranged from 6 to 82 months with a median of 24 months. Information on the total number of patients treated with BCT and on the numbers of angiosarcoma in the breast was obtained. Results. The median interval between BCT and AS was 74 months (range: 29–106) and appeared to decrease with higher age. Detection of skin changes followed by incisional biopsy provided the diagnosis. Two year overall (OS) and disease free survivals were 72% (s.e. 10.9) and 35% (s.e. 10.7), respectively. Two year OS after initial complete surgical resection was 86% (s.e. 9.3) compared to 0% after incomplete resection of the AS (P=0.04). The estimated incidence of AS after BCT is 0.16%. Conclusions. BCT-associated AS arises after a relatively short interval. Although the incidence of AS is low, the absolute number of patients at risk is increasing. This calls for vigilance concerning skin changes occurring after BCT. An incisional biopsy provides the only reliable diagnosis. The prognosis appears to be related to the completeness of surgical resection.

BRCA1-Associated Breast Cancers Present Differently From BRCA2-Associated and Familial Cases: Long-Term Follow-Up of the Dutch MRISC Screening Study

PURPOSE The Dutch MRI Screening Study on early detection of hereditary breast cancer started in 1999. We evaluated the long-term results including separate analyses of BRCA1 and BRCA2 mutation carriers and first results on survival. PATIENTS AND METHODS Women with higher than 15% cumulative lifetime risk (CLTR) of breast cancer were screened with biannual clinical breast examination and annual mammography and magnetic resonance imaging (MRI). Participants were divided into subgroups: carriers of a gene mutation (50% to 85% CLTR) and two familial groups with high (30% to 50% CLTR) or moderate risk (15% to 30% CLTR). RESULTS Our update contains 2,157 eligible women including 599 mutation carriers (median follow-up of 4.9 years from entry) with 97 primary breast cancers detected (median follow-up of 5.0 years from diagnosis). MRI sensitivity was superior to that of mammography for invasive cancer (77.4% v 35.5%; P<.00005), but not for ductal carcinoma in situ. Results in the BRCA1 group were worse compared to the BRCA2, the high-, and the moderate-risk groups, respectively, for mammography sensitivity (25.0% v 61.5%, 45.5%, 46.7%), tumor size at diagnosis≤1 cm (21.4% v 61.5%, 40.9%, 63.6%), proportion of DCIS (6.5% v 18.8%, 14.8%, 31.3%) and interval cancers (32.3% v 6.3%, 3.7%, 6.3%), and age at diagnosis younger than 30 years (9.7% v 0%). Cumulative distant metastasis-free and overall survival at 6 years in all 42 BRCA1/2 mutation carriers with invasive breast cancer were 83.9% (95% CI, 64.1% to 93.3%) and 92.7% (95% CI, 79.0% to 97.6%), respectively, and 100% in the familial groups (n=43). CONCLUSION Screening results were somewhat worse in BRCA1 mutation carriers, but 6-year survival was high in all risk groups.

Clinical presentation, endoscopic features, and treatment of gastric metastases from breast carcinoma.

Breast carcinoma is the most common malignancy in women. Metastatic involvement of the stomach is not well known.

Pathological investigation of sentinel lymph nodes

Abstract. The sentinel lymph-node procedure enables selective targeting of the first draining lymph node, where the initial metastases will form. A negative sentinel node (SN) predicts the absence of tumour metastases in the other regional lymph nodes with high accuracy. This means that in the case of a negative SN, regional lymph-node dissection is no longer necessary. Besides saving costs, this will prevent many side-effects as a result of lymph-node dissection. The task of the pathologist is to screen SNs for metastases. To this end, several techniques are available such as standard histo- and cytopathological techniques, immunohistochemistry, flow cytometry, and molecular biological techniques. These methods are explained and their sensitivity for detecting SN metastases is discussed. Some of these techniques also appear to be useful for intra-operative evaluation of SNs. The standard protocol for detection of SN metastases consists of extensive histopathological investigation including step H&E stained sections and immunohistochemistry. Intra-operative frozen-section analysis of SNs has been shown to be reliable for breast-cancer axillary lymph nodes. In the intra-operative setting, imprint cytology can also be used but its additional value to frozen section analysis is not yet clear. Further studies are necessary to establish the role of sophisticated molecular biological techniques such as reverse transcription polymerase chain reaction (RT-PCR) in detecting SN metastases. The sensitivity of flow cytometry is too low for this purpose.

The spectrum of gastrointestinal metastases of breast carcinoma: II. The colon and rectum.

In a 15-year period at the Netherlands Cancer Institute, 17 patients were found with breast carcinoma metastatic to the colon or rectum or both. The presenting symptoms and signs were non-specific and included diarrhea, crampy pain, vomiting, and palpable tumor. Endoscopic examination, possible in only 10 of the 17 patients because of luminal obstruction, yielded a correct diagnosis in seven cases. Biopsy was confirmatory in five cases. Lesions metastatic to the colorectum originated predominantly in lobular carcinoma of the breast. Systemic hormonal or chemotherapy or x-irradiation, either alone or as an adjunct to surgery, produced a favorable response in over half the patients so treated.

Continuing Risk of Ipsilateral Breast Relapse After Breast-Conserving Therapy at Long-Term Follow-up

PURPOSE Currently, the local treatment of most patients with early invasive breast cancer consists of breast-conserving therapy (BCT). We have previously reported on the risk factors for ipsilateral breast relapse (IBR) in 1,026 patients treated with BCT after a median follow-up of 5.5 years. In the present study, we evaluated the IBR incidence and the risk factors for IBR after prolonged follow-up. METHODS AND MATERIALS We updated the disease outcome for all 1,026 patients using the clinical information collected from the medical registration of The Netherlands Cancer Institute and performed step-wise proportional hazard Cox regression analysis to identify the risk factors associated with an increased risk of IBR after BCT at long-term follow-up. RESULTS After a median follow-up of 13.3 years, 114 patients had developed an IBR as the first event. The IBR rate was 9.3% and 13.8%, respectively, at 10 and 15 years. Also, the increase in IBR was continuous without reaching a plateau, even after 15 years. Univariate analysis showed that involved surgical resection margins, young age, vascular invasion, and the presence and quantity of an in situ component are risk factors for IBR. Multivariate analysis showed that tumor-positive surgical resection margins (hazard ratio, 2.9; 95% confidence interval, 1.7-5.2, p = 0.0002) or the presence of vascular invasion (hazard ratio, 2.0; 95% confidence interval, 1.2-3.2, p = 0.004) is the major independent risk factor for IBR. CONCLUSIONS The data from long-term follow-up showed a constant increase in IBR among patients treated by BCT, even after 15 years, without reaching a plateau. Involved surgical resection margins and vascular invasion were the most important risk factors for IBR.

Detection of metastases in sentinel lymph nodes of breast cancer patients by multiple mRNA markers.

Disseminated breast tumour cells in sentinel lymph nodes (SNs) were evaluated by quantitative real-time PCR and the sensitivity of this assay was compared to the routine histological analysis. First, several candidate marker genes were tested for their specificity in axillary lymph nodes (ALN) of 50 breast cancer patients and 43 women without breast cancer. The marker gene panel selected, designed to detect the mRNA of CK19, p1B, EGP2 and SBEM, was subsequently applied to detect metastases in 70 SNs that were free of metastases as determined by standard histological evaluation. Remarkably, seven negative SNs showed increased marker gene expression, suggesting the presence of (micro) metastases. Four of these seven SNs positive by real-time PCR proved to contain tumour deposits after careful review of the slides or further sectioning of the paraffin-embedded material. In three PCR positive SNs, however, no tumour cells were found by haematoxylin and eosin staining (H&E) and immunohistologically analysis. The quantitative real-time PCR assay with multiple mRNA markers for the detection of disseminated breast cancer cells in SNs thus resulted in an upstaging of SNs containing metastastic disease of 10% compared to the routine histological analysis. The application of this technique may be of clinical relevance, as it is suggested that micrometastatic disease in SNs are associated with further nodal non-SN metastases in breast cancer.