Long-term outcome of pT1a-b, cN0 breast cancer without axillary dissection or staging: a prospective observational study of 1543 women

BACKGROUND

The implementation of screening programmes in Sweden during the mid-1990s increased the number of small node-negative breast cancers. In this era before staging by sentinel node biopsy, routine axillary dissection for staging of early breast cancer was questioned owing to the increased morbidity and lack of perceived benefit. The long-term risk of axillary recurrence when axillary staging is omitted remains unclear.

METHODS

This prospective observational multicentre cohort study included Swedish women diagnosed with breast cancer between 1997 and 2002. The patients had clinically node-negative, pT1a-b, grade I-II tumours. No axillary staging or dissection was performed. The primary outcome was ipsilateral axillary recurrence and survival.

RESULTS

A total of 1543 patients were included. Breast-conserving surgery (BCS) was performed in 94·0 per cent and the rest underwent mastectomy. After surgery, 58·1 per cent of the women received adjuvant radiotherapy, 11·9 per cent adjuvant endocrine therapy and 31·5 per cent did not receive any adjuvant treatment. After a median follow-up of 15·5 years, 6·4 per cent developed contralateral breast cancer and 16·5 per cent experienced a recurrence. The first recurrence was local in 116, regional in 47 and distant in 59 patients. The breast cancer-specific survival rate was 93·7 per cent after 15 years. There were no differences in overall or breast cancer-specific survival between patients who received adjuvant radiotherapy and those who did not. Only 3·0 per cent of patients had an axillary recurrence, which was isolated in only 1·0 per cent.

CONCLUSION

Axillary surgery can safely be omitted in patients with low-grade, T1a-b, cN0 breast cancers. This large prospective cohort with 15-year follow-up had a very low incidence of axillary recurrences and high breast cancer-specific survival rate.

A prospective, multicenter validation study of a prognostic index composed of S-phase fraction, progesterone receptor status, and tumour size predicts survival in node-negative breast cancer patients: NNBC, the node-negative breast cancer trial

BACKGROUND

In a retrospective study on node-negative breast cancer, a prognostic index consisting of a proliferation factor, S-phase fraction (SPF), progesterone receptor status (PR), and tumour size identified one-third of patients as high risk, with a sixfold increased risk of breast cancer death. This prospective multicenter cohort study was set up to validate the index.

PATIENTS AND METHODS

In 576 T1-2N0 patients <60 years, prospective analyses of PR and SPF were carried out. High risk was defined as ≥2 of the following: size >20 mm, PR-negativity, and high SPF (in the absence of SPF, Bloom-Richardson grade 3). Median follow-up was 17.8 years.

RESULTS

Thirty-one percent were high risk. In univariate analysis, the index was prognostic for breast cancer-specific survival after 5 years [hazard ratio (HR) = 4.7, 95% confidence interval (95% CI) 2.5-8.9], 10 years (HR = 2.2, 95% CI 1.5-3.3), and 15 years (HR = 1.7, 95% CI 1.2-2.5), and remained significant after adjustment for adjuvant medical treatment and age. In the 37% of patients with no risk factors, only one patient died of breast cancer the first 5 years.

CONCLUSIONS

This prospective study validates a prognostic index consisting of a proliferation factor, PR-status, and tumour size. The index may be helpful for prognostic considerations and for selection of patients in need of adjuvant therapy.

Mammography casting-type calcification and risk of local recurrence in DCIS: analyses from a randomised study

BACKGROUND

We studied the association between mammographic calcifications and local recurrence in the ipsilateral breast.

METHODS

Case-cohort study within a randomised trial of radiotherapy in breast conservation for ductal cancer in situ of the breast (SweDCIS). We studied mammograms from cases with an ipsilateral breast event (IBE) and from a subcohort randomly sampled at baseline. Lesions were classified as a density without calcifications, architectural distortion, powdery, crushed stone-like or casting-type calcifications.

RESULTS

Calcifications representing necrosis were found predominantly in younger women. Women with crushed stone or casting-type microcalcifications had higher histopathological grade and more extensive disease. The relative risk (RR) of a new IBE comparing those with casting-type calcifications to those without calcifications was 2.10 (95% confidence interval (CI) 0.92-4.80). This risk was confined to in situ recurrences; the RR of an IBE associated with casting-type calcifications on the mammogram adjusted for age and disease extent was 16.4 (95% CI 2.20-140).

CONCLUSION

Mammographic appearance of ductal carcinoma in situ of the breast is prognostic for the risk of an in situ IBE and may also be an indicator of responsiveness to RT in younger women.

P2-12-22: A Prognostic Index Composed of Progesterone Receptor Status, Tumour Size and S-phase Fraction, Predicts Survival in Node-Negative Breast Cancer Patients in a Large Multicentre Prospective Cohort Study

Background

The importance of the added prognostic value of proliferation, either single factors such as Ki67 or flow cytometric S-phase fraction (SPF), or as the main common denominator in the majority of gene expression profiles, has been highlighted over the last years in node-negative breast cancer. There are however few published prospective studies. In an earlier retrospective study on node-negative breast cancer from our group, a prognostic index consisting of PR status, tumour size and a proliferation factor, SPF, identified one third of the patients as high risk, with a fourfold increased risk of distant recurrence. The present study was set up to validate this index in a large prospective multicenter cohort study with long term follow-up.

Material and Methods: 596 patients from 3 regions in Sweden were between 1991–1995 included in the study. Inclusion criteria were: 10mm≤tumour size≤50mm, node-negativity, ≥5 lymph nodes removed, age &lt;60 years, and radical surgery. Patients with bilateral breast cancer or previous malignancy were excluded. Prospective analyses of ER, PR, and flow cytometric SPF were performed. High- risk was defined as 2 or more of the following: 1. size &gt;20mm

2. PR- (in the absence of PR status, ER-) and 3. high SPF (in the absence of SPF, Bloom Richardson grade 3). 82% of the patients received no adjuvant medical treatment. Cox proportional hazards regression, stratified for centre, was used to model the impact of the index on breast cancer specific survival (BCSS). Median follow-up was 16 years for the 452 patients alive at last follow-up. Analyses were done after 5 and 10 years follow-up, during which 42 and 95 patients, respectively, died of breast cancer.

Results: 31% of the patients were identified as high-risk. In univariate analysis, the index was prognostic for BCSS after 5 years (HR 5.1, 95%CI: 2.7−9.8,) as well as 10 years (HR 2.2, 95%CI: 1.5−3.4). The prognostic impact remained significant after adjustment for adjuvant medical treatment and age. The 5- and 10-year BCSS (95%CI) was 97% (94-98) and 87% (83-90) for low risk patients, compared with 85% (79-89) and 76% (69-81) for high risk patients. In the group with no risk factors (n=218 ), no patient died of breast cancer during the first 5 years. Proliferation was the strongest factor for BCSS followed by PR and tumour size, both in uni- and multivariate analyses. In multivariate analysis, adjusted for adjuvant treatment and age, the HR for proliferation was 7.5 (95%CI: 3.2-18) after 5 years and 2.5 (95%CI: 1.6−4.0) after 10 years.

Discussion: This large prospective multicenter cohort study validates the results from an earlier retrospective study, that a prognostic index consisting of PR status, tumour size and a proliferation factor, SPF, reliably identifies one third of the node-negative patients with a high risk of relapse. The index also identifies an extreme low risk group; patients with no risk factors, with 100% 5-year survival. This group could be spared adjuvant medical treatment, especially chemotherapy. Taken together, this index may be clinically helpful for prognostic considerations and for selection of adjuvant treatment.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-12-22.

Histopathological risk factors for ipsilateral breast events after breast conserving treatment for ductal carcinoma in situ of the breast – Results from the Swedish randomised trial

AIM

The primary aims were to study risk factors for an ipsilateral breast event (IBE) after sector resection for ductal carcinoma in situ of the breast (DCIS) in a trial comparing adjuvant radiotherapy to no therapy and to assess predictive factors for response to radiotherapy. Secondary aims were to analyse reproducibility of the histopathological evaluation and to estimate correctness of diagnosis in the trial.

SETTING

A randomised trial in Sweden (the SweDCIS trial), including 1046 women with a median of 5.2 years of follow-up in a population, offered routine mammographic screening.

METHODS

A case-cohort design with a total of 161 cases of IBE (42 of those being members of the subcohort) and 284 sampled for the sub-cohort. Ninety five percent of the participants' slides could be retrieved and were re-evaluated by three experienced pathologists.

RESULTS

Low nuclear grade (NG 1-2) and absence of necrosis halves the risk of IBE in both irradiated and non-irradiated patients. Lesion size, margins of excision and age at diagnosis did not modify these associations. The presence of necrosis modified the effect of radiotherapy: relative risk was 0.40 with necrosis present and 0.07 with necrosis absent (p-value for interaction 0.068). In all subsets of prognostic factors, radiotherapy conferred a substantial benefit. The risk factors for in situ and invasive IBE were similar. The agreement between pathologists was moderate (kappa=0.486). Correctness of diagnosis in the subcohort of SweDCIS was 84.8%.

CONCLUSION

Although nuclear grade and necrosis carry prognostic information, we could not define a group with very low risk after sector resection alone. Radiotherapy has a protective effect in all substrata of risk factors studied. The interaction between the presence of necrosis and radiotherapy is a clinically and biologically relevant research area.

Cyclin D1 overexpression is a negative predictive factor for tamoxifen response in postmenopausal breast cancer patients

Antioestrogen treatment by tamoxifen is a well-established adjuvant therapy for oestrogen receptor-alpha (ERα) positive breast cancer. Despite ERα expression some tumours do not respond to tamoxifen and we therefore delineated the potential link between the cell cycle regulator and ERα co-factor, cyclin D1, and tamoxifen response in a material of 167 postmenopausal breast cancers arranged in a tissue array. The patients had been randomised to 2 years of tamoxifen treatment or no treatment and the median follow-up time was 18 years. Interestingly in the 55 strongly ERα positive samples with moderate or low cyclin D1 levels, patients responded to tamoxifen treatment whereas the 46 patients with highly ERα positive and cyclin D1 overexpressing tumours did not show any difference in survival between tamoxifen and no treatment. Survival in untreated patients with cyclin D1 high tumours was slightly better than for patients with cyclin D1 low/moderate tumours. However, there was a clearly increased risk of death in the cyclin D1 high group compared to an age-matched control population. Our results suggest that cyclin D1 overexpression predicts for tamoxifen treatment resistance in breast cancer, which is line with recent experimental data using breast cancer cell lines and overexpression systems.

Downregulation of the potential suppressor gene IGFBP-rP1 in human breast cancer is associated with inactivation of the retinoblastoma protein, cyclin E overexpression and increased proliferation in estrogen receptor negative tumors

The complex insulin-like growth factor network of ligands, receptors and binding proteins has been shown to be disturbed in breast cancer. In addition to defects in proteins controlling cell cycle checkpoints, this type of aberrations could affect tumor growth and survival thereby influencing both tumor aggressiveness and potential response to treatments. We have previously identified the T1A12/mac25 protein, which is identical to the IGFBP-rP1, as a differentially expressed gene product in breast cancer cells compared with normal cells. Here we compare the expression of IGFBP-rP1 in 106 tumor samples with known status of cell cycle aberrations and other clinicopathological data. This was done using a tumor tissue section array system that allows for simultaneous immunohistochemical staining of all samples in parallel. Cytoplasmic staining of variable intensity was observed in most tumors, 15% lacked IGFBP-rP1 staining completely, 20% had weak staining, 32% intermediate and 33% showed strong staining. Low IGFBP-rP1 was associated with high cyclin E protein content, retinoblastoma protein (pRb) inactivation, low bcl-2 protein, poorly differentiated tumors and higher stage. There was a significantly impaired prognosis for patients with low IGFBP-rP1 protein tumors. Interestingly, IGFBP-rP1 showed an inverse association with proliferation (Ki-67%) in estrogen receptor negative tumors as well as in cyclin E high tumors suggesting a separate cell cycle regulatory function for IGFBP-rP1 independent of interaction with the estrogen receptor or the pRb pathway.

DNA content in colorectal carcinoma: a flow cytometric study of the epithelial fraction

The aim of this study was to estimate the proliferative activity of the epithelial fraction in human colorectal carcinomas. Cell suspensions from 27 human colorectal carcinomas were simultaneously selected for epithelial cells and analyzed for DNA content. The staining procedure we employed, after dispersing the tumour sample into a single-cell suspension, included propidium iodide and a monoclonal antibody to the intermediate filament cytokeratin specific for secretory epithelia of normal human tissue and cells of epithelial origin in adenocarcinomas. This technique made it possible to distinguish the epithelial cell population from non-epithelial cells in the tumour. Flow cytometry was used for DNA analysis and the results obtained after epithelial selection were compared with conventional DNA analysis of crude tumour tissue. No difference in S-phase values of diploid and aneuploid cytokeratin positive cells were seen, whereas analysis of crude tumour cell suspensions showed lower S-phase values in diploid tumours compared to aneuploid ones. When cytokeratin-positive cells in the tumour were selected, we found presence of diploid tumour cells in almost all aneuploid tumours.

Retrospective DNa analysis of T3/T4 breast carcinoma using cytophotometry and flow cytometry. A comparative study with prognostic evaluation

Tumor cells from 72 patients with advanced breast carcinoma (T3/T4) were analyzed for their DNA content by cytophotometry and flow cytometry (FCM). Both methods were able to subdivide the tumors into groups with different prognoses. Patients with a normal/near-normal DNa content in the tumor had a better prognosis than did those with aneuploid tumors. FCM measurements of DNA content gave a better discrimination for both survival (P = .019) and disease-free survival (P = .059) than did cytophotometry (P = .105 and P = .067, respectively). These results indicate that FCM analysis of paraffin-embedded material is a more accurate method than is cytophotometry for characterizing the DNA content of breast carcinoma cells. The method could be useful in both retrospective studies and in daily diagnostic work.