St Gallen molecular subtypes in screening-detected and symptomatic breast cancer in a prospective cohort with long-term follow-up

Background

Diagnosis by screening mammography is considered an independent positive prognostic factor, although the data are not fully in agreement. The aim of the study was to explore whether the mode of detection (screening‐detected versus symptomatic) adds prognostic information to the St Gallen molecular subtypes of primary breast cancer, in terms of 10‐year cumulative breast cancer mortality (BCM).

Methods

A prospective cohort of patients with primary breast cancer, who had regularly been invited to screening mammography, were included. Tissue microarrays were constructed from primary tumours and lymph node metastases, and evaluated by two independent pathologists. Primary tumours and lymph node metastases were classified into St Gallen molecular subtypes. Cause of death was retrieved from the Central Statistics Office.

Results

A total of 434 patients with primary breast cancer were included in the study. Some 370 primary tumours and 111 lymph node metastases were classified into St Gallen molecular subtypes. The luminal A‐like subtype was more common among the screening‐detected primary tumours (P = 0·035) and corresponding lymph node metastases (P = 0·114) than among symptomatic cancers. Patients with screening‐detected tumours had a lower BCM (P = 0·017), and for those diagnosed with luminal A‐like tumours the 10‐year cumulative BCM was 3 per cent. For patients with luminal A‐like lymph node metastases, there was no BCM. In a stepwise multivariable analysis, the prognostic information yielded by screening detection was hampered by stage and tumour biology.

Conclusion

The prognosis was excellent for patients within the screening programme who were diagnosed with a luminal A‐like primary tumour and/or lymph node metastases. Stage, molecular pathology and mode of detection help to define patients at low risk of death from breast cancer.

Low‐risk group identified

Abstract P2-10-36: Analysis of biomarker expression and biological subtype in primary tumour, corresponding lymph node and distant metastasis with 5-year follow-up

Background: Biological variation in genotype and phenotype of primary breast cancer explains the heterogeneity of the disease and subsequent outcome. Choice of treatment is routinely based on the biomarker expression of the primary tumour with regard to estrogen- (ER) and progesterone (PR) receptor status, human epidermal growth factor receptor 2 (HER2) status and the proliferation marker Ki67, individually. Recently, gene expression profiling and subsequent immunohistochemical studies have identified biologically distinct subtypes by using a combination of biomarkers which have been shown to be of prognostic value beyond the previous known. However, tumour progression theories propose a change in biomarker expression during development from primary tumour to distant metastasis with implications on choice of therapy. The aim of this study was to compare biomarker expression individually and according to biological subtype between tumour samples from primary tumour, lymph node metastasis and distant metastasis from the same patient.

Material and methods: From an original cohort of 569 patients with primary breast cancer, tissue microarrays were constructed from archival tissue blocks of primary tumour (n = 521), paired lymph node metastasis (n = 147) and biopsies from distant metastasis (n = 42). The samples were evaluated by two independent pathologists. The individual biomarker expression as well as subtype classification (Luminal A: ER+ and/or PR+, Ki67≤ 20% and HER2−. Luminal B: ER+ and/or PR+, Ki67> 20% and/or HER2+. HER2 type: ER/PR−, HER2+. Basal-like: ER/PR−, HER2−, CK5/6+ and/or EGFR+) were compared between primary tumour, lymph node metastasis and distant metastasis. Survival outcome were estimated using the Kaplan-Meier method and log rank test. The primary end-point was distant disease-free survival (DDFS).

Results: Distribution according to subtype.

Determination of sentinel lymph node (SLN) status in primary breast cancer by prospective use of immunohistochemistry increases the rate of micrometastases and isolated tumour cells: Analysis of 174 patients after SLN biopsy

AIM

The objective of the present study was to evaluate the prospective use of immunohistochemistry (IHC) for histopathological diagnosis of sentinel lymph node(s) (SLN) in primary breast cancer using stage migration and non-SLN metastases as endpoints in relation to metastatic involvement.

METHOD

Serial sectioning and prospective use of IHC were applied to SLN examination in addition to routine haematoxylin-eosin staining in 174 consecutive patients with unifocal T1-T2 breast cancer included in a National Sentinel Node Study. Axillary lymph node dissection (ALND) was performed in all cases with macrometastases, micrometastases and isolated tumour cells (ITC).

RESULTS

The SLN was found in 173/174 patients and a metastatic foci was found in 50 patients including 28/50 with macrometastases, 16/50 with micrometastases and 6/50 with ITC. IHC detected 3/16 of the micrometastases and 4/6 of ITC. Stage migration from N0 to N1mi was encountered in 3/132 patients by use of IHC. Non-SLN metastases were noted in 15/28 of patients with macrometastases and in 3/16 of patients with micrometastases, whereas no patient with ITC had additional metastases (p=0.007).

CONCLUSION

The prospective use of IHC and serial sectioning for histopathological diagnosis of SLNs increased the detection rate of N1mi and ITC, but only 3/132 patients were stage-migrated by use of IHC. Patients with ITC did not have any risk of non-SLN metastases, supporting that ALND can safely be omitted in this group of patients.

Molecular characterization of early-stage bladder carcinomas by expression profiles, FGFR3 mutation status, and loss of 9q

We used gene expression profiling, mutation analyses of FGFR3 and TP53, and LOH analyses of chromosome 9 and the TP53 region on chromosome arm 17p, to molecularly characterize 75 Ta and T1 bladder carcinomas. We identified four major cellular processes related to cell cycle, protein synthesis, immune response, and extra cellular components that contribute to the expressional heterogeneity of early-stage urothelial cell carcinoma (UCC). Activating FGFR3 mutations were found at the highest frequency in G1 tumors (80%), and showed a strong correlation with FGFR3 expression. In contrast, G3 tumors displayed mutations in less than 10% of the cases and a low level of FGFR3 expression. Even though LOH on chromosome 9 was not associated with any specific expression pattern, our data indicate that loss of chromosome 9 is associated with tumor development rather than initiation. The combined analyses suggest the existence of two types of UCC tumors, one which is characterized by FGFR3 mutation or expression, high expression of protein synthesis genes, and low expression of cell cycle genes. Furthermore, the presented data underscore FGFR3 receptor involvement in urothelial cell transformation as the presence of FGFR3 mutations has a major impact on the global gene expression profile of bladder carcinomas.

Pathology parameters and adjuvant tamoxifen response in a randomised premenopausal breast cancer trial

BACKGROUND

Subgroups of breast cancer that have an impaired response to endocrine treatment, despite hormone receptor positivity, are still poorly defined. Breast cancer can be subdivided according to standard pathological parameters including histological type, grade, and assessment of proliferation. These parameters are the net result of combinations of genetic alterations effecting tumour behaviour and could potentially reflect subtypes that respond differently to endocrine treatment.

AIMS

To investigate the usefulness of these parameters as predictors of the response to tamoxifen in premenopausal women with breast cancer.

MATERIALS/METHODS

Clinically established pathological parameters were assessed and related to the tamoxifen response in 500 available tumour specimens from 564 premenopausal patients with breast cancer randomised to either two years of tamoxifen or no treatment with 14 years of follow up. Proliferation was further evaluated by immunohistochemical Ki-67 expression.

RESULTS

Oestrogen receptor positive ductal carcinomas responded as expected to tamoxifen, whereas the difference in recurrence free survival between control and tamoxifen treated patients was less apparent in the relatively few lobular carcinomas. For histological grade, there was no obvious difference in treatment response between the groups. The relation between proliferation and tamoxifen response seemed to be more complex, with a clear response in tumours with high and low proliferation, whereas tumours with intermediate proliferation defined by Ki-67 responded more poorly.

CONCLUSIONS

Clinically established pathology parameters seem to mirror the endocrine treatment response and could potentially be valuable in future treatment decisions for patients with breast cancer.

[Transitional cell carcinoma of the prostate in cystoprostatectomy specimens]

PURPOSE

Transitional cell carcinoma (TCC) of the prostate/prostatic urethra is a risk factor for urethral recurrence after radical cystoprostatectomy for TCC. Using conventional sectioning techniques, prostate involvement (prostatic urethra, acini, ducts and/or stroma) has been detected in a range of 10-20% of the patients, whereas transversal whole mount sectioning has revealed 43 % prostate involvement in two reported series. Due to different mechanisms of prostate involvement (intraurethral, extravesical and direct overgrowth into the prostatic stroma), preoperative transurethral biopsies of the prostate might not accurately determine such involvement. In this study we examine the prostate using a longitudinal whole mount sectioning technique, correlate TCC of the prostate with the characteristics of the bladder tumour and, thus, validate the preoperative transurethral resection biopsies.

MATERIAL AND METHODS

Patients scheduled for cystoprostatectomy or cystoprostatourethrectomy were investigated by preoperative resection biopsies from the prostatic urethra and mapping of the bladder. The cystectomy specimen was fixated with the bladder filled with formalin, and the prostate and bladder neck examined using longitudinal whole mount sectioning.

RESULTS

In 13 of the 43 (30%), patients TCC was identified in the prostate. Of these 13 patients, 9 had been identified in the preoperative resection biopsies from the prostatic urethra. Of the patients with prostatic involvement, 46% had carcinoma in situ (Cis) in the bladder neck/trigone and 38% had multifocal Cis in the bladder. Comparing this to the group of patients without prostatic involvement, the respectively figures are 20% and 23%. A tumour in the trigone, either invasive or Cis, was detected in 5/13 patients with prostatic involvement as compared to one patient (3%) without TCC of the prostate. Multiple bladder tumours were more common in patients with prostatic involvement and were larger (3.2 cm compared to 2.2 cm).

CONCLUSIONS

Preoperative resection biopsies from the prostatic urethra do not always detect TCC in the prostate. Cis in the bladder neck/trigone or multifocal and multiple bladder tumours could be risk factors for prostate involvement of TCC.

[Bladder cancer and the sentinel node concept]

PURPOSE

Lymph node status is one of the most important prognostic factors in muscle-invasive bladder cancer. The extent of lymphadenectomy performed in conjunction with cystectomy and the question as to whether this is a staging or therapeutic intervention are matters of discussion. The aim of this study was to evaluate the sentinel node (SN) concept and to correlate findings with tumour status in excised regional lymph nodes.

MATERIAL AND METHOD

26 patients scheduled for cystectomy were investigated with preoperative lymphoscintigraphy, peroperative dye detection (Patent Blue) and dynamic lymphoscintigraphy (Nanocoll or Albures 50 MBq/ml). The substances were injected adjacent to the tumour in the detrusor muscle.

RESULTS

Sentinel nodes were detected in 21 of the 26 of the investigated patients. 7/21 SN were located outside the obturator fossa. Of the eight patients with lymph node metastasis, five displayed metastasis in lymph nodes outside the obturator fossa. There was one false negative SN in a patient with multifocal tumour, while in the other seven patients with lymph node metastasis, these were detected in the SN.

CONCLUSION

Sentinel node detection is possible in most cases of bladder cancer scheduled for cystectomy. The significance of utilizing this method to detect lymph node metastasis outside the obturator fossa warrants further investigation.