Neoadjuvant systemic therapy is being used increasingly in the treatment of early-stage breast cancer. Response, in the form of pathological complete response, is a validated and evaluable surrogate ...end point of survival after neoadjuvant therapy. Thus, pathological complete response has become a primary end point for clinical trials. However, there is a current lack of uniformity in the definition of pathological complete response. A review of standard operating procedures used by 28 major neoadjuvant breast cancer trials and/or 25 sites involved in such trials identified marked variability in specimen handling and histologic reporting. An international working group was convened to develop practical recommendations for the pathologic assessment of residual disease in neoadjuvant clinical trials of breast cancer and information expected from pathology reports. Systematic sampling of areas identified by informed mapping of the specimen and close correlation with radiological findings is preferable to overly exhaustive sampling, and permits taking tissue samples for translational research. Controversial areas are discussed, including measurement of lesion size, reporting of lymphovascular space invasion and the presence of isolated tumor cells in lymph nodes after neoadjuvant therapy, and retesting of markers after treatment. If there has been a pathological complete response, this must be clearly stated, and the presence/absence of residual ductal carcinoma in situ must be described. When there is residual invasive carcinoma, a comment must be made as to the presence/absence of chemotherapy effect in the breast and lymph nodes. The Residual Cancer Burden is the preferred method for quantifying residual disease in neoadjuvant clinical trials in breast cancer; other methods can be included per trial protocols and regional preference. Posttreatment tumor staging using the Tumor-Node-Metastasis system should be included. These recommendations for standardized pathological evaluation and reporting of neoadjuvant breast cancer specimens should improve prognostication for individual patients and allow comparison of treatment outcomes within and across clinical trials.
This trial did not support routine use of ovarian suppression in premenopausal breast cancer. Nevertheless, there may be some benefit from ovarian suppression in the subgroup of younger patients ...whose menses return after adjuvant chemotherapy, but also more symptoms.
Adjuvant endocrine therapy with tamoxifen has been recommended for premenopausal women with hormone-receptor–positive breast cancer (positive for estrogen receptor, progesterone receptor, or both) during the past 15 years.
1
,
2
The value of therapeutic suppression of ovarian estrogen production in premenopausal women who receive tamoxifen is uncertain.
3
The American Society of Clinical Oncology endorsed guidelines recommending that ovarian ablation or suppression (hereafter, ovarian suppression) not be added routinely to adjuvant therapy in premenopausal women.
4
Chemotherapy-induced ovarian suppression (amenorrhea) is correlated with a reduced risk of relapse
5
–
7
but is less likely to be achieved in very young women. International consensus guidelines . . .
Multiple independent studies have shown that tumor-infiltrating lymphocytes (TIL) are prognostic in breast cancer with potential relevance for response to immune-checkpoint inhibitor therapy. ...Although many groups are currently evaluating TIL, there is no standardized system for diagnostic applications. This study reports the results of two ring studies investigating TIL conducted by the International Working Group on Immuno-oncology Biomarkers. The study aim was to determine the intraclass correlation coefficient (ICC) for evaluation of TIL by different pathologists. A total of 120 slides were evaluated by a large group of pathologists with a web-based system in ring study 1 and a more advanced software-system in ring study 2 that included an integrated feedback with standardized reference images. The predefined aim for successful ring studies 1 and 2 was an ICC above 0.7 (lower limit of 95% confidence interval (CI)). In ring study 1 the prespecified endpoint was not reached (ICC: 0.70; 95% CI: 0.62–0.78). On the basis of an analysis of sources of variation, we developed a more advanced digital image evaluation system for ring study 2, which improved the ICC to 0.89 (95% CI: 0.85–0.92). The Fleiss' kappa value for <60 vs ≥60% TIL improved from 0.45 (ring study 1) to 0.63 in RS2 and the mean concordance improved from 88 to 92%. This large international standardization project shows that reproducible evaluation of TIL is feasible in breast cancer. This opens the way for standardized reporting of tumor immunological parameters in clinical studies and diagnostic practice. The software-guided image evaluation approach used in ring study 2 may be of value as a tool for evaluation of TIL in clinical trials and diagnostic practice. The experience gained from this approach might be applicable to the standardization of other diagnostic parameters in histopathology.
HER2 status in breast cancer is assessed to select patients eligible for targeted therapy with anti-HER2 therapies. According to the American Society of Clinical Oncology (ASCO) and College of ...American Pathologists (CAP), the HER2 test positivity is defined by protein overexpression (score 3+) at immunohistochemistry (IHC) and/or gene amplification at
hybridization (ISH). The introduction of novel anti-HER2 compounds, however, is changing this paradigm because some breast cancers with lower levels of protein expression (i.e. score 1+/2+ with no gene amplification) benefited from HER2 antibody-drug conjugates (ADC). Recently, a potential for HER2 targeting in HER2 "ultra-low" (i.e. score 0 with incomplete and faint staining in ≤10% of tumor cells) and MutL-deficient estrogen receptor (estrogen receptor)-positive/HER2-negative breast cancers has been highlighted. All these novel findings are transforming the traditional dichotomy of HER2 status and have dramatically raised the expectations in this field. Still, a more aware HER2 status assessment coupled with the comprehensive characterization of the clinical and molecular features of these tumors is required. Here, we seek to provide an overview of the current state of HER2 targeting in breast cancers beyond the canonical HER2 positivity and to discuss the practical implications for pathologists and oncologists.
Aromatase inhibitors are somewhat more effective than tamoxifen as adjuvant therapy in postmenopausal women with early breast cancer. This benefit was extended to premenopausal women when they also ...received ovarian suppression to prevent ovarian compensation for aromatase inhibition.
The most effective adjuvant endocrine therapy for premenopausal women with hormone-receptor (estrogen, progesterone, or both)–positive breast cancer is uncertain. Tamoxifen for at least 5 years is a standard of care.
1
–
3
Adjuvant suppression of ovarian function (hereafter, ovarian suppression) may be recommended in addition. For postmenopausal women, adjuvant therapy with an aromatase inhibitor, as compared with tamoxifen, improves outcomes.
2
–
9
In 2003, the International Breast Cancer Study Group (IBCSG) initiated two randomized, phase 3 trials, the Tamoxifen and Exemestane Trial (TEXT) and the Suppression of Ovarian Function Trial (SOFT), involving premenopausal women with hormone-receptor–positive early breast cancer, through collaboration with . . .
Lapatinib (L) plus trastuzumab (T) improves outcomes for metastatic human epidermal growth factor 2-positive breast cancer and increases the pathologic complete response in the neoadjuvant setting, ...but their role as adjuvant therapy remains uncertain.
In the Adjuvant Lapatinib and/or Trastuzumab Treatment Optimization trial, patients with centrally confirmed human epidermal growth factor 2-positive early breast cancer were randomly assigned to 1 year of adjuvant therapy with T, L, their sequence (T→L), or their combination (L+T). The primary end point was disease-free survival (DFS), with 850 events required for 80% power to detect a hazard ratio (HR) of 0.8 for L+T versus T.
Between June 2007 and July 2011, 8,381 patients were enrolled. In 2011, due to futility to demonstrate noninferiority of L versus T, the L arm was closed, and patients free of disease were offered adjuvant T. A protocol modification required P ≤ .025 for the two remaining pairwise comparisons. At a protocol-specified analysis with a median follow-up of 4.5 years, a 16% reduction in the DFS hazard rate was observed with L+T compared with T (555 DFS events; HR, 0.84; 97.5% CI, 0.70 to 1.02; P = .048), and a 4% reduction was observed with T→L compared with T (HR, 0.96; 97.5% CI, 0.80 to 1.15; P = .61). L-treated patients experienced more diarrhea, cutaneous rash, and hepatic toxicity compared with T-treated patients. The incidence of cardiac toxicity was low in all treatment arms.
Adjuvant treatment that includes L did not significantly improve DFS compared with T alone and added toxicity. One year of adjuvant T remains standard of care.
Trastuzumab-containing therapy is a standard of care for patients with HER2+ breast cancer. HER2 status is routinely assigned using in situ hybridization to assess HER2 gene amplification, but ...interpretation of in situ hybridization results may be challenging in tumors with chromosome 17 polysomy or intratumoral genetic heterogeneity. Apparent chromosome 17 polysomy, defined by increased chromosome enumeration probe 17 (CEP17) signal number, is a common genetic aberration in breast cancer and represents an alternative mechanism for increasing HER2 copy number. Some studies have linked elevated CEP17 count (‘polysomy') with adverse clinicopathologic features and HER2 overexpression, although there are numerous discrepancies in the literature. There is evidence that elevated CEP17 (‘polysomy') count might account for trastuzumab response in tumors with normal HER2:CEP17 ratios. Nonetheless, recent studies establish that apparent ‘polysomy' (CEP17 increase) is usually related to focal pericentromeric gains rather than true polysomy. Assigning HER2 status may also be complex where multiple cell subclones with distinct HER2 amplification characteristics coexist within the same tumor. Such genetic heterogeneity affects up to 40% of breast cancers when assessed according to a College of American Pathologists guideline, although other definitions have been proposed. Recent data have associated heterogeneity with unfavorable clinicopathologic variables and poor prognosis. Genetically heterogeneous tumors harboring HER2-amplified subclones have the potential to benefit from trastuzumab, but this has yet to be evaluated in clinical studies. In this review, we discuss the implications of apparent polysomy 17 and genetic heterogeneity for assigning HER2 status in clinical practice. Among our recommendations, we support the use of mean HER2 copy number rather than HER2:CEP17 ratio to define HER2 positivity in cases where coamplification of the centromere might mask HER2 amplification. We also highlight a need to harmonize in situ hybridization scoring methodology to support accurate HER2 status determination, particularly where there is evidence of heterogeneity.
The St Gallen International Expert Consensus on the Primary Therapy of Early Breast Cancer 2013 recognized substantial progress in the pathological characterization of breast cancer subtypes. A ...useful surrogate definition was developed to distinguish luminal A-like breast cancer from luminal B-like disease based on a combination of estrogen receptor (ER), progesterone receptor (PgR) and Ki-67 status, without a requirement for molecular diagnostics. Differences depend upon the choice of the threshold value for Ki-67 and the requirement for substantial PgR positivity. We aimed to verify the suitability of the new surrogate definitions of luminal subtypes in terms of distant disease control in a large series of patients.
We studied 9,415 women with a median follow-up of 8.1 years who (1) had ER-positive, human epidermal growth factor receptor 2 (HER2)-negative early breast cancer and (2) had undergone surgery at the European Institute of Oncology between 1994 and 2006. We evaluated distant disease-free survival of patients with "low" (<14%), "intermediate" (14% to 19%) or "high" (≥20%) Ki-67 positivity stratified by PgR expression (negative or low versus high). We calculated the cumulative incidence of distant events, considered competing events and performed multivariable analysis adjusted for pathologic tumor stage, pathologic node stage, tumor grade, peritumoral vascular invasion and menopausal status.
Lack of substantial PgR positivity was associated with poorer outcomes only for patients with an intermediate Ki-67 level (P<0.001). The 4,890 patients (51.9%) with low Ki-67 level (any PgR expression level) or with intermediate Ki-67 level but substantial PgR positivity had comparably good outcomes and thus may represent a most advantageous grouping of those with luminal A-like disease.
The updated pathological definition of intrinsic molecular subtypes may maximize the number of patients classified as having the luminal A-like intrinsic subtype of breast cancer and for whom the use of cytotoxic drugs could mostly be avoided.
To retrospectively evaluate the pattern of recurrence and outcome of node-negative breast cancer (BC) according to major subtypes.
In all, 1,951 patients with node-negative, early-stage BC randomly ...assigned in International Breast Cancer Study Group Trials VIII and IX with centrally reviewed pathology data were included. BC subtypes were defined as triple negative (TN; n = 310), human epidermal growth factor receptor 2 (HER2) positive (n = 369), and hormone receptor positive with high (luminal B-like LB-like; n = 763) or low (luminal A-like LA-like; n = 509) proliferative activity by Ki-67 labeling index. BC-free interval (BCFI) events were invasive BC recurrence in local, contralateral breast, nodal, bone, or visceral sites. Time to first site-specific recurrence was evaluated by using cumulative incidence and competing risks regression analysis.
Median follow-up was 12.5 years. The 10-year BCFI was higher for patients with LA-like (86%) BC compared with LB-like (76%), HER2 (73%), and TN (71%; P < .001) BC. TN and HER2 cohorts had higher hazard of BCFI event in the first 4 years after diagnosis (pre-trastuzumab). LB-like cohorts had a continuously higher hazard of BCFI event over time compared with LA-like cohorts. Ten-year overall survival was higher for LA-like (89%) compared with LB-like (83%), HER2 (77%), and TN (75%; P < .001) BC. LB-like subtypes had higher rates of bone as first recurrence site than other subtypes (P = .005). Visceral recurrence as first site was lower for the LA-like subgroup, with similar incidence among the other subgroups when treated with chemotherapy (P = .003).
BC subtypes have different distant recurrence patterns over time. Defining different patterns of BC recurrence can improve BC care through surveillance guidelines and can guide the design of clinical studies.
PDF
