Customizing local and systemic therapies for women with early breast cancer: the St. Gallen International Consensus Guidelines for treatment of early breast cancer 2021.

The 17th St Gallen International Breast Cancer Consensus Conference in 2021 was held virtually, owing to the global COVID-19 pandemic. More than 3300 participants took part in this important bi-annual critical review of the 'state of the art' in the multidisciplinary care of early-stage breast cancer. Seventy-four expert panelists (see Appendix 1) from all continents discussed and commented on the previously elaborated consensus questions, as well as many key questions on early breast cancer diagnosis and treatment asked by the audience. The theme of this year's conference was 'Customizing local and systemic therapies.' A well-organized program of pre-recorded symposia, live panel discussions and real-time panel voting results drew a worldwide audience of thousands, reflecting the far-reaching impact of breast cancer on every continent. The interactive technology platform allowed, for the first time, audience members to ask direct questions to panelists, and to weigh in with their own vote on several key panel questions. A hallmark of this meeting was to focus on customized recommendations for treatment of early-stage breast cancer. There is increasing recognition that the care of a breast cancer patient depends on highly individualized clinical features, including the stage at presentation, the biological subset of breast cancer, the genetic factors that may underlie breast cancer risk, the genomic signatures that inform treatment recommendations, the extent of response before surgery in patients who receive neoadjuvant therapy, and patient preferences. This customized approach to treatment requires integration of clinical care between patients and radiology, pathology, genetics, and surgical, medical and radiation oncology providers. It also requires a dynamic response from clinicians as they encounter accumulating clinical information at the time of diagnosis and then serially with each step in the treatment plan and follow-up, reflecting patient experiences and treatment response.

Estimating the benefits of therapy for early-stage breast cancer: the St. Gallen International Consensus Guidelines for the primary therapy of early breast cancer 2019.

BACKGROUND: The 16th St. Gallen International Breast Cancer Conference 2019 in Vienna, Austria reviewed substantial new evidence on loco-regional and systemic therapies for early breast cancer. DESIGN: Treatments were assessed in light of their intensity, duration and side-effects, estimating the magnitude of clinical benefit according to stage and biology of the disease. The Panel acknowledged that for many patients, the impact of adjuvant therapy or the adherence to specific guidelines may have modest impact on the risk of breast cancer recurrence or overall survival. For that reason, the Panel explicitly encouraged clinicians and patients to routinely discuss the magnitude of benefit for interventions as part of the development of the treatment plan. RESULTS: The guidelines focus on common ductal and lobular breast cancer histologies arising in generally healthy women. Special breast cancer histologies may need different considerations, as do individual patients with other substantial health considerations. The panelists' opinions reflect different interpretation of available data and expert opinion where is lack of evidence and sociocultural factors in their environment such as availability of and access to medical service, economic resources and reimbursement issues. Panelists encourage patient participation in well-designed clinical studies whenever available. CONCLUSIONS: With these caveats in mind, the St. Gallen Consensus Conference seeks to provide guidance to clinicians on appropriate treatments for early-stage breast cancer and guidance for weighing the realistic tradeoffs between treatment and toxicity so that patients and clinical teams can make well-informed decisions on the basis of an honest reckoning of the magnitude of clinical benefit.

De-escalating and escalating treatments for early-stage breast cancer: the St. Gallen International Expert Consensus Conference on the Primary Therapy of Early Breast Cancer 2017.

The 15th St. Gallen International Breast Cancer Conference 2017 in Vienna, Austria reviewed substantial new evidence on loco-regional and systemic therapies for early breast cancer. Treatments were assessed in light of their intensity, duration and side-effects, seeking where appropriate to escalate or de-escalate therapies based on likely benefits as predicted by tumor stage and tumor biology. The Panel favored several interventions that may reduce surgical morbidity, including acceptance of 2 mm margins for DCIS, the resection of residual cancer (but not baseline extent of cancer) in women undergoing neoadjuvant therapy, acceptance of sentinel node biopsy following neoadjuvant treatment of many patients, and the preference for neoadjuvant therapy in HER2 positive and triple-negative, stage II and III breast cancer. The Panel favored escalating radiation therapy with regional nodal irradiation in high-risk patients, while encouraging omission of boost in low-risk patients. The Panel endorsed gene expression signatures that permit avoidance of chemotherapy in many patients with ER positive breast cancer. For women with higher risk tumors, the Panel escalated recommendations for adjuvant endocrine treatment to include ovarian suppression in premenopausal women, and extended therapy for postmenopausal women. However, low-risk patients can avoid these treatments. Finally, the Panel recommended bisphosphonate use in postmenopausal women to prevent breast cancer recurrence. The Panel recognized that recommendations are not intended for all patients, but rather to address the clinical needs of the majority of common presentations. Individualization of adjuvant therapy means adjusting to the tumor characteristics, patient comorbidities and preferences, and managing constraints of treatment cost and access that may affect care in both the developed and developing world.

Tailoring therapies--improving the management of early breast cancer: St Gallen International Expert Consensus on the Primary Therapy of Early Breast Cancer 2015.

The 14th St Gallen International Breast Cancer Conference (2015) reviewed substantial new evidence on locoregional and systemic therapies for early breast cancer. Further experience has supported the adequacy of tumor margins defined as 'no ink on invasive tumor or DCIS' and the safety of omitting axillary dissection in specific cohorts. Radiotherapy trials support irradiation of regional nodes in node-positive disease. Considering subdivisions within luminal disease, the Panel was more concerned with indications for the use of specific therapies, rather than surrogate identification of intrinsic subtypes as measured by multiparameter molecular tests. For the treatment of HER2-positive disease in patients with node-negative cancers up to 1 cm, the Panel endorsed a simplified regimen comprising paclitaxel and trastuzumab without anthracycline as adjuvant therapy. For premenopausal patients with endocrine responsive disease, the Panel endorsed the role of ovarian function suppression with either tamoxifen or exemestane for patients at higher risk. The Panel noted the value of an LHRH agonist given during chemotherapy for premenopausal women with ER-negative disease in protecting against premature ovarian failure and preserving fertility. The Panel noted increasing evidence for the prognostic value of commonly used multiparameter molecular markers, some of which also carried prognostic information for late relapse. The Panel noted that the results of such tests, where available, were frequently used to assist decisions about the inclusion of cytotoxic chemotherapy in the treatment of patients with luminal disease, but noted that threshold values had not been established for this purpose for any of these tests. Multiparameter molecular assays are expensive and therefore unavailable in much of the world. The majority of new breast cancer cases and breast cancer deaths now occur in less developed regions of the world. In these areas, less expensive pathology tests may provide valuable information. The Panel recommendations on treatment are not intended to apply to all patients, but rather to establish norms appropriate for the majority. Again, economic considerations may require that less expensive and only marginally less effective therapies may be necessary in less resourced areas. Panel recommendations do not imply unanimous agreement among Panel members. Indeed, very few of the 200 questions received 100% agreement from the Panel. In the text below, wording is intended to convey the strength of Panel support for each recommendation, while details of Panel voting on each question are available in supplementary Appendix S2, available at Annals of Oncology online.

Estimates of benefits and harms of prophylactic use of aspirin in the general population.

BACKGROUND: Accumulating evidence supports an effect of aspirin in reducing overall cancer incidence and mortality in the general population. We reviewed current data and assessed the benefits and harms of prophylactic use of aspirin in the general population. METHODS: The effect of aspirin for site-specific cancer incidence and mortality, cardiovascular events was collated from the most recent systematic reviews. Studies identified through systematic Medline search provided data regarding harmful effects of aspirin and baseline rates of harms like gastrointestinal bleeding and peptic ulcer. RESULTS: The effects of aspirin on cancer are not apparent until at least 3 years after the start of use, and some benefits are sustained for several years after cessation in long-term users. No differences between low and standard doses of aspirin are observed, but there were no direct comparisons. Higher doses do not appear to confer additional benefit but increase toxicities. Excess bleeding is the most important harm associated with aspirin use, and its risk and fatality rate increases with age. For average-risk individuals aged 50-65 years taking aspirin for 10 years, there would be a relative reduction of between 7% (women) and 9% (men) in the number of cancer, myocardial infarction or stroke events over a 15-year period and an overall 4% relative reduction in all deaths over a 20-year period. CONCLUSIONS: Prophylactic aspirin use for a minimum of 5 years at doses between 75 and 325 mg/day appears to have favourable benefit-harm profile; longer use is likely to have greater benefits. Further research is needed to determine the optimum dose and duration of use, to identify individuals at increased risk of bleeding, and to test effectiveness of Helicobacter pylori screening-eradication before starting aspirin prophylaxis.

Personalizing the treatment of women with early breast cancer: highlights of the St Gallen International Expert Consensus on the Primary Therapy of Early Breast Cancer 2013.

The 13th St Gallen International Breast Cancer Conference (2013) Expert Panel reviewed and endorsed substantial new evidence on aspects of the local and regional therapies for early breast cancer, supporting less extensive surgery to the axilla and shorter durations of radiation therapy. It refined its earlier approach to the classification and management of luminal disease in the absence of amplification or overexpression of the Human Epidermal growth factor Receptor 2 (HER2) oncogene, while retaining essentially unchanged recommendations for the systemic adjuvant therapy of HER2-positive and 'triple-negative' disease. The Panel again accepted that conventional clinico-pathological factors provided a surrogate subtype classification, while noting that in those areas of the world where multi-gene molecular assays are readily available many clinicians prefer to base chemotherapy decisions for patients with luminal disease on these genomic results rather than the surrogate subtype definitions. Several multi-gene molecular assays were recognized as providing accurate and reproducible prognostic information, and in some cases prediction of response to chemotherapy. Cost and availability preclude their application in many environments at the present time. Broad treatment recommendations are presented. Such recommendations do not imply that each Panel member agrees: indeed, among more than 100 questions, only one (trastuzumab duration) commanded 100% agreement. The various recommendations in fact carried differing degrees of support, as reflected in the nuanced wording of the text below and in the votes recorded in supplementary Appendix S1, available at Annals of Oncology online. Detailed decisions on treatment will as always involve clinical consideration of disease extent, host factors, patient preferences and social and economic constraints.

Strategies for subtypes--dealing with the diversity of breast cancer: highlights of the St. Gallen International Expert Consensus on the Primary Therapy of Early Breast Cancer 2011.

The 12th St Gallen International Breast Cancer Conference (2011) Expert Panel adopted a new approach to the classification of patients for therapeutic purposes based on the recognition of intrinsic biological subtypes within the breast cancer spectrum. For practical purposes, these subtypes may be approximated using clinicopathological rather than gene expression array criteria. In general, systemic therapy recommendations follow the subtype classification. Thus, 'Luminal A' disease generally requires only endocrine therapy, which also forms part of the treatment of the 'Luminal B' subtype. Chemotherapy is considered indicated for most patients with 'Luminal B', 'Human Epidermal growth factor Receptor 2 (HER2) positive', and 'Triple negative (ductal)' disease, with the addition of trastuzumab in 'HER2 positive' disease. Progress was also noted in defining better tolerated local therapies in selected cases without loss of efficacy, such as accelerated radiation therapy and the omission of axillary dissection under defined circumstances. Broad treatment recommendations are presented, recognizing that detailed treatment decisions need to consider disease extent, host factors, patient preferences, and social and economic constraints.

Angiogenesis and lymphangiogenesis are downregulated in primary breast cancer.

BACKGROUND: Angiogenesis and lymphangiogenesis are considered to play key roles in tumour growth, progression and metastasis. However, targeting tumour angiogenesis in clinical trials showed only modest efficacy. We therefore scrutinised the concept of tumour angiogenesis and lymphangiogenesis by analysing the expression of crucial markers involved in these processes in primary breast cancer. METHODS: We analysed the expression of angiogenic, lymphangiogenic or antiangiogenic factors, their respective receptors and specific markers for endothelial and lymphendothelial cells by quantitative real-time RT-PCR in primary breast cancer and compared the expression profiles to non-cancerous, tumour-adjacent tissues and breast tissues from healthy women. RESULTS: We found decreased mRNA amounts of major angiogenic and lymphangiogenic factors in tumour compared to healthy tissues, whereas antiangiogenic factors were upregulated. Concomitantly, angiogenic and lymphangiogenic receptors were downregulated in breast tumours. This antiangiogenic, antilymphangiogenic microenvironment was even more pronounced in aggressive tumours and accompanied by reduced amounts of endothelial and lymphatic endothelial cell markers. CONCLUSION: Primary breast tumours are not a site of highly active angiogenesis and lymphangiogenesis. Selection for tumour cells that survive with minimal vascular supply may account for this observation in clinical apparent tumours.

Thresholds for therapies: highlights of the St Gallen International Expert Consensus on the primary therapy of early breast cancer 2009.

The 11(th) St Gallen (Switzerland) expert consensus meeting on the primary treatment of early breast cancer in March 2009 maintained an emphasis on targeting adjuvant systemic therapies according to subgroups defined by predictive markers. Any positive level of estrogen receptor (ER) expression is considered sufficient to justify the use of endocrine adjuvant therapy in almost all patients. Overexpression or amplification of HER2 by standard criteria is an indication for anti-HER2 therapy for all but the very lowest risk invasive tumours. The corollary is that ER and HER2 must be reliably and accurately measured. Indications for cytotoxic adjuvant therapy were refined, acknowledging the role of risk factors with the caveat that risk per se is not a target. Proliferation markers, including those identified in multigene array analyses, were recognised as important in this regard. The threshold for indication of each systemic treatment modality thus depends on different criteria which have been separately listed to clarify the therapeutic decision-making algorithm.

Multitarget stereotactic core-needle breast biopsy (MSBB)--an effective and safe diagnostic intervention for non-palpable breast lesions: a large prospective single institution study.

Multi-target stereotactic core-needle breast biopsy (MSBB) with large core needles is a modern and effective method to quickly determine the histologic nature of non-palpable breast lesions in an easy ambulatory setting. The number of patients with mammographically detectable, suspicious breast lesions is constantly increasing due to enhanced breast cancer awareness in Western female populations and with expanding screening mammography activities. MSBB is a minimally invasive diagnostic procedure, performed on an ambulatory basis under local anaesthesia in the prone position on a specially constructed stereotactic biopsy table. The patient is able to resume normal activities 1 h after the biopsy procedure. Technical and medical complications are extremely rare. In our study, we analysed the histological results of 426 MSBB procedures in 389 consecutive female patients during the years 1998-2002, and in 91 cases we were able to compare the histologic results of MSBB with the definitive histology of subsequent excisional biopsies. MSBB was technically successful in 415 out of 426 procedures (97.4%). The sensitivity for malignancy was 94.6% (87 out of 92). MSBB, therefore, is to be qualified as a remarkably reliable, patient-friendly and economic diagnostic breast intervention and was well tolerated and highly accepted by virtually all female patients involved in this single-institution feasibility and effectiveness study.

Effective control of chemotherapy-induced nausea and vomiting with oral prednisone and metoclopramide.

Repeated oral doses of metoclopramide (50 mg) and prednisone (25 mg) completely prevented nausea and vomiting (N + V) in approximately 50% and substantially reduced N + V in an additional 27%-36% of 56 chemotherapy courses in 30 consecutive cancer patients who were receiving primarily cisplatin. Toxicity from this antiemetic regimen was minor. Simple oral N + V-prevention with metoclopramide and prednisone is as effective but less cumbersome and considerably less expensive than either high doses of intravenous corticosteroids and/or intravenous metoclopramide.

Adjuvant chemotherapy in operable breast cancer: cyclophosphamide, methotrexate, and fluorouracil versus chlorambucil, methotrexate, and fluorouracil--11-year results of Swiss Group for Clinical Cancer Research trial SAKK 27/82.

PURPOSE: To compare two adjuvant combination chemotherapies, cyclophosphamide, methotrexate, and fluorouracil (CMF) and chlorambucil, methotrexate, and fluorouracil (LMF), for patients who had undergone potentially curative surgery for unilateral breast cancer, in terms of relapse, survival, and toxicity. PATIENTS AND METHODS: Selection criteria was as follows: stage pT1-3a, N+ or N-, M0, less than 72 years of age. Eligible patients were randomized to receive either CMF (cyclophosphamide 100 mg/m2 orally on days 1 to 14, methotrexate 40 mg/m2 intravenously (I.V.) on days 1 and 8, fluorouracil 600 mg/m2 I.V. on days 1 and 8) or LMF (Leukeran [Wellcome A.G., Bern, Switzerland] 5 mg/m2 orally on days 1 to 14 with the some I.V. cytostatic drugs). Follow-up examinations were performed every 3 months during the first 3 years after mastectomy, and every 6 months thereafter. RESULTS: A total of 246 patients were randomized, of whom 232 who were fully eligible and contribute to the analyses presented here. No statistically significant difference in favor of adjuvant CMF over LMF emerges after a median follow-up duration of 11.2 years, for either overall survival (P = .15) or disease-free survival (P = .14). A consistent trend suggestive of a possible relative benefit associated with CMF should be pointed out. However, CMF presents a significantly worse toxicity profile as concerns hematologic parameters as well as alopecia, nausea, and vomiting. CONCLUSION: This prospective trial has not identified a statistically significant difference in disease-free survival or overall survival between the two adjuvant regimens LMF and CMF. Although a trend in favor of CMF has been observed in premenopausal patients, this has to be weighted against its definitely more pronounced toxicity profile.

Identifying breast cancer patients at high risk for bone metastases.

PURPOSE: To identify patient populations at high risk for bone metastases at any time after diagnosis of operable breast cancer, because these patients are potential beneficiaries of treatment with bisphosphonates. PATIENTS AND METHODS: We evaluated data from 6,792 patients who were randomized in International Breast Cancer Study Group clinical trials between 1978 and 1993. Median follow-up was 10. 7 years. A total of 1,275 patients (18.7%) presented with node-negative disease, whereas 3,354 patients (49.4%) had one to three and 2,163 patients (31.9%) had four or more involved axillary lymph nodes. We also assessed the incidence of subsequent bone metastases in the cohort of 1,220 patients who had a first event in local or regional sites or soft tissue alone. Median follow-up for this cohort was 7.7 years from first recurrence. RESULTS: For the entire population with operable disease, the cumulative incidence of bone metastases at any time was 8.2% at 2 years from randomization and 27.3% at 10 years. The highest cumulative incidences of bone metastases at any time were among patients who had four or more involved axillary nodes at the time of diagnosis (14.9% at 2 years and 40.8% at 10 years) and among patients who had as their first event a local or regional recurrence or a recurrence in soft tissue, without any other overt metastases (21.1% at 2 years from first recurrence and 36.7% at 10 years). CONCLUSION: Treatments to prevent bone metastases may have a major impact on the course of breast cancer and may be most efficiently studied in populations with several involved axillary nodes at the time of presentation and in populations with local or regional recurrence or recurrence in soft tissue.

Burdens and benefits of adjuvant cyclophosphamide, methotrexate, and fluorouracil and tamoxifen for elderly patients with breast cancer: the International Breast Cancer Study Group Trial VII.

PURPOSE: Information on the tolerability and efficacy of adjuvant chemoendocrine therapy for older women is limited. We studied these issues using the data collected as part of the International Breast Cancer Study Group Trial VII. PATIENTS AND METHODS: Postmenopausal women with operable, node-positive breast cancer were randomized to receive either tamoxifen alone for 5 years (306 patients) or tamoxifen plus three consecutive cycles of classical cyclophosphamide (100 mg/m(2) orally days 1 to 14), methotrexate (40 mg/m(2) intravenous days 1 and 8), and fluorouracil (600 mg/m(2) intravenous days 1 and 8) every 28 days (CMF; 302 patients). The median follow-up was 8.0 years. RESULTS: Among the 299 patients who received at least one dose of CMF, women 65 years of age or older (n = 76) had higher grades of toxicity compared with women less than 65 years old (n = 223) (P =.004). More women in the older age group compared with the younger women experienced grade 3 toxicity of any type (17% v 7%, respectively), grade 3 hematologic toxicity (9% v 5%, respectively), and grade 3 mucosal toxicity (4% v 1%, respectively). Older patients also received less than their expected CMF dose compared with younger postmenopausal women (P =.0008). The subjective burdens of treatment, however, were similar for younger and older patients based on quality-of-life measures (performance status, coping, physical well-being, mood, and appetite). For older patients, the 5-year disease-free survival (DFS) rates were 63% for CMF plus tamoxifen and 61% for tamoxifen alone (hazards ratio [HR], 1.00; 95% confidence interval [CI], 0.65 to 1.52; P =.99). For younger patients, the corresponding 5-year DFS rates were 61% and 53% (HR, 0.70; 95% CI, 0.53 to 0.91; P =.008), but the test for heterogeneity of CMF effect according to age group was not statistically significant. The reduced effectiveness of CMF among older women could not be attributed to dose reductions according to dose received. CONCLUSION: CMF tolerability and effectiveness were both reduced for older patients compared with younger postmenopausal node-positive breast cancer patients who received tamoxifen for 5 years. The development and evaluation of less toxic and more effective chemotherapy regimens are required for high-risk elderly patients.

Prospective randomized trial of docetaxel versus mitomycin plus vinblastine in patients with metastatic breast cancer progressing despite previous anthracycline-containing chemotherapy. 304 Study Group.

PURPOSE: This phase III study compared docetaxel with mitomycin plus vinblastine (MV) in patients with metastatic breast cancer (MBC) progressing despite previous anthracycline-containing chemotherapy. PATIENTS AND METHODS: Patients (n=392) were randomized to receive either docetaxel 100 mg/m2 intravenously (i.v.) every 3 weeks (n=203) or mitomycin 12 mg/m2 i.v. every 6 weeks plus vinblastine 6 mg/m2 i.v. every 3 weeks (n=189), for a maximum of 10 3-week cycles. RESULTS: In an intention-to-treat analysis, docetaxel produced significantly higher response rates than MV overall (30.0% v 11.6%; P < .0001), as well as in patients with visceral involvement (30% v 11%), liver metastases (33% v 7%), or resistance to previous anthracycline agents (30% v 7%). Median time to progression (TTP) and overall survival were significantly longer with docetaxel than MV (19 v 1 weeks, P=.001, and 1 1.4 v 8.7 months, P=.0097, respectively). Neutropenia grade 3/4 was more frequent with docetaxel (93.1 % v62.5%; P < .05); thrombocytopenia grade 3/4 was more frequent with MV (12.0% v 4.1%; P < .05). Severe acute or chronic nonhematologic adverse events were infrequent in both groups. Withdrawal rates because of adverse events (MV, 10.1%; docetaxel, 13.8%) or toxic death (MV, 1.6%; docetaxel, 2.0%) were similar in both groups. Quality-of-life analysis was limited by a number of factors, but results were similar in both groups. CONCLUSION: Docetaxel is significantly superior to MV in terms of response, TTP, and survival. The safety profiles of both therapies are manageable and tolerable. Docetaxel represents a clear treatment option for patients with MBC progressing despite previous anthracycline-containing chemotherapy.