Disease-specific survival outcomes for patients after locoregional treatment for ductal carcinoma in situ: observational cohort study.

BACKGROUND: Breast-conserving surgery alone, breast-conserving surgery with adjuvant radiation treatment, and mastectomy are guideline-concordant treatments for ductal carcinoma in situ. The aim of this study was to compare survival outcomes between these treatment options. METHODS: A stratified random sample of patients diagnosed with pure ductal carcinoma in situ between 2008 and 2014 was selected from 1330 sites in the USA. Data on diagnosis, treatment, and follow-up were abstracted by local cancer registrars. Population-averaged marginal estimates of disease-specific survival and overall survival for breast-conserving surgery alone, breast-conserving surgery with radiation treatment, and mastectomy were obtained by combining sampling and overlap weights. RESULTS: A total of 18 442 women were included, with a median follow-up of 67.8 (interquartile range 46.1-93.5) months. A total of 35 women died from breast cancer, at a median age of 62 (interquartile range 50-74) years. Population-averaged 8-year rates of disease-specific survival were 99.6% or higher for all treatment groups, with no significant differences between groups (breast-conserving surgery alone versus breast-conserving surgery with radiation treatment, HR 1.19 (95% c.i. 0.29 to 4.85); and mastectomy versus breast-conserving surgery with radiation treatment, HR 1.74 (95% c.i. 0.53 to 5.72). There was no difference in overall survival between the patients who underwent a mastectomy and the patients who underwent breast-conserving surgery with radiation treatment (HR 1.09 (95% c.i. 0.83 to 1.43)). Patients who underwent breast-conserving surgery alone had lower overall survival compared with the patients who underwent breast-conserving surgery with radiation treatment (HR 1.29 (95% c.i. 1.00 to 1.67)). This survival difference vanished for all but one subgroup, namely patients less than 65 years (HR 1.86 (95% c.i. 1.15 to 3.00)). CONCLUSION: There was no statistically significant difference in disease-specific survival between women operated with breast-conserving surgery alone, breast-conserving surgery with radiation treatment, or mastectomy for ductal carcinoma in situ. Given the low absolute risk of disease-specific mortality, these results provide confidence in offering individualized locoregional treatment without fear of compromising survival.

Surveillance Imaging after Primary Diagnosis of Ductal Carcinoma in Situ.

Background Guidelines recommend annual surveillance imaging after diagnosis of ductal carcinoma in situ (DCIS). Guideline adherence has not been characterized in a contemporary cohort. Purpose To identify uptake and determinants of surveillance imaging in women who underwent treatment for DCIS. Materials and Methods A stratified random sample of women who underwent breast-conserving surgery for primary DCIS between 2008 and 2014 was retrospectively selected from 1330 facilities in the United States. Imaging examinations were recorded from date of diagnosis until first distant recurrence, death, loss to follow-up, or end of study (November 2018). Imaging after treatment was categorized into 10 12-month periods starting 6 months after diagnosis. Primary outcome was per-period receipt of asymptomatic surveillance imaging (mammography, MRI, or US). Secondary outcome was diagnosis of ipsilateral invasive breast cancer. Multivariable logistic regression with repeated measures and generalized estimating equations was used to model receipt of imaging. Rates of diagnosis with ipsilateral invasive breast cancer were compared between women who did and those who did not undergo imaging in the 6-18-month period after diagnosis using inverse probability-weighted Kaplan-Meier estimators. Results A total of 12 559 women (median age, 60 years; IQR, 52-69 years) were evaluated. Uptake of surveillance imaging was 75% in the first period and decreased over time (P < .001). Across the first 5 years after treatment, 52% of women participated in consistent annual surveillance. Surveillance was lower in Black (adjusted odds ratio [OR], 0.80; 95% CI: 0.74, 0.88; P < .001) and Hispanic (OR, 0.82; 95% CI: 0.72, 0.94; P = .004) women than in White women. Women who underwent surveillance in the first period had a higher 6-year rate of diagnosis of invasive cancer (1.6%; 95% CI: 1.3, 1.9) than those who did not (1.1%; 95% CI: 0.7, 1.4; difference: 0.5%; 95% CI: 0.1, 1.0; P = .03). Conclusion Half of women did not consistently adhere to imaging surveillance guidelines across the first 5 years after treatment, with racial disparities in adherence rates. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Rahbar and Dontchos in this issue.

Exploring anxiety as an influencing factor of the impact of exercise and mind-body prehabilitation on cognitive functioning among women undergoing breast cancer surgery.

OBJECTIVE: The purpose of this secondary analysis was to describe the prevalence of anxiety, depression, and perceived stress among women newly diagnosed with breast cancer and the impact of baseline and changes in anxiety on cognitive functioning following exercise and mind-body prehabilitation interventions. METHODS: The sample consisted of 49 women with newly diagnosed breast cancer (stages I-III) who planned to undergo breast cancer surgery at two academic cancer centers. Participants were randomized to receive an exercise or mind-body prehabilitation intervention between the time of diagnosis and breast cancer surgery. Participants completed self-report measures of anxiety, depression (HADS), perceived stress, and cognitive functioning (EORTC-QLQ-C30) at study enrollment and prior to surgery (post-intervention). The relationships between change in cognitive functioning and change in anxiety among all participants were estimated using linear regression modeling. RESULTS: A significant proportion of women with newly diagnosed breast cancer had clinically significant anxiety (34.0%). Greater anxiety was moderately associated with worse cognitive functioning (r = -0.33) at baseline. Linear modeling found that changes in cognitive functioning and anxiety were inversely related: Each one-unit decrease in anxiety was associated with a two-unit improvement in cognitive function (p = .06). CONCLUSIONS: Anxiety was common in women with newly diagnosed breast cancer and was related to worse cognitive functioning. Assessment of anxiety at the time of diagnosis may allow for earlier anxiety management and subsequent improvement in cognitive functioning.

"Is it cancer or not?" A qualitative exploration of survivor concerns surrounding the diagnosis and treatment of ductal carcinoma in situ.

BACKGROUND: Of the nearly 50,000 women in the United States who undergo treatment for ductal carcinoma in situ (DCIS) annually, many may not benefit from treatment. To better understand the impact of a DCIS diagnosis, patients self-identified as having had DCIS were engaged regarding their experience. METHODS: In July 2014, a web-based survey was administered through the Susan Love Army of Women breast cancer listserv. The survey included open-ended questions designed to assess patients' perspectives about DCIS diagnosis and treatment. Deductive and inductive codes were applied to the responses; common themes were summarized. RESULTS: Among the 1832 women included in the analytic sample, the median age at diagnosis was 60 years. Four primary themes were identified: 1) uncertainty surrounding a DCIS diagnosis, 2) uncertainty about DCIS treatment, 3) concern about treatment side effects, and 4) concern about recurrence and/or developing invasive breast cancer. When diagnosed, participants were often uncertain about whether they had cancer or not and whether they should be considered a "survivor." Uncertainty about treatment manifested as questioning the appropriateness of the amount of treatment received. Participants expressed concern about the "cancer spreading" or becoming invasive and that they were not necessarily "doing enough" to prevent recurrence. CONCLUSIONS: In a large, national sample, participants with a history of DCIS reported confusion and concern about the diagnosis and treatment, which caused worry and significant uncertainty. Developing strategies to improve patient and provider communications regarding the nature of DCIS and acknowledging gaps in the current knowledge of management options should be a priority.

Exploring the impact of exercise and mind-body prehabilitation interventions on physical and psychological outcomes in women undergoing breast cancer surgery.

PURPOSE: To compare the impact of exercise and mind-body prehabilitation interventions on changes in quality of life and cancer treatment-related symptoms in women with newly diagnosed breast cancer. METHODS: The following describes a secondary analysis of a randomized window of opportunity trial (The Pre-Operative Health and Body Study). Forty-nine women were randomized to participate in either an exercise prehabilitation intervention or a mind-body prehabilitation intervention from the time of enrollment to surgery. Participants (N = 47) completed measures of quality of life, anxiety, depression, and stress at the time of enrollment (T1), post-intervention/surgery (T2), and one-month post-surgery (T3). Changes in outcome measures between groups were compared over time using longitudinal models. RESULTS: Mind-body group participants experienced significant improvements in cognitive functioning in comparison to exercise group participants between T1 and T3 (difference in average change: -9.61, p = 0.04, d = 0.31), otherwise, there were no significant differences between groups. Within group comparisons demonstrated that both groups experienced improvements in anxiety (exercise: average change = -1.18, p = 0.03, d = 0.34; mind-body: average change = -1.69, p = 0.006, d = 0.43) and stress (exercise: average change = -2.33, p = 0.04, d = 0.30; mind-body: average change = -2.59, p = 0.05, d = 0.29), while mind-body group participants experienced improvements in insomnia (average change = -10.03, p = 0.04, d = 0.30) and cognitive functioning (average change = 13.16, p = 0.0003, d = 0.67). CONCLUSIONS: Both prehabilitation interventions impacted cancer treatment-related symptoms. Further work in larger groups of patients is needed to evaluate the efficacy of prehabilitation interventions on quality of life in women with breast cancer. Pre-operative exercise and mind-body interventions may impact physical and/or psychological effects of cancer diagnosis and treatment in women with breast cancer. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01516190. Registered January 24, 2012.

Perceptions of patients with early stage breast cancer toward research biopsies.

BACKGROUND: The objective of this study was to describe the perspective of patients with early breast cancer toward research biopsies. The authors hypothesized that more patients at academic sites than at community-based sites would be willing to consider these procedures. METHODS: In total, 198 patients with early stage breast cancer were recruited from 3 academic centers (n = 102) and from 1 community oncology practice (n = 96). The primary objective was to compare the proportion of patients willing to consider donating excess tissue biospecimens from surgery, from a clinically indicated breast biopsy, or from a research purposes-only biopsy (RPOB) between practice types. RESULTS: Most patients (93% at academic sites, 94% at the community oncology site) said they would consider donating excess tissue from surgery for research. One-half of patients from academic or community sites would consider donating tissue from a clinically indicated breast biopsy. On univariate analysis, significantly fewer patients from academic sites would consider an RPOB (22% at academic sites, 42% at the community site; P = .003); however, this difference was no longer significant on multivariate analysis (P = .96). Longer transportation times and unfavorable prior experiences were associated with less willingness to consider an RPOB on multivariate analysis. Significantly fewer patients from academic sites (14%) than from the community site (35%) would consider a research biopsy in a clinical trial (P = .04). Contributing to scientific knowledge, return of results, and a personal request by their physician were the strongest factors influencing patients' willingness to undergo research biopsies. CONCLUSIONS: The current results rejected the hypothesis that more patients with early breast cancer at academic sites would be willing to donate tissue biospecimens for research compared with those at community oncology sites. These findings identify modifiable factors to consider in biobanking studies and clinical trials.

Patient-reported outcomes in the Translational Breast Cancer Research Consortium.

Members of the Translational Breast Cancer Research Consortium conducted an expert-driven literature review to identify a list of domains and to evaluate potential measures of these domains for inclusion in a list of preferred measures. Measures were included if they were easily available, free of charge, and had acceptable psychometrics based on published peer-reviewed analyses. A total of 22 domains and 52 measures were identified during the selection process. Taken together, these measures form a reliable and validated list of measurement tools that are easily available and used in multiple cancer trials to assess patient-reported outcomes in relevant patients.

Estrogen-receptor status and risk of contralateral breast cancer following DCIS.

PURPOSE: As local therapies improve, contralateral breast cancer (CBC) risk for women with ductal carcinoma in situ (DCIS) may exceed the risk of a second ipsilateral breast cancer. We sought to determine whether estrogen-receptor (ER) status influenced CBC risk. METHODS: We identified women aged 40-79 with DCIS diagnosed between 1990 and 2002 using the Surveillance, Epidemiology, and End Results database. We used multivariable competing risk regression to examine predictors of time from index DCIS to CBC (invasive or in situ). RESULTS: Multivariable competing risk regression found ER status to be a highly significant predictor of CBC. The 10-year cumulative incidence was estimated to be 5.3% (95% CI 4.8-5.8%) among ER positive (ER+) cases and 3.3% (95% CI 2.6-4.0%) among ER negative (ER-). CONCLUSIONS: This finding suggests that ER+ DCIS may represent a field effect that confers increased propensity for developing cancer across breast tissue, regardless of laterality. In contrast, ER- DCIS may represent an isolated local event. Given that the majority of DCIS is ER+, and only a minority of DCIS patients receive hormonal therapy, consideration of ER status may influence treatment and surveillance approaches.

TBCRC 057: Survey about willingness to participate in cancer clinical trials during the pandemic.

BACKGROUND: Breast cancer patients experienced heightened anxiety during the pandemic. Also, modifications to clinical trial activities allowing for virtual platforms, local assessments, and greater flexibility were introduced to facilitate participation. We sought to evaluate the association between pandemic-related anxiety and willingness to participate in trials and how pandemic-era modifications to trial activities affect the decision to participate. METHODS: We conducted an online survey from August to September, 2021 of patients with breast cancer assessing pandemic-related anxiety; clinical trials knowledge and attitudes; willingness to participate during and before the pandemic; and how each modification affects the decision to participate. Fisher's exact tests evaluated differences in proportions and two-sample t-tests evaluated differences in means. The association of pandemic-related anxiety with a decline in willingness to participate during compared to prior to the pandemic was modeled using logistic regression. RESULTS: Among 385 respondents who completed the survey, 81% reported moderate-severe pandemic-related anxiety. Mean willingness to participate in a trial was lower during the pandemic than prior [2.97 (SD 1.17) vs. 3.10 (SD 1.09), (p < 0.001)]. Severe anxiety was associated with higher odds of diminished willingness to participate during the pandemic compared to prior (OR 5.07). Each of the modifications, with the exception of opting out of research-only blood tests, were endorsed by >50% of respondents as strategies that would increase their likelihood of deciding to participate. CONCLUSIONS: While pandemic-related anxiety was associated with diminished willingness to participate in trials, the leading reasons for reluctance to consider trial participation were unrelated to the pandemic but included worries about not getting the best treatment, side effects, and delaying care. Patients view trial modifications favorably, supporting continuation of these modifications, as endorsed by the National Cancer Institute and others.

Prospective clinical experience with research biopsies in breast cancer patients.

There are ethical concerns regarding the performance of biopsies in patients for research purposes. We examined our single-institution experience regarding acceptance, safety, and success rate with research biopsies in patients with breast cancer. Among patients with data from paired samples, receptor status agreement between primary and metastatic samples was examined, either on first recurrence or after progression on one or more lines of therapy. An IRB-approved prospective study at the Dana-Farber Cancer Institute collects research biopsies as additional passes at the time of a clinical biopsy (AB, additional biopsy) or as a separate procedure for banking purposes (RPOB, research purposes only biopsy). Biopsies are not linked to a specific therapeutic or correlative trial. Grade 2-5 adverse events are prospectively collected. 151 patients were included in the analytic cohort (total procedures = 161); 80.8 % underwent AB, 17.2 % underwent RPOB, and 2.0 % underwent both AB and RPOB. Most patients were white (88.7 %) with a performance status of 0-1 (94.0 %). 96.0 % of patients underwent a biopsy in the setting of known or suspected metastatic disease. Receptor status between primary cancer and recurrent research biopsies differed in 43.2 % of patients with available data (18.8 % among patients who underwent the research biopsy before any systemic treatment, 48.1 % after treatment). Tissue was successfully collected in 92.3 % of patients undergoing AB and 100 % patients undergoing RPOB. Only three (2.0 %) patients had adverse events ≥ grade-2: one grade-2 pain; one grade-2 pneumothorax; and one grade-3 pain. Our experience suggests research biopsies can be performed safely with a high rate of successful tissue collection. Consistent with previous reports we found a high rate of discordance between primary and metastatic samples, which was even higher among treated patients. This supports continued efforts to study tissue samples at multiple points in a patient's disease course.

Use of Adjuvant Bisphosphonates and Other Bone-Modifying Agents in Breast Cancer: ASCO-OH (CCO) Guideline Update.

PURPOSE: To update recommendations of the American Society of Clinical Oncology (ASCO)-Ontario Health (Cancer Care Ontario [CCO]) adjuvant bone-modifying agents in breast cancer guideline. METHODS: An Expert Panel conducted a systematic review to identify new, potentially practice-changing data. RESULTS: Four articles met eligibility criteria and form the evidentiary basis for revision of the previous recommendations. RECOMMENDATIONS: Adjuvant bisphosphonate therapy should be discussed with all postmenopausal patients (natural or therapy-induced) with primary breast cancer, irrespective of hormone receptor status and human epidermal growth factor receptor 2 status, who are candidates to receive adjuvant systemic therapy. Adjuvant bisphosphonates, if used, are not substitutes for standard anticancer modalities. The benefit of adjuvant bisphosphonate therapy will vary depending on the underlying risk of recurrence and is associated with a modest improvement in overall survival. The NHS PREDICT tool provides estimates of the benefit of adjuvant bisphosphonate therapy and may aid in decision making. Factors influencing the decision to recommend adjuvant bisphosphonate use should include patients' risk of recurrence, risk of side effects, financial toxicity, drug availability, patient preferences, comorbidities, and life expectancy. When an adjuvant bisphosphonate is used to prevent breast cancer recurrence, the therapeutic options recommended by the Panel include oral clodronate, oral ibandronate, and intravenous zoledronic acid. The Panel supports starting bisphosphonate therapy early, consistent with the points outlined in the parent CCO-ASCO guideline; this is a consensus recommendation. The Panel does not recommend adjuvant denosumab to prevent breast cancer recurrence, because studies did not show a consistent reduction of breast cancer recurrence in any subset of those with early-stage breast cancer.Additional information can be found at www.asco.org/breast-cancer-guideline.

Road Map to Safe and Well-Designed De-escalation Trials of Systemic Adjuvant Therapy for Solid Tumors.

An important challenge in the field of cancer is finding the balance between delivering effective treatments and avoiding adverse effects and financial toxicity caused by innovative, yet expensive, drugs. To address this, several treatment de-escalation trials have been conducted, but only a few of these have provided clear answers. A few trials had poor accrual or had design flaws that led to conflicting results. Members of the Breast International Group (BIG) and North American Breast Cancer Group (NABCG) believe the way forward is to understand the lessons from these trials and listen more carefully to what truly matters to our patients. We reviewed several adjuvant trials of different cancer types and developed a road map for improving the design and implementation of future de-escalation trials. The road map incorporates patients' insights obtained through focused group discussions across the BIG-NABCG networks. Considerations for the development of de-escalation trials for systemic adjuvant treatment, including noninferiority trial design, choice of end points, and prioritization of a patient's perspectives, are presented in this consensus article.

Resistance Mechanisms to SYK Inhibition in Acute Myeloid Leukemia.

Spleen tyrosine kinase (SYK) is a nonmutated therapeutic target in acute myeloid leukemia (AML). Attempts to exploit SYK therapeutically in AML have shown promising results in combination with chemotherapy, likely reflecting induced mechanisms of resistance to single-agent treatment in vivo. We conducted a genome-scale open reading frame (ORF) resistance screen and identified activation of the RAS-MAPK-ERK pathway as one major mechanism of resistance to SYK inhibitors. This finding was validated in AML cell lines with innate and acquired resistance to SYK inhibitors. Furthermore, patients with AML with select mutations activating these pathways displayed early resistance to SYK inhibition. To circumvent SYK inhibitor therapy resistance in AML, we demonstrate that a MEK and SYK inhibitor combination is synergistic in vitro and in vivo. Our data provide justification for use of ORF screening to identify resistance mechanisms to kinase inhibitor therapy in AML lacking distinct mutations and to direct novel combination-based strategies to abrogate these. SIGNIFICANCE: The integration of functional genomic screening with the study of mechanisms of intrinsic and acquired resistance in model systems and human patients identified resistance to SYK inhibitors through MAPK signaling in AML. The dual targeting of SYK and the MAPK pathway offers a combinatorial strategy to overcome this resistance.This article is highlighted in the In This Issue feature, p. 161.

A Combination CDK4/6 and IGF1R Inhibitor Strategy for Ewing Sarcoma.

PURPOSE: Novel targeted therapeutics have transformed the care of subsets of patients with cancer. In pediatric malignancies, however, with simple tumor genomes and infrequent targetable mutations, there have been few new FDA-approved targeted drugs. The cyclin-dependent kinase (CDK)4/6 pathway recently emerged as a dependency in Ewing sarcoma. Given the heightened efficacy of this class with targeted drug combinations in other cancers, as well as the propensity of resistance to emerge with single agents, we aimed to identify genes mediating resistance to CDK4/6 inhibitors and biologically relevant combinations for use with CDK4/6 inhibitors in Ewing. EXPERIMENTAL DESIGN: We performed a genome-scale open reading frame (ORF) screen in 2 Ewing cell lines sensitive to CDK4/6 inhibitors to identify genes conferring resistance. Concurrently, we established resistance to a CDK4/6 inhibitor in a Ewing cell line. RESULTS: The ORF screen revealed IGF1R as a gene whose overexpression promoted drug escape. We also found elevated levels of phospho-IGF1R in our resistant Ewing cell line, supporting the relevance of IGF1R signaling to acquired resistance. In a small-molecule screen, an IGF1R inhibitor scored as synergistic with CDK4/6 inhibitor treatment. The combination of CDK4/6 inhibitors and IGF1R inhibitors was synergistic in vitro and active in mouse models. Mechanistically, this combination more profoundly repressed cell cycle and PI3K/mTOR signaling than either single drug perturbation. CONCLUSIONS: Taken together, these results suggest that IGF1R inhibitors activation is an escape mechanism to CDK4/6 inhibitors in Ewing sarcoma and that dual targeting of CDK4/6 inhibitors and IGF1R inhibitors provides a candidate synergistic combination for clinical application in this disease.

Inhibition of MEK and ATR is effective in a B-cell acute lymphoblastic leukemia model driven by Mll-Af4 and activated Ras.

Infant B-cell acute lymphoblastic leukemias (B-ALLs) that harbor MLL-AF4 rearrangements are associated with a poor prognosis. One important obstacle to progress for this patient population is the lack of immunocompetent models that faithfully recapitulate the short latency and aggressiveness of this disease. Recent whole-genome sequencing of MLL-AF4 B-ALL samples revealed a high frequency of activating RAS mutations; however, single-agent targeting of downstream effectors of the RAS pathway in these mutated MLL-r B-ALLs has demonstrated limited and nondurable antileukemic effects. Here, we demonstrate that the expression of activating mutant N-Ras G12D cooperates with Mll-Af4 to generate a highly aggressive serially transplantable B-ALL in mice. We used our novel mouse model to test the sensitivity of Mll-Af4/N-Ras G12D leukemia to small molecule inhibitors and found potent and synergistic preclinical efficacy of dual targeting of the Mek and Atr pathways in mouse- and patient-derived xenografts with both mutations in vivo, suggesting this combination as an attractive therapeutic opportunity that might be used to treat patients with these mutations. Our studies indicate that this mouse model of Mll-Af4/N-Ras B-ALL is a powerful tool to explore the molecular and genetic pathogenesis of this disease subtype, as well as a preclinical discovery platform for novel therapeutic strategies.

Association of Regional Intensity of Ductal Carcinoma In Situ Treatment With Likelihood of Breast Preservation.

IMPORTANCE: Large regional variation exists in the use of radiotherapy after breast-conserving surgery (BCS) for ductal carcinoma in situ (DCIS). Although patients who do not receive initial radiotherapy for DCIS are candidates for subsequent BCS if they experience a second breast event, many undergo mastectomy instead. OBJECTIVE: To examine whether regional practice patterns of radiotherapy for DCIS affect the use of mastectomy in these patients. DESIGN, SETTING, AND PARTICIPANTS: A retrospective analysis of population-based databases (Surveillance, Epidemiology, and End Results [SEER] and SEER-Medicare). Data were obtained for 2679 women in SEER with a diagnosis of DCIS between 1990 and 2011 and for 757 women in SEER-Medicare with a DCIS diagnosis between 1991 and 2009 who had not undergone radiotherapy for DCIS and experienced a subsequent breast cancer or DCIS diagnosis. EXPOSURES: Treatment intensity for primary DCIS (high, medium, low), as defined by separating health service areas (HSAs) into 3 clusters based on radiotherapy use. MAIN OUTCOMES AND MEASURES: Mastectomy vs BCS at a second breast event defined as DCIS recurrence or new invasive cancer. RESULTS: The median (SD) ages of the participants was 64 (13) years for the 2679 SEER population and 79 (6) years for the SEER-Medicare cohort. Residence in an HSA characterized by greater radiotherapy use for DCIS increased the likelihood of receiving mastectomy vs BCS at a subsequent breast event, even among women who had not previously received radiotherapy for DCIS. Adjusted odds ratios for receiving mastectomy were 1.43 (95% CI, 1.10-1.85) and 1.90 (95% CI, 1.27-2.84) in SEER and SEER-Medicare databases, respectively, among women residing in an HSA with the greatest radiotherapy use vs the least, corresponding to an adjusted increase from 40.8% to 49.6%, and from 38.6% to 54.5%. CONCLUSIONS AND RELEVANCE: Areas with more radiotherapy use for DCIS had increased use of mastectomy at the time of a second breast event even among patients eligible for breast conservation. This association suggests that physician-related factors are affecting the likelihood of breast preservation.

Use of Adjuvant Bisphosphonates and Other Bone-Modifying Agents in Breast Cancer: A Cancer Care Ontario and American Society of Clinical Oncology Clinical Practice Guideline.

Purpose To make recommendations regarding the use of bisphosphonates and other bone-modifying agents as adjuvant therapy for patients with breast cancer. Methods Cancer Care Ontario and ASCO convened a Working Group and Expert Panel to develop evidence-based recommendations informed by a systematic review of the literature. Results Adjuvant bisphosphonates were found to reduce bone recurrence and improve survival in postmenopausal patients with nonmetastatic breast cancer. In this guideline, postmenopausal includes patients with natural menopause or that induced by ovarian suppression or ablation. Absolute benefit is greater in patients who are at higher risk of recurrence, and almost all trials were conducted in patients who also received systemic therapy. Most studies evaluated zoledronic acid or clodronate, and data are extremely limited for other bisphosphonates. While denosumab was found to reduce fractures, long-term survival data are still required. Recommendations It is recommended that, if available, zoledronic acid (4 mg intravenously every 6 months) or clodronate (1,600 mg/d orally) be considered as adjuvant therapy for postmenopausal patients with breast cancer who are deemed candidates for adjuvant systemic therapy. Further research comparing different bone-modifying agents, doses, dosing intervals, and durations is required. Risk factors for osteonecrosis of the jaw and renal impairment should be assessed, and any pending dental or oral health problems should be dealt with prior to starting treatment. Data for adjuvant denosumab look promising but are currently insufficient to make any recommendation. Use of these agents to reduce fragility fractures in patients with low bone mineral density is beyond the scope of the guideline. Recommendations are not meant to restrict such use of bone-modifying agents in these situations. Additional information at www.asco.org/breast-cancer-adjuvant-bisphosphonates-guideline , www.asco.org/guidelineswiki , https://www.cancercareontario.ca/guidelines-advice/types-of-cancer/breast .