Population-based analysis of the impact and generalizability of the NSABP-B24 study on endocrine therapy for patients with ductal carcinoma in situ of the breast

Ductal carcinoma in situ of the breast: finding the balance between overtreatment and undertreatment

Ductal carcinoma in situ (DCIS) accounts for 15-25% of all breast cancer diagnoses. Its prognosis is excellent overall, the main risk being the occurrence of local breast events, as most cases of DCIS do not progress to invasive cancer. Systematic screening has greatly increased the incidence of this non-obligate precursor of invasion, lending urgency to the need to identify DCIS that is prone to invasive progression and distinguish it from non-invasion-prone DCIS, as the latter can be overdiagnosed and therefore overtreated. Treatment strategies, including surgery, radiotherapy, and optional endocrine therapy, decrease the risk of local events, but have no effect on survival outcomes. Active surveillance is being evaluated as a possible new option for low-risk DCIS. Considerable efforts to decipher the biology of DCIS have led to a better understanding of the factors that determine its variable natural history. Given this variability, shared decision making regarding optimal, personalised treatment strategies is the most appropriate course of action. Well designed, risk-based de-escalation studies remain a major need in this field.

Real-World Evidence on the Use of Endocrine Therapy for Ductal Carcinoma In Situ in Patients Treated With Breast-Conserving Surgery Followed by Postoperative Radiation Therapy: A Brazilian Retrospective Cohort Study

INTRODUCTION/BACKGROUND

This study aims to evaluate the reproducibility of findings from randomized controlled trials regarding adjuvant hormone therapy (HT) for breast ductal carcinoma in situ (DCIS) in a real-life scenario.

MATERIALS/METHODS

This retrospective cohort study used Fundação Oncocentro de São Paulo database. It included DCIS patients DCIS who received breast-conserving surgery and postoperative radiation therapy. The endpoints were local control (LC), breast cancer-specific survival (BCSS), and overall survival (OS).

RESULTS

We analyzed 2192 patients treated between 2000 and 2020. The median FU was 48.99 months. Most patients (53.33%; n = 1169) received adjuvant HT. Patients not receiving adjuvant HT tend to be older (P = .021) and have a lower educational level (P < .001). At the end of FU, 1.5% of patients had local recurrence, and there was no significant difference between groups (P = .19). The 10-year OS and BCSS were 89.4% and 97.5% for adjuvant HT versus 91.5% and 98.5% for no adjuvant HT, respectively, and there were no significant differences between groups. The 10-year OS was 93.25% for medium/high education level versus 87.31% for low (HR for death 0.51; 95% CI, 0.32-0.83; P = .007).

CONCLUSIONS

The benefits of adjuvant HT for DCIS were not reproduced in a Brazilian cohort. Education significantly impacted survival and HT usage, reflecting the influence of socioeconomic factors. These findings can allow for more precise interventions.

Clinicopathological Characteristics of Breast Ductal Carcinoma In Situ: An Analysis of Chinese Population of 617 Patients

BACKGROUND

The purpose of this study was to describe the clinicopathological characteristics of breast DCIS in Chinese women and compare with that of patients in western countries.

METHOD

From December 2005 to December 2015, 617 women diagnosed with pure DCIS after surgery at our institution were enrolled, and the clinicopathological characteristics were described.

RESULTS

In this study, the percentage of patients detected on screening, diagnosed at ≤50 years of age, with tumor size ≤2.0 cm, and with low-intermediate grade was 39.4%, 56.7%, 72.6%, and 77.4%, respectively, as compared to 50-80%, 20-30%, 70-90%, and 40-60% in published reports from western countries. The percentage of ER-positive patients was 76.3% in this study, which is similar to the mean expression rate of ER (mean: 68.7%, range: 49-96.6%) reported previously.

CONCLUSIONS

The clinicopathological characteristics of Chinese DCIS patients include less detection on screening, younger age at diagnosis, and more low-intermediate nuclear grade.

Duct carcinoma in situ: A personal perspective

In the recent past, DCIS was a rare diagnosis established by biopsy of palpable breast masses or nipple changes. Mammography increased the frequency of a DCIS diagnosis by 20 × resulting in a tsunami of small circa 10 mm lesions detected only by mammography. The impact of pathologic technique in examining and characterizing such lesions is reviewed, and the development of algorithms incorporating prognostic factors and histology based on serial sequential processing techniques are described and contrasted with those which relied on tissue sampling. The development of the initial clinical trails of irradiation all demonstrated the significant benefit of irradiation but none could identify subsets with a more favorable outcome. The latter was precluded by their common practice of tissue sampling: Size could not be calculated and margin width and microinvasion could not be reliable demonstrated. Multigene signature assays are increasingly being utilized, most prominently Oncotype DCIS. However, these assays must be interpreted in conjunction with the limitations set forth in the validating studies-in the case of Oncotype DCIS-the size, margin width, and grade which defined the baseline study (E5194). Tamoxifen and other anti-hormonal agents (aromatase inhibitor therapy) have been shown to have a limited impact on ipsilateral recurrence which makes their use given their morbidities problematic. Such interventions do impact the frequency of contralateral occult in situ and invasive lesions. In the one study which permitted a comparison of local recurrence in irradiated vs nonirradiated breast, there was no added benefit of Tamoxifen in irradiated breasts. Some are attempting to identify a low-risk subset of DCIS which can be treated without surgical re-excision for margins or adjuvant irradiation. These studies are in progress but surrogates identified within the Van Nuys prospective series defined by grade and inadequate margins (≤ 1 mm) would suggest a significant recurrence and progression rate. DCIS remains a work in progress both in terms of classification and treatment. However, limited our progress in these areas we have certainly advanced from the oft-proclaimed mantra: "Radiation and Tamoxifen are standard of care."

In the Era After the European Organisation for Research and Treatment of Cancer 'Boost' Study, is the Additional Radiotherapy to the Breast Tumour Bed Still Beneficial for Young Women?

AIMS

The European Organisation for Research and Treatment of Cancer (EORTC) 22,881-10,882 trial showed significant benefit of a radiotherapy boost (RTB) in women ≤40 years in a pre-hormone therapy (HT) era. We determined how the use of HT and RTB changed in response to clinical guidelines and whether the benefit of routine RTB was still observed in the HT era.

MATERIALS AND METHODS

Between 1996 and 2004, a provincial database identified all women ≤40 years with breast cancer who met the inclusion criteria of the EORTC trial. In total, 411 patients were classified into three eras defined by the guidelines: era 1 (discretionary HT, discretionary RTB); era 2 (routine HT, discretionary RTB); era 3 (routine HT, routine RTB). HT use, RTB use and cumulative incidence of local recurrence were calculated and compared across eras.

RESULTS

HT use increased after the first policy change from 13% to 75% for oestrogen receptor-positive patients (P < 0.01). RTB use also increased from 33% to 76% following the second policy change (P < 0.01). At 10 years, the cumulative incidence of local recurrence was 12% in era 1, 6% in era 2 and 6% in era 3 (era 2 versus era 3, P = 0.92). For patients in the routine HT era (eras 2 and 3 combined) there was no significant difference in local recurrence between RTB and 'no RTB' patients (6% versus 7%, P = 0.81).

CONCLUSIONS

The routine use of HT and RTB increased significantly after new practice guidelines. Introduction of the HT guideline was associated with a 6% improvement in local recurrence at 10 years. No improvement in local recurrence was associated with the introduction of the RTB guideline in the HT era. The routine use of a boost in unselected young women with negative margins should be re-evaluated in the current HT era.

A retrospective alternative for active surveillance trials for ductal carcinoma in situ of the breast

Ductal carcinoma in situ (DCIS) of the breast is a nonobligate precursor of invasive breast cancer, accounting for 20 % of screen-detected breast cancers. Little is known about the natural progression of DCIS because most patients undergo surgery upon diagnosis. Many DCIS patients are likely being overtreated, as it is believed that only around 50 % of DCIS will progress to invasive carcinoma. Robust prognostic markers for progression to invasive carcinoma are lacking. In the past, studies have investigated women who developed a recurrence after breast-conserving surgery (BCS) and compared them with those who did not. However, where there is no recurrence, the patient has probably been adequately treated. The present narrative review advocates a new research strategy, wherein only those patients with a recurrence are studied. Approximately half of the recurrences are invasive cancers, and half are DCIS. So-called "recurrences" are probably most often the result of residual disease. The new approach allows us to ask: why did some residual DCIS evolve to invasive cancers and others not? This novel strategy compares the group of patients that developed in situ recurrence with the group of patients that developed invasive recurrence after BCS. The differences between these groups could then be used to develop a robust risk stratification tool. This tool should estimate the risk of synchronous and metachronous invasive carcinoma when DCIS is diagnosed in a biopsy. Identification of DCIS patients at low risk for developing invasive carcinoma will individualize future therapy and prevent overtreatment.

Ductal Carcinoma In Situ

Ductal carcinoma in situ has been stable in incidence for a decade and has an excellent prognosis. Breast conservation therapy is safe and effective for most patients. Adjuvant whole breast radiation therapy is recommended to reduce the risk of local recurrence. Accelerated partial breast irradiation is a promising alternative to decrease toxicity and improve cosmetic results. Adjuvant hormonal therapy can reduce local recurrence, but should be used cautiously. Future directions in management include developing predictive tools for guidance for use of adjuvant therapy and selecting low-risk patients with ductal carcinoma in situ in whom surgery may be safely omitted.

Prescribing practices of endocrine therapy for ductal carcinoma in situ in British Columbia

Purpose

The mainstay of treatment for ductal carcinoma in situ (dcis) involves surgery in the form of mastectomy or lumpectomy. Inconsistency in the use of endocrine therapy (et) for dcis is evident worldwide. We sought to assess the variation in et prescribing for patients with dcis across a population-based radiotherapy (rt) program and to identify variables that predict its use.

Methods

Data from a breast cancer database were obtained for women diagnosed with dcis in British Columbia from 2009 to 2014. Associations between et use and patient characteristics were assessed by chi-square test and multilevel multivariate logistic regression. The Kaplan-Meier method, with propensity score matching and Cox regression analysis, was used to assess the effects of et on overall survival (os) and relapse-free survival (rfs).

Results

For the 2336 dcis patients included in the study, et use was 13% in dcis patients overall, and 17% in patients with estrogen receptor-positive (er+) tumours treated with breast-conserving surgery and rt. Significant variation in et use by treatment centre was observed (range: 8%-23%; p < 0.001), and prescription of et by individual oncologists varied in the range 0%-40%. After controlling for confounding factors, age less than 50 years [odds ratio (or): 1.72; p = 0.01], treatment centre, er+ status (or: 5.33; p < 0.001), and rt use (or: 1.77; p < 0.001) were significant predictors of et use. No difference in os or rfs with the use of et was observed.

Conclusions

In this population-based analysis, 13% of patients with dcis in British Columbia received et, with variation by treatment centre (8%-23%) and individual oncologist (0%-40%). Age less than 50 years, er+ status, and rt use were most associated with et use.

Paradigm Shift toward Reducing Overtreatment of Ductal Carcinoma In Situ of Breast

The prevalence of ductal carcinoma in situ (DCIS) of the breast has increased substantially after the introduction of breast cancer screening programs, although the clinical effects of early DCIS detection and treatment remain unclear. The standard treatment for DCIS has involved local breast-conserving surgery (BCS) followed by radiotherapy (RT) or total mastectomy with/without endocrine therapy, and the choice of local treatment is not usually based on clinicopathologic or biological factors. However, we have investigated the effectiveness of local treatment using breast surgery and RT using Surveillance, Epidemiology, and End Results data, and found that the effectiveness of breast surgery was modified by the nuclear grade. Furthermore, breast cancer-specific survival was identical between patients with low-grade DCIS who did and did not undergo surgery. Moreover, we found that RT after BCS for DCIS was only associated with a survival benefit among patients with risk factors for local recurrence, such as nuclear grade, age, and tumor size. Ongoing clinical trials and translational research have attempted to develop a treatment strategy that prevents the overdiagnosis and overtreatment of low-risk DCIS, as well as a biology-based treatment strategy for using targeted therapy. Therefore, to develop a tailored treatment strategy for DCIS, we need to identify molecular and biological classifications based on the results from translational research, national databases, and clinical trials.

Trends in adjuvant therapies after breast-conserving surgery for hormone receptor-positive ductal carcinoma in situ: findings from the National Cancer Database, 2004-2013

PURPOSE

Breast-conserving surgery (BCS) followed by radiotherapy (RT) with or without endocrine therapy (ET) is a standard treatment option for ductal carcinoma in situ (DCIS). We sought to investigate national patterns in the use of adjuvant therapy after BCS for hormone receptor (HR)-positive DCIS over time.

PATIENTS AND METHODS

Using data from the National Cancer Data Base, we identified patients diagnosed with DCIS and treated with BCS between 2004 and 2013. Multivariable logistic regression was used to estimate the odds of adjuvant therapy use controlling for clinicopathologic demographic and facility-level characteristics.

RESULTS

We identified 66,079 patients who underwent BCS for DCIS. Overall, 21% received no adjuvant treatment, 71% received RT, 48% received ET, and 38% received the combination therapy. In adjusted analyses among the patients with HR-positive DCIS (n = 50,147), the administration of RT decreased (odds ratio [OR] 0.86, 95% CI 0.77-0.97), while the use of ET increased (OR 1.5, 95% CI 1.4-1.6) in 2013 compared to 2004. Young patients, elderly patients, positive margin status, and Medicare insurance were associated with lower use of both RT and ET. We observed both clinicopathologic and geographic variation in the use of adjuvant therapies. In the lowest risk subgroup, the use of RT decreased from 57% in 2004 to 48% in 2013 (OR 0.64, 95% CI 0.45-0.89).

CONCLUSION

Our study suggests a shift in patterns of care for DCIS that is impacted by both clinicopathologic and demographic factors, with the use of RT decreasing and the use of ET increasing in HR-positive DCIS patients. Current trials are designed to address the possible over-treatment of low-risk DCIS.

Current treatment trends and the need for better predictive tools in the management of ductal carcinoma in situ of the breast

Ductal carcinoma in situ (DCIS) of the breast represents a group of heterogeneous non-invasive lesions the incidence of which has risen dramatically since the advent of mammography screening. In this review we summarise current treatment trends and up-to-date results from clinical trials studying surgery and adjuvant therapy alternatives, including the recent consensus on excision margin width and its role in decision-making for post-excision radiotherapy. The main challenge in the clinical management of DCIS continues to be the tailoring of treatment to individual risk, in order to avoid the over-treatment of low-risk lesions or under-treatment of DCIS with higher risk of recurring or progressing into invasion. While studies estimate that only about 40% of DCIS would become invasive if untreated, heterogeneity and complex natural history have prevented adequate identification of these higher-risk lesions. Here we discuss attempts to develop prognostic tools for the risk stratification of DCIS lesions and their limitations. Early results of a UK-wide audit of DCIS management (the Sloane Project) have also demonstrated a lack of consistency in treatment. In this review we offer up-to-date perspectives on current treatment and prediction of DCIS, highlighting the pressing clinical need for better prognostic indices. Tools integrating both clinical and histopathological factors together with molecular biomarkers may hold potential for adequate stratification of DCIS according to risk. This could help develop standardised practices for optimal management of patients with DCIS, improving clinical outcomes while providing only the amount of therapy required for each individual patient.

Hypofractionation Is an Acceptable Alternative to Conventional Fractionation in the Treatment of Postlumpectomy Ductal Carcinoma In Situ With Radiotherapy

PURPOSE

The standard dose of postlumpectomy radiotherapy (RT) for ductal carcinoma in situ (DCIS) is 50 Gy in 25 fractions using conventional fractionation (CF). However, in invasive carcinoma, hypofractionation (HF) with 40 to 42.6 Gy in 15 to 16 fractions has largely become a standard of care. The purpose of this study was to review the management of postlumpectomy DCIS in terms of RT dose-fractionation and its impact on local recurrence (LR), in one of the largest Canadian academic centers.

METHODS AND MATERIALS

Between 2003 and 2008, a total of 348 women with DCIS were treated with postlumpectomy RT. Patient characteristics, histopathology, dose-fractionation, use of endocrine therapy, local, regional, contralateral breast recurrences, and cause of death were collected. Local recurrence-free survival was determined. Univariate and multivariate analyses were performed to identify risk factors for LR.

RESULTS

The median age of the cohort was 59 years. Two hundred two (58%) patients received CF and 146 (42%) HF. Initially, the yearly proportion of HF was 34%, but increased up to 68% since 2007. Estrogen receptor was positive in 195 patients, and 43% of those received endocrine therapy. With a median follow-up of 64.8 months, 36 LRs were detected. The 5-year local recurrence-free survival rate was 94% for the HF group versus 91% for the CF group (P = .80). On multivariate analysis, only the use of endocrine therapy showed a trend towards decreasing LR (hazard ratio, 0.44; 95% confidence interval, 0.18-1.08; P = .07).

CONCLUSIONS

The utilization of HF for DCIS postlumpectomy has increased over time and is a valid option as it results in similar rates of local control.

The Role of MicroRNAs as Predictors of Response to Tamoxifen Treatment in Breast Cancer Patients

Endocrine therapy is a key treatment strategy to control or eradicate hormone-responsive breast cancer. However, resistance to endocrine therapy leads to breast cancer relapse. The recent extension of adjuvant tamoxifen treatment up to 10 years actualizes the need for identifying biological markers that may be used to monitor predictors of treatment response. MicroRNAs are promising biomarkers that may fill the gap between preclinical knowledge and clinical observations regarding endocrine resistance. MicroRNAs regulate gene expression by posttranscriptional repression or degradation of mRNA, most often leading to gene silencing. MicroRNAs have been identified directly in the primary tumor, but also in the circulation of breast cancer patients. The few available studies investigating microRNA in patients suggest that seven microRNAs (miR-10a, miR-26, miR-30c, miR-126a, miR-210, miR-342 and miR-519a) play a role in tamoxifen resistance. Ingenuity Pathway Analysis (IPA) reveals that these seven microRNAs interact more readily with estrogen receptor (ER)-independent pathways than ER-related signaling pathways. Some of these pathways are targetable (e.g., PIK3CA), suggesting that microRNAs as biomarkers of endocrine resistance may have clinical value. Validation of the role of these candidate microRNAs in large prospective studies is warranted.