Patterns of adjuvant care and outcomes of elderly women with stage I breast cancer after breast-conserving surgery: a population-based analysis

Early-Stage Breast Cancer: A Critical Review of Current and Emerging Practice

Breast-conserving surgery followed by adjuvant radiation to reduce the risk of ipsilateral breast tumor recurrence is the mainstay of treatment for early-stage breast cancer (ESBC). However, improved understanding of the heterogeneity of the clinical and molecular characteristics of ESBC has led to greater efforts to personalize approaches to treatment. Furthermore, advances in the understanding of the radiobiology of breast cancer have led to several practice-changing trials on the effectiveness and tolerability of moderate and ultrahypofractionated radiation. Here, we review the recent evidence and ongoing research in the radiotherapeutic management of ESBC, including the use of boost for high-risk disease and opportunities for accelerated fractionation, partial breast irradiation, and radiation omission for low-risk disease. We also discuss how molecular profiling can inform decision-making and new opportunities for primary radiation therapy and reirradiation.

Efficacy and safety of adjuvant therapies in older patients with breast cancer: a systematic review and meta-analysis of real-world data

BACKGROUND

Insufficient data available for older patients with breast cancer complicates decision-making regarding optimal treatment. A systematic review that uses real-world data is required for assessing the effectiveness and potential adverse effects of various therapies for this age group of patients.

METHODS

Databases of PubMed, Embase, and Cochrane Library were searched. We included clinical studies that evaluated various treatments for geriatric breast cancer, including adjuvant radiation therapy, hypofractionated radiation therapy (hypo-RT) and accelerated and partial breast irradiation (APBI), endocrine therapy, chemotherapy, and targeted therapy.

RESULTS

A total of 71 studies were retrieved. Adjuvant radiation therapy significantly improved overall survival (OS) compared with no radiation [hazard ratio (HR) = 0.60, 95% confidence interval (CI) 0.54-0.67]. The pooled estimates of OS for hypo-RT and APBI demonstrated no inferiority compared with conventional radiation. Both endocrine treatment (HR = 0.63, 95% CI 0.43-0.92) and chemotherapy (HR = 0.76, 95% CI 0.65-0.88) significantly increased OS compared with no treatment. Trastuzumab monotherapy significantly enhanced OS compared with no trastuzumab use (HR = 0.23, 95% CI 0.07-0.73).

CONCLUSION

Despite concerns about potential complications during treatment in older patients, proactive therapies significantly increase their survival rates. For patients who are frailer, hypo-RT and APBI offer survival rates comparable to traditional modalities. Additionally, targeted therapy as a monotherapy holds promise as a viable option for patients with HER2-positive breast cancer who cannot undergo chemotherapy. Therefore, by conducting thorough general assessments and clinical evaluations, the side effects of postoperative treatments can be effectively managed.

Frequency of use and characterization of frailty assessments in observational studies on older women with breast cancer: a systematic review

BACKGROUND

Breast cancer and frailty frequently co-occur in older women, and frailty status has been shown to predict negative health outcomes. However, the extent to which frailty assessments are utilized in observational research for the older breast cancer population is uncertain. Therefore, the aim of this review was to determine the frequency of use of frailty assessments in studies investigating survival or mortality, and characterize them, concentrating on literature from the past 5 years (2017-2022).

METHODS

MEDLINE, EMBASE and Cochrane Library were systematically queried to identify observational studies (case-control, cohort, cross-sectional) published from 2017-2022 that focus on older females (≥ 65 years) diagnosed with breast cancer, and which evaluate survival or mortality outcomes. Independent reviewers assessed the studies for eligibility using Covidence software. Extracted data included characteristics of each study as well as information on study design, study population, frailty assessments, and related health status assessments. Risk of bias was evaluated using the appropriate JBI tool. Information was cleaned, classified, and tabulated into review level summaries.

RESULTS

In total, 9823 studies were screened for inclusion. One-hundred and thirty studies were included in the final synthesis. Only 11 (8.5%) of these studies made use of a frailty assessment, of which 4 (3.1%) quantified frailty levels in their study population, at baseline. Characterization of frailty assessments demonstrated that there is a large variation in terms of frailty definitions and resulting patient classification (i.e., fit, pre-frail, frail). In the four studies that quantified frailty, the percentage of individuals classified as pre-frail and frail ranged from 18% to 29% and 0.7% to 21%, respectively. Identified frailty assessments included the Balducci score, the Geriatric 8 tool, the Adapted Searle Deficits Accumulation Frailty index, the Faurot Frailty index, and the Mian Deficits of Accumulation Frailty Index, among others. The Charlson Comorbidity Index was the most used alternative health status assessment, employed in 56.9% of all 130 studies. Surprisingly, 31.5% of all studies did not make use of any health status assessments.

CONCLUSION

Few observational studies examining mortality or survival outcomes in older women with breast cancer incorporate frailty assessments. Additionally, there is significant variation in definitions of frailty and classification of patients. While comorbidity assessments were more frequently included, the pivotal role of frailty for patient-centered decision-making in clinical practice, especially regarding treatment effectiveness and tolerance, necessitates more deliberate attention. Addressing this oversight more explicitly could enhance our ability to interpret observational research in older cancer patients.

Optimal adjuvant therapy in older (≥70 years of age) women with low-risk early-stage breast cancer

Older women are under-represented in breast cancer (BC) clinical trials, and treatment guidelines are primarily based on BC studies in younger women. Studies uniformly report an increased incidence of local relapse with omission of breast radiation therapy. Review of the available literature suggests very low rates of distant relapse in women ≥70 years of age. The incremental benefit of endocrine therapy in decreasing rate of distant relapse and improving disease-free survival in older patients with low-risk BC remains unclear. Integration of molecular genomic assays in diagnosis and treatment of estrogen receptor positive BC presents an opportunity for optimizing risk-tailored adjuvant therapies in ways that may permit treatment de-escalation among older women with early-stage BC. The prevailing knowledge gap and lack of risk-specific adjuvant therapy guidelines suggests a compelling need for prospective trials to inform selection of optimal adjuvant therapy, including omission of adjuvant endocrine therapy in older women with low risk BC.

Effect of adjuvant radiotherapy after breast-conserving surgery in elder women with early-stage breast cancer: a propensity-score matching analysis

Purpose

The study aimed to explore the role of adjuvant radiotherapy (RT) after breast-conserving surgery (BCS) in elder women with early-stage breast cancer (BC).

Methods

BC patients with 70-79 years of age, stage T1-2N0-1M0, undergoing BCS were screened in the Surveillance, Epidemiology and End Results (SEER) database between 2010 and 2015. The clinicopathological characteristics were balanced with propensity-score matching (PSM) method. Kaplan-Meier curves and Cox regression analyses were performed to determine the impact of adjuvant RT on BC patients.

Results

Ultimately, 12,310 patients treated with adjuvant RT and 4837 patients treated with no RT, were involved in the analysis. Overall, patients treated with adjuvant RT was associated with a better breast cancer-specific survival (BCSS) (HR: 1.980 [1.596- 2.456], P < 0.001) and overall survival (OS) (HR: 2.214 [1.966- 2.494], P < 0.001) than those who did not undergo RT. After 1:1 PSM, adjuvant RT still performed advantage in both BCSS (HR: 1.918 [1.439- 2.557], P < 0.001) and OS (HR: 2.235 [1.904- 2.624], P < 0.001). In the multivariate COX analysis of BCSS, widowed, divorced and separated patients, tumor grade III, T2 stage, N1 stage, no RT, molecular subtypes with luminal B and triple negative were associated with a shorter BCSS (P < 0.05). In the multivariate COX analysis of OS, age ≥74 years, widowed, divorced and separated patients, tumor grade II/III, T2 stage, no RT, no chemotherapy, molecular subtypes with triple negative were associated with a shorter OS (P < 0.05). Furthermore, the advantages of adjuvant RT were observed in all subgroup analysis.

Conclusion

Adjuvant RT after BCS can improve both BCSS and OS in elderly patients with early-stage BC. Additionally, all subgroups analysis-derived BCSS and OS were in support of RT.

Impact of non-adherence to endocrine therapy on recurrence risk in older women with stage I breast cancer after breast-conserving surgery

PURPOSE

We examined the impact of non-adherence to adjuvant endocrine therapy (ET) on the risk and site of recurrence among older women with early stage, hormone receptor positive (HR+) breast cancer (EBC).

METHODS

A population-based cohort of women age ≥ 65 years with T1N0 HR + EBC who were diagnosed between 2010 and 2016 and treated with breast-conserving surgery (BCS) + ET was identified. Treatment and outcomes were ascertained through linkage with administrative databases. ET non-adherence was examined as a time-dependent covariate in multivariable cause-specific Cox regression models to evaluate its effect on the risks of ipsilateral local recurrence (LR), contralateral breast cancer, and distant metastases.

RESULTS

The population cohort includes 2637 women; 73% (N = 1934) received radiation (RT) + ET and 27% (N = 703) received ET alone. At a median follow-up of 8.14 years, the first event was LR in 3.6% of women treated with ET alone and 1.4% for those treated with RT + ET (p < 0.001); the risk of distant metastases was < 1% in both groups. The proportion of time adherent to ET was 69.0% among those treated with RT + ET and 62.8% for those treated with ET alone. On multivariable analysis, increasing proportion of time non-adherent to ET was associated with increased risk of LR ((HR = 1.52 per 20% increase in time; 95%CI 1.25, 1.85; p < 0.001), contralateral BC (HR = 1.55; 95%CI 1.30, 1.84; p < 0.001), and distant metastases (HR = 1.44; 95%CI 1.08, 1.94; p = 0.01) but absolute risks were low.

CONCLUSION

Non-adherence to adjuvant ET was associated with an increased risk of recurrence, but absolute recurrence rates were low.

Accelerated Partial Breast Irradiation with Intraoperative Radiotherapy Is Effective in Luminal Breast Cancer Patients Aged 60 Years and Older

Adjuvant whole breast irradiation (AWBI) improves local control and survival in breast cancer patients after breast-conserving surgery. Between 2010 and 2017, 823 patients ≥ 60 years with ER-positive, Her-2 negative, clinically N0 breast cancer underwent breast-conserving surgery (BCS) at the West Pomeranian Oncology Center. Intraoperative radiotherapy (IORT) with kV photons was applied to 199 (24.2%) patients according to the IORT protocol, and AWBI only was applied to 624 (75.8%). IORT patients in cases with lymph node metastasis, lobular type presence, extensive in situ components, lymphatic vessel invasion, or resection margin < 2 mm, additionally underwent AWBI. Median follow-up was 74 months. There were two (1%) breast relapses in the IORT protocol group and one (0.2%) in the AWBI-only group. In each group, one axillary lymph node relapse was diagnosed (0.5% and 0.2%, respectively). There were two local relapses in the IORT-only group, and they were treated further with BCS and AWBI. Although locoregional relapse-free survival differed between the AWBI-only and IORT protocol groups (98.5% vs. 99.7%, p = 0.048), the local control, distant metastasis-free survival, and breast cancer-specific survival were similar. IORT is a reasonable option to avoid AWBI in ER-positive, Her-2 negative, cN0 women with breast cancer aged ≥ 60 years.

Experiences and Perceptions of Older Adults with Lower-Risk Hormone Receptor-Positive Breast Cancer about Adjuvant Radiotherapy and Endocrine Therapy: A Patient Survey

Older patients with lower-risk hormone receptor-positive (HR+) breast cancer are frequently offered both radiotherapy (RT) and endocrine therapy (ET) after breast-conserving surgery (BCS). A survey was performed to assess older patients’ experiences and perceptions regarding RT and ET, and participation interest in de-escalation trials. Of the 130 patients approached, 102 eligible patients completed the survey (response rate 78%). The median age of respondents was 74 (interquartile range 71–76). Most participants (71%, 72/102) received both RT and ET. Patients felt the role of RT and ET, respectively, was to: reduce ipsilateral tumor recurrence (91%, 90/99 and 62%, 61/99) and improve survival (56%, 55/99 and 49%, 49/99). More patients had significant concerns regarding ET (66%, 65/99) than RT (39%, 37/95). When asked which treatment had the most negative effect on their quality of life, the results showed: ET (35%, 25/72), RT (14%, 10/72) or both (8%, 6/72). Participants would rather receive RT (57%, 41/72) than ET (43%, 31/72). Forty-four percent (44/100) of respondents were either, “not comfortable” or “not interested” in participating in potential de-escalation trials. Although most of the adjuvant therapy de-escalation trials evaluate the omission of RT, de-escalation studies of ET are warranted and patient centered.

De-escalating adjuvant therapies in older patients with lower risk estrogen receptor-positive breast cancer treated with breast-conserving surgery: A systematic review and meta-analysis

PURPOSE

Radiation therapy (RT) and endocrine therapy (ET) are standard treatments for hormone receptor-positive (HR+) breast cancer after breast-conserving surgery (BCS). However, many older patients are at greater risk of treatment-related toxicities and non-cancer related death, and less likely to benefit from these standard treatments. A systematic review was performed evaluating outcomes of omitting RT or ET in older patients aged ≥50 treated with BCS for lower-risk breast cancer.

METHODS

Medline, Embase, and the Cochrane Register of Controlled Trials were queried from 1980 to April 30th, 2020 for randomized controlled studies (RCTs) and prospective cohort studies (PCSs) evaluating omission of RT and/or ET compared to RT plus ET in patients. Meta-analysis was performed using random-effects models with findings reported as risk ratios (RR) with 95% confidence intervals (CI).

RESULTS

From 3860 citations, 10 prospective studies met eligibility criteria. Omission of RT alone was evaluated in 7 RCTs (n = 4604) and one PCS (n = 667); omission of ET alone was assessed in 1 PCS (n = 271); and omission of either ET or RT was compared to ET plus RT in 1 RCT (n = 495). Adjuvant RT compared to no RT reduced 5- and 10-year in-breast tumor recurrence [5-year: RR 0.16, 95 %CI 0.09-0.27 l 10-year: 0.28, 95 %CI 0.16-0.5], but had no effect on survival [5-year: RR 0.94, 95 %CI 0.77-1.15; 10-year: 1.01, 95 %CI 0.9-1.12].

CONCLUSION

The current body of evidence suggests that RT can be omitted in older patients with lower-risk disease. However, more trials on the omission of ET are required to better inform treatment decisions.

Effects of Adjuvant Endocrine Therapy Adherence and Radiation on Recurrence and Survival Among Older Women with Early-Stage Breast Cancer

BACKGROUND

The Cancer and Leukemia Group-B 9343 (CALGB 9343) trial demonstrated that women aged ≥ 70 years with early-stage breast cancer can safely omit radiation therapy (RT) and be treated with breast-conserving surgery (BCS) and adjuvant endocrine therapy (AET) alone. AET adherence is low, leaving an undertreated cohort who may be at increased risk of recurrence and death. We hypothesized that AET adherence and adjuvant treatment choice impact recurrence and survival among CALGB 9343 eligible women.

PATIENTS AND METHODS

SEER-Medicare was used to identify CALGB 9343 eligible women who underwent BCS between 2007 and 2016. Medicare claims were used to identify AET use, and the proportion of days covered by AET was used to categorize adherent (PDC ≥ 0.80) versus nonadherent patients (PDC < 0.80). Recurrence-free, cancer-specific, and overall survival were assessed using Cox proportional hazards models.

RESULTS

In total, 10,719 women were identified, of whom 780 (7.3%) underwent BCS alone, 1490 (13.9%) underwent BCS + RT, 1663 (15.5%) underwent BCS + AET, and 6786 (63.3%) had BCS + RT + AET. Among women treated with BCS + AET, adherent patients had lower recurrence than did nonadherent patients (HR = 0.65, 95% CI: 0.50-0.85). With respect to adjuvant treatment combinations, there was no recurrence difference between the BCS + RT + AET group and BCS + AET group (HR = 0.81, 95% CI: 0.54-1.21). There was equivalent cancer-specific but worse overall survival in the BCS + AET group versus the BCS + AET + RT group.

CONCLUSIONS

While BCS + RT + AET may represent overtreatment for some, AET nonadherent women who omit RT are at risk for worse outcomes. Treatment decisions regarding RT omission should be tailored to the individual patient, taking into consideration the chances of AET nonadherence and the patients' own risk tolerance.

Radiation Without Endocrine Therapy in Older Women With Stage I Estrogen-Receptor-Positive Breast Cancer Is Not Associated With a Higher Risk of Second Breast Cancer Events

PURPOSE

The omission of radiation therapy (RT) in older women with stage 1 estrogen-receptor-positive (ER+) breast cancer receiving endocrine therapy (ET) is an acceptable strategy based on randomized trial data. Less is known about the omission of ET with or without RT.

METHODS AND MATERIALS

We analyzed surveillance, epidemiology, and end results (SEER)-Medicare data for 13,321 women age 66 years or older with stage I ER+ breast cancer from 2007 to 2012 who underwent breast-conserving surgery. Patients were classified into 4 groups: (1) ET + RT (reference); (2) ET alone; (3) RT alone; and (4) neither RT nor ET (NT). Second breast cancer events (SBCEs) were captured using the Chubak high-specificity algorithm. We used χ² tests for descriptive statistics, multivariable multinomial logistic regression to estimate relative risk of undergoing a treatment, and multivariable, propensity-weighted competing-risks survival regression to estimate standardized hazard ratio (SHR) of SBCE. We set significance at P ≤ .01.

RESULTS

Most women underwent both treatments, with 44% undergoing ET + RT, 41% RT alone, 6.6% ET alone, and 8.6% NT, but practice patterns varied over time. From 2007 to 2012, RT decreased from 49% to 30%, whereas ET alone and ET + RT increased (ET alone, 5.4%-9.6%; ET + RT, 38%-51%). Compared with patients age 66 to 69 years, patients age 80 to 85 years were more likely to receive NT (odds ratio [OR], 8.9), RT (OR, 1.9), or ET (OR, 8.8) versus ET + RT (P < .01). Three percent of subjects had an SBCE (2.2% ET + RT, 3.0% RT alone, 3.2% ET alone, 7.0% NT). Relative to ET + RT, NT and ET alone were associated with higher SBCE (NT: SHR, 3.7, P < .001; ET alone: SHR, 2.2, P = .008), whereas RT was not associated with a higher SBCE (SHR 1.21; P = .137). Clinical factors associated with higher SBCE were HER2 positivity and pT1c (SHR, 1.7; P = .006).

CONCLUSIONS

Treatment with RT alone in older women with stage I ER+ disease is decreasing. RT alone is not associated with an increased risk for SBCE. By contrast, NT and ET are both associated with higher SBCE in multivariable analysis with propensity weighting. Further study of the omission of endocrine therapy in this patient population is warranted.

TARGIT-R (Retrospective): 5-Year Follow-Up Evaluation of Intraoperative Radiation Therapy (IORT) for Breast Cancer Performed in North America

BACKGROUND

Intraoperative radiation therapy (IORT) has been investigated for patients with low-risk, early-stage breast cancer. The The North American experience was evaluated by TARGIT-R (retrospective) to provide outcomes for patients treated in "real-world" clinical practice with breast IORT. This analysis presents a 5-year follow-up assessment.

METHODS

TARGIT-R is a multi-institutional retrospective registry of patients who underwent lumpectomy and IORT between the years 2007 and 2013. The primary outcome of the evaluation was ipsilateral breast tumor recurrence (IBTR).

RESULTS

The evaluation included 667 patients with a median follow-up period of 5.1 years. Primary IORT (IORT at the time of lumpectomy) was performed for 72%, delayed IORT (after lumpectomy) for 3%, intended boost for 8%, and unintended boost (primary IORT followed by whole-breast radiation) for 17% of the patients. At 5 years, IBTR was 6.6% for all the patients, with 8% for the primary IORT cohort and 1.7% for the unintended-boost cohort. No recurrences were identified in the delayed IORT or intended-boost cohorts. Noncompliance with endocrine therapy (ET) was associated with higher IBTR risk (hazard ratio [HR], 3.67). Patients treated with primary IORT who were complaint with ET had a 5-year IBTR rate of 3.9%.

CONCLUSION

The local recurrence rates in this series differ slightly from recent results of randomized IORT trials and are notably higher than in previous published studies using whole-breast radiotherapy for similar patients with early-stage breast cancer. Understanding differences in this retrospective series and the prospective trials will be critical to optimizing patient selection and outcomes going forward.

Endocrine therapy and radiotherapy use among older women with hormone receptor-positive, clinically node-negative breast cancer

PURPOSE

To examine patterns of radiotherapy (RT) and endocrine therapy (ET) use, associations between RT omission and ET adherence, and associations among ET and RT use and disease recurrence in older women with early-stage, estrogen receptor-positive breast cancer.

METHODS

Women age 65 and older diagnosed with hormone receptor-positive, clinically node-negative breast cancer between 2005 and 2018 and who did not undergo mastectomy were included. Multinomial logistic regression was used to examine the trends in practice patterns over time and by age. Kaplan-Meier estimates were used to estimate the probability of ET discontinuation. Cox proportional hazards models were constructed to assess associations between recurrence and ET/RT.

RESULTS

Of the 484 enrolled patients, 47.9% patients underwent RT and initiated ET, 27.4% received ET alone, 10.2% received RT alone, and 13.8% patients received neither. Older patients had a higher probability of receiving ET alone or neither ET nor RT (both p < 0.001). The probability of initiating ET was greater among patients who underwent RT than those who omitted RT (p < 0.001). Regardless of RT status (RT or no RT), initiation and continuation of ET may be associated with reduced risk of recurrence.

CONCLUSION

Patients who opt for no adjuvant therapy, or who do not tolerate ET, are at increased risk of disease recurrence if they omit RT. Clinicians should consider the likelihood a patient will adhere to ET prior to recommending omission of RT.

A population-based study of treatment patterns, 10-year recurrence and breast cancer-specific mortality in a cohort of elderly patients with breast cancer

BACKGROUND

We compared disease characteristics, therapies offered and received, and outcomes between older (>75 years) and younger (60-75 years) women with breast cancer (BC) from a regional database in Ontario, Canada.

METHODS

BC surgical cases from 12 hospitals were included. Younger (60-75 years) and older (>75 years) groups were compared. Cox proportional hazards regression with competing risk analyses assessed the relationship between predictor variables, 10-year recurrence and BC-specific mortality.

RESULTS

Our sample comprised 774 women; 33.5% were older. Older women had larger tumours, were more likely to have positive nodes, had more comorbidities, were more likely to undergo mastectomy, had less nodal surgery, were less likely to receive adjuvant therapies, and experienced more recurrences and BC-specific deaths (p < 0.05). Significant predictors of recurrence were older age, higher grade and disease stage, and omission of nodal surgery. Older age, higher grade, and stage were predictors of BC-specific mortality.

CONCLUSION

Older BC patients (>75 years) received less treatment and experienced increased recurrence and BC-specific mortality.

Radiation and/or endocrine therapy? Recurrence and survival outcomes in women over 70 with early breast cancer after breast-conserving surgery

PURPOSE

Women over 70 with early breast cancer treated with breast-conserving surgery are typically offered adjuvant endocrine and radiation therapy. Prior studies have supported the omission of adjuvant radiation in this low-risk population. We sought to compare the effect of adjuvant treatment with endocrine therapy alone, radiation therapy alone or both versus no adjuvant treatment on local control and survival in this population.

METHODS

Data were extracted on 1363 breast cancer patients over the age of 70 treated with a breast-conserving surgery from 2003 until 2018. 460 patients met inclusion criteria of pT1N0, invasive disease with negative margins and not treated with chemotherapy. The primary outcome of this population-based study was local recurrence-free survival at 5 and 10 years.

RESULTS

Patients receiving no adjuvant therapy had worse local recurrence-free, loco-regional recurrence-free and disease-free survival than patients receiving at least one form of adjuvant therapy (p < 0.05). 5-year local recurrence rates were 0.8% in patients receiving both endocrine and radiation therapy, 1.5% in those receiving radiation alone, 4.2% in those receiving endocrine therapy alone and 12% in those receiving no adjuvant therapy.

CONCLUSIONS

This study supports the benefit of some form of adjuvant therapy (radiation alone, endocrine therapy alone or both) in low-risk breast cancer patients over 70. Receiving no adjuvant therapy is associated with poorer outcomes. Many of these patients are candidates for Accelerated Partial Breast Irradiation which can be completed in less than a week. These patients should be offered radiation therapy, endocrine therapy or both.