Is there a role for locoregional treatment of the primary tumor in de novo metastatic breast cancer in the era of tailored therapies?: Evidences, unresolved questions and a practical algorithm

[Updated surgical indications and quality and safety indicators in the management of infiltrative breast carcinoma]

OBJECTIVES

Breast surgery is the cornerstone of breast cancer treatment. Its indications and procedures are constantly evolving. To update best practices, four questions were submitted to the Senology Commission (SC) of the Collège national des gynécologues et obstétriciens français (CNGOF), covering the indications and modalities of tumor surgery: (1) initially, (2) following neoadjuvant systemic treatment, (3) in case of local recurrence, and (4) the quality and safety of care indicators applicable to this surgery.

METHODS

The CNGOF SC essentially based its responses on the clinical practice recommendations and guidelines of the French Cancer Institute concerning invasive carcinomas of the breast. Exclusion criteria were carcinoma in situ, sarcoma and axillary surgery.

RESULTS

To define the type of breast surgery, knowledge of four parameters is essential: the patient's level of risk, the presence of metastases, the size of the breast tumor and its focality (assessed by the clinical/mammography/ultrasound tripod). (1) In the case of initial management, the 6 indications for mastectomy are patient choice (particularly in case of high risk), contraindication to radiotherapy, inflammatory cancer (T4d), surgery with positive margins (after several surgical intervention), surgery that cannot be performed as a monobloc in the case of tumors with multiple foci, and poor expected aesthetic results. All other situations should be treated conservatively. (2) The same criteria apply after neoadjuvant systemic treatment, with conservative treatment still possible whatever the size (excluding carcinomatous mastitis) and focality of the initial tumor. (3) In case of local recurrence, total mastectomy is the reference treatment, with a second conservative treatment reserved for patients with no risk factors for a second recurrence, and no poor prognostic factors, after validation in a multidisciplinary meeting. (4) Four quality and safety indicators apply to breast surgery: it must be performed after obtaining a histological diagnosis, within less than 6 weeks of mammography, in a single surgery in over 80% of cases, and followed by local radiotherapy in the case of conservative treatment.

CONCLUSION

The indications and modalities of breast surgery are evolving rapidly. To improve aesthetic results, oncoplastic techniques, immediate breast reconstruction, and preservation of the skin or nipple-areolar complex need to be further developed and evaluated in the long-term. These developments must necessarily be accompanied in France by a training policy for breast surgeons.

Breast surgery for patients with de novo metastatic breast cancer: A meta-analysis of randomized controlled trials

The role of breast surgery in the treatment of patients with de novo metastatic breast cancer(dnMBC) remains controversial, with conflicting trial results. We did a meta-analysis to comprehensively investigate and assess whether breast surgery is associated with survival and quality of life outcomes in patients with dnMBC.We systematically searched PubMed, Embase, Google Scholar, Scopus, and Web of Science, from database inception to March 30, 2022, for randomized controlled trials(RCTs) that compared breast surgery or locoregional therapy with non-surgical treatment based on systemic therapy for managing dnMBC.We also reviewed abstracts and presentations from major conference proceedings. We excluded non-randomised trials and considered only papers published in English. The primary outcomes were overall survival(OS),locoregional progression-free survival(LPFS), distant progression-free survival(DPFS), and quality of life(QoL). The quality of RCTs was appraised with the Cochrane Collaboration risk of bias tool. Random-effects model or fixed effects model were used to calculate the effect sizes of included RCTs.Quality of evidence was assessed with GRADE criteria. Data analysis was performed with STATA 17.0. A total of 1018 women from seven randomized clinical trials were included in the analysis. Pooled analyses revealed that compared with systemic therapy, breast surgery was not associated with beneficial outcomes in OS(hazard ratio [HR],0.87; 95%CI,0.68 to 1.11; I2 = 53.08 %; p = 0.265),DPFS(HR,1.20; 95%CI,0.94 to 1.54; I2 = 86.45 %; p = 0.136), or QoL-global health status (standardized mean difference[SMD],0.08; 95%CI,-0.15 to 0.32; I2 = 79.45 %; p = 0.478) and QoL-mental-physical functionality(SMD,-0.19; 95%CI,-0.50 to 0.13; I2 = 0.00 %; p = 0.255), but was associated with a benefit in LPFS(HR,0.27; 95%CI,0.19 to 0.38; I2 = 84.16 %; p < 0.001). These findings were consistent in subgroup analyses of the timing of surgery, site and number of metastases and tumor molecular subtype. The evidence grade was moderate because of the substantial heterogeneity among studies. Based on the RCTs evidence, we found that breast surgery may benefit locoregional control but does not prolong OS and improve QoL in patients with dnMBC. The Prospero registration number: CRD42020206460.

Impact of high dose radiotherapy for breast tumor in locoregionally uncontrolled stage IV breast cancer: a need for a risk-stratified approach

AIM

Patients with locoregionally uncontrolled breast tumors are frequently referred for breast palliative radiotherapy (PRT) to mitigate symptoms. We analyzed the outcomes following breast PRT to optimize PRT according to risk groups.

METHODS

We reviewed 133 patients who underwent breast PRT. A median total dose of 45 Gy was prescribed with an equivalent dose in 2 Gy fractions (EQD2, α/β = 3.5) of 53 Gy. The Cox proportional hazards model was used to analyze the prognostic factors of local control (LC).

RESULTS

Most (90.2%) had polymetastatic disease (> 5 lesions), and 48.9% had bone metastasis. With a median follow-up of 17.2 months, the 2-year LC and overall survival (OS) rates were 49.4%, and 48.3%, respectively. Multivariable analyses demonstrated progressive or mixed responses outside the breast and > 2 lines of previous therapy as adverse features for clinical outcomes. Group 1 (0 risk factors) showed favorable 2-year LC and OS of 63.9%, and 72.8%, respectively, whereas group 3 (2 risk factors) showed the worst outcomes of 0%, and 6.8%, respectively. Breast PRT with EQD2 ≥ 63 Gy showed a significant benefit in LC for group 1 and marginal benefit (p = 0.055) for group 2, but no improvement for group 3 (p = 0.300).

CONCLUSION

Breast PRT showed favorable LC outcomes in patients with stable disease outside the breast and treated with ≤ 2 lines of systemic treatment. Our findings warrant future clinical trials investigating the role of higher than palliative dose and early intervention of PRT in stage IV patients.

HR+/HER2- de novo metastatic breast cancer: a true peculiar entity?

De novo metastatic breast cancer (dnMBC) accounts for ~6-10% of all breast cancers and for ~30% of MBC with increasing incidence over time. Hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR⁺/HER2^-) tumours are the most frequent subtype with a similar incidence to that observed amongst recurrent MBC (rMBC). Higher frequency of PI3KCA and ARID2 mutations and a lower frequency of ESR1 mutations and of genes involved in DNA damage, as compared with rMBC, have been reported in HR⁺/HER2^- dnMBC; however, these are not correlating with prognosis, whilst tumour mutational burden is inversely correlated with outcome. Bone represents the most frequent metastatic site, being the single site in up to 60% of patients with dnMBC. HR⁺/HER2^- dnMBC has been generally reported to have better outcomes than rMBC, with a median overall survival ranging from 26 months to nearly 5 years in patients with favourable features such as age <40 years and bone-only disease, but not when compared with patients with late recurring disease (≥2-5 years). Analyses of the de novo cohorts within randomized clinical trials and large real-world series report a better outcome after treatment with CDK4/6 inhibitors and endocrine agents as compared to rMBC. Despite the limitations of retrospective studies and controversial results of the randomized trials, locoregional treatment of the primary tumour after response to systemic therapy appears to confer a survival benefit, particularly in patients with favourable prognostic factors. Altogether genomic, biological and clinical findings highlight HR⁺/HER2^- dnMBC as a peculiar entity as compared with rMBC and deserve a dedicated treatment algorithm. This article is part of the Tackling clinical complexity in breast cancer Special Issue: https://www.drugsincontext.com/special_issues/tackling-clinical-complexity-in-breast-cancer/.

Primary-Site Local Therapy for Patients with De Novo Metastatic Breast Cancer: An Educational Review

BACKGROUND

Until 2001, the paradigm guiding the management of women with de novo metastatic breast cancer (dnMBC) stipulated that primary-site locoregional therapy (PSLT) did not alter the course of metastatic disease and was necessary only for palliation of symptoms. Since 2002, retrospective data have begun questioning this paradigm. However, selection biases driving an observed survival advantage associated with PSLT in dnMBC were quickly recognized and led to several randomized clinical trials (RCTs) addressing this question.

METHODS AND RESULTS

Four published RCTs have since tested the value of PSLT added to systemic therapy (ST) or not, with overall survival (OS) as the primary end point. The results of three published trials show no OS benefit for the addition of PSLT: Indian Tata Memorial, U.S./Canada E2108, and Austrian POSYTIVE (although POSYTIVE did not reach full accrual). The fourth RCT (Turkey, MF07-01) shows an OS benefit for PSLT at 5 years (42 % vs 24 % in the ST arm; hazard ratio [HR], 0.66; 95 % confidence interval [CI], 0.49-0.88). However, the 5-year survival in the PSLT arm of MF07-01 is similar to that in both arms of E2108, suggesting that the worse survival in the ST arm of MF07-01 is a result of biologically worse disease (from imbalanced randomization). Locoregional control was improved by PSLT in all trials, but without improvement in quality of life.

CONCLUSIONS

The current evidence fails to refute the 20th century paradigm guiding management of de novo metastatic breast cancer. Discussion continues regarding the survival value of PSLT for patients with bone-only disease or oligometastases, but unbiased evidence is lacking.

Combination of Olaparib with radiotherapy for triple-negative breast cancers: One-year toxicity report of the RADIOPARP Phase I trial

Triple-negative breast cancer (TNBC) cells are sensitive to PARP1 inhibitors in vitro. The combination of Olaparib and radiotherapy for TNBC is currently evaluated in the Phase I RADIOPARP trial. RADIOPARP is a monocentric prospective open-label Phase I dose-escalation trial evaluating the combination of breast radiotherapy and Olaparib in TNBC patients with inflammatory, locoregionally advanced or metastatic disease, or with residual disease after neoadjuvant chemotherapy. Olaparib was orally given at increasing dose levels (50, 100, 150 or 200 mg twice a day [BID]); radiotherapy consisted of 50 Gy to the breast or chest wall with or without lymph node irradiation. Twenty-four TNBC patients were enrolled between September 2017 and November 2019. Olaparib was escalated to 200 mg BID without dose-limiting toxicities. At 1-year follow-up, no treatment-related grade ≥3 toxicity was observed. One patient (4.2%) had persistent grade 2 adverse events (breast pain, fibrosis and deformity). There was no cardiac, pulmonary or digestive toxicity related to treatment. The 1-year follow-up report of the RADIOPARP Phase I trial, evaluating Olaparib associated with breast radiotherapy in TNBC patients, consequently demonstrated an excellent toxicity profile of this combination with few low-grade adverse events.

Effect of Postoperative Radiotherapy after Primary Tumor Resection in De Novo Stage IV Breast Cancer: A Multicenter Retrospective Study (KROG 19-02)

Purpose

To investigate the impact of postoperative radiotherapy (PORT) in de novo metastatic breast cancer (dnMBC) patients undergoing planned primary tumor resection (PTR) and to identify the subgroup of patients who would most benefit from PORT.

Materials and Methods

This study enrolled 426 patients with dnMBC administered PTR alone or with PORT. The primary and secondary outcomes were overall and progression-free survival (OS and PFS), respectively.

Results

The median follow-up time was 53.7 months (range, 3.1-194.4). The 5-year OS and PFS rates were 73.2% and 32.0%, respectively. For OS, clinical T3/4 stage, triple-negative breast cancer (TNBC), postoperative chemotherapy alone were significantly poor prognostic factors, and administration of PORT failed to show its significance. Regarding PFS, PORT was a favorable prognostic factor (hazard ratio [HR]: 0.64, 95% confidence interval [CI]: 0.50-0.82, p <0.001), in addition to T1/2 stage, ≤5 metastases, and non-TNBC. According to the multivariate analyses of OS in the PORT group, we divided the patients into three groups [Group 1, T1/2 and non-TNBC (n=193); Group 2, T3/4 and non-TNBC (n=171); and Group 3, TNBC (n=49)], and evaluated the effect of PORT. Although PORT had no significance for OS in all subgroups, it was a significant factor for good prognosis regardingPFS in Group 1 and 2, not in Group 3.

Conclusion

PORT was associated with a significantly better PFS in patients with dnMBC who underwent PTR. Patients with clinical T1/2 stage and non-TNBC benefited most from PORT, while those with TNBC showed little benefit.