Can Interrogation of Tumour Characteristics Lead us to Safely Omit Adjuvant Radiotherapy in Patients with Early Breast Cancer?

Personalization in Modern Radiation Oncology: Methods, Results and Pitfalls. Personalized Interventions and Breast Cancer

Breast cancer, the most frequent malignancy in women worldwide, is a heterogeneous group of diseases, characterized by distinct molecular aberrations. In precision medicine, radiation oncology for breast cancer aims at tailoring treatment according to tumor biology and each patient’s clinical features and genetics. Although systemic therapies are personalized according to molecular sub-type [i.e. endocrine therapy for receptor-positive disease and anti-human epidermal growth factor receptor 2 (HER2) therapy for HER2-positive disease] and multi-gene assays, personalized radiation therapy has yet to be adopted in the clinical setting. Currently, attempts are being made to identify prognostic and/or predictive factors, biomarkers, signatures that could lead to personalized treatment in order to select appropriate patients who might, or might not, benefit from radiation therapy or whose radiation therapy might be escalated or de-escalated in dosages and volumes. This overview focuses on what has been achieved to date in personalized post-operative radiation therapy and individual patient radiosensitivity assessments by means of tumor sub-types and genetics.

When the World Throws You a Curve Ball: Lessons Learned in Breast Cancer Management

In the care of patients with operable breast cancer, there has been a shift toward increasing use of neoadjuvant therapy. There are benefits to neoadjuvant therapy, such as monitoring for response, as well as an increased rate of breast conservation and reduction of potential morbidity associated with breast surgery, including axillary management. Among patients with highly proliferative tumors, such as HER2-positive or triple-negative breast cancer, those with residual disease are at higher risk of recurrence, which informs the recommended systemic therapy in the adjuvant setting. For instance, in patients with residual disease after neoadjuvant chemotherapy and HER2-targeted therapy, there is a role for adjuvant trastuzumab emtansine for those with residual disease at the time of surgery. The same holds true regarding the role of adjuvant capecitabine in patients with residual disease after neoadjuvant chemotherapy. With the added complexities of treating patients in the era of the COVID-19 outbreak, additional considerations are critical, including initiation of surgery within an appropriate time from completion of neoadjuvant therapy. National consensus guidelines on time to surgery must be developed to improve measurement and comparison across systems. In addition, there is emerging radiation treatment management research addressing a number of factors, including hypofractionation, role of proton beam therapy, safe omission of radiotherapy, and preoperative radiotherapy with or without drug combination. In this article, the multidisciplinary approach of treating patients with operable breast cancer is highlighted, with updates and future considerations described.

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.

The 2018 assisi think tank meeting on breast cancer: International expert panel white paper

We report on the second Assisi Think Tank Meeting (ATTM) on breast cancer which was held under the auspices of the European Society for RadioTherapy & Oncology (ESTRO). In discussing in-depth current evidence and practice it was designed to identify grey areas in diverse forms of the disease. It aimed at addressing uncertainties and proposing future trials to improve patient care. Before the meeting, three key topics were selected: 1) primary systemic therapy, mastectomy, breast reconstruction and post-mastectomy radiation therapy, 2) therapeutic options in ductal carcinoma in situ, and 3) therapy de-escalation in early stage breast cancer. Clinical practice in these areas was investigated by means of an online questionnaire. The time lapse period between the survey and the meeting was used to review the literature and on-going clinical trials. At the ATTM both were discussed in depth and research protocols were proposed.

Individualised target volume selection and dose prescription after conservative surgery, mastectomy and reconstruction

Progress in radiotherapy (RT) for early breast cancer, driven by advances in radiobiology and radiation techniques is enabling individualised target volume and dose-fractionation according to recurrence risk. Conventionally fractionated WBI (CF-WBI) has been justified on the basis that it spares dose-limiting late-responding normal tissues more than breast cancer. However, randomised clinical trials (RCTs) testing hypofractionated WBI (HF-WBI) showed equivalent tumour control, improved acute toxicity and similar late toxicity between selected HF-WBI schedules and CF-WBI. RCTs showed that tumour bed boost (TBB) after WBI improved local control but increased breast fibrosis compared to no TBB. RCT comparing sequential TBB and simultaneous integrated TBB using dose intensity modulation showed similar toxicity. Partial breast irradiation (PBI) limits target volume to the tumour bed, which permits safe treatment acceleration. RCTs showed that PBI resulted in low local relapse rates but in some RCTs, higher rates of late toxicity and adverse cosmetic outcome than WBI. Given heterogeneity of PBI techniques, target volumes and dose-fractionation schedules used in RCTs, interpretation of results to distinguish whether outcome variations are caused by target volume or dose-fractionation effect is challenging. RCTs demonstrating efficacy of post-mastectomy RT (PMRT) included the chest wall and regional nodes but did not distinguish relative contributions of nodal target sub-volumes. In patients with smaller axillary tumour burden, IMC irradiation is controversial. RCTs were not powered for comparison between CF-PMRT and HF-PMRT. No increase in arm or shoulder dysfunction with HF-PMRT was observed. No RCT data exist on HF-PMRT in patients with breast reconstruction.

The 21-gene recurrence score and effects of adjuvant radiotherapy after breast conserving surgery in early-stage breast cancer

Aim: To investigate the associations with the 21-gene recurrence score (RS) and effect of adjuvant radiotherapy (RT) for early-stage breast cancer after breast conserving surgery. Methods: We included 13,246 patients in the SEER database. Results: Patients with a higher RS were independently related to nonreceipt of RT (p < 0.001). In both the traditional and Trial Assigning Individualized Options for Treatment (TAILORx) RS cut-offs, the receipt of RT was not related to better breast cancer-specific survival in low- and high-risk RS groups, but was independently related to better breast cancer-specific survival in intermediate-risk RS group before (p = 0.029) and after (p = 0.001) propensity score matching. Conclusion: The 21-gene-RS may impact the decision-making of adjuvant RT in early-stage breast cancer after breast conserving surgery. The survival benefit of adjuvant RT may be limited to patients with intermediate-risk RS.

Practice-changing radiation therapy trials for the treatment of cancer: where are we 150 years after the birth of Marie Curie?

As we mark 150 years since the birth of Marie Curie, we reflect on the global advances made in radiation oncology and the current status of radiation therapy (RT) research. Large-scale international RT clinical trials have been fundamental in driving evidence-based change and have served to improve cancer management and to reduce side effects. Radiation therapy trials have also improved practice by increasing quality assurance and consistency in treatment protocols across multiple centres. This review summarises some of the key RT practice-changing clinical trials over the last two decades, in four common cancer sites for which RT is a crucial component of curative treatment: breast, lung, urological and lower gastro-intestinal cancer. We highlight the global inequality in access to RT, and the work of international organisations, such as the International Atomic Energy Agency (IAEA), the European SocieTy for Radiotherapy and Oncology (ESTRO), and the United Kingdom National Cancer Research Institute Clinical and Translational Radiotherapy Research Working Group (CTRad), that aim to improve access to RT and facilitate radiation research. We discuss some emerging RT technologies including proton beam therapy and magnetic resonance linear accelerators and predict likely future directions in clinical RT research.

De-escalation of breast radiotherapy after conserving surgery in low-risk early breast cancer patients

The reduction in the burden related to treatment is becoming more and more important in modern oncology. Radiation therapy is a mainstay option in the postoperative setting for early breast cancer patients after breast-conserving surgery. Nowadays, different options are available to de-escalate radiotherapy in this scenario such as the use of hypofractionated whole-breast radiation, the selective delivery of the boost dose to the lumpectomy cavity, the introduction of accelerated partial breast irradiation and the omission of treatment in appropriately selected patients with low-risk features. We herein provide a review article on this topic.