The 2016 Assisi Think Tank Meeting on breast cancer: white paper

The 2022 Assisi Think Tank Meeting: White paper on optimising radiation therapy for breast cancer

The present white paper, referring to the 4th Assisi Think Tank Meeting on breast cancer, reviews state-of-the-art data, on-going studies and research proposals. < 70% agreement in an online questionnaire identified the following clinical challenges: 1: Nodal RT in patients who have a) 1-2 positive sentinel nodes without ALND (axillary lymph node dissection); b) cN1 disease transformed into ypN0 by primary systemic therapy and c) 1-3 positive nodes after mastectomy and ALND. 2. The optimal combination of RT and immunotherapy (IT), patient selection, IT-RT timing, and RT optimal dose, fractionation and target volume. Most experts agreed that RT- IT combination does not enhance toxicity. 3: Re-irradiation for local relapse converged on the use of partial breast irradiation after second breast conserving surgery. Hyperthermia aroused support but is not widely available. Further studies are required to finetune best practice, especially given the increasing use of re-irradiation.

Ways to improve breast cancer patients' management and clinical outcome: The 2020 Assisi Think Tank Meeting

We report on the third Assisi Think Tank Meeting (ATTM) on breast cancer, a brainstorming project which involved European radiation and clinical oncologists who were dedicated to breast cancer research and treatment. Held on February 2020, the ATTM aimed at identifying key clinical questions in current clinical practice and "grey" areas requiring research to improve management and outcomes. Before the meeting, three key topics were selected: 1) managing patients with frailty due to either age and/or multi-morbidity; 2) stereotactic radiation therapy and systemic therapy in the management of oligometastatic disease; 3) contralateral breast tumour prevention in BCRA-mutated patients. Clinical practice in these areas was investigated by means of an online questionnaire. In the lapse period between the survey and the meeting, the working groups reviewed data, on-going studies and the clinical challenges which were then discussed in-depth and subjected to intense brainstorming during the meeting; research protocols were also proposed. Methodology, outcome of discussions, conclusions and study proposals are summarized in the present paper. In conclusion, this report presents an in-depth analysis of the state of the art, grey areas and controversies in breast cancer radiation therapy and discusses how to confront them in the absence of evidence-based data to guide clinical decision-making.

The Assisi Think Tank Meeting Breast Large Database for Standardized Data Collection in Breast Cancer-ATTM.BLADE

Background: During the 2016 Assisi Think Tank Meeting (ATTM) on breast cancer, the panel of experts proposed developing a validated system, based on rapid learning health care (RLHC) principles, to standardize inter-center data collection and promote personalized treatments for breast cancer. Material and Methods: The seven-step Breast LArge DatabasE (BLADE) project included data collection, analysis, application, and evaluation on a data-sharing platform. The multidisciplinary team developed a consensus-based ontology of validated variables with over 80% agreement. This English-language ontology constituted a breast cancer library with seven knowledge domains: baseline, primary systemic therapy, surgery, adjuvant systemic therapies, radiation therapy, follow-up, and toxicity. The library was uploaded to the BLADE domain. The safety of data encryption and preservation was tested according to General Data Protection Regulation (GDPR) guidelines on data from 15 clinical charts. The system was validated on 64 patients who had undergone post-mastectomy radiation therapy. In October 2018, the BLADE system was approved by the Ethical Committee of Fondazione Policlinico Gemelli IRCCS, Rome, Italy (Protocol No. 0043996/18). Results: From June 2016 to July 2019, the multidisciplinary team completed the work plan. An ontology of 218 validated variables was uploaded to the BLADE domain. The GDPR safety test confirmed encryption and data preservation (on 5000 random cases). All validation benchmarks were met. Conclusion:BLADE is a support system for follow-up and assessment of breast cancer care. To successfully develop and validate it as the first standardized data collection system, multidisciplinary collaboration was crucial in selecting its ontology and knowledge domains. BLADE is suitable for multi-center uploading of retrospective and prospective clinical data, as it ensures anonymity and data privacy.

OPTimizing Irradiation through Molecular Assessment of Lymph node (OPTIMAL): a randomized open label trial

BACKGROUND

Conservative surgery followed by breast and nodal irradiation is the standard loco-regional early breast cancer (BC) treatment for patients with four or more involved lymph nodes. However, the treatment strategy when fewer nodes are involved remains unclear, especially when lymphadenectomy has not been performed. Sensitive nodal status assessment molecular techniques as the One-Step Nucleic Acid Amplification (OSNA) assay can contribute to the definition and standardization of the treatment strategy. Therefore, the OPTIMAL study aims to demonstrate the feasibility of incidental irradiation of axillary nodes in patients with early-stage BC and limited involvement of the SLN.

METHODS

BC patients who underwent conservative surgery and whose SLN total tumour load assessed with OSNA ranged between 250-15,000 copies/µL will be eligible. Patients will be randomized to receive irradiation on the breast, tumour bed, axillary and supraclavicular lymph node areas (intentional arm) or only on the breast and tumour bed (incidental arm). All areas, including the internal mammary chain, will be contoured. The mean, median, D5% and D95% doses received in all volumes will be calculated. The primary endpoint is the non-inferiority of the incidental irradiation of axillary nodes compared to the intentional irradiation in terms of 5-year disease free survival. Secondary endpoints comprise the comparison of acute and chronic toxicity and loco-regional and distant disease recurrence rates.

DISCUSSION

Standardizing the treatment and diagnosis of BC patients with few nodes affected is crucial due to the lack of consensus. Hence, the quantitative score for the metastatic burden of SLN provided by OSNA can contribute by improving the discrimination of which BC patients with limited nodal involvement can benefit from incidental radiation as an adjuvant treatment strategy.

TRIAL REGISTRATION

ClinicalTrial.gov, NCT02335957; https://clinicaltrials.gov/ct2/show/NCT02335957.

Feasibility and surgical impact of Z0011 trial criteria in a single-Institution practice

The purpose of this study is the evaluation of clinical and surgical impact of the Z0011 trial criteria on the management of breast cancer (BC) patients undergoing breast conservative surgery (BCS) at the European Institute of Oncology (IEO). We studied 1386 patients who underwent BCS and sentinel lymph node biopsy (SLNB) from July 2016 to July 2018. Clinical evaluation, breast ultrasound, mammogram, and cyto/histological examination were performed for all patients at the time of diagnosis. Frozen sections of the sentinel lymph node (SLN) were not performed for any patient. Patients who underwent neo-adjuvant therapy were excluded. To evaluate the results before and after the introduction of Z0011 criteria, a group of 1425 patients with the same characteristics who underwent BCS and SLNB from July 2013 to July 2015 were analyzed. We studied the characteristics of the patients by nodal status, and we observed that T stage, tumor grade, and lymphovascular invasion were statistically related with the highest rate of positive SLN. Of the 1386 patients who underwent surgery after the introduction of the Z011 trial, 1156 patients (83.4%) had negative SLN, 230 patients (16.6%) had positive SLN. Subsequent axillary lymph node dissection (ALND) was performed in only 7 cases (3.0%). Of the 1425 patients operated before the introduction of the Z0011 trial, 216 patients had subsequent ALND (15%). The reduction in the number of ALND performed after the introduction of Z0011 is statistically significant, and this could result in a remarkable reduction of the comorbidities of our patients.

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.

Effects of radiotherapy on plasma energy metabolites in patients with breast cancer who received neoadjuvant chemotherapy

PURPOSE

Neoadjuvant chemotherapy (NACT) is employed in patients with breast cancer (BC) with the aim of reducing tumor burden and improving surgical outcomes. We evaluated the levels of energy metabolites pre- and post-radiotherapy (RT) in breast cancer (BC) patients who previously received NACT and investigated the alterations of these metabolites in relation to the patient achieving a pathologic complete response to NACT.

MATERIALS AND METHODS

We included 37 BC patients who were treated with NACT following surgery and analyzed the concentrations of energy balance-related metabolites using targeted metabolomics before and one month after the end of RT. The control group was composed of 44 healthy women.

RESULTS

Pre-radiotherapy, patients had significant decreases in the plasma levels of 12 metabolites. RT corrected these alterations and the improvement was superior in patients with a pathologic complete response.

CONCLUSION

Our results highlight the importance of metabolism in the outcomes of patients with BC.

The 2017 Assisi Think Tank Meeting on rectal cancer: A positioning paper

BACKGROUND AND PURPOSES

To describe current practice in the management of rectal cancer, to identify uncertainties that usually arise in the multidisciplinary team (MDT)'s discussions ('grey zones') and propose next generation studies which may provide answers to them.

MATERIALS AND METHODS

A questionnaire on the areas of controversy in managing T2, T3 and T4 rectal cancer was drawn up and distributed to the Rectal-Assisi Think Tank Meeting (ATTM) Expert European Board. Less than 70% agreement on a treatment option was indicated as uncertainty and selected as a 'grey zone'. Topics with large disagreement were selected by the task force group for discussion at the Rectal-ATTM.

RESULTS

The controversial clinical issues that had been identified within cT2-cT3-cT4 needed further investigation. The discussions focused on the role of (1) neoadjuvant therapy and organ preservation on cT2-3a low-middle rectal cancer; (2) neoadjuvant therapy in cT3 low rectal cancer without high risk features; (3) total neoadjuvant therapy, radiotherapy boost and the best chemo-radiotherapy schedule in T4 tumors. A description of each area of investigation and trial proposals are reported.

CONCLUSION

The meeting successfully identified 'grey zones' and, in the light of new evidence, proposed clinical trials for treatment of early, intermediate and advanced stage rectal cancer.

ESTRO ACROP consensus guideline for target volume delineation in the setting of postmastectomy radiation therapy after implant-based immediate reconstruction for early stage breast cancer

Immediate breast reconstruction (IBR) rates after mastectomy are increasing. Postmastectomy radiation therapy (PMRT) contouring guidelines for target volumes in the setting of IBR are lacking. Therefore, many patients who have had IBR receive PMRT to target volumes similar to conventional simulator-based whole breast irradiation. The aim of this paper is to describe delineation guidelines for PMRT after implant-based IBR based on a thorough understanding of the surgical procedures, disease stage, patterns of recurrence and radiation techniques. They are based on a consensus endorsed by a global multidisciplinary group of breast cancer experts.

The Assisi Think Tank Meeting Survey of post-mastectomy radiation therapy in ductal carcinoma in situ: Suggestions for routine practice

BACKGROUND

Risk factors for local recurrence after mastectomy in ductal carcinoma in situ (DCIS) emerged as a grey area during the second "Assisi Think Tank Meeting" (ATTM) on Breast Cancer.

AIM

To review practice patterns of post-mastectomy radiation therapy (PMRT) in DCIS, identify risk factors for recurrence and select suitable candidates for PMRT.

METHODS

A questionnaire concerning DCIS management, focusing on PMRT, was distributed online via SurveyMonkey.

RESULTS

142 responses were received from 15 countries. The majority worked in academic institutions, had 5-20 years work-experience and irradiated <5 DCIS patients/year. PMRT was more given if: surgical margins <1 mm, high-grade, multicentricity, young age, tumour size >5 cm, skin- or nipple- sparing mastectomy. Moderate hypofractionation was the most common schedule, except after immediate breast reconstruction (57% conventional fractionation).

CONCLUSIONS

The present survey highlighted risk factors for PMRT administration, which should be further evaluated.

Metabolite normalization with local radiotherapy following breast tumor resection

The aims of this study were to investigate changes in energy balance-associated metabolites associated with radiotherapy in patients with breast cancer, and to relate these changes to the clinical and pathological response-to-treatment. We studied 151 women with breast cancer who received radiotherapy following surgical excision of the tumor. Blood was obtained before and after the irradiation procedure. The control group was composed of 44 healthy women with a similar age distribution to that of the patients. We analyzed the concentrations of metabolites involved in glycolysis, citric acid cycle and amino acid metabolism using targeted quantitative metabolomics. Post-surgery, pre-radiotherapy, patients had major alterations in the serum concentrations of products of glycolysis, citric acid cycle and amino acid metabolism. The strongest alterations were decreases in serine, leucine and isoleucine concentrations. Alterations in metabolite levels were partially, or totally, reversed after irradiation; the concentrations of serine, leucine and isoleucine approached equivalence to those of the control group. Estrogen receptor-positive patients were those with lower concentrations, while triple negative patients had higher concentrations of these amino acids. The normalization of the amino acids serine, leucine and isoleucine concentrations could be clinically relevant because the normalization of these energy-balance metabolites would suggest that residual micro-metastatic disease had been effectively diminished by the radiotherapy, and may be an indicator of its efficacy.

Effect of radiotherapy on activity and concentration of serum paraoxonase-1 in breast cancer patients

Paraoxonase-1 (PON1) is an intra-cellular antioxidant enzyme found also in the circulation associated with high-density lipoproteins. The activity of this enzyme has been shown to be decreased in breast cancer (BC) patients. The aims of our study were to investigate the changes produced by radiotherapy (RT) on activity and concentration of serum PON1 in BC patients, and to evaluate the observed variations in relation to clinical and pathological characteristics of patients and tumors, and the response to treatment. We studied 200 women with BC who were scheduled to receive RT following excision of the tumor. Blood for analyses was obtained before and after the irradiation procedure. The control group was composed of 200 healthy women. Relative to control, BC patients had significantly lower serum PON1 activities pre-RT, while PON1 concentrations were at similar levels. RT was associated with a significant increase in serum PON1 activities and concentrations. We observed significant differences in serum PON1 concentrations post-RT between patients with luminal A or luminal B tumors. Serum PON1 concentration post-RT was markedly lower in BC patients with metastases. We conclude that benefit from RT accrues to the BC patients not only through its direct effect on cancer cells but also indirectly by improving the organism’s anti-oxidant defense mechanisms. In addition, our preliminary evidence suggests that the measurement of serum PON1 concentration post-RT could be an efficient prognostic biomarker, and may be used as an index of the efficacy of the RT.

Partial breast irradiation with interstitial multi-catheter high-dose-rate brachytherapy. Long-term results of a phase II prospective study

PURPOSE

We report the long-term results of phase II prospective study with accelerated partial breast irradiation (APBI) using interstitial multi-catheter high-dose-rate brachytherapy.

METHODS

240 patients received APBI (4Gy, twice daily; total dose 32Gy).

RESULTS

Median follow-up was 96months. Recurrences in the treated breast developed in 8 patients (3.3%) at a median of 73months after APBI. The 5- and 10-year cumulative incidences were respectively, 1.8% (95%CI: 0.6-4.3) and 6.6% (95%CI: 2.7-12.9). Regional recurrences developed in 5 patients (2%) at a median of 28months and distant metastases in 8 (3.3%) at a median of 32.5months. Breast cancer specific mortality occurred in 6 patients (2.5%) at a median of 60months. Acute toxicity developed in 71 (29.6%) patients (G1 in 60 and G2 in 11). Almost all were skin toxicity and hematomas. Late toxicity was observed in 90 patients (37.5%), G1 in 97 cases and G2 in 11. Some patients presented with more than one type of toxicity. Teleangectasia and fibrosis were the most common (48 and 44 cases respectively), followed by fat necrosis (in 18 patients) Tamoxifen emerged as the only risk factor for breast fibrosis (p=0.007). Cosmetic results were judged by the physicians as excellent in 174 (83.7%) patients, good in 25 (12%) fair in 8 (3.8%) and poor in 1 (0.5%); 174 patients (83.7%) judged outcomes as excellent, 26 (12.4%) as good, 7 (3.4%) as fair and 1 (0.5%) as poor. Physician/patient agreement was good (weighted k-value 0.72).

CONCLUSIONS

APBI with interstitial multi-catheter brachytherapy was associated with good outcomes, low relapse and toxicity rates. Few events during this long-term follow-up preclude identifying specific features of patients at risk of relapse and illustrate the need for a large data-base.