Indication and perspectives of radiation therapy in the setting of de-novo metastatic prostate cancer.

Prostate cancer is the most common cancer and the third leading cause of cancer mortality in men. Each year, approximately 10% of prostate cancers are diagnosed metastatic at initial presentation. The standard treatment option for de-novo metastatic prostate cancer is androgen deprivation therapy with novel hormonal agent or with chemotherapy. Recently, PEACE-1 trial highlighted the benefit of triplet therapy resulting in the combination of androgen deprivation therapy combined with docetaxel and abiraterone. Radiotherapy can be proposed in a curative intent or to treat local symptomatic disease. Nowadays, radiotherapy of the primary disease is only recommended for de novo low-burden/low-volume metastatic prostate cancer, as defined in the CHAARTED criteria. However, studies on stereotactic radiotherapy on oligometastases have shown that this therapeutic approach is feasible and well tolerated. Prospective research currently focuses on the benefit of intensification by combining treatment of the metastatic sites and the primary all together. The contribution of metabolic imaging to better define the target volumes and specify the oligometastatic character allows a better selection of patients. This article aims to define indications of radiotherapy and perspectives of this therapeutic option for de-novo metastatic prostate cancer.

[Targeted systemic treatments and locoregional radiotherapy for breast cancer: Can we expect a benefit from the potentiation of local treatment?] / Traitements systémiques ciblés et radiothérapie locorégionale pour les cancers du sein : peut-on espérer un bénéfice de la potentialisation du traitement local ?

Breast cancer is the first most common cancer worldwide, and radiation therapy has a major role to play in locoregional adjuvant treatment. In recent years, we have seen the emergence of adjuvant targeted systemic therapies improving the prognosis of patients at high risk of recurrence. Practices concerning combinations of targeted therapies and locoregional radiation therapy for non-metastatic breast cancers often remain heterogeneous due to the low level of evidence and lack of validated recommendations. This literature review covers immunotherapy, CDK 4/6 inhibitors, PARP inhibitors and anti-Her2 therapies. Combining these targeted systemic therapies with radiation therapy could potentiate local treatment. The optimal therapeutic sequence and fractionation for maximum synergistic effect remain to be defined. However, while efficacy may be enhanced, radiosensitization of healthy tissue may also lead to increased toxicity. It appears possible to continue immunotherapy, trastuzumab, pertuzumab, TDM-1 or lapatinib during locoregional breast and lymph node irradiation. PARP inhibitors and CDK4/6 inhibitors are still to be suspended, due to the lack of data in the adjuvant setting and their short half-life, which does not necessitate prolonged discontinuation. As with the new antibody-drug conjugates, prospective data are needed in conjunction with adjuvant radiation therapy.

Stereotactic body radiotherapy for mediastinal lymph node with CyberKnife®: Efficacy and toxicity.

PUPRPOSE: Stereotactic body radiotherapy is more and more used for treatment of oligometastatic mediastinal lymph nodes. The objective of this single-centre study was to evaluate its efficacy in patients with either a locoregional recurrence of a pulmonary or oesophageal cancer or with distant metastases of extrathoracic tumours. PATIENTS AND METHODS: Patients with oligometastatic mediastinal lymph nodes treated with CyberKnife from June 2010 to September 2020 were screened. The primary endpoint was to assess local progression free survival and induced toxicity. Secondary endpoints were overall survival and progression free survival. The delay before introduction of systemic treatment in the subgroup of patients who did not receive systemic therapy for previous progression was also evaluated. RESULTS: Fifty patients were included: 15 with a locoregional progression of a thoracic primary tumour (87% pulmonary) and 35 with mediastinal metastasis of especially renal tumour (29%). Median follow-up was 27 months (6-110 months). Local progression free survival at 6, 12 and 18 months was respectively 94, 88 and 72%. The rate of local progression was significantly lower in patients who received 36Gy in six fractions (66% of the cohort) versus other treatment schemes. Two grade 1 acute oesophagitis and one late grade 2 pulmonary fibrosis were described. Overall survival at 12, 18 and 24 months was respectively 94, 85 and 82%. Median progression free survival was 13 months. Twenty-one patients were treated by stereotactic body irradiation alone without previous history of systemic treatment. Among this subgroup, 11 patients (52%) received a systemic treatment following stereotactic body radiotherapy with a median introduction time of 17 months (5-52 months) and 24% did not progress. CONCLUSION: Stereotactic body irradiation as treatment of oligometastatic mediastinal lymph nodes is a well-tolerated targeted irradiation that leads to a high control rate and delay the introduction of systemic therapy in selected patients.