Standard Treatment +/- SBRT in Solid Tumors Patients With Between 1 and 5 Bone-only Metastases

Bone Metastases, Metastatic Breast Cancer, Metastatic Lung Cancer, Metastatic Prostate Cancer

Bone-only metastases, solid tumors, SBRT

Bone metastases occur frequently during the evolution of solid tumors, either isolated or associated with visceral metastases. The incidence varies between 20 and 85% depending on the primary cancer. Breast, prostate, and lung cancers are responsible for 70% of bone metastases. Cancer with bone metastases compared to other metastatic sites is considered as associated with a better prognosis, particularly for breast and prostate cancer. Bone metastases may be present at diagnosis (synchronous metastasis) or appear at a later time (metachronous metastasis). The concept of oligometastases was proposed in patients with about 3 up to 5 metastases (without restriction on the primary site) and associated with an intermediate prognosis. It was hypothesized that local treatment with curative intent, aiming at the few metastatic sites, would yield long-term survival probabilities, along with systemic therapies. Long-term survivors have been reported after curative-intent treatment of metastasis in sarcoma and colorectal cancers with liver or lung metastasis. We chose to focus on bone metastasis because of their high incidence, their impact on the patient's quality of life and autonomy, and their accessibility to potentially curative radiotherapy. The systemic treatment of metastatic cancer includes hormonal therapy (breast and prostate cancer), biologically-targeted drugs and chemotherapy (all cancers). Stereotactic radiotherapy is a highly accurate technique was initially developed for performing the radiosurgery of brain tumors in patients for whom it was deemed be too difficult to proceed to classical excision surgery. In this process, a high total dose of radiation is delivered in a single fraction to a well-defined intra-cranial target. The concept of radiotherapy in stereotactic conditions was extended to one or several fractions delivered to small volumes primary tumors/ metastases in extra-cranial sites (Stereotactic Body RadioTherapy \[SBRT\]). At present, high control rates have been achieved for lung metastases. Similarly, very high local control rates have been reported in bone metastases after stereotactic radiotherapy. In this protocol, our purpose is to demonstrate, via a randomized phase III trial, that high doses of radiotherapy, delivered in stereotactic conditions to the bone metastases (between 1 and 5 metastases) in solid tumor patients is able to improve the survival without progression.

France