Combined kyphoplasty and intraoperative radiotherapy (Kypho-IORT) versus external beam radiotherapy (EBRT) for painful vertebral metastases - a randomized phase III study

Background

The spine is the most frequent location of bone metastases. Local treatment aims at palliation of pain and, given the increased likelihood of long-term cancer survival, at local control. Kyphoplasty and intraoperative radiotherapy (Kypho-IORT) provided instantaneous pain relief in 70% of patients at the first day after the intervention and resulted in local control rates of > 93% at 1 year in a recently conducted phase I/II trial. To assess its clinical value, we designed a phase III trial which tests Kypho-IORT against the most widespread standard-of-care, external beam radiotherapy (EBRT), in patients with painful vertebral metastases.

Methods

This phase III study includes patients ≥50 years of age with up to 4 vertebral metastases and a pain score of at least 3/10 points on the visual/numeric analogy scale (VAS). Patients randomized into the experimental arm (A) will undergo Kypho-IORT (Kyphoplasty plus IORT with 8 Gy prescribed to 13 mm depth). Patients randomized into the control arm (B) will receive EBRT with either 30 Gy in 10 fractions or 8 Gy as a single dose. The primary end point is pain reduction defined as at least − 3 points on the VAS compared to baseline at day 1. Assuming that 40% of patients in the Kypho-IORT arm and 5% of patients in the control arm will achieve this reduction and 20% will drop out, a total of 54 patients will have to be included to reach a power of 0.817 with a two-sided alpha of 0.05. Secondary endpoints are evaluation of the percentage of patients with a pain reduction of at least 3 points at 2 and 6 weeks, local tumor control, frequency of re-intervention, secondary fractures/sintering, complication rates, skin toxicity/wound healing, progression-free survival (PFS), overall survival (OS) and quality of life.

Discussion

This trial will generate level 1 evidence on the clinical value of a one-stop procedure which may provide instantaneous pain relief, long-term control and shortened intervals to further adjuvant (systemic) therapies in patients with spinal metastases.

Trial registration

Registered with ClinicalTrials.gov, number: NCT02773966 (Registration date: 05/16/2016).

Phase I/II trial of combined kyphoplasty and intraoperative radiotherapy in spinal metastases

BACKGROUND CONTEXT

Spinal metastases occur in 30%-50% of patients with systemic cancer. The primary goals of palliation are pain control and prevention of local recurrence.

PURPOSE

This study aimed to test the safety and efficacy of a combined modality approach consisting of kyphoplasty and intraoperative radiotherapy (Kypho-IORT).

STUDY DESIGN/SETTING

Kyphoplasty and intraoperative radiotherapy was a prospective, single-center phase I/II trial. Patients were enrolled in a classical 3+3 scheme within the initial phase I, where Kypho-IORT was applied using a needle-shaped 50 kV X-ray source at three radiation dose levels (8 Gy in 8-mm, 8 Gy in 11-mm, and 8 Gy in 13-mm depth). Thereafter, cohort expansion was performed as phase II of the trial. The trial is registered with clinicaltrials.gov, number NCT01280032.

PATIENT SAMPLE

Patients aged 50 years and older with a Karnofsky Performance Status of at least 60% and with one to three painful vertebral metastases confined to the vertebral body were eligible to participate.

OUTCOME MEASURES

The primary end point was safety as per the occurrence of dose-limiting toxicities. The secondary end points were pain reduction, local progression-free survival (L-PFS), and overall survival (OS).

METHODS

Pain was measured using the visual analog scale (VAS) and local control was assessed in serial computed tomography or magnetic resonance imaging scans.

RESULTS

None of the nine patients enrolled in the phase I showed dose-limiting toxicities at any level and thus, 52 patients were subsequently enrolled into a phase II, where Kypho-IORT was performed at various dose levels. The median pain score significantly dropped from 5 preoperatively to 2 at the first postoperative day (p<.001). Of 43 patients who reported a pre-interventional pain level of 3 or more, 30 (69.8%) reported a reduction of ≥3 points on the first postoperative day. A persistent pain reduction beyond the first postoperative day of ≥3 points was seen in 34 (79.1%) patients. The 3, 6, and 12 month L-PFS was excellent with 97.5%, 93.8%, and 93.8%. The 3, 6, and 12 months OS was 76.9%, 64.0%, and 48.4%.

CONCLUSION

Kyphoplasty and intraoperative radiotherapy is safe and immediately provided sustained pain relief with excellent local control rates in patients with painful vertebral metastases.

Keynote Address at the American Society of Breast Surgeons 18th Annual Meeting : Current and Future Application of Intraoperative Radiotherapy (IORT) in the Curative and Palliative Treatment of Breast Cancer

Intraoperative radiotherapy (IORT) is increasingly used worldwide. Breast cancer is the most rapidly growing indication for IORT, approaching 70-80% of cases in most centers. This report reviews the theoretical background and clinical use of IORT for primary and metastasized breast cancer. There are established applications such as tumor bed boost during breast-conserving surgery followed by whole breast radiotherapy or IORT as a form of accelerated partial-breast irradiation (APBI) for selected patients. Novel applications such as IORT for vertebral or brain metastases are presented as well as technological developments, widening the spectrum of potential clinical applications for IORT.

[The management of bone metastasis]

Bone metastasis are the most common cause of pain related to cancer, reducing patients' quality of life, and sometimes threatening their life-expectancy. Their management has to be pluridisciplinary, because of all the therapeutic options and the diversity of bone metastasis locations. The aim of this work is to propose a rational decisional algorithm for the treatment strategy of these secondary locations. Anti-resorbtive drugs with systemic action, surgery, conventional or stereotactic radiation therapy, and new techniques of interventional radiology are options that could be used separately or combined. They have shown benefits on symptomatic treatment, improving quality of life. Their indications vary according to the tumor site (short vs. long bones, carrier vs. non-carrier bones), the symptomatology (pain, neurologic symptoms), and the presence of complications (most of all fractures). The diverse presentations lead us to define this decisional algorithm, to guide the practice, while giving the maximal benefit to each patient according to each metastasis.

First reported treatment of aggressive hemangioma with intraoperative radiation therapy and kyphoplasty (Kypho-IORT)

Aggressive hemangiomas invade the spinal canal and/or paravertebral space and may cause cord compression and neurological symptoms. Radiation therapy was recognized as an effective strategy for the treatment of aggressive hemangiomas. Here, it is reported the first case of aggressive vertebral hemangioma treated by a combination of intraoperative radiation therapy and kyphoplasty (Kypho-IORT).

[Operative therapy of spinal metastases from urological tumors]

The treatment of bone metastases from urological tumors represents a palliative form of therapy, apart from the resection of solitary metastases from renal cell carcinomas. Due to the high incidence of spinal metastases this can result in clinically significant symptoms and possible complications for patients, such as pain, spinal instability and compression of the spinal canal with corresponding neurological deficits. By the use of targeted diagnostics and induction of radiotherapeutic and/or surgical treatment, for the majority of patients an immediate reduction in pain as well as early mobilization and sometimes even regression of existing neurological deficits and therefore an improved quality of life can be achieved.

A novel approach for superficial intraoperative radiotherapy (IORT) using a 50 kV X-ray source: a technical and case report

The use of IORT as a treatment modality for patients with close or positive margins has increased over the past decade. For situations where a flat area (up to 6 cm in diameter) has to be treated intraoperatively, new applicators for superficial treatment with a miniature X‐ray source (INTRABEAM system) were developed. Here we report our evaluation of the dosimetric characteristics of these new applicators and their first clinical use. Each of these flat and surface applicators consists of a radiation protective metal tube and a flattening filter, which converts the spherical dose distribution of the X‐ray source into a flat one. The homogeneity of each dose distribution and depth‐dose measurements were evaluated using film dosimetry in a solid water phantom and a soft X‐ray ionization chamber in a water tank. The first patient was treated with 5 Gy delivered in 5 mm using a 4 cm FLAT applicator over 21 minutes. The flat applicators show the maximum homogeneity, with a uniformity ratio of 1.02‐1.08 in certain depths. In 1 mm depth surface applicators show a uniformity ratio of 1.15‐1.28. They also show a higher dose rate and a steeper dose gradient compared to the flat applicators. The results of this investigation demonstrated that the flat and surface applicators have unique dosimetric characteristics that need to be considered during the treatment planning stages. This work also showed that it is possible to perform a superficial localized IORT which provides new application possibilities for use of the INTRABEAM system.

PACS number: 87.55.ne

Present status and future directions of intraoperative radiotherapy

In this Review, we summarise recent published work on the use of intraoperative radiotherapy to treat common tumour sites in the primary or recurrent setting. Techniques, radiobiology, and the physics of intraoperative radiotherapy are also explored. Disease sites discussed in this Review include head and neck cancer, breast cancer, sarcoma, gastrointestinal cancer, genitourinary cancer, gynaecological cancer, thoracic cancer, and palliative applications.

Radiation protection for an intraoperative X-ray source compared to C-arm fluoroscopy

BACKGROUND

Intraoperative radiotherapy (IORT) using the INTRABEAM(®) system promises a flexible use regarding radiation protection compared to other approaches such as electron treatment or HDR brachytherapy with (192)Ir or (60)Co. In this study we compared dose rate measurements of breast- and Kypho-IORT with C-arm fluoroscopy which is needed to estimate radiation protection areas.

MATERIALS AND METHODS

C-arm fluoroscopy, breast- and Kypho-IORTs were performed using phantoms (silicon breast or bucket of water). Dose rates were measured at the phantom's surface, at 30 cm, 100 cm and 200 cm distance. Those measurements were confirmed during 10 Kypho-IORT and 10 breast-IORT patient treatments.

RESULTS

The measured dose rates were in the same magnitude for all three paradigms and ranges from 20 μSv/h during a simulated breast-IORT at two meter distance up to 64 mSv/h directly at the surface of a simulated Kypho-IORT. Those measurements result in a circle of controlled area (yearly doses >6 mSv) for each paradigm of about 4 m±2 m.

DISCUSSION/CONCLUSIONS

All three paradigms show comparable dose rates which implies that the radiation protection is straight forward and confirms the flexible use of the INTRABEAM(®) system.