Effective local control of vertebral metastases by simultaneous integrated boost radiotherapy: preliminary results

Dose-escalated radiotherapy with simultaneous integrated boost for bone metastases in selected patients with assumed favourable prognosis

BACKGROUND

Stereotactic body radiotherapy (SBRT) concepts for dose escalation are increasingly used for bone metastases in patients with oligometastatic or oligoprogressive disease. For metastases that are not suitable for SBRT-regimens, a treatment with 30/40 Gy with simultaneous integrated boost (SIB) in 10 fractions represents a possible regimen. The aim of this study was to investigate the feasibility of this concept and the acute and subacute toxicities.

PATIENTS AND METHODS

Clinical records for dose-escalated radiotherapy of all consecutive patients treated with this regimen were evaluated retrospectively (24 patients with 28 target volumes for oncologic outcomes and 25 patients with 29 target volumes for treatment feasibility and dose parameters analysis). Analysis of radiotherapy plans included size of target volumes and dosimetric parameter for target volumes and organs at risk (OAR). Acute and subacute toxicities were evaluated according to Common Terminology Criteria for Adverse Events (CTCAE) V4.0.

RESULTS

The most common localization was the spine (71.4%). The most common histology was prostate cancer (45.8%). Oligometastatic or oligoprogressive disease was the indication for dose-escalated radiotherapy in 19/24 patients (79.2%). Treatment was feasible with all patients completing radiotherapy. Acute toxicity grade 1 was documented in 36.0% of the patients. During follow up, one patient underwent surgery due to bone instability. The 1-year local control and patient-related progression-free survival (PFS) were 90.0 ± 6.7% and 33.3 ± 11.6%, respectively.

CONCLUSIONS

Dose-escalated hypofractionated radiotherapy with simultaneous integrated boost for bone metastases resulted in good local control with limited acute toxicities. Only one patient required surgical intervention. The regimen represents an alternative to SBRT in selected patients.

Palliative radiotherapy of bone metastases in octogenarians: How do the oldest olds respond? Results from a tertiary cancer center with 288 treated patients

BACKGROUND

Accompanied by the demographic change, the number of octogenarian cancer patients with bone metastases will increase in the future. Palliative radiotherapy constitutes an effective analgesic treatment; however, as pain perception and bone metabolism change with increasing age, the analgesic efficacy of radiotherapy may be altered in elderly patients. We therefore investigated the treatment outcomes of palliative radiotherapy for bone metastases in octogenarians.

METHODS

Patients between 80 and 89 years undergoing radiotherapy for bone metastases between 2009 and 2019 at a tertiary cancer center were analyzed for patterns-of-care, pain response and overall survival (OS). Logistic regression analyses were carried out to examine parameters associated with pain response, and Cox analyses were conducted to reveal prognostic parameters for OS.

RESULTS

A total of 288 patients with 516 irradiated lesions were included in the analysis. The majority (n = 249, 86%) completed all courses of radiotherapy. Radiotherapy led to pain reduction in 176 patients (61%) at the end of treatment. Complete pain relief at the first follow-up was achieved in 84 patients (29%). Bisphosphonate administration was significantly associated with higher rates of pain response at the first follow-up (p < 0.05). Median OS amounted to 9 months, and 1-year, 2-year and 3-year OS were 43%, 28% and 17%. In the multivariate analysis, ECOG (p < 0.001), Mizumoto score (p < 0.01) and Spinal Instability Neoplastic Score (SINS) (p < 0.001) were independent prognosticators for OS.

CONCLUSION

Palliative radiotherapy for bone metastases constitutes a feasible and effective analgesic treatment in octogenarian patients. ECOG, Mizumoto score and SINS are prognosic variables for survival and may aid treatment decisions regarding radiotherapy fractionation in this patient group. Single-fraction radiotherapy with 8 Gy should be applied for patients with uncomplicated bone metastases and poor prognosis. Prospective trials focusing on quality of life of these very old cancer patients with bone metastases are warranted to reveal the optimal radiotherapeutic management for this vulnerable population.

Personalized Automation of Treatment Planning for Linac-Based Stereotactic Body Radiotherapy of Spine Cancer

Purpose/Objective(s)

Stereotactic ablative body radiotherapy (SBRT) for vertebral metastases is a challenging treatment process. Planning automation has recently reported the potential to improve plan quality and increase planning efficiency. We performed a dosimetric evaluation of the new Personalized engine implemented in Pinnacle3 for full planning automation of SBRT spine treatments in terms of plan quality, treatment efficiency, and delivery accuracy.

Materials/Methods

The Pinnacle3 treatment planning system was used to reoptimize six patients with spinal metastases, employing two separate automated engines. These two automated engines, the existing Autoplanning and the new Personalized, are both template-based algorithms that employ a wishlist to construct planning goals and an iterative technique to replicate the planning procedure performed by skilled planners. The boost tumor volume (BTV) was defined as the macroscopically visible lesion on RM examination, and the planning target volume (PTV) corresponds with the entire vertebra. Dose was prescribed according to simultaneous integrated boost strategy with BTV and PTV irradiated simultaneously over 3 fractions with a dose of 30 and 21 Gy, respectively. Dose-volume histogram (DVH) metrics and conformance indices were used to compare clinically accepted manual plans (MP) with automated plans developed using both Autoplanning (AP) and Personalized engines (Pers). All plans were evaluated for planning efficiency and dose delivery accuracy.

Results

For similar spinal cord sparing, automated plans reported a significant improvement of target coverage and dose conformity. On average, Pers plans increased near-minimal dose D98% by 10.4% and 8.9% and target coverage D95% by 8.0% and by 4.6% for BTV and PTV, respectively. Automated plans provided significantly superior dose conformity and dose contrast by 37%–47% and by 4.6%–5.7% compared with manual plans. Overall planning times were dramatically reduced to about 15 and 23 min for Pers and AP plans, respectively. The average beam-on times were found to be within 3 min for all plans. Despite the increased complexity, all plans passed the 2%/2 mm γ-analysis for dose verification.

Conclusion

Automated planning for spine SBRT through the new Pinnacle3 Personalized engine provided an overall increase of plan quality in terms of dose conformity and a major increase in efficiency. In this complex anatomical site, Personalized strongly reduce the tradeoff between optimal accurate dosimetry and planning time.

Stereotactic Body Radiation Therapy With Simultaneous Integrated Boost in Patients With Spinal Metastases

Stereotactic body radiation therapy in patients with spine metastases maximizes local tumor control and preserves neurologic function. A novel approach could be the use of stereotactic body radiation therapy with simultaneous integrated boost delivering modality. The aim of the present study is to report our experience in the treatment of spine metastases using a frameless radiosurgery system delivering stereotactic body radiation therapy–simultaneous integrated boost technique. The primary endpoints were the pain control and the time to local progression; the secondary ones were the overall survival and toxicity. A total of 20 patients with spine metastases and 22 metastatic sites were treated in our center with stereotactic body radiation therapy–simultaneous integrated boost between December 2007 and July 2018. Stereotactic body radiation therapy–simultaneous integrated boost treatments were delivered doses of 8 to 10 Gy in 1 fraction to isodose line of 50%. The median follow-up was 35 months (range: 12-110). The median time to local progression for all patients was not reached and the actuarial 1-, 2-, and 3-years local free progression rate was 86.36%. In 17 of 20 patients, a complete pain remission was observed and 3 of 20 patients had a partial pain remission (complete pain remission + partial pain remission: 100%). The median overall survival was 38 months (range 12-83). None of the patients experienced neither radiation adverse events (grade 1-4) nor reported pain flair reaction. None of the patients included in our series experienced vertebral compression fracture. Spine radiosurgery with stereotactic body radiation therapy–simultaneous integrated boost is safe. The use of this modality in spine metastases patients provides an excellent local control.

Clinical outcome of concomitant vs interrupted BRAF inhibitor therapy during radiotherapy in melanoma patients

Background:

Concomitant radiation with BRAF inhibitor (BRAFi) therapy may increase radiation-induced side effects but also potentially improve tumour control in melanoma patients.

Methods:

A total of 155 patients with BRAF-mutated melanoma from 17 European skin cancer centres were retrospectively analysed. Out of these, 87 patients received concomitant radiotherapy and BRAFi (59 vemurafenib, 28 dabrafenib), while in 68 patients BRAFi therapy was interrupted during radiation (51 vemurafenib, 17 dabrafenib). Overall survival was calculated from the first radiation (OS_RT) and from start of BRAFi therapy (OS_BRAFi).

Results:

The median duration of BRAFi treatment interruption prior to radiotherapy was 4 days and lasted for 17 days. Median OS_RT and OS_BRAFi in the entire cohort were 9.8 and 12.6 months in the interrupted group and 7.3 and 11.5 months in the concomitant group (P=0.075/P=0.217), respectively. Interrupted vemurafenib treatment with a median OS_RT and OS_BRAFi of 10.1 and 13.1 months, respectively, was superior to concomitant vemurafenib treatment with a median OS_RT and OS_BRAFi of 6.6 and 10.9 months (P=0.004/P=0.067). Interrupted dabrafenib treatment with a median OS_RT and OS_BRAFi of 7.7 and 9.8 months, respectively, did not differ from concomitant dabrafenib treatment with a median OS_RT and OS_BRAFi of 9.9 and 11.6 months (P=0.132/P=0.404). Median local control of the irradiated area did not differ in the interrupted and concomitant BRAFi treatment groups (P=0.619). Skin toxicity of grade ≥2 (CTCAE) was significantly increased in patients with concomitant vemurafenib compared to the group with treatment interruption (P=0.002).

Conclusions:

Interruption of vemurafenib treatment during radiation was associated with better survival and less toxicity compared to concomitant treatment. Due to lower number of patients, the relevance of treatment interruption in dabrafenib treated patients should be further investigated. The results of this analysis indicate that treatment with the BRAFi vemurafenib should be interrupted during radiotherapy. Prospective studies are desperately needed.

Intensity-modulated radiotherapy with integrated-boost in patients with bone metastasis of the spine: study protocol for a randomized controlled trial

BACKGROUND

Stereotactic body radiation therapy (SBRT) using intensity-modulated radiotherapy (IMRT) with dose escalation by simultaneous integrated boost (SIB) can be a safe modality for treating spinal bone metastases with enhanced targeting accuracy and improve local tumor control.

METHODS/DESIGN

This is a single-center, prospective, randomized, controlled trial. One hundred and twenty patients with spinal bone metastases will receive palliative radiation therapy at the Heidelberg University Hospital. SBRT will be given in five or ten fractions with or without SIB. Four treatment arms are planned: IMRT with 30 Gy in ten fractions, IMRT with 30 Gy in ten fractions and SIB to 40 Gy, IMRT with 20 Gy in five fractions, and IMRT with 20 Gy in five fractions and SIB to 30Gy in five fractions will be compared. The target parameters will be measured at baseline level and at three and six months after radiation.

DISCUSSION

The primary endpoint of this study was to assess and compare the local tumor control (by means of different fractionation schedules and biological doses to the tumor area). Secondary endpoints are acute and chronic adverse events, pain relief, quality of life, and fatigue.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02832765 . Registered on 27 July 2016.

Spinal cord constraints in the era of high-precision radiotherapy : Retrospective analysis of 62 spinal/paraspinal lesions with possible infringements of spinal cord constraints within a minimal volume

OBJECTIVE

Current constraints aim to minimize the risk of radiation myelitis by the use of restrictive maximal spinal cord doses, commonly 50 Gy. However, several studies suggested that a dose-volume effect could exist. Based on these observations, we evaluated patients receiving potentially excessive doses to the spinal cord within minimal volumes.

PATIENTS AND METHODS

Patients receiving radiotherapy between June 2010 and May 2015 using the Novalis^TM (Varian, Palo Alto, CA, USA; Brainlab, Heimstetten, Germany) radiosurgery system were retrospectively analyzed. A total of 56 patients with 62 treated lesions that had been prescribed radiation doses close to the spinal cord potentially higher than the common 50 Gy 2‑Gy equivalent-dose (EQD2) constraint were selected for further analysis. Of these patients, 26 with 31 lesions had no history of previous irradiation, while 30 patients with 31 lesions had been previously irradiated within the treatment field.

RESULTS

According to different dose evaluation approaches (spinal canal, spinal cord contour), 16 and 10 out of 31 primary irradiated lesions infringed constraints. For the 16 lesions violating spinal canal doses, the maximum doses ranged from 50.5 to 61.9 Gy EQD2. Reirradiated lesions had an average and median cumulative dose of 70.5 and 69 Gy, respectively. Dose drop-off was steep in both groups. Median overall survival was 17 months. No radiation myelitis or radiomorphological alterations were observed during follow-up.

CONCLUSION

This study adds to the increasing body of evidence indicating that excessive spinal cord doses within a minimal volume, especially in a reirradiation setting with topographically distinct high-point doses, may be given to patients after careful evaluation of treatment- and tumor-associated risks.

Dose Evaluation of Fractionated Schema and Distance From Tumor to Spinal Cord for Spinal SBRT with Simultaneous Integrated Boost: A Preliminary Study

BACKGROUND This study investigated and quantified the dosimetric impact of the distance from the tumor to the spinal cord and fractionation schemes for patients who received stereotactic body radiation therapy (SBRT) and hypofractionated simultaneous integrated boost (HF-SIB). MATERIAL AND METHODS Six modified planning target volumes (PTVs) for 5 patients with spinal metastases were created by artificial uniform extension in the region of PTV adjacent spinal cord with a specified minimum tumor to cord distance (0-5 mm). The prescription dose (biologic equivalent dose, BED) was 70 Gy in different fractionation schemes (1, 3, 5, and 10 fractions). For PTV V100, Dmin, D98, D95, and D1, spinal cord dose, conformity index (CI), V30 were measured and compared. RESULTS PTV-to-cord distance influenced PTV V100, Dmin, D98, and D95, and fractionation schemes influenced Dmin and D98, with a significant difference. Distances of ≥2 mm, ≥1 mm, ≥1 mm, and ≥0 mm from PTV to spinal cord meet dose requirements in 1, 3, 5, and 10 fractionations, respectively. Spinal cord dose, CI, and V30 were not impacted by PTV-to-cord distance and fractionation schemes. CONCLUSIONS Target volume coverage, Dmin, D98, and D95 were directly correlated with distance from the spinal cord for spine SBRT and HF-SIB. Based on our study, ≥2 mm, ≥1 mm, ≥1 mm, and ≥0 mm distance from PTV to spinal cord meets dose requirements in 1, 3, 5 and 10 fractionations, respectively.