Oligometastatic cancer: stereotactic ablative radiotherapy for patients affected by isolated body metastasis

BACKGROUND

To evaluate the outcome of patients affected by a single isolated body metastasis treated with stereotactic body radiotherapy (SBRT).

MATERIAL AND METHODS

Seven-eight patients were treated with SBRT for isolated body metastasis. The most frequent primary tumor was prostate cancer (28.2%), followed by colorectal cancer (23.1%) and lung cancer (20.5%). Median age at diagnosis of oligometastatic disease was 70 years (range 47-88). Median Karnofsky Performance Status (KPS) was 90 (range 70-100). The most common SBRT fractionation scheme was 5 × 7 Gy (total dose 35 Gy). Response to radiotherapy was determined according to RECIST criteria v1.1. Toxicity was registered according to Common Terminology Criteria for Adverse Events (CTCAE) v4.0. The survival analysis was performed with the Kaplan-Meier method. The correlation between time actuarial incidence and clinical parameters was studied, and the Kaplan-Meier method of log-rank test was applied.

RESULTS

With a median follow-up of 22.68 months, local control was achieved in 89.7% of the cases. The two-year overall survival (OS) and progression-free survival (PFS) were 68% and 42%, respectively. On univariate analysis, KPS ≥80 is predictive for improved OS (p = .001) and PFS (p = .001). Acute toxicity of grade ≥2 occurred in eight (10.2%) patients and late grade ≥2 toxicity in five (6.4%) patients.

CONCLUSIONS

Ablative radiotherapy in 'early oligometastatic state' is a safe, effective and minimally invasive treatment modality. A good performance status (KPS ≥80) seems to influence the clinical outcome.

Stereotactic body radiotherapy in oligometastatic prostate cancer patients with isolated lymph nodes involvement: a two-institution experience

OBJECTIVE

Stereotactic body radiotherapy (SBRT) is emerging as a treatment option in oligometastatic cancer patients. This retrospective study aimed to analyze local control, biochemical progression-free survival (b-PFS), and toxicity in patients affected by isolated prostate cancer lymph node metastases. Finally, we evaluated androgen deprivation therapy-free survival (ADT-FS).

METHODS

Forty patients with 47 isolated lymph nodes of recurrent prostate cancer were treated with SBRT. Mostly, two different fractionation schemes were used: 5 × 7 Gy in 23 (48.9 %) lesions and 5 × 8 Gy in 13 (27.7 %) lesions. Response to treatment was assessed with periodical PSA evaluation. Toxicity was registered according to RTOG/EORTC criteria.

RESULTS

With a mean follow-up of 30.18 months, local control was achieved in 98 % of the cases, with a median b-PFS of 24 months. We obtained a 2-year b-PFS of 44 % with 40 % of the patients ADT-free at last follow-up (mean value 26.18 months; range 3.96-59.46), whereas 12.5 % had a mean ADT-FS of 13.58 months (range 2.06-37.13). Late toxicity was observed in one (2.5 %) patient who manifested a grade 3 gastrointestinal toxicity 11.76 months after the end of SBRT.

CONCLUSION

Our study demonstrates that SBRT is safe, effective, and minimally invasive in the eradication of limited nodal metastases, yielding an important delay in prescribing ADT.

Salvage Stereotactic Body Radiotherapy for Patients With Prostate Cancer With Isolated Lymph Node Metastasis: A Single-Center Experience

OBJECTIVE

The study objective was to evaluate the efficacy of salvage stereotactic body radiation therapy (SBRT) as a treatment modality in patients with oligometastatic prostate cancer.

METHODS

A total of 16 patients with 18 isolated lymph nodes with recurrent prostate cancer were treated between 2008 and 2013. All patients underwent [(11)C] choline-positron emission tomography/computed tomography before SBRT. Two patients were treated in different sessions for metachronous metastases. Ten patients received androgen deprivation therapy concomitant to SBRT (total dose range, 12-35 Gy, delivered in 1-5 daily fractions).

RESULTS

The mean and median follow-up periods were 29.35 and 29.38 months, respectively (range, 6.3-68.8 months). Local disease control and a decrease in serum prostate-specific antigen were obtained in 15 of 16 patients (94%); only 1 patient had an in-field progression. In the 6 patients without androgen deprivation therapy at the time of SBRT, the mean time of deferment of palliative androgen deprivation therapy was 23.7 months (range, 2.5-51 months). At last follow-up, 8 patients had active prostate cancer disease; biochemical progression was observed after a mean time of 7.9 months from the completion of SBRT. One patient died of disease. Overall survival was 94%. The 2-year biochemical relapse-free survival was 44%. Late toxicity (gastrointestinal) was observed in 1 patient who had a G3 toxicity.

CONCLUSIONS

SBRT seems to be safe, effective, and minimally invasive in the eradication of limited nodal recurrence from oligometastatic prostate cancer. SBRT is well tolerated by patients with low toxicity and yielded a local control of the disease.

Standard or hypofractionated radiotherapy in the postoperative treatment of breast cancer: a retrospective analysis of acute skin toxicity and dose inhomogeneities

BACKGROUND

To identify predictive factors of radiation-induced skin toxicity in breast cancer patients by the analysis of dosimetric and clinical factors.

METHODS

339 patients treated between January 2007 and December 2010 are included in the present analysis. Whole breast irradiation was delivered with Conventional Fractionation (CF) (50 Gy, 2.0/day, 25 fractions) and moderate Hypofractionated Schedule (HS) (44 Gy, 2.75 Gy/day, 16 fractions) followed by tumour bed boost. The impact of patient clinical features, systemic treatments and, in particular, dose inhomogeneities on the occurrence of different levels of skin reaction has been retrospectively evaluated.

RESULTS

G2 and G3 acute skin toxicity were 42% and 13% in CF patients and 30% and 7.5% in HS patients respectively. The retrieval and revaluation of 200 treatment plans showed a strong correlation between areas close to the skin surface, with inhomogeneities >107% of the prescribed dose, and the desquamation areas as described in the clinical records.

CONCLUSIONS

In our experience dose inhomogeneity underneath G2 - G3 skin reactions seems to be the most important predictor for acute skin damage and in these patients more complex treatment techniques should be considered to avoid skin damage. Genetic polymorphisms too have to be investigated as possible promising candidates for predicting acute skin reactions.

Is the in vivo dosimetry with the OneDosePlusTM system able to detect intra-fraction motion? A retrospective analysis of in vivo data from breast and prostate patients

Background

The OneDosePlus^TM system, based on MOSFET solid-state radiation detectors and a handheld dosimetry reader, has been used to evaluate intra-fraction movements of patients with breast and prostate cancer.

Methods

An Action Threshold (AT), defined as the maximum acceptable discrepancy between measured dose and dose calculated with the Treatment Planning System (TPS) (for each field) has been determined from phantom data. To investigate the sensitivity of the system to direction of the patient movements, fixed displacements have been simulated in phantom. The AT has been used as an indicator to establish if patients move during a treatment session, after having verified the set-up with 2D and/or 3D images. Phantom tests have been performed matching different linear accelerators and two TPSs (TPS1 and TPS2).

Results

The ATs have been found to be very similar (5.0% for TPS1 and 4.5% for TPS2). From statistical data analysis, the system has been found not sensitive enough to reveal displacements smaller than 1 cm (within two standard deviations). The ATs applied to in vivo treatments showed that among the twenty five patients treated for breast cancer, only four of them moved during each measurement session. Splitting data into medial and lateral field, two patients have been found to move during all these sessions; the others, instead, moved only in the second part of the treatment. Patients with prostate cancer have behaved better than patients with breast cancer. Only two out of twenty five moved in each measurement session.

Conclusions

The method described in the paper, easily implemented in the clinical practice, combines all the advantages of in vivo procedures using the OneDosePlus^TM system with the possibility of detecting intra-fraction patient movements.

Cone-beam computed tomography in hypofractionated stereotactic radiotherapy for brain metastases

Background

To assess interfraction translational and rotational setup errors, in patients treated with image-guded hypofractionated stereotactic radiotherapy, immobilized by a thermoplastic mask and a bite-block and positioned using stereotactic coordinates.

Methods

37 patients with 47 brain metastases were treated with hypofractionated stererotactic radiotherapy. All patients were immobilized with a combination of a thermoplastic mask and a bite-block fixed to a stereotactic frame support. Daily cone-beam CT scans were acquired for every patient before the treatment session and were matched online with planning CT images, for 3D image registration. The mean value and standard deviation of all translational (X, Y, Z) and rotational errors (θ_x, θy, θ_z) were calculated for the matching results of bone matching algorithm.

Results

A total of 194 CBCT scans were analyzed. Mean +/- standard deviation of translational errors (X, Y, Z) were respectively 0.5 +/- 1.6 mm (range -5.7 and 5.9 mm) in X; 0.4 +/- 2.7 mm (range -8.2 and 12.1 mm) in Y; 0.4 +/- 1.9 mm (range -7.0 and 14 mm) in Z; median and 90th percentile were respectively within 0.5 mm and 2.4 mm in X, 0.3 mm and 3.2 mm in Y, 0.3 mm and 2.2 mm in Z. Mean +/- standard deviation of rotational errors (θ_x, θy, θ_z) were respectively 0.0 degrees+/- 1.3 degrees (θ_x) (range -6.0 degrees and 3.1 degrees); -0.1 degrees +/- 1.1 degrees (θy) (range -3.0 degrees and 2.4 degrees); -0.6 degrees +/- 1.4 degrees (θ_z) (range -5.0 degrees and 3.3 degrees). Median and 90th percentile of rotational errors were respectively within 0.1 degrees and 1.4 degrees (θ_x), 0.0 degrees and 1.2 degrees (θy), 0.0 degrees and 0.9 degrees (θ_z). Mean +/- SD of 3D vector was 3.1 +/- 2.1 mm (range 0.3 and 14.9 mm); median and 90th percentile of 3D vector was within 2.7 mm and 5.1 mm.

Conclusions

Hypofractionated stereotactic radiotherapy have the significant limitation of uncertainty in interfraction repeatability of the patient setup; image-guided radiotherapy using cone-beam computed tomography improves the accuracy of the treatment delivery reducing set-up uncertainty, giving the possibility of 3-dimensional anatomic informations in the treatment position.

Image-Guided-Radiotherapy Retreatment of Spine Metastasis: A Case Report and Radiobiological Evaluation

Aims and background

The present case report describes vertebral metastasis retreatment using kilovoltage cone-beam computed tomography (CBCT) for setup error correction, in order to improve target irradiation and prevent spinal cord toxicity. We evaluated the feasibility of the second radiation therapy course on the overlapping treatment volume.

Methods and study design

A patient with metastatic kidney cancer, previously treated to the tenth dorsal vertebra with conventional radiation planning (21 Gy; 3 × 7 Gy), underwent retreatment. In order to deliver 30 Gy (15 × 2 Gy) to the target volume with the second irradiation, we evaluated the residual dose that could be received by the spinal cord. We calculated the biologically effective dose according to the linear-quadratic model, using an α/β ratio of 2 Gy. A 3-dimensional conformal plan was generated; CBCT imaging was used to ensure accurate repositioning.

Results

A total of 15 CBCT scans were performed; the mean setup corrections in the lateral, longitudinal and vertical directions were 3.38 mm (SD 2.09; range, −0.2 mm ÷ 7.6 mm), 2.13 mm (SD 3.38; range, −5.9 mm ÷ 6 mm), and −1.28 mm (SD 2.02; range, −7.1 mm ÷ 0.3 mm), respectively.

Conclusion

Image-guided radiotherapy is an alternative approach for the retreatment of spine tumors; it ensures accurate patient setup correction and high-precision treatment delivery, which are required for target volumes very close to critical structures. Free full text available at www.tumorionline.it