Session Item

Tuesday
August 31
09:15 - 10:30
N105-N106
Radiotherapy in oesophageal cancer
Astrid van Lier, The Netherlands;
Martijn Intven, The Netherlands
4130
Symposium
Clinical
Prospective evaluation of robotic radiosurgery in Indian patients with oligo-metastases
Ramakrishna Kamath, India
PO-1516

Abstract

Prospective evaluation of robotic radiosurgery in Indian patients with oligo-metastases
Authors:

Ramakrishna Kamath1, Sruthi K1, Ajinkya Gupte1, Yarlagadda Sreenija1, Pushpaja K U1, Anoop R1, Ajay Sasidharan2, Haridas Nair1, Annex E H3, Debnarayan Dutta1

1Amrita Institute of Medical Sciences, Radiation Oncology, Kochi, India; 2Amrita Institute of Medical Sciences, Radiation oncology, Kochi, India; 3Amrita Institute of Medical Sciences, Medical Physics, Kochi, India

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Purpose or Objective

SRS in Brain Metastases and Stereotactic radiotherapy (SBRT) in extracranial oligomets is at present considered as a treatment option. Recent prospective studies in western patient population showed the improved local control & survival function with SRS and SBRT. The present prospective study is to evaluate the impact of SRS and SBRT in Indian oligo-metastasis patients. 

Material and Methods

Between May 2017 and February 2021, 179 patients with 167 brain metastases and 109 extra-cranial oligometastases were accrued prospectively and treated with robotic radiosurgery (CK) (M6, Multiplan, VOLO). Patients with small volume oligomets (<3 sites) with good PS (0-1) and controlled primary were accrued. Frameless sterotactic based immobilization was ensured with thermoplastic masks. Contrast CT simulation was done with 0.625 mm slices and fused with T1 contrast/T2 Flair MRI images for contouring done for brain mets. PTV margin of 2-3 mm and a dose of 20-30Gy in 1-5 fractions was decided based on the treatment volume. In extra-cranial mets, immobilization with vacloc used and CT scan with contrast done as per protocol. Response to treatment, new lesion free survival, overall survival and toxicity profile after CK was evaluated. 

Results

Between 2017 - 2020, 179 patients with 276 oligomets (167 brain lesion, 109 extra-cranial site) were treated with CK. In extra-cranial mets, 15 were bone mets, 13 lymphnode mets, 11 liver mets, 3 choroidal mets and 1 each adrenal and pancreas. In 100 accrued brain mets patients with 167 brain lesions, 42 % had lung primary, 32% breast and 9% RCC. One, 3 & 5 fraction SRS was done in 61%, 15% and 24%.SRS dose was 12 Gy in 4%,13-18Gy in 19%, 20-24Gy in 42% and 25-30Gy in 35%. Solitary mets was in 59%, up to 3 in 32% and >3 in only 9% patients. At mean follow up 58.8 wks (4-164 wk), 86 had follow up evaluation (39 patients were alive, 47 expired). Among 32 patients had recurrent brain mets, 20 underwent treatment (12 received re-SRS, 5 WBRT, 3 had surgery). In 22 patients with lung oligomets, 3 had synchronous and 19 had metachronous lung mets. Primary site was colorectal in 9, thyroid in 3, kidney 4, head neck in 2, liver in 1, endometrium in 1, pancreas in 1, sarcoma 1. Mean PTV was 21cc (range: 2.8 – 78 cc). 18–24 Gy/1fr, 45-54Gy/3fr, 35-50Gy/1fr & 48Gy/8fr in 6, 8, 5 and 1 patient respectively. Among 17 evaluable patients CR was in 76% (13/17) and PR 12% (2/17). 2 (12%) papillary carcinoma thyroid patients had progressive disease. At mean Follow up of 11 months, 7 (32%) were alive with controlled disease, 8 (36%) were alive with disease progression. 2 (9%) had local and distant failure and 10 (45%) had systemic progression. 2/3 (66%) of choroidal metastasis had CR. In liver metastasis, 8/11 (72%) had CR. In bone metastasis 10/15 (66%) had excellent symptomatic relief with radiological response.

Conclusion

SBRT with CK is feasible in Indian patients with small volume oligo-metastasis.