ESTRO 2024 - Abstract Book

S1955

Clinical - Mixed sites, palliation

ESTRO 2024

Keywords: Quality of Life, Oligometastasis, SBRT

2042

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Clinical Predictors of Death Following Spatially Fractionated Radiation Therapy

Jared N Hobson, Daniel K Ebner, Michael P Grams, Kimberly S Corbin

Mayo Clinic, Radiation Oncology, Rochester, USA

Purpose/Objective:

Palliative radiation is utilized in 10% of cancer patients within their last 30 days of life, with the most common regimen being 30 Gy in 10 fractions 1 . Associated predictors of 30-day mortality and overall survival have been reported, including performance status, treatment site, and lung primary 2-4 . Grid radiotherapy, a form of spatially fractionated radiation therapy (SFRT), delivers alternating regions of high and low doses of radiation to bulky tumors, with reports of significant symptom relief, tumor regression, and improved local control rates 5 . This study investigates predictors of mortality with palliative radiation in the context of SFRT.

Material/Methods:

A single institution retrospective chart analysis of patients treated with SFRT was performed, with evaluation of primary tumor and treatment site, ECOG status, 30-day mortality and hospitalization rates. SPSS 28.0 (IBM) Crosstabs and Kaplan-Meier analyses were employed.

Results:

307 patients treated with SFRT grid radiotherapy were analyzed, of which 111 (36.2%) were hospitalized within 30 days, with 52 (16.9%) receiving SFRT inpatient and 34 (11.1%) dying within 30 days. 76.4% of patients had metastatic disease at baseline. ECOG functional status included ECOG 0 (69; 22.5%), 1 (129; 42.0%), 2 (69; 22.5%), 3 (34; 11.1%), and 4 (2; 0.7%). ECOG status was highly correlated with 30-day hospitalization (p<0.001) and associated with both overall death (p<0.001) and death within 30 days (p=0.003). Hospitalization overall, including those receiving SFRT inpatient and those admitted within 30 days of radiation was also associated with overall death (p<0.001). Neither the location of the treated site nor primary tumor were significantly correlated to hospitalization or overall mortality. The primary tumor was significantly related to 30-day mortality (p=0.029) while the treatment site was not, with higher rates of 30-day mortality seen with small cell lung cancer, renal cell, head and neck squamous cell, and anaplastic thyroid (>20%) compared with colorectal, endometrial, melanoma, and neuroendocrine primaries (0%). 30-day mortality was 13.9% in sarcoma, 23.1% renal cell, 28.6% anaplastic thyroid, 30.0% head and neck squamous cell, 12.5% non-small cell lung cancer, 26.3% small cell lung cancer, and 7.7% for breast primary. Of the 34 patients who died within 30 days of the end of their collective SFRT radiotherapy course, 23.5% reported qualitive palliation of symptoms with SFRT (17.6% unable to be assessed) with 82.3% dying from complications of their overall disease burden. No deaths within 30 days appeared attributable to SFRT.