Palliative Radiotherapy in Symptomatic Pelvic Soft Tissue Tumors

Studies and clinical practice have proven palliative radiotherapy to provide efficient symptom relief in patients with symptomatic pelvic soft tissue tumors. However, studies are mainly retrospective, are difficult to compare due to a variety of radiotherapy fractionation schedules used, and lack data on patient-reported quality of life. Consequently, no recommended standard of care is established, and several schedules are employed with variations in both number of fractions and total radiation dose (measured in Gray=Gy). Given the limited life expectancy of palliative patients, a short-course radiotherapy schedule would be preferable provided efficient symptom relief and good health-related quality of life.

PALLSOFT is a national, randomized, non-inferiority study that will investigate whether the symptomatic effect of a short-course radiotherapy schedule of 8 Gy x 1-2 is non-inferior to a more prolonged schedule of 5 Gy x 5. The study will include patients with symptomatic pelvic soft tissue tumors from either gastrointestinal, urological or gynecological cancer. Patients will defined a target symptom from 5 predefined cathegories (pain, bleeding, bowel/lower urinary tract/vaginal dysfunction), and change in symptom intensity will be assessed, as well as overall toxicities, quality of life and survival. Prognostic and predictive biomarkers will be explores, the latter with particular emphasis on the significance of tumor hypoxia in palliative radiotherapy.

Inclusion criteria

• Patients unsuitable for curative treatment due to either advanced disease or medical contradictions (i.e comorbidity, old age, poor general condition)
• Histologically verified primary cancer originated from gastrointestinal, urological or gynecological organs (histological verification can be performed on other lesions than the symptomatic pelvic tumor)
• Primary, residual, recurrent or metastatic pelvic tumor from the above-mentioned cancers not amenable for curative treatment
• Tumor-related symptoms including within the 5 defined categories pain, bleeding, bowel/lower urinary/vaginal dysfunction
• Considered candidate for palliative radiotherapy according to both study arms
• Patient reported severity of symptoms ≥4 on a NRS- scale of 0-10
• ≥18 years of age
• Speaks and understands Norwegian or English
• Ability to understand and willing to sign a written informed consent
• ECOG performance status 0-3
• Expected survival > 12 weeks
• Able to pause systemic cancer treatment for one week prior to, during, and one week after the radiotherapy treatment
• Women of childbearing potential (WOCBP) should have a negative highly sensitive serum pregnancy test within 72 hours prior to study intervention. WOCBP must agree to the use of highly effective birth control methods or abstain from heterosexual sexual activity from randomization and until completed study intervention

Exclusion criteria

• Neuroendocrine histology of any kind
• Sarcoma or sarcomal components in the histology
• Tumors that originate from bony metastases without a soft tissue component
• Unable to comply with study questionnaires
• Ongoing treatment with an investigational drug at inclusion
• Planned inclusion in another interventional clinical trial within 4 weeks after radiotherapy
• Patients who are pregnant due to risk of teratogenic and abortifacient effects of radiotherapy