The utility of 1.5 tesla MR-guided adaptive stereotactic body radiotherapy for recurrent ovarian tumor - Case reports and review of the literature.

Introduction: Although epithelioid ovarian cancer (EOC) is a radiosensitive tumor and radiotherapy (RT) played a significant role in adjuvant treatment management in the past, the role of RT has evolved with the advent of platinum-based chemotherapy regimens. Nonetheless, modern RT techniques may be useful in certain patients particularly those with recurrent disease.

Presentation Of Case: After surgery and chemotherapy, two patients, aged 57 and 70, presented with recurrent lesions in the parailiac region. The recurrent lesions were treated with high field 1.5-Tesla MR-Linac treatment in 5 fractions at a dose of 30 Gy. The patients tolerated the treatment well and were disease free after 12 and 20 months of magnetic resonance guided radiotherapy (MRgRT), respectively.

Discussion: MRgRT is a novel and rapidly evolving technology that allows for the highly precise treatment of even mobile targets through direct visualization of the tumor. The majority of patients with EOC frequently present with abdominal-pelvic recurrences. It has been demonstrated that EOC requires high radiation doses for curative treatment. MR-Linac enables monitoring of organ motion during treatment, which is necessary for delivering higher doses to target volumes while sparing surrounding organs.

Conclusion: To reduce radiation doses to nearby normal tissues, MRgRT allows for the delivery of hypofractionated RT with tight safety margins. Regardless of initial resistance or gradual development of intolerance to standard chemotherapy regimens, the role of RT in patients with persistent or recurrent EOC should be reconsidered.