PV QA 4 - Poster Viewing Q&A 4
TU_16_3474 - Definitive External Beam Radiation Therapy With Stereotactic Body Radiation Therapy Boost for FIGO Stage IB - IIB Cancer of the Cervix: Minimum 5-Year Disease Control, Toxicity and Quality of Life Outcomes From a Phase 2 Trial
Tuesday, October 23
2:45 PM - 4:15 PM
Location: Innovation Hub, Exhibit Hall 3
Definitive External Beam Radiation Therapy With Stereotactic Body Radiation Therapy Boost for FIGO Stage IB - IIB Cancer of the Cervix: Minimum 5-Year Disease Control, Toxicity and Quality of Life Outcomes From a Phase 2 Trial
C. A. Mantz; 21st Century Oncology, Fort Myers, FL
Purpose/Objective(s): SBRT for gynecologic cancers may offer practical advantages over brachytherapy at similar radiobiologic dosing. Dose-fractionation SBRT schedules may be selected to approximate those of HDR, and SBRT eliminates the needs of optimal applicator placement and sedation. Herein, we report health-related quality of life (HRQOL), toxicity and disease control outcomes of a prospective, phase II trial of SBRT for primary cervical cancers.
Materials/Methods: Eligible patients included those with (1) pathologically confirmed cervical squamous cell carcinoma or adenocarcinoma; (2) FIGO stage IB, IIA or IIB disease; (3) technical or medical contraindication to brachytherapy; and (4) primary GTV < 125 cc following induction therapy. Induction therapy consisted of external beam radiotherapy (EBRT) to a minimum dose of 45.0 Gy encompassing primary tumor and regional pelvic lymphatics. All patients received cisplatin-based chemotherapy concurrent to EBRT. SBRT boost treatment planning then followed, and GTV delineation was aided by co-registration of the boost planning CT set to a pre-EBRT FDG PET/CT scan and post-EBRT MRI. A boost dose of 40.0 Gy was prescribed to the primary tumor and delivered over a 10-day schedule of 5 fractions of 8.0 Gy each. Assessments included (1) disease response was determined pathologically by 3-month post-therapy biopsy and radiographically by biannual PET/CT imaging for 2 years; (2) acute and chronic toxicities were assessed using the National Cancer Institute's CTCAE v3 toxicity scales; and (3) quality-of-life was scored using FACT-G measurements.
Results: Forty-four patients with FIGO stage IB - IIB cervical cancer have been treated since June 2007 and have been followed for a median of 72.0 months and a minimum of 60.0 months. Stage distribution was as follows: 5/44 FIGO stage IB1, 14/44 FIGO stage IB2, 3/44 FIGO stage IIA1, 5/44 FIGO stage IIA2 and 17/44 FIGO stage IIB. Post-SBRT biopsy at 3 months was negative for 41 of 44 patients, or 93.1%, for all patients. At 5 years, estimated local control by combined pathologic and radiographic (i.e., PET SUVmax < 2.5) criteria at the SBRT treatment site is 91.5 % for all patients. No NCI CTCAE grade 3 or greater urinary or bowel toxicities have been observed to date. Post-treatment FACT-G scores were statistically superior compared to pre-treatment assessments for the following studied domains: physical, emotional and functional well-being.
Conclusion: At a minumum followup of 5 years, SBRT offers an effective and well-tolerated boost modality for selected FIGO stage IB - IIB cervix cancer patients otherwise contraindicated for brachytherapy. To our knowledge, this propsective phase 2 study reports the largest cohort of cervical cancer cases treated with curative intent using boost SBRT.
Author Disclosure: C.A. Mantz: None.