Researchers say they have identified risk factors for local failure in patients with locally advanced cervical cancer treated with chemoradiation and MRI-guided adaptive brachytherapy (MR-IGABT). The findings were published in the Journal of Clinical Oncology.
The researchers analyzed data from 1318 patients in the EMBRACE-I study (ClinicalTrials.gov Identifier: NCT00920920) who were treated with external beam radiotherapy, concurrent chemotherapy, and MR-IGABT.
The median follow-up was 52 months. The complete response (CR) rate was 98%. At the 3-month mark, 81 patients had persistent disease. However, 60 of those patients achieved a CR at 6-9 months with no further treatment.
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Seventy-seven patients had a local recurrence after CR. When these patients were combined with 21 patients who had persistent disease, there were a total of 98 local failures.
Most (90%) local failures were located inside the MR-IAGBT target volumes. The median survival after local failure was 10 months.
A multivariable analysis revealed several factors associated with a higher risk of local failure, including:
- Maximum tumor dimension at diagnosis (continuous, P <.01)
- The presence of tumor necrosis on MRI at diagnosis (P =.037)
- Adeno/adenosquamous carcinoma vs squamous cell carcinoma (P <.01)
- Uterine corpus infiltration at diagnosis (lower infiltration, P =.03) and at MR-IAGBT (lower infiltration, P =.045)
- Mesorectal infiltration at MR-IGABT (P =.016)
- Overall treatment time (continuous, P =.024)
- Minimal dose to 90% of high-risk clinical target volume (P <.01).
A dose-response analysis indicated that a minimal dose to 90% of 85 Gy to the high-risk clinical target volume led to a 95% local control rate at 3 years in patients with squamous cell histology, compared with an 86% local control rate at 3 years for patients with adenocarcinoma or adenosquamous carcinoma.
“Patients with squamous cell carcinoma have a lower risk of local failure and require lower doses to achieve the same effect than patients with adeno- or adenosquamous carcinoma. Increasing high-risk clinical target volume, however, decreases the absolute effect of a specific dose and decreases the local tumor control probability,” JCO Associate Editor Gini F. Fleming, MD, wrote in a comment about the results.
“Most patients with persistent disease at 3-month follow-up achieved complete remission at a later time with no further treatment. A watch-and-wait policy including gynecologic exam and magnetic resonance imaging can be considered for patients with residual disease that is regressing at 3 months.”
Disclosures: This research was partly supported by Elekta AB and Varian Medical Systems. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Reference
Schmid MP, Lindegaard JC, Mahantshetty U, et al. Risk factors for local failure following chemoradiation and magnetic resonance image–guided brachytherapy in locally advanced cervical cancer: Results from the EMBRACE-I study. J Clin Oncol. Published online January 4, 2023. doi:10.1200/JCO.22.01096
