KEY POINTS
- This prospective single-arm study enrolled 30 patients with FIGO 2018 stage IB1–IIB or selected IIIC1 cervical squamous-cell carcinoma. External-beam treatment delivered 43.35 Gy in 17 fractions, with involved nodes receiving an SIB to 54.40 Gy in 17 fractions, followed by image-guided brachytherapy 30 Gy in five fractions.
- Concurrent cisplatin was prescribed weekly at 40 mg/m², with at least three cycles required. Median EBRT duration was 22 days and median overall treatment time including brachytherapy was 43 days; all patients completed planned radiotherapy without interruption.
- Across 510 adaptive fractions, first-attempt adaptation succeeded in 99.0%, and the newly optimized adaptive plan was selected in 99.4%. Mean online adaptation time was 17 min 20 s, and mean total treatment-room time was 23 min 18 s.
- Compared with recalculating the original plan on daily anatomy, adaptation increased PTV V100% by 7.26 percentage points for the uterus and 8.79 points for the cervix. Uterine PTV V100% fell below 95% in 363/510 scheduled-plan fractions versus only 21/510 adapted fractions.
- Adaptation also reduced normal-tissue dose. Mean rectal dose fell from 34.43 to 30.90 Gy, rectal V30Gy from 70.58% to 58.53%, bladder mean dose from 28.22 to 27.49 Gy, and bladder V40Gy from 25.40% to 20.14%; multiple bowel and bone-marrow metrics also improved.
- Acute grade ≥3 gastrointestinal toxicity occurred in 10%, grade ≥3 genitourinary toxicity in 0%, and grade ≥3 hematologic toxicity in 40%; one patient developed grade 4 neutropenia. The prespecified early GI safety criterion was met because the one-sided 95% upper confidence bound was 23.9%, below the predefined 30% limit.
- All 30 patients had a clinical complete response at three months, but this early response cannot establish disease-control efficacy. The study was small, highly selected, single-centre and nonrandomized, and its dosimetric comparison was between paired daily plans rather than accumulated delivered dose.
CLINICAL TAKEAWAY
Daily CBCT-guided adaptation appears capable of making a 17-fraction definitive cervical regimen technically deliverable despite large uterine and cervical motion. The strategy now needs randomized evidence, particularly because encouraging target coverage and GI safety coexist with substantial hematologic toxicity and essentially no mature oncologic follow-up.