Work

Real-world experience with INTERLACE-style induction chemotherapy: Tumor regression and MRI-guided brachytherapy in locally advanced cervical cancer

Year: 2026

Type: article

Abstract: Objective Achieving optimal brachytherapy coverage for bulky cervical tumors (>30 cc) remains challenging, and the ideal treatment approach is unclear. This study describes real-world tumor volume response, brachytherapy dose delivery, and toxicity in patients treated with an INTERLACE-style induction chemotherapy regimen followed by chemoradiation and MRI-guided adaptive brachytherapy. Methods This retrospective, two-institution cohort included eight patients with locally advanced cervical cancer treated with weekly carboplatin/paclitaxel induction chemotherapy followed by cisplatin-based chemoradiation and MRI-guided brachytherapy. All three serial tumor measurements (at diagnosis, after induction chemotherapy, and after chemoradiation/before brachytherapy) were obtained by pelvic MRI. Gross tumor volumes (GTV) were contoured by the treating radiation oncologist; organ-at-risk volumes were delineated by treating physicians. Results FIGO stage was IIIC1 in 6 patients, IIA in 1, and IB3 in 1. Five patients (62.5%) were PD-L1 positive. Seven patients received tandem-and-ovoid brachytherapy and one received a Syed-Neblett interstitial implant. Median GTV was 88.3 cc (range 18–370) at diagnosis, 15.3 cc (range 0–187.1) after induction chemotherapy, and 2.2 cc (range 0–11.5) after chemoradiation. Median per-patient GTV reduction was 70% (range, 45–100%) after induction chemotherapy alone and 97% (range 74–100%) by completion of chemoradiation. Seven patients presented with bulky disease (>30 cc); three remained bulky after induction chemotherapy and none after chemoradiation. Median high-risk clinical target volume (HR-CTV) D90 cumulative dose in 2-Gy fraction equivalents (EQ.D2) was 90.5 Gy (range 87–93.7) and median HR-CTV D98 was 79.8 Gy EQ.D2 (range 77.2–84.8; n = 7). Grade ≥ 3 hematologic toxicity was more common during chemoradiation than during induction chemotherapy (neutropenia in 3/8 [37.5%] vs 1/8 [12.5%]; leukopenia in 2/8 [25%] vs 0/8); thrombocytopenia (1/8) and one case of anemia occurred only during induction chemotherapy. Two patients discontinued cisplatin early because of hematologic toxicity. Seven of eight patients achieved a complete metabolic response on PET at 3 months post-treatment and remained disease-free at last follow-up (median 62.4 months; range 23.0–72.9). Conclusion In this real-world cohort, INTERLACE-style induction chemotherapy produced substantial tumor regression that facilitated tandem-and-ovoid brachytherapy in most patients while achieving EMBRACE-aligned HR-CTV doses with manageable, phase-specific toxicity. These hypothesis-generating findings warrant confirmation in larger, prospective, and comparative cohorts.

Source: Gynecologic Oncology Reports

DOI: 10.1016/j.gore.2026.102231