Uterine corpus volume changes during definitive chemoradiotherapy for cervical cancer in pregnancy

Cervical cancer in pregnancy (CCIP) is rare, and evidence on definitive (chemo)radiotherapy is limited. Within our institutional CCIP cohort, we focused on the subset who received definitive concurrent chemoradiotherapy and, using weekly cone beam computed tomography (CBCT), characterized uterine volume dynamics during treatment — an analysis not reported previously — alongside a matched comparison with non-pregnant patients. We retrospectively analyzed patients with CCIP who received definitive concurrent chemoradiotherapy at our center between January 1, 2013 and June 30, 2023. As far as the small numbers allowed, each case was matched to non-pregnant patients at a 1:2 ratio by age, year of diagnosis, histology and FIGO 2018 stage; exact balance on all covariates was not achievable. Clinical data and weekly uterine volume on CBCT were analyzed. Given the cohort size, analyses were descriptive and exploratory. Five patients with CCIP and ten matched non-pregnant patients were included; all had FIGO 2018 stage III disease. We analyzed 135 CBCT scans. Baseline characteristics did not differ significantly, although the groups were not balanced on every covariate. In patients with CCIP, uterine volume decreased progressively and significantly from week 4 onward relative to baseline ( P < 0.05), whereas changes in non-pregnant patients were smaller and non-significant. The relative volume reduction from baseline to week 8 was significantly greater in CCIP than in non-pregnant patients (-52.1% vs. -28.1%, P = 0.003). With follow-up updated to May 2026 (median 38.3 months), distant metastasis occurred in 3/5 (60%) patients with CCIP versus 2/10 (20%) non-pregnant patients, and one patient with CCIP died. Survival endpoints were not formally compared given the sample size. In this small single-center series, delayed definitive chemoradiotherapy after delivery or pregnancy termination was feasible for locally advanced CCIP, and weekly CBCT revealed pronounced uterine volume reduction during treatment that may warrant adaptive replanning. These descriptive findings are hypothesis-generating; the higher rate of distant metastasis and the limited, incompletely matched sample preclude any conclusion of oncological equivalence with non-pregnant patients. Larger studies are needed.