Cervical Cancer Patient Reported Gastrointestinal Outcomes: Intensity/Volumetric Modulated vs. 3D Conformal Radiation Therapy

Abstract

To evaluate gastrointestinal (GI) patient reported outcomes (PROs) in cervical cancer patients treated with definitive radiotherapy (RT), comparing 3D conformal RT (3DCRT) vs. intensity modulated /volumetric modulated arc therapy (IMRT/VMAT).A retrospective analysis of cervical cancer patients treated with curative intent RT between 2015-2018 was performed. GI PROs were collected at baseline, during RT (acute), ≤12 weeks after RT (subacute), and > 12 weeks after RT (late) using the Prospective Outcomes and Support Initiative (POSI) which includes validated questions from EPIC Bowel 2, PRO-CTAE, and EORTC QLQ CX24. GI PROs evaluated three symptom domains: bowel problems (BP), bowel bother (BB), and abdominal problems (AP).The cohort included 167 patients. The median age was 48 (27-86), 74% had squamous cell carcinoma, and 51% had FIGO stage I/II disease. All patients received brachytherapy, 99% received a 45Gy elective pelvic dose, 31% had para-aortic fields, and 97% received concurrent chemotherapy. 100 (60%) patients were treated with IMRT/VMAT and 67 (40%) with 3DCRT. The median follow-up was 24 (5-67) months. In the BP domain, mean changes in symptom scores compared to baseline for 3DCRT vs. IMRT/VMAT were +2.29 vs. +1.82 (P = 0.55) during RT, +0.9 vs. -1.15 (P = 0.01) ≤12 weeks after RT, and +0.72 vs. -0.82 (P = 0.01) > 12 weeks after RT. In the BB domain, mean changes in symptom scores compared to baseline for 3DCRT vs. IMRT/VMAT were +3.58 vs. +3.16 (P = 0.67) during RT, +2.18 vs. -0.10 (P = 0.02) ≤12 weeks after RT, and +1.98 vs. -0.03 (P = 0.01) > 12 weeks after RT. In the AP domain, mean changes in symptom scores compared to baseline for 3DCRT vs. IMRT/VMAT were +2.52 vs. +2.01 (P = 0.32) during RT, +1.41 vs. -0.38 (P = 0.02) ≤12 weeks after RT, and +1.29 vs. -0.31 (P = 0.01) > 12 weeks after RT. On multivariable analysis 3DCRT was associated with greater mean changes in subacute and late symptom scores in BP (subacute 0.29 (0.08-0.51), P = 0.01; late 0.22 (0.03-0.41), P = 0.02), BB (subacute 0.32 (0.04-0.61), P = 0.03; late 0.26 (0.03-0.48), P = 0.03), and AP (subacute 0.27 (0.05-0.48), P = 0.01; late 0.24 (0.08-0.40), P = 0.01) compared to IMRT/VMAT. Age, smoking status, prior abdominal surgery, FIGO stage, RT volume (pelvic vs. para-aortic), and use of external beam boost were not associated with symptom score changes (P > 0.05). Three-year estimates of overall survival, local control, and regional control were 87%, 97%, 86% in the IMRT/VMAT cohort and 91% (P = 0.32), 97% (P = 0.99), and 92% (P = 0.26) in the 3DCRT cohort, respectively.Cervical cancer patients treated with IMRT/VMAT had significantly less worsening of their GI PRO symptom scores compared to baseline in all three GI domains ≤12 weeks and > 12 weeks after RT. 3DCRT was associated with greater subacute and late patient reported GI toxicity.