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

PURPOSE/OBJECTIVE(S) 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). MATERIALS/METHODS 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). RESULTS 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. CONCLUSION 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.