Comparison of dosimetric parameters and acute toxicity of intensity-modulated and three-dimensional radiotherapy in patients with cervix carcinoma: A randomized prospective study.

PURPOSE

The use of intensity-modulated radiotherapy (IMRT) to treat cervix carcinoma has increased, however prospective randomized trials are still lacking.

AIM

To compare the dosimetric parameters and associated acute toxicity in patients with cervix carcinoma treated with three-dimensional (3D) conformal radiotherapy and IMRT.

PATIENTS AND METHODS

Forty patients were randomized in two arms each consisting of 20 patients. Patients in both arms received concurrent chemoradiation (cisplatin 40mg/m(2) weekly; 50Gy/25 fractions). Patients were treated with 3D conformal radiotherapy in one arm and with IMRT in another arm. After external beam radiotherapy, all patients received brachytherapy (21Gy/3 fractions at weekly interval). For dosimetric comparison, both kinds of the plans were done for all the patients. All patients were assessed throughout and until 90 days after completion of treatment for acute gastrointestinal, genitourinary and hematologic toxicities.

RESULTS

Both plans achieved adequate planning target volume coverage, while mean conformity index was found significantly better in IMRT plans (P-value=0.001). D35 (dose to 35% volume) and D50 for bladder was reduced by 14.62 and 32.57% and for rectum by 23.82 and 43.68% in IMRT. For IMRT, V45 (volume receiving 45Gy) of bowel were found significantly lesser (P-value=0.0001), non-tumour integral dose was found significantly higher (P-value=0.0240) and V20 of bone marrow was found significantly reduced (P-value=0.019) in comparison to that in 3D conformal radiotherapy. Significant reduction of grade 2 or more (20 vs 45%; P-value=0.058) and grade≥3 (5 vs 15%, P-value=0.004) acute genitourinary toxicity and grade 2 or more (20 vs 45%, P-value=0.003) and grade 3 or more (5 vs. 20%, P-value=0.004) acute gastrointestinal toxicity while no significant difference for grade 2 and 3 or more haematological toxicity was noted in patients treated with IMRT compared to 3D conformal radiotherapy.

CONCLUSION

IMRT provide a good alternative for treatment of cervix carcinoma with lower acute gastrointestinal and acute genitourinary toxicity with similar target coverage compared to 3D conformal radiotherapy.