Objective To explore the application value of 192 Ir interstitial implantation paracervical boost radiotherapy in the treatment of locally advanced cervical cancer LACC . Method A prospective randomized controlled study enrolled 104 LACC patients from August 2023 to February 2025 who were randomized at a 2 ∶ 1 ratio using a random number table method into an experimental group n = 69 and a control group n = 35 . Finally 96 patients completed the treatment and follow-up 64 in the experimental group and 32 in the control group . Both groups received pelvic external beam radiotherapy combined with concurrent chemotherapy. The experimental group was additionally treated with 192 Ir interstitial implantation paracervical boost radiotherapy while the control group received conventional intracavitary brachytherapy ICBT . The two groups were compared in terms of target volume dosimetric parameters radiation doses to organs at risk short - term therapeutic efficacy Karnofsky performance score KPS nutritional indicators serum albumin prealbumin body weight change and adverse reactions. Result In the experimental group the D90 dose covering 90% of the target volume of the high-risk clinical target volume HR-CTV was 86. 2±5. 3 Gy which was higher than that of the control group 83. 5±3. 2 Gy the conformity index CI was 0. 85±0. 06 which was higher than that of the control group 0. 76±0. 05 and the homogeneity index HI was 0. 15±0. 04 which was lower than that of the control group 0. 23±0. 05 all P<0. 05 . The D2cc dose to 2 cm 3 of the organ of the rectum 70. 3±4. 2 Gy and bladder 71. 5±3. 9 Gy in the experimental group were lower than those in the control group both P<0. 05 . One month after treatment the complete response CR rate in the experimental group 76. 56% was higher than that in the control group P<0. 05 . Three months after treatment the improvement rate of KPS 45. 3% serum albumin level 38. 5±3. 2 g / L and prealbumin level 235. 6±28. 4 mg / L in the experimental group were all higher than those in the control group whereas the rate of weight loss 12. 5% proportion of patients with PG-SGA grade C 6. 2% and incidence of rectal toxicity 42. 19% were lower than those in the control group all P < 0. 05 . Conclusion 192 Ir interstitial implantation paracervical boost radiotherapy can optimize the target volume dose distribution in LACC patients improve tumor control rate enhance short-term quality of life and nutritional status without increasing the incidence of severe acute-phase adverse reactions.