ABSTRACT
Objective To analyze the therapeutic efficacy and treatment related toxicities for patients with locally advanced cervical cancer treated with three-dimensional conformal radiotherapy (3DCRT) combined with concurrent chemotherapy. Methods From January 2007 to February 2008, 181 patients with stage ⅡA-ⅣA cervical cancer were retrospectively analyzed. All patients were treated with CT-based three-dimensional external beam and 192Ir intracavity radiotherapy combined with concurrent weekly cisplatin-based chemotherapy. The median age was 50 years (range, 32 to 82 years). The overall survival ( OS), disease-free survival (DFS) and local control (LC) rates were calcalated by Kaplan-Meier method and the difference was compared using Log-rank test. The treatment related toxicities were evaluated according to Radiotherapy Oncology Group (RTOG) criteria. Results With a median follow-up time of 34 months and following rate of 92. 2%, the 3-year OS, DFS and LC rates were 73.4%, 70. 4% and 91.3%,respectively. The 3-year OS rate was 66. 9% for patients with tumor diameter ≥4 cm and 86. 4% for those with tumor diameter ＜4 cm( χ2 =6. 29 ,P =0. 012). The incidences of grade 1 and grade 2 acute toxicities of the lower gastrointestinal tract and the genitourinary system were 40. 0% ,45.0% and 19. 9% ,4. 4%,retrospectively. There were no grade 3 or more acute toxicities. The incidence of grades 3 or 4 late toxicities of the lower gastrointestinal tract was 4. 9%. Conclusions CT-based three-dimensional external beam and 192Ir intracavity radiotherapy combined with concurrent chemotherapy can achieve good therapeutic effects for locally advanced cervical cancer. The acute and late toxicities are significantly reduced compared with historic controls as a result of incorporation of 3DCRT technique.
ABSTRACT
Objective To investigate the correlation between dose volume histogram(DVH)of tumor targets and organs at risk(OAR)at CT-image based 192Ir brachytherapy and effects and complications for patients with locally advanced cervical cancer. Methods Ten patients with FIGO stage ⅢB cervical cancer received CT image-based 192Ir intracavitary brachytherapy after 54 Gy of three-dimentional four-field pelvic external beam radiotherapy and concurrent weekly cisplatin chemotherapy. Before each brachytherapy,CT images were acquired with applicators in place. Gross tumor volume(GTV), clinical target volume (CTV)and OAR were contoured and inverse treatment planning was designed and optimized by using PLATO treatment planning system. Conventional two-dimensional plans were also designed for comparison.The total intracavitary brachytherapy dose was 30 -42 Gy in 5 -7 fractions. The patients were followed, and the local control and complications were analyzed. The biologically equivalent dose(BED)and biologically equivalent dose in 2 Gy fractions(BED2)for GTV, CTV and OAR were calculated. The minimum dose in the most irradiated tissue volume 2 cm3(D2 cm3)adjacent to the applicator of the sigmoid colon, rectum,bladder and small bowel was determined from the DVH. Results The 1-year local pelvic control rate was 90% and grade 1-2 late complication of sigmoid colon and rectum was 50%. No grade 3 or more complications developed. On CT-image based planning, the BED and BED2 to 90% of the CTV(D90)were 95.50 Gy ± 7. 81 Gy and 79. 73 Gy ± 6. 57 Gy. The BED and BED2 to 90% of the GTV(D90)were 101.86 Gy ± 7.27 Gy and 84. 95 Gy ± 6. 1 Gy. The volume enclosed by 90% of prescribed dose(V90)for GTV and CTV were 92% ±4% and 87% ±7% respectively. The D2cm3 for rectum and sigmoid colon were 74. 97 Gy ±1.64 Gy and 67. 93 Gy ± 4. 30 Gy(EQD2, α/β = 3). Comparing with 2D brachytherapy plans , CT - image based planning has improved D90 and V90 for GTV and CTV with similar dose at point A and rectum reference point. Conclusions Computer tomography-image based 192Ir brachytherapy has resulted in the better dose distribution to the tumor targets with excellent tumor control and acceptable toxicity.