Dosimetric Comparison between Three-Dimensional Magnetic Resonance Imaging-Guided and Conventional Two-Dimensional Point A-Based Intracavitary Brachytherapy Planning for Cervical Cancer

OBJECTIVE

The purpose of this study was to comprehensively compare the 3-dimensional (3D) magnetic resonance imaging (MRI)-guided and conventional 2-dimensional (2D) point A-based intracavitary brachytherapy (BT) planning for cervical cancer with regard to target dose coverage and dosages to adjacent organs-at risk (OARs).

METHODS

A total of 79 patients with cervical cancer were enrolled to receive 2D point A-based BT planning and then immediately to receive 3D planning between October 2011 and April 2013 at the First Hospital Affiliated to Xi'an Jiao Tong University (Xi'an, China). The dose-volume histogram (DVH) parameters for gross tumor volume (GTV), high-risk clinical target volume (HR-CTV), intermediate-risk clinical target volume (IR-CTV) and OARs were compared between the 2D and 3D planning.

RESULTS

In small tumors, there was no significant difference in most of the DVHs between 2D and 3D planning (all p>0.05). While in big tumors, 3D BT planning significantly increased the DVHs for most of the GTV, HR-CTV and IR-CTV, and some OARs compared with 2D planning (all P<0.05). In 3D planning, DVHs for GTV, HR-CTV, IR-CTV and some OARs were significantly higher in big tumors than in small tumors (all p<0.05). In contrast, in 2D planning, DVHs for almost all of the HR-CTV and IR-CTV were significantly lower in big tumors (all p<0.05). In eccentric tumors, 3D planning significantly increased dose coverage but decreased dosages to OARs compared with 2D planning (p<0.05). In tumors invading adjacent tissues, the target dose coverage in 3D planning was generally significantly higher than in 2D planning (P<0.05); the dosages to the adjacent rectum and bladder were significantly higher but those to sigmoid colon were lower in 3D planning (all P<0.05).

CONCLUSIONS

3D MRI image-guided BT planning exhibits advantages over 2D planning in a complex way, generally showing advantages for the treatment of cervical cancer except small tumors.

Validity of 18F-fluorodeoxyglucose positron emission tomography/computed tomography for pretreatment evaluation of patients with cervical carcinoma: a retrospective pathology-matched study

OBJECTIVE

The aim of this study was to evaluate the validity of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) for pretreatment evaluation of patients with cervical carcinoma.

METHODS

Retrospective evaluation of 63 patients, diagnosed with stage IA-IIA cervical carcinoma who underwent 18F-FDG PET/CT before surgery, was performed. Sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratios (LRs) of PET/CT for predicting the positive cervix, vagina, uterine body, and lymph node invasion at the surgical specimen was calculated.

RESULTS

Sensitivity, specificity, positive predictive value, and negative predictive value of the positive cervix invasion in PET/CT to detect positive surgical specimen were 88.2%, 75%, 93.8%, and 60%, respectively. The LR+ ratio was 3.5, and the LR- ratio was 0.2. Sensitivity, specificity, positive predictive value, and negative predictive value of the positive vagina invasion in PET/CT to detect positive surgical specimen were 100%, 70.97%, 5.3%, and 100%, respectively. The LR+ ratio was 3.4, and the LR- ratio was 0. Sensitivity, specificity, positive predictive value, and negative predictive value of the positive uterine body invasion in PET/CT to detect positive surgical specimen were 75%, 83.1%, 23.1%, and 98%, respectively. The LR+ ratio was 4.4, and the LR- ratio was 0.3. Sensitivity, specificity, positive predictive value, and negative predictive value of the positive lymph node invasion in PET/CT to detect positive surgical specimen were 87.5%, 78.4%, 38.9%, and 97.6%, respectively. The LR+ ratio was 4.1, and the LR- ratio was 0.2.

CONCLUSIONS

The cervix invasion, negative uterine body invasion, and negative lymph node invasion are effective 18F-FDG PET/CT findings.

Comparative evaluation of two-dimensional radiography and three dimensional computed tomography based dose-volume parameters for high-dose-rate intracavitary brachytherapy of cervical cancer: a prospective study

BACKGROUND

Dosimetric comparison of two dimensional (2D) radiography and three-dimensional computed tomography (3D-CT) based dose distributions with high-dose-rate (HDR) intracavitry radiotherapy (ICRT) for carcinoma cervix, in terms of target coverage and doses to bladder and rectum.

MATERIALS AND METHODS

Sixty four sessions of HDR ICRT were performed in 22 patients. External beam radiotherapy to pelvis at a dose of 50 Gray in 27 fractions followed by HDR ICRT, 21 Grays to point A in 3 sessions, one week apart was planned . All patients underwent 2D-orthogonal and 3D-CT simulation for each session. Treatment plans were generated using 2D-orthogonal images and dose prescription was made at point A. 3D plans were generated using 3D-CT images after delineating target volume and organs at risk. Comparative evaluation of 2D and 3D treatment planning was made for each session in terms of target coverage (dose received by 90%, 95% and 100% of the target volume: D90, D95 and D100 respectively) and doses to bladder and rectum: ICRU-38 bladder and rectum point dose in 2D planning and dose to 0.1cc, 1cc, 2cc, 5cc, and 10cc of bladder and rectum in 3D planning.

RESULTS

Mean doses received by 100% and 90% of the target volume were 4.24 ± 0.63 and 4.9 ± 0.56 Gy respectively. Doses received by 0.1cc, 1cc and 2cc volume of bladder were 2.88 ± 0.72, 2.5 ± 0.65 and 2.2 ± 0.57 times more than the ICRU bladder reference point. Similarly, doses received by 0.1cc, 1cc and 2cc of rectum were 1.80 ± 0.5, 1.48 ± 0.41 and 1.35 ± 0.37 times higher than ICRU rectal reference point.

CONCLUSIONS

Dosimetric comparative evaluation of 2D and 3D CT based treatment planning for the same brachytherapy session demonstrates underestimation of OAR doses and overestimation of target coverage in 2D treatment planning.

Accuracy of magnetic resonance imaging in pretreatment lymph node assessment for gynecological malignancies

OBJECTIVE

To determine the accuracy of magnetic resonance imaging (MRI) in detection of metastasis in pelvic and para-aortic lymph nodes from different gynecological malignancies.

MATERIALS AND METHODS

This retrospective cross sectional analytic study was conducted at the Department of Diagnostic Radiology, Aga Khan University Hospital Karachi Pakistan from January 2011 to December 2012. A sample of 48 women, age range between 20-79 years, fulfilling inclusion criteria were included. All patients had histopathologically proven gynecological malignancies in the cervix, endometrium or ovary and presented for a pretreatment MRI to our radiology department.

RESULTS

MRI was 100% sensitive and had a 100% positive predictive value to detect lymph node metastasis in lymph nodes with spiculated margins and 100% sensitive with a 75% positive predictive value to detect lymph node metastasis in a lymph node with lobulated margins. The sensitivity and positive predictive value of MRI to detect heterogeneous nodal enhancement were 100% and 75% respectively.

CONCLUSIONS

Our study results reinforce that MRI should be used as a modality of choice in the pretreatment assessment of lymph nodes in proven gynaecological malignancies in order to determine the line of patient management, distinguishing surgical from non-surgical cases.

The role of magnetic resonance imaging in pretreatment evaluation of early-stage cervical cancer

OBJECTIVE

The aim of this study is to evaluate the accuracy of magnetic resonance imaging (MRI) in the preoperative assessments of primary tumor size, parametrial invasion, and pelvic lymph node metastasis in patients with early-stage cervical cancer.

MATERIALS AND METHODS

A cohort of 125 patients with International Federation of Gynecology and Obstetrics stage IA2 to IIA cervical cancer who had preoperative MRI and underwent radical hysterectomy were enrolled and analyzed. The accuracy of preoperative MRI scan and pelvic examination in the measurement of tumor size was assessed based on postoperative measurement and pathologic findings. The accuracy of detection of lymph node status and parametrial invasion was also assessed by comparing the MRI and pathologic findings.

RESULTS

The mean diameter of the tumor size measured by postoperative measurement, MRI, and pelvic examination was 2.97 ± 1.39 cm, 2.78 ± 1.24 cm, and 1.97 ± 1.70 cm, respectively. There were significant differences in the mean diameter of the tumor size between pelvic examinations and MRI scan or postoperative measurement (P < 0.0001). Based on postoperative measurement findings, accuracy of tumor size measurement between pelvic examination and MRI was determined by the degree of agreement with a difference of less than 0.5 or 1.0 cm. Pelvic examination and MRI had an accuracy of 24.75% and 39.60%, respectively, with a difference of less than 0.5 cm, and had an accuracy of 43.56% and 61.39%, respectively, with a difference of less than 1.0 cm. Correlation with postoperative measurement in tumor size was higher for MRI (r[s] = 0.481) than that for pelvic examination (r[s] = 0.362). The sensitivity, specificity, and accuracy of MRI in detecting lymph node metastasis were 27.78%, 85.98%, 77.60%, respectively. The negative predictive value of MRI in detecting parametrial invasion is 100%.

CONCLUSIONS

Magnetic resonance imaging is an accurate noninvasive modality for preoperative evaluation of tumor size and also gives important information to parametrial invasion and lymph node status in patients with early-stage cervical cancer.

Palliative treatment of advanced cervical cancer with radiotherapy and thai herbal medicine as supportive remedy - analysis of survival

BACKGROUND

To evaluate outcomes using a Thai herbal medicine, Vilac Plus (G716/45) with standard radiotherapy in comparison with historic controls from literature reports of the results of treatment in stage IIIB cervical cancer.

MATERIALS AND METHODS

Between March 2003 and June 2005, thirty patients with advanced cervical cancer stage IIIB-IV who had a poor performance status were treated by palliative radiotherapy along with an adjuvant daily dose of 15-30 ml of Thai herbal tonic solution (Vilac Plus G716/45) administered orally three times after meals as an additional supportive therapy. The results were analyzed from the aspect of the overall survival rates with curves estimated by the Kaplan-Meier method.

RESULTS

The median follow -up time for stage IIIB was 4.2 years with a range of 7.9 months - 6.1 years. The overall 1, 3, and 5 year survival rates for stage IIIB were 88%, 60% and 52%.

CONCLUSIONS

The overall 5 year survival rate for stage IIIB with a poor performance status was 52% when compared with 34-54.8% for historic controls. The combined complementary palliative radiotherapy (CCPR) had low rates of radiation morbidity. It was a simple technique and feasible for developing countries. The pilot study was limited by the small number of patients and further research will be necessary to assess interrelated and confounding factors in treatment of cervical cancer patients.