A prospective observational study with dose volume parameters predicting rectosigmoidoscopic findings and late rectosigmoid bleeding in patients with uterine cervical cancer treated by definitive radiotherapy

Predictive Factors for Toxicity After Primary Chemoradiation for Locally Advanced Cervical Cancer: A Systematic Review

PURPOSE

Women with locally advanced cervical cancer (LACC) undergoing primary platinum-based chemoradiotherapy and brachytherapy often experience toxicities. Normal-tissue complication probability (NTCP) models quantify toxicity risk and aid in optimizing radiation therapy to minimize side effects. However, it is unclear which predictors to include in an NTCP model. The aim of this systematic review was to provide an overview of the identified predictors contributing to gastrointestinal (GI), genitourinary (GU), and vaginal toxicities and insufficiency fractures for LACC.

METHODS AND MATERIALS

A systematic search was performed and articles evaluating the relationship between predictors and toxicities in women with LACC treated with primary chemoradiation were included. The Quality In Prognosis Studies tool was used to assess risk of bias, with high-risk studies being excluded from further analysis. Relationships between dose-volume parameters, patient and treatment characteristics, and toxicity endpoints were analyzed.

RESULTS

Seventy-three studies were identified. Twenty-six had a low or moderate risk of bias and were therefore included. Brachytherapy-related dose-volume parameters of the GI tract, including rectum and bowel equivalent dose in 2 Gy fractions (EQD2) D2 cm3, were frequently related to toxicities, unlike GU dose-volume parameters. Furthermore, (recto)vaginal point doses predicted toxicities. Few studies evaluated external beam radiation therapy dose-volume parameters and identified rectum EQD2 V30 Gy, V40 Gy, and V55 Gy, bowel and bladder EQD2 V40 Gy as toxicity predictors. Also, total reference air kerma and vaginal reference length were associated with toxicities. Relationships between patient characteristics and GI toxicity were inconsistent. The extent of vaginal involvement at diagnosis, baseline symptoms, and obesity predicted GU or vaginal toxicities. Only 1 study evaluated insufficiency fractures and demonstrated lower pretreatment bone densities to be associated.

CONCLUSIONS

This review detected multiple candidate predictors of toxicity. Larger studies should consider insufficiency fractures, assess dose levels from external beam radiation therapy, and quantify the relationship between the predictors and treatment-related toxicities in women with LACC to further facilitate NTCP model development for clinical use.

Dosimetric evaluation of Point A and volume-based high-dose-rate plans: a single institution study on adaptive brachytherapy planning for cervical cancer

Purpose

External beam radiation therapy (EBRT) and brachytherapy (BT) with concurrent cisplatin is the standard of care for locally advanced cervical cancer. The applicability of image-guided adaptive volume-based high-dose-rate (HDR) intracavitary brachytherapy planning is an active area of investigation. In this study, we examined whether volume-based HDR-BT (HDR_VOL) plans leads to more conformal plans compared to Point A (HDR_PointA)-based plans.

Material and methods

Two hundred and forty HDR_PointA plans from 48 cervical cancer patients treated with chemoradiotherapy were retrospectively collected. Point A plans were renormalized with respect to the high-risk clinical target volume (HR-CTV) for the HDR_VOL plans. The doses to organs at risk (OAR; rectum, sigmoid, and bladder), and HR-CTV and the conformal index were compared between HDR_PointA and HDR_VOL plans.

Results

HDR_VOL plans resulted in a 6-12% reduction in the total dose (EBRT + HDR-BT) to 0.1 cc, 1.0 cc, and 2.0 cc of the OAR as well as an 8-37% reduction in the dose to 2 cc of OAR per HDR-BT fraction compared to HDR_PointA plans. Differences in the conformal indexes between the two groups of plans showed an 18-31% relative increase per HDR-BT fraction for HDR_VOL plans. The D₉₀ of the HR-CTV was reduced by 11% by HDR_VOL planning and had a median dose of 86 Gy.

Conclusions

Our study reports the relative improvement in OAR doses per HDR-BT fraction by HDR_VOL planning compared to HDR_PointA planning and demonstrates the dosimetric advantages of volume-based HDR-BT planning in creating more conformal plans.

Investigating rectal toxicity associated dosimetric features with deformable accumulated rectal surface dose maps for cervical cancer radiotherapy

BACKGROUND

Better knowledge of the dose-toxicity relationship is essential for safe dose escalation to improve local control in cervical cancer radiotherapy. The conventional dose-toxicity model is based on the dose volume histogram, which is the parameter lacking spatial dose information. To overcome this limit, we explore a comprehensive rectal dose-toxicity model based on both dose volume histogram and dose map features for accurate radiation toxicity prediction.

METHODS

Forty-two cervical cancer patients treated with combined external beam radiotherapy (EBRT) and brachytherapy (BT) were retrospectively studied, including 12 with Grade ≥ 2 rectum toxicity and 30 patients with Grade 0-1 toxicity (non-toxicity patients). The cumulative equivalent 2-Gy rectal surface dose was deformably summed using the deformation vector fields obtained through a recent developed local topology preserved non-rigid point matching algorithm. The cumulative three-dimensional (3D) dose was flattened and mapped to a two-dimensional (2D) plane to obtain the rectum surface dose map (RSDM). The dose volume parameters (DVPs) were calculated from the 3D rectum surface, while the texture features and the dose geometric parameters (DGPs) were extracted from the 2D RSDM. Representative features further computed from DVPs, textures and DGPs by principle component analysis (PCA) and statistical analysis were respectively fed into a support vector machine equipped with a sequential feature selection procedure. The predictive powers of the representative features were compared with the GEC-ESTRO dosimetric parameters D_0.1/1/2cm³.

RESULTS

Satisfactory predictive accuracy of sensitivity 74.75 and 84.75%, specificity 72.67 and 79.87%, and area under the receiver operating characteristic curve (AUC) 0.82 and 0.91 were respectively achieved by the PCA features and statistical significant features, which were superior to the D_0.1/1/2cm³ (AUC 0.71). The relative area in dose levels of 64Gy, 67Gy, 68Gy, 87Gy, 88Gy and 89Gy, perimeters in dose levels of 89Gy, as well as two texture features were ranked as the important factors that were closely correlated with rectal toxicity.

CONCLUSIONS

Our extensive experimental results have demonstrated the feasibility of the proposed scheme. A future large patient cohort study is still needed for model validation.

The Efficacy and Late Toxicities of Computed Tomography-based Brachytherapy with Intracavitary and Interstitial Technique in Advanced Cervical Cancer

Purpose: To report the efficacy and late side effects(LSEs) of CT-based image-guided brachytherapy for the treatment of cervical cancer.

Materials: Between 2008 and 2014, 100 patients with FIGO stage IIB-IVA cervical carcinoma were analyzed. The patients received pelvic irradiation (45-50 Gy in 25 fractions) with concurrent chemotherapy, whereas the mean prescribed EBRT dose, including initial and boost doses to positive lymph nodes, ranged from 54 to 64 Gy. Afterwards, intracavitary(IC) or combined intracavitary/interstitial(IC/IS) brachytherapy was performed using a CT-based procedure with prescribed doses of 6 or 8 Gy in 3-7 fractions.

Results: The median follow-up time was 46 months. The 5-year local control, distant metastasis-free survival, and overall survival rates were 88.9%, 81.8%, 77.9%, respectively. IC/IS brachytherapy improved the HR-CTV D90 compared with IC (p<0.01). Seven patients (7.0%) had grade 2 bladder LSEs and none had grade 3/4 bladder LSEs. There was no significant relationship between bladder LSEs and the dose-volume histogram (p>0.05 for all). Thirty-seven patients (37%) had grade 2 rectal LSEs, 3(3%) had grade 3 rectal LSE. The rectum D_1cc, D_2cc, and D_5cc values were significantly higher in patients with grades 2/3 rectal toxicity than in those with grades 0/1 (p<0.05 for all). There was no grade 2 and above small bowel LSEs.

Conclusions: CT-based brachytherapy planning can achieve excellent local control with acceptable morbidity. HR-CTV D90 can increase in the IC/IS group compared with the IC group. The D_1cc, D_2cc, and D_5cc all showed excellent predictive values for rectal LSEs.

[Rectal toxicity prediction based on accurate rectal surface dose summation for cervical cancer radiotherapy]

OBJECTIVE

To propose arectal toxicity prediction method based on deformable surface dose accumulation.

METHODS

The clinical data were collected retrospectively from 42patients receiving radiotherapy for cervical cancer. With the first fraction as the reference, the other fractions of rectum surface were registered to the reference fraction to obtain the deformation vector fields (DVFs), which were used to deform and sum the fractional rectal doses to yield the cumulative rectal dose. The cumulative rectal dose was flattened via 3D-2D mapping to generate a 2D rectum surface dose map. Two dosimetric features, namely DVPs and DGPs were extracted. Logistic regression embedded with sequential forward feature selection was used as the prediction model. The predictive performance was evaluated in terms of the accuracy, sensitivity, specificity, and the area under the receiver operating characteristic (ROC) curve (AUC).

RESULTS

Significant improvements for rectum surface DIR were achieved. The best predictive results were achieved by using both DVPs and DGPs as the features with a sensitivity of 79.5%, a specificity of 81.3% and an AUC of 0.88.

CONCLUSION

The proposed method is feasible for predicting clinical rectal toxicity in patients undergoing radiotherapy for cervical cancer.

Toxicities and dose-volume histogram parameters of MRI-based brachytherapy for cervical cancer

PURPOSE

To analyze the toxicities and dose-volume histogram parameters of external-beam and magnetic resonance imaging-based intracavitary brachytherapy in cervical cancer patients.

METHODS AND MATERIALS

Acute and late toxicities were assessed in 135 patients divided into four groups: group 1, grade 0; group 2, grades 1-4; group 3, grades 0-1; and group 4, grades 2-4. The doses at the International Commission on Radiation Units and Measurements (D_ICRU) and minimum doses to the most exposed 0.1, 1, 2, and 5 cc (D_0.1cc, D_1cc, D_2cc, and D_5cc) of normal organs were calculated as equivalent doses in 2 Gy (α/β = 3).

RESULTS

The median follow-up was 35.2 months. For rectum, D_ICRU, D_0.1cc, D_1cc, and D_2cc were significantly different between groups 1 and 2 and D_ICRU, D_0.1cc, and D_1cc between groups 3 and 4. For bladder, D_0.1cc, D_1cc, and D_2cc were significantly different between groups 1 and 2 and D_ICRU, D_1cc, D_2cc, and D_5cc between groups 3 and 4. Grade 2-4 bladder toxicity occurred in fewer patients with D_2cc ≤ 95 Gy than those with D_2cc > 95 Gy (7% vs. 22%, p = 0.014).

CONCLUSIONS

D_ICRU, D_0.1cc, D_1cc, and D_2cc are relevant for predicting late rectal toxicities. The patients with bladder D_2cc > 95 Gy are required to be in close observation for severe late toxicities.

Late rectal toxicity determined by dose-volume parameters in computed tomography-based brachytherapy for locally advanced cervical cancer

The aim of this study was to observe the relationship between dose–volume histogram (DVH) parameters and rectal late side effects (LSE) in computed tomography (CT)‐based brachytherapy (BT) for patients with locally advanced cervical cancer. In total, 144 cervical cancer patients received external beam radiotherapy and CT‐based BT. The data from 111 survival cases with pelvic local control (LC) were used to analyze the relationship between DVH parameters and rectal LSE. The total doses, manifesting 2, 1, and 0.1 cm³ (D_2cc, D_1cc, and D_0.1cc) of the rectum, and D₉₀ for high‐risk clinical target volume (HR CTV) were computed and normalized to 2 Gy fractions (EQD2) using a linear‐quadratic model. The rectal LSE were evaluated by the late effects in normal tissues‐subjective, objective, management, and analytic (LENT‐SOMA) scale. A dose–response relationship was evaluated by probit analyses. For all patients, the total rate of rectal LSE was 56%, and the rate of ≥Grade 2 LSE was 27.4%. For the 111 survival cases with pelvic LC, the total mean for D_2cc was 71.23 ± 5.54 Gy for the rectum, and the D_2cc, D_1cc, and D_0.1cc values for Grades 2 and 3 were higher than those for Grades 0 and 1. In addition, the number of complications increased, and the complications became more severe as the dose increased, with a dose of 73.5 Gy resulting in a 10% probability of ≥Grade 3 LSE. In conclusion, DVH parameters could predict the incidence and grades of rectal LSE in CT‐based BT. D_2cc showed an excellent predictive value, and 73.5 Gy for D_2cc of the rectum might be considered as an alternative dose limit.

Vascular changes responsible for the reduced effectiveness of obliteration of uterine arteries in women with advanced cervical cancer

Introduction

Haemorrhages from the genital tract remain a major threat to the life of patients with advanced cervical cancer. It is possible to achieve haemostasis by both surgical techniques and the procedure of endovascular uterine artery embolization. However, in some women with loco-regionally advanced cervical cancer the obliteration of the uterine arteries is not effective.

Aim

Evaluation of morphological changes in uterine arteries in patients with advanced cervical cancer and comparison of their changes with the achieved haemostatic effect of obliteration.

Material and methods

The prospective study included a group of 8 women with cervical cancer at a clinical stage of IIB to IIIC according to the FIGO classification. 3D quantitative coronary angiography (QCA) was performed before uterine embolization. The haemostatic effect of uterine artery embolization was compared with observed vascular changes.

Results

Mean uterine artery length in patients who achieved complete hemostasis: 39.5 mm – right uterine artery; 38.7 mm – left uterine artery. Mean uterine artery length in patients who achieved partial satisfactory haemostasis: 32 mm – right uterine artery; 30.5 mm – left uterine artery. Mean uterine artery length in patients who achieved unsatisfactory haemostasis: 10.5 mm – right uterine artery; 19 mm – left uterine artery.

Conclusions

Shortening of uterine arteries worsens prognosis of the haemostatic effect of their obliteration in patients with advanced cervical cancer.

Second Primary Cancer after Diagnosis and Treatment of Cervical Cancer

Purpose

This study was conducted to investigate the incidence and survival outcomes of second primary cancers after the diagnosis of cervical cancer.

Materials and Methods

Data from the Korea Central Cancer Registry between 1993 and 2010 were reviewed and analyzed. Standardized incidence ratios (SIRs) of second primary cancers among women with cervical cancer were analyzed. Kaplan-Meier survival curves were constructed for cervical cancer patients with or without a second primary cancer.

Results

Among 72,805 women with cervical cancer, 2,678 (3.68%) developed a second primary cancer within a mean follow-up period of 7.34 years. The overall SIR for a second cancer was 1.08 (95% confidence interval, 1.04 to 1.12). The most frequent sites of second primary cancers were the vagina, bone and joints, vulva, anus, bladder, lung and bronchus, corpus uteri, and esophagus. However, the incidence rates of four second primary cancers (breast, rectum, liver, and brain) were decreased. The 5-year and 10-year overall survival rates were 78.3% and 72.7% in all women with cervical cancer, and for women with a second primary cancer, these rates were 83.2% and 65.5% from the onset of cervical cancer and 54.9% and 46.7% from the onset of the second primary cancer, respectively.

Conclusion

The incidence rates of second primary cancers were increased in women with cervical cancer compared to the general population, with the exception of four decreasing cancers. The 10-year overall survival rates were decreased in cervical cancer patients with a second primary cancer.