Different effects of bladder distention on point A-based and 3D-conformal intracavitary brachytherapy planning for cervical cancer

MRI-guided brachytherapy for cervical cancer treatment: The significance of bladder morphology in dose distribution planning

Purpose

This retrospective study aimed to investigate the influence of bladder filling type (BFT) on the relationship between bladder volume (BV) and maximum absorbed dose (D2cc) in intra-cavitary brachytherapy (ICBT) for cervical cancer.

Material and methods

The study enrolled 269 patients who underwent 3D-optimized ICBT guided by MRI scans between 2016 and 2022. Bladder shape (categorized as tilted, curved, or E) was determined based on specific applicators used. D2cc values were recorded for critical organs, such as bladder, rectum, sigmoid colon, and small bowel.

Results

The tilted group exhibited lower D2cc values for the small bowel when BV was less than 400 cc, while still ensuring minimal doses to the rectum and sigmoid colon. In the curved group (BV ≤ 100 cc), significant variations in D2cc for organs at risk were observed. However, in the E group, no substantial correlation between BV and D2cc was identified (p = -0.035). Additionally, the mean mid-sagittal line differences in the tilted group were 8.47 mm (pre-ICBT) and 7.11 mm (during ICBT simulation), surpassing measurements in the other two groups.

Conclusions

This study underscores the substantial impact of bladder shape on both the optimal bladder filling volume and maximum absorbed dose in cervical cancer ICBT. The implementation of BFT based on pre-ICBT MRI scans is both practical and beneficial. It accentuates the necessity of accounting for bladder shape when determining appropriate bladder filling volume, thus facilitating effective management of bladder and small bowel doses. Further prospective studies are warranted to assess the effect of BFT on the incidence of cystitis and proctitis following ICBT, all while maintaining consistent bladder distension.

Variations and effects of bladder and rectal volume following uniform preparation procedure in cervical cancer: Five fractions of 6 Gy

Purpose

To analyze the effects of different bladder and rectal volumes on the dose of organ at risks (OARs) and primary tumors following uniform preparation procedure.

Material and methods

In this retrospective study, a total of 60 patients with cervical cancer treated with external beam radiation therapy (EBRT) combined with chemotherapy and brachytherapy (BT) during 2019-2022 were included (300 insertions). Then, tandem-ovoid applicators were placed and computed tomography (CT) scanning was performed after each insertion. Delineation of OARs and clinical target volumes (CTVs) were done according to GEC-ESTRO group recommendations. Finally, doses of high-risk clinical target volume (HR-CTV) and OARs were obtained from dose volume histogram (DVH) automatically generated by BT treatment planning system.

Results

Following a uniform preparation procedure, the median bladder volume of 68.36 cc (range, 29.9-235.68 cc) was in optimal agreement with the recommended bladder volume of ≤ 70 ml, which avoided more manipulation and possible risk of adverse events during general anesthesia. As the bladder filling volume increased, there was no corresponding increase in rectal, HR-CTV, and small bowel volumes, while the sigmoid colon volume decreased. The median rectal volume was 54.95 cc (range, 24.92-168.1 cc), and as the rectal volume increased, HR-CTV, sigmoid colon, and rectum volumes increased, and conversely, small bowel volume decreased. HR-CTV changes with volume affected the rectum, bladder, and HR-CTV, but not the sigmoid colon and small intestine.

Conclusions

Following a uniform preparation procedure, the bladder and rectum can also be controlled to an optimal volume (B ≤ 70 cc, R ≈ 40 cc), which is related to the dose of the bladder, rectum, and sigmoid colon.

Dose Prediction Models Based on Geometric and Plan Optimization Parameter for Adjuvant Radiotherapy Planning Design in Cervical Cancer Radiotherapy

The prediction of an additional space for the dose sparing of organs at risk (OAR) in radiotherapy is still difficult. In this pursuit, the present study was envisaged to find out the factors affecting the bladder and rectum dosimetry of cervical cancer. Additionally, the relationship between the dose-volume histogram (DVH) parameters and the geometry and plan dose-volume optimization parameters of the bladder/rectum was established to develop the dose prediction models and guide the planning design for lower OARs dose coverage directly. Thirty volume modulated radiation therapy (VMAT) plans from cervical cancer patients were randomly chosen to build the dose prediction models. The target dose coverage was evaluated. Dose prediction models were established by univariate and multiple linear regression among the dosimetric parameters of the bladder/rectum, the geometry parameters (planning target volume (PTV), volume of bladder/rectum, overlap volume of bladder/rectum (OV), and overlapped volume as a percentage of bladder/rectum volume (OP)), and corresponding plan dose-volume optimization parameters of the nonoverlapping structures (the structure of bladder/rectum outside the PTV (NOS)). Finally, the accuracy of the prediction models was evaluated by tracking d = (predicted dose-actual dose)/actual in additional ten VMAT plans. V ₃₀, V ₃₅, and V ₄₀ of the bladder and rectum were found to be multiple linearly correlated with the relevant OP and corresponding dose-volume optimization parameters of NOS (regression R ² > 0.99, P < 0.001). The variations of these models were less than 0.5% for bladder and rectum. Percentage of bladder and rectum within the PTV and the dose-volume optimization parameters of NOS could be used to predict the dose quantitatively. The parameters of NOS as a limited condition could be used in the plan optimization instead of limiting the dose and volume of the entire OAR traditionally, which made the plan optimization more unified and convenient and strengthened the plan quality and consistency.

Intra-fractional dosimetric analysis of image-guided intracavitary brachytherapy of cervical cancer

Background

To assess the intra-fractional dosimetric variations of image-guided brachytherapy of cervical cancer.

Methods

A total of 38 fractions (9 patients) undergoing brachytherapy for cervical cancer underwent a CT scanning for treatment planning (planning CT) and a Cone-beam CT (CBCT) scanning immediately prior to delivery (pre-delivery CBCT). The variations of volumes as well as the dosimetric impact from treatment planning to delivery (intra-application) were evaluated. The dose volume histogram parameters including volume, D90 of high-risk clinical target volume (HRCTV) and D2cc of organs at risk (OARs) were recorded.

Results

The relative differences (mean ± 1SD) of the volume and D90 HRCTV across the two scans were − 2.0 ± 3.3% and − 1.2 ± 4.5%, respectively. The variations of D2cc for bladder, rectum, sigmoid and small intestine are − 0.6 ± 17.1%, 9.3 ± 14.6%, 7.2% ± 20.5% and 1.5 ± 12.6%, respectively. Most of them are statistically nonsignificant except the D2cc for rectum, which showed a significant increase (P = 0.001). Using 5% and 10% uncertainty of physical dose for HRCTV at a 6 Gy × 5 high-dose-rate schedule, the possibility of total equivalent doses in 2 Gy fractions (EQD2) lower than 85 Gy is close to 0% and 3%, respectively. Performing similar simulation at 15% and 20% uncertainty of a 4 Gy physical dose for OARs, the possibility of total EQD2 dose exceeding 75 Gy is about 70%. Less than 1% of the total EQD2 of OARs would exceed 80 Gy.

Conclusions

Average intra-fractional dosimetric variation of HRCTV was small in an interval of less than 1 h, and the possibility of total EQD2 exceeding 85 Gy is higher than 97%. The intra-fractional dosimetric variations of OARs might result in an overdose for OARs in a single fraction or the whole treatment. It is necessary to detect unfavorable anatomical changes by re-imaging and take interventions to minimize applied doses and reduce the risk of complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-021-01870-x.

Targetability of cervical cancer by magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU)-mediated hyperthermia (HT) for patients receiving radiation therapy

PURPOSE

To evaluate the targetability of late-stage cervical cancer by magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU)-induced hyperthermia (HT) as an adjuvant to radiation therapy (RT).

METHODS

Seventy-nine cervical cancer patients (stage IIIB-IVA) who received RT with lesions visible on positron emission tomography-computed tomography (PET-CT) were retrospectively analyzed for targetability using a commercially-available HT-capable MRgHIFU system. Targetability was assessed for both primary targets and/or any metastatic lymph nodes using both posterior (supine) and anterior (prone) patient setups relative to the transducer. Thirty-four different angles of rotation along subjects' longitudinal axis were analyzed. Targetability was categorized as: (1) Targetable with/without minimal intervention; (2) Not targetable. To determine if any factors could be used for prospective screening of patients, potential associations between demographic/anatomical factors and targetability were analyzed.

RESULTS

72.15% primary tumors and 33.96% metastatic lymph nodes were targetable from at least one angle. 49.37% and 39.24% of primary tumors could be targeted with patient laying in supine and prone positions, respectively. 25°-30° rotation and 0° rotation had the highest rate of the posterior and anterior targetability, respectively. The ventral depth of the tumor and its distance to the coccyx were statistically correlated with the anterior and posterior targetability, respectively.

CONCLUSION

Most late-stage cervical cancer primaries were targetable by MRgHIFU HT requiring either no/minimal intervention. A rotation of 0° or 25°-30° relative to the transducer might benefit anterior and posterior targetability, respectively. Certain demographic/anatomic parameters might be useful in screening patients for treatability.

Robotic radical hysterectomy is superior to laparoscopic radical hysterectomy and open radical hysterectomy in the treatment of cervical cancer

Objective

Cervical cancer (CC) continues to be a global burden for women, with higher incidence and mortality rates reported annually. Many countries have witnessed a dramatic reduction in the prevalence of CC due to widely accessed robotic radical hysterectomy (RRH). This network meta-analysis aims to compare intraoperative and postoperative outcomes in way of RRH, laparoscopic radical hysterectomy (LTH) and open radical hysterectomy (ORH) in the treatment of early-stage CC.

Methods

A comprehensive search of PubMed, Cochrane Library and EMBASE databases was performed from inception to June 2016. Clinical controlled trials (CCTs) of above three hysterectomies in the treatment of early-stage CC were included in this study. Direct and indirect evidence were incorporated for calculating values of weighted mean difference (WMD) or odds ratio (OR), and drawing the surface under the cumulative ranking curve (SUCRA).

Results

Seventeen 17 CCTs were ultimately enrolled in this network meta-analysis. The network meta-analysis showed that patients treated by RRH and LRH had lower estimated blood loss compared to patients treated by ORH (WMD = -399.52, 95% CI = -600.64~-204.78; WMD = -277.86, 95%CI = -430.84 ~ -126.07, respectively). Patients treated by RRH and LRH had less hospital stay (days) than those by ORH (WMD = -3.49, 95% CI = -5.79~-1.24; WMD = -3.26, 95% CI = -5.04~-1.44, respectively). Compared with ORH, patients treated with RRH had lower postoperative complications (OR = 0.21, 95%CI = 0.08~0.65). Furthermore, the SUCRA value of three radical hysterectomies showed that patients receiving RRH illustrated better conditions on intraoperative blood loss, operation time, the number of resected lymph nodes, length of hospital stay and intraoperative and postoperative complications, while patients receiving ORH demonstrated relatively poorer conditions.

Conclusion

The results of this meta-analysis confirmed that early-stage CC patients treated by RRH were superior to patients treated by LRH and ORH in intraoperative blood loss, length of hospital stay and intraoperative and postoperative complications, and RRH might be regarded as a safe and effective therapeutic procedure for the management of CC.

Effect of bladder distension on doses to organs at risk in Pulsed-Dose-Rate 3D image-guided adaptive brachytherapy for locally advanced cervical cancer

PURPOSE

To evaluate the impact of bladder distension on doses to organs at risk in patients treated with 3D image-guided adaptive pulsed-dose-rate (PDR) brachytherapy (BT) for locally advanced cervical cancer.

METHODS AND MATERIALS

Twenty-two patients who had previously been treated by external beam radiation therapy (EBRT), underwent BT treatment planning to a pelvic MRI (or a CT scan in case of contraindication) after their bladder was filled with 100 cc of physiological saline (full bladder). This was immediately followed by a CT scan after emptying of the bladder. A fusion of these two examinations was conducted, and the dosimetry was duplicated for the study with an empty bladder. Equieffective doses of 2 Gy per fraction from EBRT and BT of bladder/rectum/sigmoid colon/small bowel were compared.

RESULTS

A full bladder condition was found to be non-inferior in terms of the bladder D2cc (a difference of -0.9 Gy; 97.5% CI [-∞; 2.6]), and it resulted in a reduction in the bladder D0.1cc (p = 0.038). Bladder expansion resulted in a significant reduction of maximum doses received by the small bowel, both in terms of the D0.1cc (51.2 Gy vs. 63.4 Gy, p < 0.001) and the D2cc (48.5 Gy vs. 53.6 Gy, p < 0.001). A negative correlation was seen between the difference in the small bowel D2cc and the body mass index; (r = -0.55; p = 0.008). No differences were noted in regard to doses to the rectum and sigmoid colon.

CONCLUSIONS

Bladder distension with 100 cc of physiological saline can reduce maximum doses received by the small bowel without the alteration of the doses received by the other organs at risk during a 3D image-guided adaptive PDR BT for locally advanced cervical cancer. However, the maintenance of a predefined bladder volume is difficult to achieve with PDR BT, whereas it could be easily managed before each session in case of high-dose-rate BT.

Optimal bladder filling during high-dose-rate intracavitary brachytherapy for cervical cancer: a dosimetric study

Purpose

The aim of this study is to compare 3D dose volume histogram (DVH) parameters of bladder and other organs at risk with different bladder filling protocol during high-dose-rate intracavitary brachytherapy (HDR-ICBT) in cervical cancer, and to find optimized bladder volume.

Material and methods

This dosimetric study was completed with 21 patients who underwent HDR-ICBT with computed tomography/magnetic resonance compatible applicator as a routine treatment. Computed tomography planning was done for each patient with bladder emptied (series 1), after 50 ml (series 2), and 100 ml (series 3) bladder filling with a saline infusion through the bladder catheter. Contouring was done on the Eclipse Planning System. 7 Gy to point A was prescribed with the standard loading patterns. Various 3D DVH parameters including 0.1 cc, 1 cc, 2 cc doses and mean doses to the OAR’s were noted. Paired t-test was performed.

Results

The mean (± SD) bladder volume was 64.5 (± 25) cc, 116.2 (± 28) cc, and 172.9 (± 29) cc, for series 1, 2, and 3, respectively. The 0.1 cm³,1 cm³, 2 cm³ mean bladder doses for series 1, series 2, and series 3 were 9.28 ± 2.27 Gy, 7.38 ± 1.72 Gy, 6.58 ± 1.58 Gy; 9.39 ± 2.28 Gy, 7.85 ± 1.85 Gy, 7.05 ± 1.59 Gy, and 10.09 ± 2.46 Gy, 8.33 ± 1.75 Gy, 7.6 ± 1.55 Gy, respectively. However, there was a trend towards higher bladder doses in series 3. Similarly, for small bowel dose 0.1 cm³, 1 cm³, and 2 cm³ in series 1, 2, and 3 were 5.44 ± 2.2 Gy, 4.41 ± 1.84 Gy, 4 ± 1.69 Gy; 4.57 ± 2.89 Gy, 3.78 ± 2.21 Gy, 3.35 ± 2.02 Gy, and 4.09 ± 2.38 Gy, 3.26 ± 1.8 Gy, 3.05 ± 1.58 Gy. Significant increase in small bowel dose in empty bladder (series 1) compared to full bladder (series 3) (p = 0.03) was noted. However, the rectal and sigmoid doses were not significantly affected with either series.

Conclusions

Bladder filling protocol with 50 ml and 100 ml was well tolerated and achieved a reasonably reproducible bladder volume during cervical brachytherapy. In our analysis so far, there is no significant impact of bladder filling on DVH parameters, although larger bladders tend to have higher doses. Small bowel doses are lesser with higher bladder volumes. Further evaluation and validation are necessary.

Efficacy and toxicity of different concurrent chemoradiotherapy regimens in the treatment of advanced cervical cancer: A network meta-analysis

OBJECTIVE

The aim of this study was to compare the efficacy and toxicity of different concurrent chemoradiotherapy (CCRT) regimens in the treatment of advanced cervical cancer (CC) by adopting a network meta-analysis.

METHODS

We searched PubMed and Cochrane Library from the inception of these databases to September 2016, and all cohort studies (CSs) related to different CCRT regimens in the treatment of CC were included. A network analysis was adopted to compare the combination of direct and indirect evidence, to analyze the odds ratio (OR), and to draw a surface under the cumulative ranking curve of the efficacy and toxicity of different CCRT regimens for CC. Cluster analyses were used to group each category based on similar treatment regimens.

RESULTS

Nineteen CSs were enrolled in this network meta-analysis, including 12 CCRT regimens (radiotherapy [RT], CCRT [cisplatin], CCRT [vinorelbine], CCRT [paclitaxel], CCRT [hydroxyurea], CCRT [cisplatin + FU], CCRT [cisplatin + gemcitabine], CCRT [cisplatin + docetaxel], CCRT [cisplatin + paclitaxel], CCRT [cisplatin + amifostine], CCRT [cisplatin + FU + hydroxyurea], and CCRT [cisplatin + vincristine + bleomycin]). The results of the network meta-analysis showed that regarding efficacy, the overall response rate of CCRT (cisplatin + docetaxel) was higher than RT, and the 5-year overall survival (OS) rate of CCRT (cisplatin + FU + hydroxyurea) was relatively higher than CCRT (hydroxyurea). As for toxicity, CCRT (cisplatin) had a lower incidence of leukopenia than CCRT (hydroxyurea), CCRT (cisplatin + FU) and CCRT (cisplatin + paclitaxel), and the incidences of diarrhea and vomiting in CCRT (cisplatin) were lower than those in CCRT (cisplatin + gemcitabine). Additionally, the cluster analysis showed that CCRT (cisplatin) had relatively lower incidences of both hematotoxicity and gastrointestinal toxicity, and CCRT (paclitaxel) had lower gastrointestinal toxicity than other regimens.

CONCLUSION

Our study demonstrated that CCRT (cisplatin + docetaxel) might be the best choice of CCRT regimens in the treatment of CC, and the 5-year OS rate of CCRT (cisplatin + FU + hydroxyurea) might be the highest among these different regimens. CCRT (cisplatin) might have the lowest toxicity among all the CCRT regimens.

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.

Pulsed-dose rate image-guided adaptive brachytherapy in cervical cancer: Dose-volume effect relationships for the rectum and bladder

PURPOSE

To establish dose-volume effect correlations for late bladder and rectum side effects in patients treated for locally advanced cervical cancer with concomitant chemoradiation followed by pulsed-dose rate image-guided adaptive brachytherapy.

MATERIAL AND METHODS

The dosimetric data, converted in 2 Gy equivalent, from 217 patients were confronted to late morbidity defined as any event lasting or occurring 90 days after treatment initiation. Toxicity was assessed using the CTC-AE 3.0. Probit analyses and Log rank tests were performed to assess relationships.

RESULTS

One hundred and sixty-one urinary and 58 rectal events were reported, affecting 98 (45.1%) and 51 (23.5%) patients, respectively. Cumulative incidences for grade 2-4 bladder and rectal morbidity were 24.3% and 9.6% at 3 years, respectively. Significant relationships were observed between grade 2-4 and 3-4 events and D0.1cm(3) and D2 cm(3) for the bladder and between grade 1-4 and 2-4 event probability and rectal D2 cm(3). The effective doses for 10% grade 2-4 morbidity were 65.3 Gy (59.8-81.3), and 55.4 Gy (15.7-63.6), respectively, for the rectum and bladder. Without considering urinary and rectal incontinence, for which the pertinence of correlating them with D2 cm(3) is questionable, ED10 were 68.5 Gy (62.9-110.6) and 65.5 Gy (51.4-71.6 Gy). When sorting patients according to D2 cm(3) levels, patients with high D2 cm(3) had significantly lower morbidity free survival rates for grade 1-4 and 2-4 urinary and rectal morbidity.

CONCLUSION

Significant dose-volume effect relationships were demonstrated between the modern dosimetric parameters and the occurrence of late rectal and urinary morbidity in patients treated with pulsed-dose-rate brachytherapy. Further studies are required to refine these relationships according to clinical cofactors, such as comorbidities.