Postoperative external beam irradiation with and without brachytherapy in pelvic node-positive IB1-IIA2 cervical cancer patients: a retrospective clinical study

Evaluation of PTV margins with daily iterative online adaptive radiotherapy for postoperative treatment of endometrial and cervical cancer: a prospective single-arm phase 2 study

BACKGROUND

To determine the optimal planning target volume (PTV) margins for adequate coverage by daily iterative cone-beam computed tomography (iCBCT)-guided online adaptive radiotherapy (oART) in postoperative treatment of endometrial and cervical cancer and the benefit of reducing PTV margins.

METHODS

Fifteen postoperative endometrial and cervical cancer patients treated with daily iCBCT-guided oART were enrolled in this prospective phase 2 study. Pre- and posttreatment iCBCT images of 125 fractions from 5 patients were obtained as a training cohort, and clinical target volumes (CTV) were contoured separately. Uniform three-dimensional expansions were applied to the PTVpre to assess the minimum margin required to encompass the CTVpost. The dosimetric advantages of the proposed online adaptive margins were compared with conventional margin plans (7-15 mm) using an oART emulator in another cohort of 125 iCBCT scans. A CTV-to-PTV expansion was verified on a validation cohort of 253 fractions from 10 patients, and further margin reduction and acute toxicity were studied.

RESULTS

The average time from pretreatment iCBCT to posttreatment iCBCT was 22 min. A uniform PTV margin of 5 mm could encompass nodal CTVpost in 100% of the fractions (175/175) and vaginal CTVpost in 98% of the fractions (172/175). The margin of 5 mm was verified in our validation cohort, and the nodal PTV margin could be further reduced to 4 mm if ≥ 95% CTV coverage was predicted to be achieved. The adapted plan with a 5 mm margin significantly improved pelvic organ-at-risk dosimetry compared with the conventional margin plan. Grade 3 toxicities were observed in only one patient with leukopenia, and no patients experienced acute urinary toxicity.

CONCLUSION

In the postoperative treatment of endometrial and cervical cancer, oART could reduce PTV margins to 5 mm, which significantly decrease the dose to critical organs at risk and potentially lead to a lower incidence of acute toxicity.

Automatic reconstruction of interstitial needles using CT images in post-operative cervical cancer brachytherapy based on deep learning

Purpose

The purpose of this study was to investigate the precision of deep learning (DL)-based auto-reconstruction in localizing interstitial needles in post-operative cervical cancer brachytherapy (BT) using three-dimensional (3D) computed tomography (CT) images.

Material and methods

A convolutional neural network (CNN) was developed and presented for automatic reconstruction of interstitial needles. Data of 70 post-operative cervical cancer patients who received CT-based BT were used to train and test this DL model. All patients were treated with three metallic needles. Dice similarity coefficient (DSC), 95% Hausdorff distance (95% HD), and Jaccard coefficient (JC) were applied to evaluate the geometric accuracy of auto-reconstruction for each needle. Dose-volume indexes (DVI) between manual and automatic methods were used to analyze the dosimetric difference. Correlation between geometric metrics and dosimetric difference was evaluated using Spearman correlation analysis.

Results

The mean DSC values of DL-based model were 0.88, 0.89, and 0.90 for three metallic needles. Wilcoxon signed-rank test indicated no significant dosimetric differences in all BT planning structures between manual and automatic reconstruction methods (p > 0.05). Spearman correlation analysis demonstrated weak link between geometric metrics and dosimetry differences.

Conclusions

DL-based reconstruction method can be used to precisely localize the interstitial needles in 3D-CT images. The proposed automatic approach could improve the consistency of treatment planning for post-operative cervical cancer brachytherapy.

Role of brachytherapy in post-operative cervical cancer patients with risk factors other than positive stump

OBJECTIVE

This study aimed to determine the effectiveness of brachytherapy in post-operative cervical cancer patients with risk factors other than positive stump, and to identify the candidates most likely to benefit.

METHODS

Newly diagnosed, non-metastatic cervical cancer patients treated in our hospital between January 2012 and November 2015 were retrospectively reviewed. Early stage patients receiving radical surgery and needing adjuvant external radiotherapy were included, but those with positive stump were excluded. All patients received external radiotherapy. They were divided into two groups: one group received vaginal brachytherapy and the other did not. The 5-year local-regional recurrence free survival (LRRFS) and overall survival (OS) rates in the two groups were compared.

RESULTS

Two hundred and twenty-five patients were included in this study; while 99 received brachytherapy, 126 did not. The brachytherapy group had significantly superior 5-year LRRFS (87.7% vs. 72.5%, p = 0.004), but did not show a significant overall survival benefit (78.4% vs. 75.3%, p = 0.055). In multivariate analysis, brachytherapy, pathological type, high-risk factors, duration of radiotherapy, and transfusion were independent prognostic factors for 5-year LRRFS. In stratified analysis, the brachytherapy group showed superior LRRFS in those meeting Sedlis criteria (p = 0.017).

CONCLUSION

The combination of external beam radiation therapy and brachytherapy can improve LRRFS in post-operative cervical cancer patients with risk factors other than positive stump. Therefore, brachytherapy should be considered for these patients.

Electronic brachytherapy for gynecological cancers - a systematic review

Background

The purpose of this manuscript is to provide an in-depth literature review of the management of endometrial and cervical cancers with electronic brachytherapy.

Materials and methods

An extensive literature search was performed and 9 articles were selected based on preset criteria.

Results

The reviewed studies provided dosimetric and clinical results. Patient populations were diverse and prescribed doses varied. When treatment plans were compared to those using cobalt 60 (⁶⁰Co) and iridium 192 (¹⁹²Ir) sources researchers found lower or equivalent doses in organs at risk while the doses at the applicator surface were significantly higher for electronic brachytherapy. In the eligible studies, a total of 72 patients received treatment with AxxentXoft vaginal applicator, 29 were treated with the Intrabeam vaginal applicator, and 8 with AxxentXoft cervical applicator.

Conclusions

All authors found that electronic brachytherapy was safe and well tolerated as higher mucosal doses did not present as adverse clinical effects. Electronic brachytherapy for gynecological cancers has the potential to achieve equivalent tumor control while minimizing bowel and urinary toxicity thus improving the quality of life. More clinical data is needed to stratify patients who would benefit the most.

Incorporation of vaginal brachytherapy to external beam radiotherapy in adjuvant therapy for high-risk early-stage cervical cancer: A comparative study

PURPOSE

To examine trends, characteristics, and outcomes related to addition of vaginal brachytherapy (VBT) to external beam radiotherapy (EBRT) for adjuvant radiotherapy in high-risk early-stage cervical cancer.

METHODS AND MATERIALS

This comparative study is a retrospective observational analysis of the National Cancer Institutes' Surveillance, Epidemiology, and End Results Program. Surgically treated women with stage T1-2 cervical cancer who had high-risk factors (nodal metastasis and/or parametrial invasion) and received adjuvant radiotherapy from 2000 to 2018 were examined. Propensity score inverse probability of treatment weighting was used to assess the survival estimates for addition of VBT use.

RESULTS

Among 2470 women with high-risk factors receiving EBRT, 760 (30.8%) had additional VBT. During the study period, there was an increasing trend of VBT use from 27.4% to 36.1% (p< 0.001). In a multivariable analysis, year of diagnosis and high-risk tumor factors: parametrial involvement, large tumor size, and use of chemotherapy remained independent characteristics associated with VBT use (all, p< 0.05). In propensity score-weighted models, VBT use with EBRT and EBRT alone had comparable overall survival (5-year rates 73.8% vs. 77.4%, hazard ratio [HR] 1.07, 95% confidence interval [CI] 0.92-1.25). Nonsignificant association was also observed in squamous or nonsquamous tumors, young or old age, low or high nodal ratio, chemotherapy use, and simple or radical hysterectomy (all, p> 0.05). Lastly, the addition of VBT was not associated with cervical cancer-specific survival (subdistribution-HR 1.15, 95% CI 0.94-1.41).

CONCLUSIONS

Utilization of VBT with EBRT for adjuvant radiotherapy in high-risk early-stage cervical cancer is increasing in the United States. Addition of VBT was associated with neither overall survival nor cancer-specific survival.

The Case Selection for Vaginal Cuff Brachytherapy in Cervical Cancer Patients After Radical Hysterectomy and External Beam Radiation Therapy

Objective

To explore the suitable cases for vaginal cuff brachytherapy (VCB) combined with external beam radiation therapy (EBRT) in the postoperative treatment of cervical cancer.

Methods

We retrospectively analyzed the clinical data of 214 postoperative cervical cancer patients who received radiotherapy from January 2008 to December 2015. Among them, 146 patients received postoperative EBRT, 68 received EBRT plus VCB. There was no statistical difference in clinical and pathological characteristics between these two groups. Those who with negative vaginal cuff underwent supplemented 12–18 Gy/2–3 Fx VCB. Survival analyses were performed using Kaplan–Meier method, and Cox model was used to analyze prognostic factors.

Results

The median follow-up was 52 months (9–136 months), and 4-year RFS (recurrence-free survival) was 77%. Among them, 58 patients (27.10%) had local or distant recurrences, 29 (13.55%) in pelvis, six (2.80%) with metastases to para-aortic, 19 (8.88%) with distant metastases (including inguinal lymph nodes) and four (1.87%) with both local and distant recurrences. The postoperative brachytherapy boost did not improve RFS or OS (overall survival) among the investigated subjects, P = 0.77, P = 0.99, respectively. Neither it decreased the local relapse in the pelvis or vaginal cuff, P = 0.56, P = 0.59. Subgroup analyses showed that brachytherapy boost improved RFS in patients who had bulky mass (>4 cm) as well as 1) with deep stromal invasion (>50% stromal invasion), P = 0.012 or 2) received low EBRT dose (≤45 Gy), P = 0.033, and in patients with deep stromal invasion as well as received low EBRT dose (P = 0.018).

Conclusions

We first proposed the case selection model for postoperative EBRT plus VCB. Brachytherapy boost were considered in the setting of postoperative radiotherapy if the patients had at least two out of these following factors: bulky mass, deep stromal invasion and low EBRT dose.

Role of vaginal brachytherapy boost following adjuvant external beam radiotherapy in cervical cancer: Turkish Society for Radiation Oncology Gynecologic Group Study (TROD 04-002)

OBJECTIVE

There are a limited number of studies supporting vaginal brachytherapy boost to external beam radiotherapy in the adjuvant treatment of cervical cancer. The aim of this study was to assess the impact of the addition of vaginal brachytherapy boost to adjuvant external beam radiotherapy on oncological outcomes and toxicity in patients with cervical cancer.

METHODS

Patients treated with post-operative external beam radiotherapy ± chemotherapy ± vaginal brachytherapy between January 2001 and January 2019 were retrospectively evaluated. The treatment outcomes and prognostic factors were analyzed in patients treated with external beam radiotherapy with or without vaginal brachytherapy.

RESULTS

A total of 480 patients were included in the analysis. The median age was 51 years (range 42-60). At least two intermediate risk factors were observed in 51% of patients, while 49% had at least one high-risk factor. The patients in the external beam radiotherapy + vaginal brachytherapy group had worse prognostic factors than the external beam radiotherapy alone group. With a median follow-up time of 56 months (range 33-90), the 5-year overall survival rate was 82%. There was no difference in 5-year overall survival (87% vs 79%, p=0.11), recurrence-free survival (74% vs 71%, p=0.49), local recurrence-free survival (78% vs 76%, p=0.16), and distant metastasis-free survival (85% vs 76%, p=0.09) rates between treatment groups. There was no benefit of addition of vaginal brachytherapy to external beam radiotherapy in patients with positive surgical margins. In multivariate analysis, stage (overall survival and local recurrence-free survival), tumor histology (recurrence-free survival, local recurrence-free survival and distant metastasis-free survival), parametrial invasion (recurrence-free survival and distant metastasis-free survival), lymphovascular space invasion (recurrence-free survival), and lymph node metastasis (distant metastasis-free survival) were found as negative prognostic factors.

CONCLUSION

Adding vaginal brachytherapy boost to external beam radiotherapy did not provide any benefit in local control or survival in patients with cervical cancer.

Impact of postoperative intravaginal brachytherapy on survival for patients with intermediate-risk cervical cancer at National Cancer Institute (NCI), Egypt

Background

Cervical cancer is considered to be the fourth most frequent cancer among women. Postoperative treatment is indicated depending up on surgical findings and disease stage.

Objective

The objective of this study was to assess the long-term postoperative outcomes of cervical cancer patients with intermediate risk factors who have received pelvic external beam radiotherapy with or without vaginal brachytherapy, and treatment-related toxicities.

Patients and methods

In this retrospective study, the records were collected for all patients with cervical cancer who received postoperative radiotherapy at the National Cancer Institute between the years 2008 and 2013. The end points of the study were local control, progression-free survival, overall survival (OS) and delayed complications.

Results

Out of 248 patients, the median age of patients who did not receive brachytherapy was 53 years and the median age of patients who received brachytherapy was 52 years. A statistically significant difference was found in OS, progression-free survival and recurrence-free survival for those who received brachytherapy, with a p value<0·001, 0·01 and 0·004, respectively.

Conclusion

The addition of brachytherapy to postoperative external beam radiotherapy improves OS, progression-free survival and local control for patients with intermediate-risk cervical cancer.

Dosimetric advantages of using multichannel balloons compared to single-channel cylinders for high-dose-rate vaginal cuff brachytherapy

PURPOSE

To evaluate the dosimetric advantages of using multichannel balloons (MCBs) vs. single-channel cylinders (SCCs) for high-dose-rate vaginal cuff brachytherapy.

METHODS AND MATERIALS

A total of 91 consecutive high-dose-rate vaginal cuff brachytherapy including 45 MCB and 46 SCC treatments were reviewed. The clinical target volume (CTV) was defined as a 0.5-cm uniform expansion of the applicator surface from vaginal apex for 3 cm. For dosimetric comparison, we normalized prescription dose per fraction to 700 cGy and optimized each plan to cover at least 90% of CTV. CTV-1 cm, the true vaginal cuff volume, was defined as proximal 1 cm of CTV from vaginal apex. Four quality indices including conformity index (CI), dose homogeneity index, dose nonuniformity index, and overdose index were compared.

RESULTS

The CTV and CTV-1 cm were significantly larger for MCB cases compared to SCC cases. Evaluating CTV coverage, the mean dose homogeneity index and dose nonuniformity index were superior for MCB than SCC. No differences were noted regarding CI and overdose index between MCB and SCC cases. However, focusing on CTV-1 cm, the difference of CI became significant in favor of MCB cases. In addition, the mean point dose at 0.5-cm depth from the apex was significantly lower in SCC cases compared to cases by MCB treatment, indicating inadequate vaginal apex coverage by SCC treatment.

CONCLUSIONS

Compared to SCC, MCB treats a larger volume and offers a more conformal and homogeneous target coverage. In addition, a lower dose at the vaginal apex due to SCCs source anisotropy can be minimized.