High-dose-rate brachytherapy boost for locally advanced cervical cancer: Oncological outcome and toxicity analysis of 4 fractionation schemes

The influence of time and implants in high-dose rate image-guided adaptive brachytherapy for locally advanced cervical cancer

PURPOSE

To compare the clinical outcomes of two different schedules of modern image-guided adaptive brachytherapy (IGABT) in patients underwent chemoradiotherapy (CCRT) and high-dose rate (HDR) brachytherapy (BT) for locally advanced cervical cancer treated (LACC) METHODS AND MATERIALS: Data from medical records of all consecutive patients with histologically proven cervical cancer (FIGO 2018 stage IB-IVA) treated by HDR-BT after CCRT at our institution between 2016 and 2021 were reviewed.

RESULTS

Two hundred and 8 patients with LACC FIGO 2018 stages (IB 20.7%; II 26.5%, III 51%, IVA 1.9%) underwent brachytherapy at our institution. Depending on initial clinical features of disease and the clinical response to CCRT, HDR-BT was delivered with one implant (BT1i) or two implants (BT2i) in 39% and 61% of patients respectively. FIGO stages (≥IIB) were 63% vs. 78% for BT1i and BT2i patient group respectively. Combined brachytherapy technique [endocavitary/interstitial (IC/IS)] was required in 14.8% vs. 68.5% for BT1i and BT2i respectively. With a median follow-up of 32.5 months (95% confidence interval, [29.7-35.8]), local relapse was observed in sixteen patients: 8 patients (3.8%) had local (exclusive) relapse and 8 patients (3.8%) had locally persistent and progressive disease, without significant difference for each BT modality group (p = 0.27), even if BT2i group had more aggressive initial disease. The estimated 3-year disease free survival and overall survival for the entire population was 69% (95% confidence interval, [62-75%]) and 88% (95% confidence interval, [82-92%]) respectively. There was a significant difference in the incidence of global toxicity grade G≥2 in favour to the BT2i group (p = 0.026).

CONCLUSIONS

HDR brachytherapy delivered with a long time interval between fractions, two implants, and combined IC/IS brachytherapy is the best way to ensure local control and to perform IGABT with low toxicity, even in advanced stages of disease.

Radiochemotherapy and interstitial brachytherapy for cervical cancer: clinical results and patient-reported outcome measures

OBJECTIVE

To evaluate clinical results and long-term patient-reported outcome measures (PROMs) on quality of life in cervical cancer patients following radiochemotherapy (RCT) and brachytherapy (BT) as definitive treatment.

MATERIALS AND METHODS

Between 2003 and 2023, a total of 132 patients with advanced cervical cancer were evaluated for possible treatment. Patients treated by postoperative RCT, palliative radiotherapy, and those treated for recurrent disease were excluded. Thus, 46 patients receiving standard RCT and BT as their curative treatment were included in this study. PROMs were assessed prospectively by patients' self-completion of the EORTC-QLQ-C30 and EORTC-QLQ-CX24 questionnaires.

RESULTS

Five-year overall survival (OS), distant metastases-free survival (DMFS), and pelvic tumor-free survival rates (PTFS) were 53%, 54%, and 83%, respectively. A significant impact on OS was seen for FIGO (International Federation of Gynecologic Oncology) stage (IIB-IIIA: 79% vs. IIIB-IVA: 33%, p = 0.015), for overall treatment time (OTT; 50-65 d: 64% vs. > 65 d: 38%, p = 0.004), and for rectal D2cc (≤ 73 Gy: 50% vs. > 73 Gy: 38%, p = 0.046). The identical parameters were significantly associated with DMFS (FIGO stage: p = 0.012, OTT: p = 0.008, D2cc: p = 0.024). No parameters with a significant influence on PTFS were seen. In multivariate analysis, an impact of FIGO stage on OS (p = 0.05) and DMFS (p = 0.014) was detected, and of rectal D2cc on DMFS (p = 0.031). The overall QoL score was 63/100. Cognitive function was the least impaired (84/100), while role functioning was the worst (67/100). On the symptom scale, insomnia (46/100), fatigue (41/100), dyspnea (32/100), pain (26/100), and financial difficulties (25/100) were scored the worst. According to EORTC-QLQ-CX24, peripheral neuropathy (36/100) and lymphedema (32/100) occurred most frequently. Impaired sexual/vaginal functioning (32/100) and body image (22/100) were also frequently recorded.

CONCLUSION

In patients with advanced cervical cancer, a combination of RCT and BT remains an excellent treatment option. In terms of patient-reported long-term quality of life, specific support is needed to alleviate symptoms including lymphedema, peripheral neuropathy, and impaired sexual activity.

High-dose-rate brachytherapy in uterine cervix carcinoma: a comparison of dosimetry and clinical outcomes among three fractionation schedules

Background

To assess the differences among three dose-fractionation schedules of image-guided adaptive brachytherapy (IGABT) in cervical squamous cell carcinoma (CSCC) by comparing the dosimetry and clinical outcomes.

Methods

Forty-five patients with CSCC who underwent chemoradiotherapy and IGABT were retrospectively enrolled and divided into three groups based on their dose-fractionation schedules of brachytherapy as: Group-5.5 (5.5 Gy × 6 fractions), Group-6.0 (6.0 Gy × 5 fractions), and Group-7.0 (7.0 Gy × 4 fractions). The analyzed dose-volume histogram parameters included D90% and D98% of the high-risk clinical target volume (HR-CTV), D90% and D98% of intermediate-risk clinical target volume (IR-CTV), and D0.1cc and D2cc of the organs-at-risk (OARs, namely the bladder, rectum, sigmoid and small intestine). Furthermore, the therapeutic efficacy and late toxicities were also compared among the three groups.

Results

The doses of HR-CTV and IR-CTV in Group-5.5 were found to be the highest among the three groups, followed by those in Group-6.0. Significant differences were found for the doses of HR-CTV between Group-5.5 and the other groups. There were no significant differences in the bladder, sigmoid and small intestine dose among the three groups. However, Group-6.0 yielded the lowest rectum received doses, with a significant difference in D0.1cc being detected between Group-6.0 and Group-5.5. The median follow-up time was 30.08 months [range, 6.57-46.3]. The numbers of patients with complete response in Group-5.5, Group-6.0 and Group-7.0 were 13, 14 and 14, respectively (P > 0.05). In regard to the toxicitiy, the incidence of radiation cystitis and proctitis in Group-6.0 was lower than that in Group-5.5 and Group-7.0 (P > 0.05).

Conclusions

The dose-fractionation schedule of 6.0 Gy × 5 fractions provided the most beneficial effects with relatively low OARs doses, suggesting that this dose-fractionation schedule should be prioritized in the clinical application of brachytherapy in cervical cancer.

Monocentric Retrospective Study: Efficacy, Feasibility, and Prognostic Factors of Single-Insertion High-Dose-Rate Brachytherapy With 4 Sessions for Locally Advanced Cervical Cancer

Purpose

This study aims to assess the feasibility and efficacy of high-dose rate (HDR) brachytherapy (BT) administered in a single insertion with 4 treatment sessions for locally advanced cervical cancer and to identify the prognostic factors influencing outcomes.

Methods and Materials

We retrospectively analyzed the clinical data of patients with cervical cancer with locally advanced disease (International Federation of Gynecology and Obstetrics 2018 IB-IVB) treated at our institution from January 2014 through December 2021. Each patient received definitive radiation therapy with an external irradiation dosage between 45 and 50.4 Gy along with concurrent chemotherapy. HDR-BT (24 Gy) was prescribed to a high-risk clinical target volume.

Results

One hundred thirty-nine patients were included and the HDR-BT program could be fully performed in 136 patients (98%). Over a median follow-up duration of 40.5 months, the 2-year local control (LC), overall survival (OS), and disease-free survival rates stood at 79.4%, 77.7%, and 61.7%, respectively, with 5-year rates at 78.2%, 61.6%, and 55.7%. Multivariate analysis revealed the primary determinant of LC as the tumor's response to external beam radiation therapy as determined via magnetic resonance imaging before BT. Parametrial involvement demonstrated a significant multivariate association with disease-free survival (P = .04). Regarding OS, parametrial invasion (P = .01) and the tumor's response postchemoradiotherapy (P = .02) emerged as significant factors. Regarding chronic toxicities, 18% (25 patients) experienced grade 3 complications. An optimal D2 cc (bowel) threshold of 70 Gy (P = .001) was identified to limit chronic digestive complications of grade 3 or higher.

Conclusions

The implementation of single-insertion, 4-session HDR-BT could be performed in 98% of the patients. It yields favorable LC and OS rates, coupled with tolerable toxicity in patients with locally advanced cervical cancer. Response to initial chemoradiotherapy evaluated on pre-BT magnetic resonance imaging is an important prognostic factor and could help to individualize therapeutic strategies.

Comparing dosimetry of locally advanced cervical cancer patients treated with 3 versus 4 fractions of MRI-guided brachytherapy

PURPOSE

To demonstrate the feasibility of treating cervical cancer patients with MRI-guided brachytherapy (MRgBT) using 24 Gy in 3 fractions (F) versus a standard, more resource-intensive regimen of 28 Gy in 4F, and its ability to meet EMBRACE II planning aims.

METHODS AND MATERIALS

A retrospective review of 224 patients with FIGO Stage IB-IVA cervical cancer treated with 28 Gy/4F (n = 91) and 24 Gy/3F (n = 133) MRgBT between 2016-2021 was conducted. Multivariable linear regression models were fitted to compare dosimetric parameters between the two groups, adjusting for CTV_HR and T stage.

RESULTS

Most patients had squamous cell carcinoma, T2b disease, and were treated with intracavitary applicator plus interstitial needles (96%). The 28 Gy/4F group had higher CTV_HR (median 28 vs. 26 cm³, p = 0.04), CTV_IR D_98% (mean 65.5 vs. 64.5 Gy, p = 0.03), rectum D_2cm3 (mean 61.7 vs. 59.2 Gy, p = 0.04) and bladder D_2cm3 (81.3 vs. 77.9 Gy, p = 0.03). There were no significant differences in the proportion of patients meeting the EMBRACE II OAR dose constraints and planning aims, except fewer patients treated with 28 Gy/4F met rectum D_2cm3 < 65 Gy (73 vs. 85%, p = 0.027) and ICRU rectovaginal point < 65 Gy (65 vs. 84%, p = 0.005).

CONCLUSIONS

Cervical cancer patients treated with 24 Gy/3F MRgBT had comparable target doses and lower OAR doses compared to those treated with 28 Gy/4F. A less-resource intense fractionation schedule of 24 Gy/3F is an alternative to 28 Gy/4F in cervix MRgBT.

Brachytherapy outcome modeling in cervical cancer patients: A predictive machine learning study on patient-specific clinical, physical and dosimetric parameters

PURPOSE

To predict clinical response in locally advanced cervical cancer (LACC) patients by a combination of measures, including clinical and brachytherapy parameters and several machine learning (ML) approaches.

METHODS

Brachytherapy features such as insertion approaches, source metrics, dosimetric, and clinical measures were used for modeling. Four different ML approaches, including LASSO, Ridge, support vector machine (SVM), and Random Forest (RF), were applied to extracted measures for model development alone or in combination. Model performance was evaluated using the area under the curve (AUC) of receiver operating characteristics curve, sensitivity, specificity, and accuracy. Our results were compared with a reference model developed by simple logistic regression applied to three distinct clinical features identified by previous papers.

RESULTS

One hundred eleven LACC patients were included. Nine data sets were obtained based on the features, and 36 predictive models were built. In terms of AUC, the model developed using RF applied to dosimetric, physical, and total BT sessions features were found as the most predictive [AUC; 0.82 (0.95 confidence interval (CI); 0.79 -0.93), sensitivity; 0.79, specificity; 0.76, and accuracy; 0.77]. The AUC (0.95 CI), sensitivity, specificity, and accuracy for the reference model were found as 0.56 (0.52 ...0.68), 0.51, 0.51, and 0.48, respectively. Most RF models had significantly better performance than the reference model (Bonferroni corrected p-value < 0.0014).

CONCLUSION

Brachytherapy response can be predicted using dosimetric and physical parameters extracted from treatment parameters. Machine learning algorithms, including Random Forest, could play a critical role in such predictive modeling.

The impact of different treatment protocols on achieved radiation doses of high-dose-rate brachytherapy for locally advanced cervical cancer: a comparison between 2 fractions in 1 application and separate applications for each fraction

PURPOSE

To compare radiation doses achieved by image-guided brachytherapy for locally advanced cervical carcinoma implemented with two different protocols.

MATERIAL AND METHODS

Medical records of 117 patients with locally advanced cervical carcinoma treated with brachytherapy from 2009 to 2018 at our institution were retrospectively reviewed. All patients had received previous external beam radio/chemotherapy. We performed magnetic resonance image-guided adaptive high-dose-rate brachytherapy delivered by intra-cavitary/interstitial applicators. Dose prescription was 7 Gy for four fractions within two weeks. Original schedule of brachytherapy was two fractions delivered on consecutive days with one applicator insertion; this process was repeated one week later (group 1, 54 patients). From 2015 onwards, another protocol of brachytherapy was mainly used, separately performing applicator insertions for each of the four administered fractions (group 2, 63 patients).

RESULTS

The high-risk clinical target volume (HR-CTV) D90 planning aim (PA) of ≥ 85 Gy (hard constraint) was not achieved in 9 cases out of 54 (17%) in group 1 compared with only 2 out of 63 cases (3%) in group 2 (p = 0.022). A difference between the two groups was also found in the fulfillment of PA 90 Gy (soft constraint) (p = 0.027). We conducted a sub-group analysis of target volume groups and observed that the differences were most pronounced with very large tumors (> 50 cm3). In these patients, PA 85 Gy was only fulfilled in 67% cases when treatment involved two applications, but in all cases with four separate applicator insertions (p = 0.010).

CONCLUSIONS

In our experience, by performing an applicator insertion for each of the fractions, it is possible to correct the non-optimal position of the applicator immediately, and to deliver better doses for consecutive fractions. As a result, the planning aim is more often achieved, especially for large tumors.

Comparative Analysis of 60Co and 192Ir Sources in High Dose Rate Brachytherapy for Cervical Cancer

High-dose-rate (HDR) brachytherapy (BT) is an essential treatment for cervical cancer, one of the most prevalent gynecological malignant tumors. In HDR BT, high radiation doses can be delivered to the tumor target with the minimum radiation doses to organs at risk. Despite the wide use of the small HDR 192Ir source, as the technique has improved, the HDR 60Co source, which has the same miniaturized geometry, has also been produced and put into clinical practice. Compared with 192Ir (74 days), 60Co has a longer half-life (5.3 years), which gives it a great economic advantage for developing nations. The aim of the study was to compare 60Co and 192Ir sources for HDR BT in terms of both dosimetry and clinical treatment. The results of reports published on the use of HDR BT for cervical cancer over the past few years as well as our own research show that this treatment is safe and it is feasible to use 60Co as an alternative source.

Four-Dimensional Image-Guided Adaptive Brachytherapy for Cervical Cancer: A Systematic Review and Meta-Regression Analysis

Purpose

The ICRU/GEC-ESTRO released the ICRU Report No. 89, which introduced the concept of four-dimensional brachytherapy and ushered in a new era of brachytherapy for cervical cancer. The purpose of this study was to evaluate the local control and late toxicity of four-dimensional brachytherapy in cervical cancer through a systematic review and to reveal the dose-response relationship between the volumetric dose paraments and the local control rate via a probit model.

Material and Methods

We identified studies that reported the HR-CTV D90 and local control probabilities by searching the PubMed Database, the Web of Science Core Collection and the Cochrane Library Database through February 1st, 2022. Regression analyses were performed between the HR-CTV D90 and the local control probability using a probit model.

Results

Nineteen studies enrolling 3,616 patients were included. The probit model showed a significant relationship between the HR-CTV D90 value and IR-CTV D90 Vs. the local control probability, P &lt; 0.001 and P = 0.003, respectively. The D90 for HR-CTV and IR-CTV corresponding to a probability of 90% local control was 79.1 GyEQD2,10 (95% CI:69.8 – 83.7 GyEQD2,10) and 66.5 GyEQD2,10 (95% CI: 62.8 - 67.9 GyEQD2,10), respectively. The limits for the prescribed dose of 85 GyEQD2,10 for HR-CTV D90 theoretically warranted a 92.1% (95% CI: 90.2% - 95.3%) local control rate, and 87.2% (95% CI: 82.4% - 91.8%) local control probability was expected for 65 GyEQD2,10 to IR-CTV D90. The probit model showed no significant relationship between the D2cc to organs at risk and the probability of grade 3 and above gastrointestinal or genitourinary toxicity.

Conclusions

Four-dimensional brachytherapy takes into account uncertain factors such as tumour regression, internal organ motion and organ filling, and provides a more accurate and more therapeutic ratio delivery through adaptive delineation and replanning, replacement of the applicator, and the addition of interstitial needles. The dose volume effect relationship of four-dimensional brachytherapy between the HR-CTV D90 and the local control rate provides an objective planning aim dose.