A volumetric analysis of GTVD and CTVHR as defined by the GEC ESTRO recommendations in FIGO stage IIB and IIIB cervical cancer patients treated with IGABT in a prospective multicentric trial (EMBRACE)

Cancer stem cell biomarkers SOX2 and Oct4 in cervical cancer patients undergoing chemoradiotherapy

BACKGROUND

Cancer stem cell biomarkers SRY (sex-determining region Y)-box 2 (SOX2) and octamer-binding transcription factor 4 (Oct4) account for radioresistance in cervical squamous cell cancers (CSCCs). Their clinical implications are limited and contradictory.

METHODS

In this prospective cohort study, we recruited patients with FIGO IB2-IVA CSCC treated with primary chemoradiotherapy on regular follow-up. Tissue biopsy specimens were evaluated for SOX2 and Oct4 expression by immunohistochemistry, quantified by a product of proportion and intensity scores.

RESULTS

A total of 59 patients were included. Most had a moderately differentiated (81%), keratinizing (59%) CSCC, and ≥FIGO stage IIB disease (95%). SOX2 expression (high:low 21:38 patients) and Oct4 expression (high:low 4:55 patients) had a significant interrelation (p = 0.005, odds ratio (95% CI) - 1.23 (1.004-1.520)). At a median follow-up of 36 months, the 3-year overall survival (OS) was 60% and 53% for low and high SOX2 expression (p = 0.856), and 54% and 100% for low and high Oct4 expression (p = 0.114). The 3-year disease-frese survival (DFS) was 65% and 50% in the low and high SOX2 expression (p = 0.259), and 59% and 75% for low and high Oct4 expression (p = 0.598). SOX2 expression was the only variable significantly associated with a lower OS and DFS on regression analysis.

CONCLUSION

Our study demonstrated a trend toward improved OS and DFS with low SOX2 and high Oct4 expression in CSCC patients undergoing chemoradiotherapy.

Radiotherapy for postoperative vaginal recurrences of cervical squamous cell carcinoma: analysis of dosing and prognosis

Squamous cell carcinoma (SCC) is the most common type of vaginal recurrence in cervical cancer patients, and the role of salvage radiotherapy on these patients remains unclear. This study aimed to investigate the efficacy of salvage radiotherapy for vaginal recurrence of SCC in patients who previously underwent surgery and to explore prognostic factors associated with survival. Ninety-seven patients with histologically proven SCC who were treated for vaginal recurrence at Peking Union Medical College Hospital were identified. All patients had previously undergone surgery and received salvage radiotherapy. Factors predictive of overall survival (OS), progression-free survival (PFS), and local control (LC) were investigated. The median follow-up time was 42.5 months. The estimated 5-year OS, PFS, and LC rates were 84%, 79%, and 91%. On multivariate analysis, inguinal lymph node metastasis was significantly associated with poor OS; a tumour size ≤4 cm was associated with longer PFS (p < 0.05); the recurrence pattern was an independent predictor of LC (p < 0.05). In the 45 patients with recurrences that were paravaginal or invasive of surrounding organs, biologically equivalent doses in 2 Gy fractions of ≥72.6 Gy were independently predictive of longer LC (p < 0.05). RT is an effective treatment for postoperative vaginal recurrence in patients with cervical SCC. For patients with extravaginal recurrence, a salvage dose of ≥72.6 Gy appears to be optimal.Impact statementWhat is already known on this subject? Radiotherapy plays a critical role in treating recurrent cervical cancer, but the effectiveness of RT for vaginal recurrence in patients who previously underwent surgery remains limited. Few studies have focussed on the effect of RT dose on patient survival.What do the results of this study add? This study investigated the efficacy of RT in patients with cervical squamous cell carcinoma who experienced postoperative recurrence. Lymph node metastasis, tumour size and recurrence pattern were significantly associated with survival. Moreover, an EQD2 ≥ 72.6 Gy was independently predictive of longer LC.What are the implications of these findings for clinical practice and/or further research? RT is an effective treatment for postoperative vaginal recurrence in patients with cervical squamous cell carcinoma. For patients with extravaginal recurrence, a salvage dose of ≥72.6 Gy appears to be optimal.

ESGO/ESTRO quality indicators for radiation therapy of cervical cancer

BACKGROUND

The European Society of Gynaecological Oncology (ESGO) has previously defined and established a list of quality indicators for the surgical treatment of cervical cancer. As a continuation of this effort to improve overall quality of care for cervical cancer patients across all aspects, ESGO and the European SocieTy for Radiotherapy and Oncology (ESTRO) initiated the development of quality indicators for radiation therapy of cervical cancer.

OBJECTIVE

To develop a list of quality indicators for radiation therapy of cervical cancer that can be used to audit and improve clinical practice by giving to practitioners and administrators a quantitative basis to improve care and organizational processes, notably for recognition of the increased complexity of modern external radiotherapy and brachytherapy techniques.

METHODS

Quality indicators were based on scientific evidence and/or expert consensus. The development process included a systematic literature search for identification of potential quality indicators and documentation of scientific evidence, consensus meetings of a group of international experts, an internal validation process, and external review by a large international panel of clinicians (n = 99).

RESULTS

Using a structured format, each quality indicator has a description specifying what the indicator is measuring. Measurability specifications are detailed to define how the quality indicators will be measured in practice. Targets were also defined for specifying the level which each unit or center should be aiming to achieve. Nineteen structural, process, and outcome indicators were defined. Quality indicators 1-6 are general requirements related to pretreatment workup, time to treatment, upfront radiation therapy, and overall management, including active participation in clinical research and the decision making process within a structured multidisciplinary team. Quality indicators 7-17 are related to treatment indicators. Quality indicators 18 and 19 are related to patient outcomes.

DISCUSSION

This set of quality indicators is a major instrument to standardize the quality of radiation therapy in cervical cancer. A scoring system combining surgical and radiotherapeutic quality indicators will be developed within an envisaged future ESGO accreditation process for the overall management of cervical cancer, in an effort to support institutional and governmental quality assurance programs.

ESGO/ESTRO quality indicators for radiation therapy of cervical cancer

BACKGROUND

The European Society of Gynaecological Oncology (ESGO) has previously defined and established a list of quality indicators for the surgical treatment of cervical cancer. As a continuation of this effort to improve overall quality of care for cervical cancer patients across all aspects, ESGO and the European SocieTy for Radiotherapy and Oncology (ESTRO) initiated the development of quality indicators for radiation therapy of cervical cancer.

OBJECTIVE

To develop a list of quality indicators for radiation therapy of cervical cancer that can be used to audit and improve clinical practice by giving to practitioners and administrators a quantitative basis to improve care and organizational processes, notably for recognition of the increased complexity of modern external radiotherapy and brachytherapy techniques.

METHODS

Quality indicators were based on scientific evidence and/or expert consensus. The development process included a systematic literature search for identification of potential quality indicators and documentation of scientific evidence, consensus meetings of a group of international experts, an internal validation process, and external review by a large international panel of clinicians (n=99).

RESULTS

Using a structured format, each quality indicator has a description specifying what the indicator is measuring. Measurability specifications are detailed to define how the quality indicators will be measured in practice. Targets were also defined for specifying the level which each unit or center should be aiming to achieve. Nineteen structural, process, and outcome indicators were defined. Quality indicators 1-6 are general requirements related to pretreatment workup, time to treatment, upfront radiation therapy, and overall management, including active participation in clinical research and the decision making process within a structured multidisciplinary team. Quality indicators 7-17 are related to treatment indicators. Quality indicators 18 and 19 are related to patient outcomes.

DISCUSSION

This set of quality indicators is a major instrument to standardize the quality of radiation therapy in cervical cancer. A scoring system combining surgical and radiotherapeutic quality indicators will be developed within an envisaged future ESGO accreditation process for the overall management of cervical cancer, in an effort to support institutional and governmental quality assurance programs.

The Prognostic Value of Tumor Size, Volume and Tumor Volume Reduction Rate During Concurrent Chemoradiotherapy in Patients With Cervical Cancer

Objective

This study aimed to investigate the relationship between prognostic and tumor parameters of cervical cancer patients, such as tumor size (TS), tumor volume (TV), and tumor volume reduction rate (TVRR) after external beam radiotherapy.

Methods

A total of 217 patients with advanced cervical cancer, classified as Federation of Gynecology and Obstetrics (FIGO) IIa–IVa, were enrolled in the study. Pre- and mid-RT pelvic magnetic resonance imaging (MRI) were performed twice, during RT and just before brachytherapy.

Results

The median follow-up time was 51 months (range, 7–111 months). The 5-year overall survival (OS), progression-free survival (PFS), and local failure-free survival (LFFS) rates were 81.3, 85.1, and 92.9%, respectively. Multivariate analysis revealed that tumor parameters including FIGO stage >II (Hazard Ratio, 2.377 and 95% confidence interval [CI], 1.091–5.182; P = 0.029), pre-RT TV >61.6 cm³ (HR, 0.417 and 95% CI, 0.188–0.926; P = 0.032), and mid-RT TV >11.38 cm³ (HR, 3.192 and 95% CI, 1.094–9.316; P = 0.034) were observably associated with OS. Univariate analysis showed that the tumor volume reduction rate (TVRR) was dramatically associated with overall survival (HR, 0.204 and 95% CI 0.033–1.282; P <0.001) and local failure-free survival (P = 0.050).

Conclusions

In this retrospective study, TVRR and mid-radiotherapy tumor volume are independent and strong prognostic parameters for patients with local advanced cervical cancer receiving CCRT.

Clinical outcome of combined intracavitary / interstitial brachytherapy using a hybrid applicator in locally advanced cervical cancer

OBJECTIVE

The aim of this study was to evaluate the clinical outcome in locally advanced cervical cancer (LACC) after image-guided adaptive brachytherapy (IGABT) with combined intracavitary and interstitial (IC/IS) techniques using the hybrid Venezia applicator (Elekta AB, Sweden).

METHODS

LACC patients (UICC Stage IIB - IVB) treated with radiochemotherapy followed by IGABT with the hybrid IC/IS Venezia applicator at a single institution were retrospectively analyzed. Treatment comprised EBRT of the pelvis with 45 Gy and concomitant weekly cisplatin chemotherapy (40 mg/m²) followed by MRI-based IGABT. Dosimetry, oncological outcome and toxicity were investigated.

RESULTS

Forty-six patients underwent a total of 184 fractions of IGABT between 2017 and 2020. Median follow-up was 24 months. Combined IC/IS techniques were used in 40 patients (87%). The median HRCTV volume was 31.2 cm³ and the median HRCTV D_90% was 92.3 Gy (EQD2₁₀). The median D_2cm³ was 74.8 Gy for bladder, 57.9 Gy for rectum, 60.0 Gy for sigmoid and 52.2 Gy for bowel (EQD2₃). The 3-yr actuarial rates were 97.6% for local control, 97.6% for pelvic control, 59.9% for distant metastasis-free survival and 81.6% for overall survival. The crude rate for G2 and G3 late toxicity was 21.7% and 4.3%.

CONCLUSIONS

IGABT with the hybrid Venezia applicator and a pronounced use of a combined IC/IS technique achieved high target doses, while maintaining low doses to organs at risk, leading to excellent local control and overall survival rates with acceptable toxicity.

Contemporary image-guided cervical cancer brachytherapy: Consensus imaging recommendations from the Society of Abdominal Radiology and the American Brachytherapy Society

PURPOSE

To present recommendations for the use of imaging for evaluation and procedural guidance of brachytherapy for cervical cancer patients.

METHODS

An expert panel comprised of members of the Society of Abdominal Radiology Uterine and Ovarian Cancer Disease Focused Panel and the American Brachytherapy Society jointly assessed the existing literature and provide data-driven guidance on imaging protocol development, interpretation, and reporting.

RESULTS

Image-guidance during applicator implantation reduces rates of uterine perforation by the tandem. Postimplant images may be acquired with radiography, computed tomography (CT), or magnetic resonance imaging (MRI), and CT or MRI are preferred due to a decrease in severe complications. Pre-brachytherapy T2-weighted MRI may be used as a reference for contouring the high-risk clinical target volume (HR-CTV) when CT is used for treatment planning. Reference CT and MRI protocols are provided for reference.

CONCLUSIONS

Image-guided brachytherapy in locally advanced cervical cancer is essential for optimal patient management. Various imaging modalities, including orthogonal radiographs, ultrasound, computed tomography, and magnetic resonance imaging, remain integral to the successful execution of image-guided brachytherapy.

An Asian multi-national multi-institutional retrospective study comparing intracavitary versus the hybrid of intracavitary and interstitial brachytherapy for locally advanced uterine cervical carcinoma

This study is an international multi-institutional retrospective study comparing the clinical outcomes between intracavitary brachytherapy (ICBT) and the hybrid of intracavitary and interstitial brachytherapy (HBT) for locally advanced cervical cancer patients treated with definitive radiation therapy. Locally advanced cervical cancer, the initial size of which is larger than 4 cm and treated by concurrent chemoradiotherapy and image-guided adaptive brachytherapy, were eligible for this retrospective study. Patients who received HBT at least once were included in the HBT group, and patients who received only ICBT were included in the ICBT group. Anonymized data from 469 patients from 13 institutions in Japan, one from Korea and one from Thailand, were analyzed. Two hundred eighty and 189 patients were included in the ICBT group and the HBT group, respectively. Patients in the HBT group had more advanced stage, non-Scc histopathology, a higher rate of uterine body involvement, larger tumor at diagnosis, larger tumor before brachytherapy and a lower tumor reduction ratio. With a median follow-up of 51.3 months (2.1-139.9 months), 4-y local control (LC), progression-free survival (PFS) and overall survival (OS) for the entire patient population were 88.2%, 64.2% and 83%, respectively. The HBT group received a higher HR-CTV D90 than that of the ICBT group (68.8 Gy vs 65.6 Gy, P = 0.001). In multivariate analysis, the non-Scc histological subtype, HR-CTV D95 ≤ 60 Gy, reduction ratio ≤ 29% and total treatment time (TTT) ≥ 9 weeks were identified as the independent adverse prognostic factors for LC. Regarding LC, no difference was found between ICBT and HBT (4-y LC 89.3% vs 86.8%, P = 0.314). After adjustment for confounding factors by propensity score matching, no advantage of applying HBT was demonstrated regarding LC, PFS, or OS. Despite the fact that HBT patients had more adverse clinical factors than ICBT patients, HBT delivered a higher dose to HR-CTV and resulted in comparable LC.

Evaluation of sociodemographic and baseline patient characteristic differences in cervical cancer patients treated with either external beam or brachytherapy boost

PURPOSE

Chemoradiation is considered the standard of care for locally advanced cervical cancer. While brachytherapy (BT) boost is associated with improved survival and less toxicity compared to external beam radiation therapy (EBRT) boost, it is unclear why many patients do not receive a BT boost. In this study, we compared sociodemographic and baseline patient characteristics between patients receiving EBRT boost versus BT boost.

METHODS

We analyzed patients in the National Cancer Database diagnosed between 2004 and 2016 with FIGO stage IIB-IVA cervical cancer treated with nonpalliative doses of chemoradiation. Logistic regression analysis was utilized to evaluate BT utilization over time and by other clinicopathological and sociodemographic factors.

RESULTS

Overall, 5764 patients were evaluated, of which 4937 (86%) underwent BT boost. Using multivariable logistic regression, higher FIGO stage was a significant predictor for utilization of EBRT versus BT boost, with odds ratio 2.92 (95% confidence interval [CI] 2.04-4.16; p < 0.001), 2.68 (95%CI 2.22-3.24; p < 0.001), and 4.51 (95%CI 3.05-6.67; p < 0.001) for IIIA, IIIB, and IVA, respectively, compared to IIB. Increased utilization of EBRT boost was also associated with community cancer facility types, lower income (based on zip code), earlier year of diagnosis, and higher comorbidity score.

CONCLUSIONS

In FIGO stage IIB-IVA cervical cancer patients treated with nonpalliative doses of chemoradiation, overall utilization of BT is 86%. Higher FIGO stage, community cancer facilities, lower income, earlier year of diagnosis, and higher comorbidity score were significant predictors of EBRT boost utilization. Future studies are needed to better understand reasons for this as higher FIGO stage patients are the mostly likely to benefit from a BT boost.

Quantitative and qualitative application of clinical drawings for image-guided brachytherapy in cervical cancer patients

Purpose

Clinical drawings are integral part of image-guided adaptive brachytherapy (IGABT) of cervical cancer. It was used in EMBRACE study protocol as a useful tool. In our study clinical drawings from EMBRACE study were modified to include scales in all the dimensions for more accurate representation of various tumor related volumes. The aim of the present study was to understand patterns of tumor regression and relationship between gross tumor at diagnosis (GTVD) and high-risk clinical target volume (CTV-T_HR)/intermediate-risk clinical target volume (CTV-T_IR) in brachytherapy (BRT), using modified clinical drawings.

Material and methods

42 cervical cancer patients, staged as FIGO IIB-IIIB according to EMBRACE study, were enrolled. Advanced schematic 3D mapping diagram (3D-MD) in axial, coronal, and sagittal orientations, with a measurement scale (grid with 10 mm distance) for precise assessment and documentation was applied (through MRI at diagnosis and during brachytherapy). Dimensions, including height, width, and thickness as well as volumes (GTVD, CTV-T_HR and CTV-T_IR) were compared both qualitatively and quantitatively.

Results and conclusions

We found qualitative and quantitative correlation of the dimensions of final CTV-T_HR with initial GTVD. Meticulous mapping of tumor volumes can provide useful insights to CTV-T_HR volume during brachytherapy.

An endovaginal MRI array with a forward-looking coil for advanced gynecological cancer brachytherapy procedures: Design and initial results

PURPOSE

To develop an endovaginal MRI array that provides signal enhancement forward into the posterior parametrium and sideways into the vaginal wall, accelerating multiple-contrast detection of residual tumors that survive external beam radiation. The array's enclosure should form an obturator for cervical cancer brachytherapy, allowing integration with MRI-guided catheter placement, CT, and interstitial radiation dose delivery.

METHODS

The endovaginal array consisted of forward-looking and sideways-looking components. The forward-looking element imaged the cervix and posterior endometrium, and the sideways-looking elements imaged the vaginal wall. Electromagnetic simulation was performed to optimize the geometry of a forward-looking coil placed on a conductive-metallic substrate, extending the forward penetration above the coil's tip. Thereafter, an endovaginal array with one forward-looking coil and four sideways-looking elements was constructed and tested at 1.5 Tesla in saline and gel phantoms, and three sexually mature swine. Each coil's tuning, matching, and decoupling were optimized theoretically, implemented with electronic circuits, and validated with network-analyzer measurements. The array enclosure emulates a conventional brachytherapy obturator, allowing use of the internal imaging array together with tandem coils and interstitial catheters, as well as use of the enclosure alone during CT and radiation delivery. To evaluate the receive magnetic field ( B 1 - ) spatial profile, the endovaginal array's specific absorption-rate (SAR) distribution was simulated inside a gel ASTM phantom to determine extreme heating locations in advance of a heating test. Heating tests were then performed during high SAR imaging in a gel phantom at the predetermined locations, testing compliance with MRI safety standards. To assess array imaging performance, signal-to-noise-ratios (SNR) were calculated in a saline phantom and in vivo. Swine images were acquired with the endovaginal array combined with the scanner's body and spine arrays.

RESULTS

Simulated B 1 - profiles for the forward-looking lobe pattern, obtained while varying several geometric parameters, disclosed that a forward-looking coil placed on a metal-backed substrate could double the effective forward penetration from approximately 25 to ∼40 mm. An endovaginal array, enclosed in an obturator enclosure was then constructed, with all coils tuned, matched, and decoupled. The ASTM gel-phantom SAR test showed that peak local SAR was 1.2 W/kg in the forward-looking coil and 0.3 W/kg in the sideways-looking elements, well within ASTM/FDA/IEC guidelines. A 15-min 4 W/kg average SAR imaging experiment resulted in less than 2^o C temperature increase, also within ASTM/FDA/IEC heating limits. In a saline phantom, the forward-looking coil and sideways-looking array's SNR was four to eight times, over a 20-30 mm field-of-view (FOV), and five to eight times, over a 15-25 mm FOV, relative to the spine array's SNR, respectively. In three sexually mature swine, the forward-looking coil provided a 5 + 0.2 SNR enhancement factor within the cervix and posterior endometrium, and the sideways-looking array provided a 4 + 0.2 SNR gain factor in the vaginal wall, relative to the Siemens spine array, demonstrating that the array could significantly reduce imaging time.

CONCLUSIONS

Higher SNR gynecological imaging is supported by forward-looking and sideways-looking coils. A forward-looking endovaginal coil for cervix and parametrium imaging was built with optimized metal backing. Array placement within an obturator enhanced integration with the brachytherapy procedure and accelerated imaging for detecting postexternal-beam residual tumors.

The integration of bevacizumab improves tumor response and survival in patients with refractory cervical cancer treated with radical chemoradiotherapy

Background

Management of refractory cervical cancers (CC) is a debated question and rises dilemma in clinical practice. This study aimed to assess the safety and effectiveness of bevacizumab combined with concurrent chemoradiotherapy in the treatment of refractory CC.

Methods

A total of 129 patients with refractory CC who received radical concurrent chemoradiotherapy (CCRT) were included in this study. Among the patients, 64 received combination treatment with bevacizumab, while the 65 remaining patients did not receive bevacizumab. Treatment response was evaluated according to the Response Evaluation Criteria in Solid Tumorsversion1.1. The Cox proportional-hazards model was applied to determine prognostic factors associated with overall survival and the tumor response during treatment was analyzed for patients treated with bevacizumab.

Results

Bevacizumab was an independent prognostic factor (P=0.017). Therefore, we only analyzed 64 patients who received combination treatment with bevacizumab. In the 64 patients treated with bevacizumab, the 3-year OS, locoregional relapse-free survival, and distant metastasis-free survival rates were 87.2%, 98.1%, and 81%, respectively. Complete clinical response rates were 37.8% (17/45) for patients with neoadjuvant chemotherapy and chemoradiotherapy after neoadjuvant chemotherapy (NACT), complete clinical response rates were 62.5% (40/64), 73.3% (33/45) and 52.6% (10/19) before brachytherapy (BT), respectively for the entire cohort, patients with NACT and chemoradiotherapy and patients with chemoradiotherapy only. The 2-year OS rate was higher for patients who achieved a complete clinical response BT than for patients who did not, 94.6% vs. 73.2%, P=0.03. Among the 64 patients who received it, 28 (43.8%) experienced hematological toxicities of grade 3 or 4, and 3 (4.7%) experienced grade 3 gastrointestinal toxicities.

Conclusions

Bevacizumab combined with radical chemoradiotherapy is a safe and tolerable treatment option for refractory CC, with quicker tumor regression and high OS, locoregional relapse-free survival, and distant metastasis-free survival rates.

Prognostic value of post-radiation serum squamous cell carcinoma antigen and primary tumor regression for cervical squamous cell carcinoma

OBJECTIVE

In this study, we determined the prognostic values of magnetic resonance imaging (MRI)-based primary tumor regression and serum squamous cell carcinoma antigen (SSCC-Ag) levels 4 weeks after definitive radiotherapy (RT) in cervical squamous cell carcinoma (CSCC) patients.

METHODS

This was a retrospective study involving 218 patients with histologically confirmed CSCC (stages IB-IVA). All the patients received definitive RT. Pre- and post-RT pelvic MRI and SSCC-Ag levels were measured. Locoregional control (LRC), distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS) were evaluated, and possible OS prognostic factors were analyzed.

RESULTS

The median follow-up time was 25.57 (1.73-58.93) months. Thirty-six and 68 patients died and experienced recurrence, respectively, and the primary tumors of 130 (59.6%) and 88 (40.4%) patients exhibited complete response (CR) and non-CR, respectively. The 3-year OS, DFS, LRC, and DMFS rates were significantly higher in the CR than in the non-CR patients (85.2% vs. 67.9%, 78.9% vs. 39.0%, 93.4% vs. 63.8%, and 83.4% vs. 54.5%, respectively; p< 0.05). The 3-year OS, DFS, LRC, and DMFS rates were significantly lower in the patients with high post-RT SSCC-Ag levels than in those with low post-RT SSCC-Ag levels (38.0% vs. 83.9%, 21.2% vs. 66.3%, 73.0% vs. 84.9%, and 26.5% vs. 79.0%, respectively; p<0.05). Multivariate analyses indicated that SSCC-Ag levels were an independent OS predictor (HR: 5.749, 95% CI: 2.598-12.723, p< 0.001).

CONCLUSION

Post-RT SSCC-Ag levels are OS independent prognostic factors in CSCC patients receiving RT. Timely and optimized treatment plans for CSCC patients after 4 weeks of RT are necessary when patients with persistent tumor and/or positive SSCC-Ag.

Pre-treatment prediction of early response to chemoradiotherapy by quantitative analysis of baseline staging FDG-PET/CT and MRI in locally advanced cervical cancer

BACKGROUND

Early prediction of response to concurrent chemoradiotherapy (cCRT) could aid to further optimize treatment regimens for locally advanced cervical cancer (LACC) in the future.

PURPOSE

To explore whether quantitative parameters from baseline (pre-therapy) magnetic resonance imaging (MRI) and FDG-PET/computed tomography (CT) have potential as predictors of early response to cCRT.

MATERIAL AND METHODS

Forty-six patients with LACC undergoing cCRT after staging with FDG-PET/CT and MRI were retrospectively analyzed. Primary tumor volumes were delineated on FDG-PET/CT, T2-weighted (T2W)-MRI and diffusion-weighted MRI (DWI) to extract the following quantitative parameters: T2W volume; T2W signal_mean; DWI volume; ADC_mean; ADC_SD; MTV_42%; and SUV_max. Outcome was the early treatment response, defined as the residual tumor volume on MRI 3-4 weeks after start of external beam radiotherapy with chemotherapy (before the start of brachytherapy): patients with a residual tumor volume <10 cm³ were classified as early responders. Imaging parameters were analyzed together with FIGO stage to assess their performance to predict early response, using multivariable logistic regression analysis with bi-directional variable selection. Leave-one-out cross-validation with bootstrapping was used to simulate performance in a new, independent dataset.

RESULTS

T2W volume (OR 0.94, P = 0.003) and SUV_max (OR 1.15, P = 0.18) were identified as independent predictors in multivariable analysis, rendering a model with an AUC of 0.82 in the original dataset, and AUC of 0.68 (95% CI 0.41-0.81) from cross-validation.

CONCLUSION

Although the predictive performance achieved in this small exploratory dataset was limited, these preliminary data suggest that parameters from baseline MRI and FDG-PET/CT (in particular pre-therapy tumor volume) may contribute to prediction of early response to cCRT in cervical cancer.

IBS-GEC ESTRO-ABS recommendations for CT based contouring in image guided adaptive brachytherapy for cervical cancer

MR Imaging is regarded asthe gold standardfor Image Gudied Adaptive Brachytherapy (IGABT) for cervical cancer. However, its wide applicability is limited by its availability, logistics and financial implications. Use of alternative imaging like CTand Ultrasound (US) for IGABT has been attempted. In order to arrive at a systematic, uniform and international approach for CT based definition and contouring of target structures, GEC ESTRO, IBS and ABS agreed to jointly develop such recommendations based on the concepts and terms as published in the ICRU Report 89. The minimum requirements are clinical examination & documentation, CT or MR imaging at diagnosis and at a minimum, CT imaging with the applicator in place. The recommendations are based on (i) assessment of the GTV at diagnosis and at brachytherapy, (ii) categorizing the response to external radiation into different clinical remission patterns, (iii) defining various clinico-radiological environments and (iv) definition & delineation of a target on CT imaging at the time of brachytherapy with the applicator in situ. CT based target contouring recommendations based on 4 remission categories within 8 defined environments, aim at improving the contouring accuracy for IGABT using CT, US and MRI as available. For each clinico-radiological environment, there is an attempt to minimize the specific uncertainties in order to arrive at the best possible contouring accuracy. Evaluating feasibility & reproducibility, to achieve a benchmark towards a gold standard MR IGABT and further clinical research including outcomes with CT Based IGABT will become the next steps.

High-dose-rate brachytherapy using inverse planning optimization with tandem and ovoid applicators for locally advanced cervical cancer: a simulation study

The purpose of this study was to evaluate the dosimetric advantage of inverse planning optimization (IPO) in locally advanced cervical cancer using high-dose-rate (HDR) brachytherapy (BT). IPO was compared with point A plan and geometric optimization (GO). The three planning methods were evaluated using doses to the virtual organ-at-risk (OAR) and D90 (the minimum dose covering of 90% of the volume) to the virtual high-risk clinical target volume (HR-CTV) based on quantitative analysis. HR-CTV structures measuring 38.5 cm³ and 59.5 cm³ were created based on the outcomes of a European Group cohort study. The HR-CTVs were located either at the center of the cervix (cervical center model) or shifted toward the left (extensive disease model). The distances from the HR-CTVs to the rectum were set at 0 mm, 3 mm, 5 mm, 8 mm, 10 mm, and 15 mm. We analyzed 336 conditions in this study. All doses were evaluated by conversion to doses in 2-Gy fractions of conventional radiotherapy. The D90 of the HR-CTV using GO and IPO could achieve the desired dose in all conditions, providing better results than that of point A plan. IPO makes it possible to deliver a sufficient dose for the D90 of the HR-CTV while reducing OAR doses with smaller HR-CTV values (< 38.5 cm³) in HDR BT. However, taking into consideration the whole treatment planning time, IPO should be used only when the HR-CTV-to-rectum distance is ≤ 5 mm, and the use of GO cannot spare OARs.

Moving Forward in Cervical Cancer: Enhancing Susceptibility to DNA Repair Inhibition and Damage, an NCI Clinical Trials Planning Meeting Report

Cervical cancer is the fourth most common cancer in women worldwide, and prognosis is poor for those who experience recurrence or develop metastatic disease, in part due to the lack of active therapeutic directions. The National Cancer Institute convened a Cervical Cancer Clinical Trials Planning Meeting in October 2018 to facilitate the design of hypothesis-driven clinical trials focusing on locally advanced, metastatic, and recurrent cervical cancer around the theme of enhancing susceptibility to DNA repair inhibition and DNA damage. Before the meeting, a group of experts in the field summarized available preclinical and clinical data to identify potentially active inducers and inhibitors of DNA. The goals of the Clinical Trials Planning Meeting focused on identification of novel experimental strategies capitalizing on DNA damage and repair (DDR) regulators and cell cycle aberrations, optimization of radiotherapy as a DDR agent, and design of clinical trials incorporating DDR regulation into the primary and recurrent or metastatic therapies for cervical carcinoma. Meeting deliverables were novel clinical trial concepts to move into the National Clinical Trials Network. This report provides an overview for the rationale of this meeting and the state of the science related to DDR regulation in cervical cancer.

Impact of pre-brachytherapy magnetic resonance imaging on dose-volume histogram of locally advanced cervical cancer patients treated with radiotherapy including high-dose-rate brachytherapy

Purpose

This study investigated the suitability of brachytherapy technique selection based on pre-brachytherapy magnetic resonance imaging (MRI) findings in cervical cancer by evaluating dose-volume histogram parameters.

Material and methods

We retrospectively evaluated data from 61 patients with cervical cancer who underwent pre-brachytherapy MRI within 7 days before their first high-dose-rate brachytherapy treatment, selected according to pre-brachytherapy MRI findings. Combined intracavitary brachytherapy with interstitial techniques (IC/ISBT) or interstitial brachytherapy (ISBT) were favored treatments for poor-responding tumors after concurrent chemoradiotherapy, asymmetrical tumors, bulky parametrial extensions, bulky primary disease, and extensive paravaginal or distal vaginal involvement. Intracavitary brachytherapy (ICBT) was the preferred treatment for small tumors without extensive involvement of the vagina and parametrium.

Results

The median tumor size was 58 mm on pre-treatment MRI and 38 mm on pre-brachytherapy MRI. On pre-brachytherapy MRI, 13 patients had a tumor with severe vaginal invasion, 15 patients presented with an asymmetrical bulky tumor, and 4 patients had bulky residual tumors. IC/ISBT or ISBT were administered to 26 patients (43%). Median equivalent dose in 2 Gy fractions of clinical target volume D₉₀ was 70.8 Gy for all patients. Median clinical target volume D₉₀ in each brachytherapy session exceeded the prescribed dose in both patients treated with ICBT and IC/ISBT or ISBT. Median equivalent dose in 2 Gy fractions of D_2cc to the bladder, sigmoid colon, and rectum was 69.5, 52.0, and 58.4 Gy, respectively. All cases remained within the doses recommended for organs at risk.

Conclusions

Pre-brachytherapy MRI may be helpful in selecting suitable candidates for each type of brachytherapy and deliver the recommended doses to the tumor and organs at risk, particularly in cases with large tumors, poor response to concurrent chemoradiotherapy, asymmetrical tumors, severe vaginal invasion, extensive parametrial invasion, and/or corpus invasion.

Venezia applicator with oblique needles improves clinical target volume coverage in distal parametrial tumor residue compared to parallel needles only

Purpose

Residual distal parametrial involvement after radiochemotherapy is a true challenge for brachytherapists since the width and asymmetry of high-risk clinical target volume (HR-CTV) are difficult to cover properly with a standard implant.

Material and methods

Dosimetric plans of five patients treated with Venezia advanced gynecological applicator at our institution were reviewed. For each patient, we compared the original plan with a new plan where oblique needles were removed and re-optimized manually. Optimization process was halted when EQD2₁₀ D₉₀ HR-CTV reached 90 Gy, when one hard constraint to organs at risk (OARs) was reached according to the EMBRACE II protocol, or when dose-rate of one of OARs exceeded 0.6 Gy/h.

Results

Tumors were large; median HR-CTV volume was 64 cc and median distance between tandem and outer contour of HR-CTV was 40 mm. For the five patients, HR-CTV EQD2₁₀ D₉₀ was superior in the plan using oblique needles, with a median difference of 6.5 Gy (range, 1.7-8.5 Gy). Median D₉₀ HR-CTV and intermediate-risk CTV (IR-CTV) were significantly increased with oblique needles: 85.9 Gy (range, 83.2-90.3 Gy) vs. 81.5 Gy (range, 77.4-84 Gy), and 68.7 Gy (range, 66.3-72.3 Gy) vs. 67 Gy (range, 64.3-69.1 Gy), p = 0.006 for both. There were no significant differences in the dose to OARs. Plans with only parallel needles had less favorable dose distribution, with cold spots on the outer parametria and higher vaginal activation to compensate parametrial coverage in its inferior part.

Conclusions

Venezia^TM applicator permits reproducible application to increase CTV coverage in patients with distal parametrial tumor residue during brachytherapy, while maintaining acceptable dose to OARs.

Predicting the necessity of adding catheters to intracavitary brachytherapy for women undergoing definitive chemoradiation for locally advanced cervical cancer

PURPOSE

To identify if baseline patient or magnetic resonance imaging (MRI) features can predict which women are at risk for inadequate tumor coverage with only intracavitary tandem and ovoid (T + O) brachytherapy and to correlate tumor coverage with clinical outcomes.

METHODS AND MATERIALS

We performed a retrospective study of 50 women with cervical cancer treated with chemoradiation at a single institution between January 2014 and December 2015. All patients had a 3T-MRI performed at baseline (MRI1) and at the completion of external beam radiation therapy (MRI2). Gross tumor volume initial (GTV-T_init) was measured on MRI1 and high-risk clinical tissue volume (CTV_HR) on MRI2. CTV_HR extending beyond point A was classified as too large for adequate coverage with T + O and requiring interstitial needles. Multivariate analysis was performed to determine predictive factors of inadequate coverage. Kaplan-Meier and Cox Regression were performed to correlate inadequate coverage with outcomes.

RESULTS

Mean patient age was 49.2 ± 13.2 years, and 84% had Federation of Gynecology and Obstetrics IIB/IIIB disease. Forty-two percent of women were estimated to have inadequate tumor coverage with T + O brachytherapy. The GTV-T_init volume and dimensions (superior-inferior, left-right, anterior-posterior) on MRI1 were all important predictive factors of inadequate coverage on multivariate analysis. Receiver operating characteristics curves identified optimal thresholds of superior-inferior ≥ 4.5 cm (area under the curve [AUC] = 0.718), left-right ≥ 4.5 cm (AUC = 0.745), anterior-posterior ≥ 5.0 cm (AUC = 0.767), and GTV-T_init ≥ 85 cm³ (AUC = 0.842). Patients with inadequate coverage had worse clinical outcomes.

CONCLUSIONS

Baseline MRI tumor size may predict inadequate CTV_HR coverage at the time of brachytherapy (i.e., the need for interstitial needles). This may help identify a subset of women requiring early referral to adequately resourced centers to improve clinical outcomes.

CLINICAL PROBLEMS OF DIRECT DOSIMETRY (IN VIVO) IN CONTACT RADIATION THERAPY

The use of multicomponent methods of special treatment (surgery, polychemotherapy, radiation therapy, laser photodynamic therapy) in oncology requires the control of doses in the tumor and healthy organs with high accuracy. A method of direct dosimetry using fiber-optic scintillation dosimeter MCD-4 is proposed. The dosimeter is fixed on endostats and is visualized on CT/MRI. The coordinates are entered into the anatomical units and dosimetry calculations, the data are mapped, the doses are adjusted on medical grounds. The developed technique of direct dosimetry allows monitoring of the contact radiation therapy (CRT) procedure in real time and making the necessary changes and corrections during the treatment. The refinement of the absorbed dose values using calculations and direct dosimetry minimizes the risk of complications and ensures the possibility of effective use of other treatment methods, including photodynamic therapy, after CRT.

Tumor Shrinkage During Chemoradiation in Locally Advanced Cervical Cancer Patients: Prognostic Significance, and Impact for Image-Guided Adaptive Brachytherapy

PURPOSE

To study the prognostic value of gross tumor volume (GTV) shrinkage and its dosimetric implication in a large cohort of patients with cervical cancer receiving definitive chemoradiotherapy plus image guided adaptive brachytherapy.

METHODS AND MATERIALS

Clinical records of consecutive patients treated in our institution between February 2004 and November 2015 by concurrent chemoradiotherapy (45 Gy in 25 fractions ± lymph node boosts) followed by a magnetic resonance imaging-guided adaptive pulse-dose rate brachytherapy were included. The prognostic value of GTV and its evolution after chemoradiotherapy were examined first on initial staging magnetic resonance imaging and then at time of brachytherapy. All measures and measurement cutoffs were selected using time-dependent area under the curve for 3-year progression-free survival (PFS).

RESULTS

GTV evolution between diagnosis and the time of brachytherapy was assessed in 247 patients. After chemoradiotherapy, complete response was observed in 75 patients (28%). Optimal cutoffs were GTV = 55 cm³ at diagnosis, GTV = 7.5 cm³ at brachytherapy, and GTV reduction ≥90%. All patients with volume above or reduction below these cutoffs had significant reduced overall survival, PFS, local control, and distant metastasis control (P < .001). Patients with anemia at diagnosis had a lower tumor volume response rate (P < .001). In multivariate analysis, incorporating the International Federation of Gynecology and Obstetrics stage, N+ stage, anemia, and dosimetric parameters for image guided adaptive brachytherapy, GTV optimal volume reduction after chemoradiotherapy was independently associated with improved overall survival, PFS, local control, and distant metastasis control (P < .001).

CONCLUSIONS

These results could provide a rationale for dose de-escalation studies in brachytherapy for patients displaying optimal GTV volumetric reduction after chemoradiotherapy and may reinforce the need for dose escalation in poorly responding patients.

Computed tomography-based image-guided brachytherapy for cervical cancer: correlations between dose-volume parameters and clinical outcomes

This study evaluated the oncologic outcomes and complications of cervical cancer patients in terms of CT-based image-guided brachytherapy (IGBT) parameters. Of 68 cervical cancer patients treated with definitive radiotherapy/concurrent chemoradiotherapy, most received whole-pelvis external beam RT (EBRT) of 40 Gy in 20 fractions, pelvic EBRT with central shield of 10 Gy in 5 fractions, and CT-based IGBT of 18 Gy in 3 fractions prescribed to point A. Cumulative EBRT and IGBT doses were calculated as the total equivalent dose in 2 Gy fractions (EQD2). The median follow-up was 31 (3-52) months. The 2-year overall survival, local control, pelvic control, and disease-free survival rates of the 68 patients were 92%, 83%, 82% and 73%, respectively. The HR-CTV D90, length from the tandem axis to left/right margin of the HR-CTV (T-LR), and HR-CTV volume were significant IGBT parameters for predicting local/pelvic control. Patients who received an HR-CTV D90 of >60 Gy, compared with ≤60 Gy, had significantly better local/pelvic control. Furthermore, 70 Gy was a marginally significant HR-CTV D90 cut-off affecting local control. T-LR was an independent IGBT parameter predicting local/pelvic control on multivariate analysis. Three patients developed Grade 3 or higher treatment-related complications. The D2cm3 of organs at risk were not significant predictors of complications. Future challenges for further improving outcomes include additional interstitial needles for irregularly shaped HR-CTVs, and moderate dose escalation, especially for patients with poor tumor responses.

Patterns of care survey: Radiotherapy for women with locally advanced cervical cancer

BACKGROUND AND PURPOSE

Regarding latest developments, the need of a radiotherapy 'Patterns of Care' survey was expressed by the Dutch National Platform Radiotherapy for Gynaecological Cancer (LPRGT). Therefore, this study investigated current practice for cervical cancer in all 16 radiation oncology centres in the Netherlands specialised in gynaecological oncology.

MATERIAL AND METHODS

A structured 'patterns of care' questionnaire was completed and followed by an in-depth interview with radiation oncologists from all radiotherapy centres specialised in gynaecological oncology. Specific topics addressed were: definition of target volumes, treatment preparation, imaging for treatment planning, treatment planning, and image-guided adaptive radiotherapy for external beam radiotherapy and brachytherapy.

RESULTS

Current radiotherapy practice in the Netherlands for cervical cancer appears to be in accordance with international standards. However, at the time of the survey some differences were revealed that might have relevant clinical impact. For instance: 1) Half of the centres acquired positron emission tomography combined with CT (PET-CT) for staging and target delineation for every patient, 2) The definition of upper border of the para-aortal lymph node area and dose prescription for external beam radiotherapy varied between the centres, and 3) 12 centres used a single treatment plan for delivering EBRT, and four used a plan-of-the-day strategy with a library of 3-4 treatment plans.

CONCLUSIONS

Most differences were found at the cutting edge of clinical evidence. However, the majority of these uncertainties are topics being addressed in current and planned (inter)national studies.