Magnetic resonance image-guided brachytherapy for cervical cancer : Prognostic factors for survival

Current Status and Future Directions of Image-Guided Adaptive Brachytherapy for Locally Advanced Cervical Cancer

PURPOSE

The standard of care for patients with locally advanced cervical cancer is definitive chemoradiation followed by a brachytherapy boost. This review describes the current status and future directions of image-guided adaptive brachytherapy for locally advanced cervical cancer.

METHODS

A systematic search of the PubMed and Clinicaltrials.gov databases was performed, focusing on studies published within the last 10 years. The search queried "cervical cancer [AND] image-guided brachytherapy [OR] magnetic resonance imaging (MRI) [OR] adaptive brachytherapy".

DISCUSSION

The retroEMBRACE and EMBRACE-I trials have established the use of MRI as the standard imaging modality for brachytherapy application and planning. Quantitative imaging and radiomics have the potential to improve outcomes, with three ongoing prospective studies examining the use of radiomics to further risk-stratify patients and personalize brachytherapy. Another active area of investigation includes utilizing the superior soft tissue contrast provided by MRI to increase the dose per fraction and decrease the number of fractions needed for brachytherapy, with several retrospective studies demonstrating the safety and feasibility of three-fraction courses. For developing countries with limited access to MRI, trans-rectal ultrasound (TRUS) appears to be an effective alternative, with several retrospective studies demonstrating improved target delineation with the use of TRUS in conjunction with CT guidance.

CONCLUSIONS

Further investigation is needed to continue improving outcomes for patients with locally advanced cervical cancer treated with image-guided brachytherapy.

Dose-effect relationship between dose-volume parameters of residual gross tumor volume and clinical prognosis in MRI-guided adaptive brachytherapy for locally advanced cervical cancer: a single-center retrospective study

PURPOSE

To investigate the dose-effect relationship between the dose-volume parameters of residual gross tumor volume (GTV_res) and clinical prognosis in MRI image-guided adaptive brachytherapy (IGABT) of patients with locally advanced cervical cancer in our center.

MATERIALS AND METHOD

The clinical data of 93 patients with locally advanced cervical squamous cell cancer who received external beam radiotherapy (EBRT) combined with IGABT ± chemotherapy in our center were retrospectively analyzed. The disease stage, overall treatment time (OTT), chemotherapy, and the dose-volume parameters D₉₀, D₉₈, and D₁₀₀ of GTV_res, the intermediate-risk clinical target volume (CTV_IR), and the high-risk clinical target volume (CTV_HR) of the patients were statistically analyzed. Kaplan-Meier and uni- and multivariable Cox regression analyses were used to analyze 2‑year overall survival (OS), progression-free survival (PFS), and local control rate (LC). A probit model was employed to assess the dose-effect relationship between the volume and dose-volume parameters of GTV_res and 2‑year OS, PFS, and LC.

RESULTS

The median follow-up time was 19.6 months and 2‑year OS, PFS, and LC were 79.6%, 68.8%, and 94.6%, respectively. CTV_HR D₉₀ was an independent influencing factor for 2‑year PFS (P = 0.041); GTV_resBT1 volume was an independent factor for 2‑year OS, PFS, and LC (P < 0.001). The probit model showed that at GTV_resBT1 volume < 32.86 cm³, the expected 2‑year LC was > 90%; at GTV_res D₉₈ > 129.12 Gy_EQD2, the expected 2‑year OS was > 90%.

CONCLUSION

Both the volume and dose-volume parameters of GTV_res are promising predictors in assessment of IGABT prognosis of cervical cancer.

Point-A vs. volume-based brachytherapy for the treatment of cervix cancer: A meta-analysis

BACKGROUND & PURPOSE

To report disease-free survival (DFS) for volume-based and point-A based brachytherapy (BT) in locally advanced cervical cancer.

MATERIALS & METHODS

We conducted a meta-analysis of studies assessing the effects of point-A and volume-based brachytherapy on 3-year DFS. Studies including stage I-IVA cervical cancer patients were included if standard treatment of concomitant chemo-radiotherapy and high-dose- or pulsed dose rate BT was delivered. The primary outcome was 3-year DFS, and secondary outcomes were 3-year local control (LC), 3-year overall survival (OS) and late toxicity. A random-effects subgroup meta-analysis was done.

RESULTS

In total, 5499 studies were screened, of which 24 studies with 5488 patients were eligible. There was significant heterogeneity among point-A studies (1538 patients) (I² = 82%, p < 0.05) relative to volume-based studies (3950 patients) (I² = 58, p = 0.01). The 3-year DFS for point-A and volume-based studies were 67% (95% CI 60%-73%) and 79% (95% CI 76%-82%) respectively (p = 0.001). Three-year LC for point-A and volume-based studies were 86% (95% CI 81%-90%) and 92% (91%-94%) respectively (p = 0.01). The difference in 3-year OS (72% vs. 79%, p = 0.12) was not statistically significant. The proportion of prospectively enrolled patients was 23% for point-A studies and 33% for volume-based studies. There was no difference in late grade 3 or higher gastrointestinal (3% vs. 4%, p = 0.76) genitourinary toxicities (3% vs. 3% p = 0.45) between the two groups.

CONCLUSION

Volume-based BT results in superior 3-year DFS and 3-year LC. In the absence of randomized trials, this meta-analysis provides the best evidence regarding transition to 3D planning.

Clinical outcomes after positron emission tomography/computed tomography-based image-guided brachytherapy for cervical cancer

INTRODUCTION

Although positron-emission tomography (PET) plays an integral role in cervix cancer diagnosis, there are limited data on PET-based image-guided brachytherapy (IGBT). We aimed to report the long-term outcomes of PET-based IGBT.

METHODS

We reviewed 151 patients treated with definitive radiotherapy (RT), including PET-based IGBT between 2009 and 2018. After median 45 Gy of external beam RT with the four-field technique, a median 24 Gy of high-dose-rate iridium-192 IGBT was delivered in six fractions with Fletcher-Suit tandem and ovoids. All patients underwent 18F-fluorodeoxyglucose-PET/computed tomography planning with a brachytherapy applicator. Multivariable analysis of local control (LC) was performed using Cox regression analysis.

RESULTS

The median high-risk clinical target volume (HRCTV) and HRCTV D90% were 51.8 (interquartile range [IQR] 35.9-79.4) cm³ and 77.7 (IQR 74.7-81.2) Gy, respectively. With a median follow-up of 57 (IQR 24.3-81.4) months, the 5-year LC rate was 89.2%. HRCTV ≥72 cm³ was associated with inferior LC (hazard ratio, 3.72, p = .017) after multivariable analysis: the 5-year LC rates were 94.0% and 77.9% for HRCTVs ≥72 and < 72 cm³ , respectively (p = .002). The impact of HRCTV D_90% ≥70 Gy on LC was significant in patients with an HRCTV ≥72 cm³ compared to that in those with HRCTV < 72 cm³ . Patients with adeno/adenosquamous carcinoma demonstrated inferior LC in both groups. There were 13 (8.6%) and 11 (7.3%) patients with acute and late severe toxicities after RT.

CONCLUSION

PET-based IGBT leads to favorable LC, and HRCTV ≥72 cm³ requires further dose escalation to improve outcomes.

Brachytherapy utilization rate and effect on survival in cervical cancer patients in Korea

OBJECTIVE

External beam radiation therapy (EBRT) with concurrent chemotherapy followed by intracavitary brachytherapy is the standard treatment in locally advanced cervical cancer. This study examined the brachytherapy utilization rate and evaluated the effect of brachytherapy on survival in cervical cancer patients in Korea.

METHODS

In this study, data from the Korea Central Cancer Registry and Korean National Health Insurance Service and data on mortality from Statistics Korea were linked and used. Patients with other cancers, distant metastasis at diagnosis, or unknown stage or who underwent hysterectomy were excluded. A total of 12,721 cervical cancer patients were analyzed in this study.

RESULTS

The brachytherapy utilization rate (%) was calculated as the proportion of patients who received brachytherapy among those who received curative EBRT. The brachytherapy utilization rate decreased from 84% in 2005 to 78% in 2013 (p<0.001). Brachytherapy utilization rates varied by region, ranging from 72% to 100% except for in Jeju Island, where the rate was 56%. The brachytherapy utilization rate was lower in patients older than 80 years; patients with localized disease, non-squamous cell carcinoma, or Charlson comorbidity index 3 or more; patients diagnosed after 2010; patients from certain regions; patients receiving medical aid; and patients who underwent gynecologic procedures. Multivariable Cox regression analysis showed that brachytherapy when added to curative EBRT was independently associated with better cancer-specific survival (CSS) and overall survival (OS) than curative EBRT only.

CONCLUSION

The brachytherapy utilization rate decreased from 2005 to 2013 and varied by region in Korea. Brachytherapy use is independently associated with significantly higher CSS and OS in cervical cancer.

Definitive Chemoradiotherapy versus Radical Hysterectomy Followed by Tailored Adjuvant Therapy in Women with Early-Stage Cervical Cancer Presenting with Pelvic Lymph Node Metastasis on Pretreatment Evaluation: A Propensity Score Matching Analysis

Simple Summary

Pelvic nodal involvement is frequently present in early-stage cervical cancer patients on pretreatment imaging studies. However, it is unclear whether radical chemoradiotherapy (CRT) or radical hysterectomy RH followed by tailored adjuvant radiotherapy is more appropriate in these patients. We compared oncological outcomes of up-front surgery followed by tailored adjuvant radiotherapy and definitive CRT in these patients. We found no differences in outcomes existed between definitive CRT and hysterectomy with tailored adjuvant radiotherapy. However, after surgery, 88.7% of patients required adjuvant radiotherapy. These findings suggest that definitive CRT can avoid unplanned tri-modality therapy without compromising oncologic outcomes.

Abstract

To compare the oncologic outcomes between chemoradiotherapy (CRT) and radical hysterectomy followed by tailored adjuvant therapy in patients with early cervical cancer presenting with pelvic lymph node metastasis. We retrospectively analyzed the medical records of women with early cervical cancer presenting with positive pelvic nodes identified on pretreatment imaging assessment. Propensity score matching was employed to control for the heterogeneity between two groups according to confounding factors. Overall survival, disease-free survival, and pattern of failure were compared between the two groups. A total of 262 patients were identified; among them, 67 received definitive CRT (group A), and 195 received hysterectomy (group B). Adjuvant therapy was administered to 88.7% of group B. There were no significant differences between group A and group B regarding the 5-year overall survival rates (89.2% vs. 89.0%) as well as disease-free survival rates (80.6% vs. 82.7%), and patterns of failure. Distant metastasis was the major failure pattern identified in both groups. In multivariate analysis, non-squamous histology was significantly associated with poorer overall survival. As there are no significant differences in 5-year OS, DFS, and patterns of failure, definitive CRT could avoid the combined modality therapy without compromising oncologic outcomes.

Effect of addition of bevacizumab to chemoradiotherapy in newly diagnosed stage IVB cervical cancer: a single institution experience in Korea

OBJECTIVE

The aim of this study was to compare the clinical outcomes of chemoradiotherapy with or without bevacizumab in patients with newly diagnosed International Federation of Gynecology and Obstetrics (FIGO) stage IVB cervical cancer.

METHODS

41 patients with stage IVB cervical cancer who underwent chemoradiotherapy between August 2015 and December 2017 were retrospectively analyzed. This study included 11 patients who received bevacizumab before or after radiotherapy (group A) and 30 patients who received conventional chemoradiotherapy without bevacizumab (group B). We excluded the following patients: those with dual primary cancers; those whose pathologic diagnosis was neither squamous cell carcinoma nor adenocarcinoma; those who did not undergo radiotherapy; or those from whom follow-up data could not be collected. We analyzed the treatment responses, toxicities, progression-free survival, and overall survival rates.

RESULTS

A total of 41 patients were included in the analysis. The median follow-up was 19 months (range 3-108). The response rates at 3 months after treatment were 90.9% in group A and 83.3% in group B (p=0.54). After completing all treatments, the complete response rates were 81.8% in group A and 47% in group B (p=0.04). Grade ≥3 gastrointestinal toxicities, including bleeding, fistula, perforation, and obstruction, were more frequent in group A (54.5%) than in group B (6.7%) (p=0.003). The 12 month progression-free survival and overall survival rates were similar in both arms (12 month progression-free survival: 45.5% vs 46.7%, respectively, p=0.22; 12 month overall survival: 81.8% vs 72.9%, respectively, p=0.57). Patients with node-only metastasis had better 12 month progression-free survival in group B than in group A (59.1% vs 42.9%, respectively, p=0.04). However, the responses to both treatments did not differ in patients with organ metastasis.

CONCLUSIONS

Bevacizumab for stage IVB cervical cancer is associated with higher complete response rates. However, patients treated with bevacizumab experienced more bowel toxicities. Bevacizumab did not improve progression-free survival among patients with node-only metastasis.

Age-corrected hearing loss after chemoradiation in cervical cancer patients

OBJECTIVE

This study aimed to evaluate subjective and objective hearing loss in cervical cancer patients after chemoradiation with cisplatin (mono).

PATIENTS AND METHODS

A total of 51 cervical cancer patients with indication for chemoradiation were included. Pure tone and impedance audiometry were performed before and after chemoradiation. Hearing loss was scaled according to ASHA criteria. Subjective hearing was assessed with the Oldenburger Sentence Test. To consider age-dependent changes, hearing loss was corrected for age and the time interval between measurements.

RESULTS

Median age at diagnosis was 46 years, 46% were active/former smokers (n = 24), 28 (54%) patients were never-smokers. Median total weekly cisplatin dose was 70 ± 14.2 mg. Cumulative doses of cisplatin during chemoradiation ranged between 115.2 and 400 mg cisplatin (mean 336.1 mg, median 342 ± 52.7 mg). The median interval between last chemotherapy and second audiometry was 320 ± 538 days (35-2262 days). Changes in hearing threshold ≥20 dB were experienced by 32/52 patients (62%) following chemoradiation, 55% of them for frequencies ≥6000 Hz. No statistically significant hearing loss remained after chemoradiation upon correction for age and time interval. Patients >40 years had a higher risk of hearing loss than younger patients. Objective data on hearing function did not correlate with subjective hearing loss and did not impair daily activity in any patient.

CONCLUSION

Chemoradiation with cumulative cisplatin doses up to 400 mg did not lead to significant impairment of objective or subjective hearing. For cervical cancer patients undergoing chemoradiation, standard audiometry is not indicated.

Target tailoring and proton beam therapy to reduce small bowel dose in cervical cancer radiotherapy : A comparison of benefits

PURPOSE

The aim of the study was to investigate the potential clinical benefit from both target tailoring by excluding the tumour-free proximal part of the uterus during image-guided adaptive radiotherapy (IGART) and improved dose conformity based on intensity-modulated proton therapy (IMPT).

METHODS

The study included planning CTs from 11 previously treated patients with cervical cancer with a >4-cm tumour-free part of the proximal uterus on diagnostic magnetic resonance imaging (MRI). IGART and robustly optimised IMPT plans were generated for both conventional target volumes and for MRI-based target tailoring (where the non-invaded proximal part of the uterus was excluded), yielding four treatment plans per patient. For each plan, the V15Gy, V30Gy, V45Gy and Dmean for bladder, sigmoid, rectum and bowel bag were compared, and the normal tissue complication probability (NTCP) for ≥grade 2 acute small bowel toxicity was calculated.

RESULTS

Both IMPT and MRI-based target tailoring resulted in significant reductions in V15Gy, V30Gy, V45Gy and Dmean for bladder and small bowel. IMPT reduced the NTCP for small bowel toxicity from 25% to 18%; this was further reduced to 9% when combined with MRI-based target tailoring. In four of the 11 patients (36%), NTCP reductions of >10% were estimated by IMPT, and in six of the 11 patients (55%) when combined with MRI-based target tailoring. This >10% NTCP reduction was expected if the V45Gy for bowel bag was >275 cm3 and >200 cm3, respectively, during standard IGART alone.

CONCLUSIONS

In patients with cervical cancer, both proton therapy and MRI-based target tailoring lead to a significant reduction in the dose to surrounding organs at risk and small bowel toxicity.

General health status of long-term cervical cancer survivors after radiotherapy

PURPOSE

To evaluate the global health status of long-term cervical cancer survivors (LCCS) who survived for more than 4 years after curative radiation treatment (RT).

PATIENTS AND METHODS

Medical records of 562 women treated with RT in our institution between 2003 and 2010 were reviewed. Excluding 259 women who died of disease or were lost to follow-up, disease status and late morbidities were evaluated in 303 LCCS. Quality of life (QoL) was analyzed in 168 LCCS using a questionnaire from the European Organization for the Research and Treatment of Cancer, and the results were compared with an age-matched healthy Korean female population.

RESULTS

Median follow-up was 6.8 years (range 4.1-12.5 years). There were 14 deaths (7 cancer specific) and 14 recurrences (5 local recurrences and 9 distant metastases). The median time to recurrence was 6.0 years (range 4.1-8.2 years). Grade ≥2 late toxicities were frequently observed in the bladder (19%) and small/large intestine (15%). Multivariate analysis revealed a higher rate of late toxicity in patients aged ≥51 years at diagnosis (small/large intestine: hazard ratio, HR, 2.5 [1.2-5.5]; bladder: HR 2.4 [1.3-4.5]; and bone: HR 4.3 [1.2-15.8]) than patients aged <51 years. Compared to the general population, LCCS exhibited a significantly higher rate of body image concerns, sexual dysfunction, lymphedema, and peripheral neuropathy.

CONCLUSION

New recurrences occurred in 5% of LCCS and grade ≥2 treatment-related morbidities were present in 33%. A significant proportion of LCCS also showed decreased cervical-cancer-specific QoL. These results suggest the need for long-term surveillance and follow-up care for LCCS.