Addressing the burden of cervical cancer through IAEA global brachytherapy initiatives

ceRNA Network and WGCNA Analyses of Differentially Expressed Genes in Cervical Cancer Tissues for Association with Survival of Patients

The study aims to search and identify differentially expressed genes (DEGs) in cervical cancer tissues as novel biomarkers to predict cervical cancer prognosis. The Cancer Genome Atlas (TCGA) data on gene expression profiles in cervical cancer were downloaded and analyzed using R software to identify DEGs in cervical cancer tissues. miRNAs targeted by differentially expressed long non-coding RNAs (DElncRNAs) and mRNAs targeted by microRNAs (miRNAs) were identified using the online miRcode, miRTarBase, TargetScan, and miRDB tools. The ceRNA network and lncRNA expression modules in cervical cancer tissues were constructed using weighted gene co-expression network analysis (WGCNA) and analyzed bioinformatically. The Kaplan-Meier analysis was performed to confirm these DEGs as prognostic markers. Immunohistochemical (IHC) analysis was used to verify expression of the hub genes in 10 paired cervical cancer and normal tissues. A total of 1914 DEmRNAs, 210 DElncRNAs, and 67 DEmiRNAs were identified in cervical cancer samples. There were 39 lncRNAs, 19 miRNAs, and 87 mRNAs involved in the ceRNA network and 25 DElncRNAs, three DEmiRNAs, and four mRNAs involved in the ceRNA sub-network. CACNA1C-AS1 was associated with the yellow and blue modules in the ceRNA sub-network, and LIFR-AS1 was associated with the blue module. The DEmRNAs were involved in cancer-related pathways, and three hub genes (i.e., E2F1, CCNB1, and CCNE1) were highly expressed in cervical squamous cell carcinoma and adenocarcinoma tissues and associated with the prognosis of patients. The ceRNA network and WGCNA analyses are useful to identify novel DEGs that can serve as prognostic markers in cervical cancer. The DEGs will be validated in future studies.

Clinical Outcomes of 3 Versus 4 Fractions of Magnetic Resonance Image-Guided Brachytherapy in Cervical Cancer

PURPOSE

Magnetic resonance image-guided brachytherapy is essential in the management of locally advanced cervical cancer. This study compares disease and toxicity outcomes in cervical cancer patients treated with 24 Gy/3 fractions (Fr) versus the conventional 28 Gy/4 Fr.

METHODS AND MATERIALS

This retrospective study included 241 consecutive patients with International Federation of Gynecology and Obstetrics 2018 stage IB to IVA cervical cancer treated with definitive chemoradiation between April 2014 and March 2021. Disease-free survival (DFS) was estimated using the Kaplan-Meier method and compared using the log-rank test. Cumulative incidence of local failure (LF), distant failure (DF), and G2+ gastrointestinal (GI), urinary and vaginal toxicity were estimated using the cumulative incidence function with death as a competing risk and compared using Gray's test.

RESULTS

Of the 241 patients, 42% received 24 Gy/3 Fr and 58% received 28 Gy/4 Fr. With a median follow-up of 3.2 (range, 0.2-9.2) years, there were 14 local, 41 regional nodal, and 51 distant failures in 63 (26%) patients. No significant differences were found between the 24 Gy/3 Fr and 28 Gy/4 Fr groups in 3-year DFS (77% vs 68%, P = .21), the 3-year cumulative incidence of LF (5% vs 7%, P = .57), DF (22% vs 25%, P = .86), G2+ GI toxicity (11% vs 20%, P = .13), or G2+ vaginal toxicity (14% vs 17%, P = .48), respectively. The 3-year cumulative G2+ urinary toxicity rate was lower in the 24 Gy/3 Fr group (9% vs 23%, P = .03).

CONCLUSIONS

Patients with cervical cancer treated with 24 Gy/3 Fr had similar DFS, LF, DF, GI, and vaginal toxicity rates and a trend toward a lower G2+ urinary toxicity rate compared with those treated with 28 Gy/4 Fr. A less resource-intensive brachytherapy fractionation schedule of 24 Gy/3 Fr is a safe alternative to 28 Gy/4 Fr for definitive treatment of cervical cancer.

Mapping of Radiation Oncology and Gynecologic Oncology Services Available to Treat the Growing Burden of Cervical Cancer in Africa

PURPOSE

To meet the demand for cervical cancer care in Africa, access to surgical and radiation therapy services needs to be understood. We thus mapped the availability of gynecologic and radiation therapy equipment and staffing for treating cervical cancer.

METHODS AND MATERIALS

We collected data on gynecologic and radiation oncology staffing, equipment, and infrastructure capacities across Africa. Data was obtained from February to July 2021 through collaboration with international partners using Research Electronic Data Capture. Cancer incidence was taken from the International Agency for Research on Cancer's GLOBOCAN 2020 database. Treatment capacity, including the numbers of radiation oncologists, radiation therapists, physicists, gynecologic oncologists, and hospitals performing gynecologic surgeries, was calculated per 1000 cervical cancer cases. Adequate capacity was defined as 2 radiation oncologists and 2 gynecologic oncologists per 1000 cervical cancer cases.

RESULTS

Forty-three of 54 African countries (79.6%) responded, and data were not reported for 11 countries (20.4%). Respondents from 31 countries (57.4%) reported access to specialist gynecologic oncology services, but staffing was adequate in only 11 countries (20.4%). Six countries (11%) reported that generalist obstetrician-gynecologists perform radical hysterectomies. Radiation oncologist access was available in 39 countries (72.2%), but staffing was adequate in only 16 countries (29.6%). Six countries (11%) had adequate staffing for both gynecologic and radiation oncology; 7 countries (13%) had no radiation or gynecologic oncologists. Access to external beam radiation therapy was available in 31 countries (57.4%), and access to brachytherapy was available in 25 countries (46.3%). The number of countries with training programs in gynecologic oncology, radiation oncology, medical physics, and radiation therapy were 14 (26%), 16 (30%), 11 (20%), and 17 (31%), respectively.

CONCLUSIONS

We identified areas needing comprehensive cervical cancer care infrastructure, human resources, and training programs. There are major gaps in access to radiation oncologists and trained gynecologic oncologists in Africa.

Safety and efficacy of single insertion accelerated MR-image guided brachytherapy following chemo-radiation in locally advanced cervix cancer: modifying our EMBRACE during the COVID pandemic

BACKGROUND

Utero-vaginal brachytherapy (BT) is an irreplaceable care component for the curative treatment of locally advanced cervix cancer (LACC). Magnetic Resonance Imaging (MRI)-image guided adaptive BT (IGABT) using the GYN-GEC-ESTRO EMBRACE guidelines is the international care standard. Usually following chemo-radiation therapy (CRT), IGABT has high proven utility in LACC but requires significant health system resources. Timely access was disrupted by the COVID-19 pandemic which challenged us to re-design our established IGABT care pathway.

METHODS

From April 2020 consecutive patients with LACC were enrolled after CRT in a single arm exploratory non-inferiority study of a modified IGABT (mIGABT) protocol. This delivered an iso-effective IGABT dose (39.3 Gy: EQD2: α/β10Gy concept) over a 24-h period during a single overnight hospitalisation.

RESULTS

Fourteen LACC patients received mIGABT from April 2020 to March 2022. Median age was 62.5 years (37-82 years). LACC histology was primary squamous (9/14) or adeno-carcinoma (5/14). International Federation of Gynaecology and Obstetrics (FIGO) 2018 stages ranged from IB1/2 (N = 3), IIA1/IIB (5), IIIB (2), IIIC1/2 (4) with mean ± standard deviation (SD) gross tumour volume-at-diagnosis (GTV_D) of 37.7 cc ± 71.6 cc. All patients achieved complete metabolic, clinical, and cytologic cancer response with CRT and IGABT. High-risk HPV was cleared by 6-months. Complete MRI-defined cancer response before mIGABT (GTV_Fx1) was seen in 77% of cases (10/13). Only two women developed metastatic disease and one died at 12-months; 13 patients were alive without cancer at mean 20.3 ± 7.2 months follow-up. Actuarial 2-year overall survival was 93%. Compared with our pre-COVID IGABT program, overall mIGABT cost-saving in this cohort was USD 22,866. Prescribed dose covered at least 90% (D90) of the entire cervix and any residual cancer at time of BT (HRCTV_D90: high-risk clinical target volume) with 3-fractions of 8.5 Gy delivered over 24-h (22.8 ± 1.7 h). Total treatment time including CRT was 38 days. The mIGABT schedule was well tolerated and the entire cohort met EMBRACE recommended (EQD2: α/β10Gy) combined HRCTV_D90 coverage of 87.5 ± 3.7 Gy. Similarly, organ-at-risk (OAR) median: interquartile range D2cc constraints (EQD2: α/β3Gy) were EMBRACE compliant: bladder (65.9 Gy: 58.4-72.5 Gy), rectum (59.1 Gy: 55.7-61.8 Gy), and sigmoid colon (54.6 Gy: 50.3-58.9 Gy). ICRU recto-vaginal point dose was significantly higher (75.7 Gy) in our only case of severe (G4) pelvic toxicity.

CONCLUSIONS

This study demonstrated the utility of mIGABT and VMAT CRT in a small cohort with LACC. Loco-regional control was achieved in all cases with minimal emergent toxicity. Single insertion mIGABT was logistically efficient, cost-saving, and patient-centric during the COVID-19 pandemic.

Brachytherapy training survey among radiation oncology residents in Europe

We aim to investigate the current state of brachytherapy (BT) training among the radiation oncology trainees in Europe.

MATERIAL AND METHODS

A 22-question online survey based on the one by the American Association of Radiation Oncology Residents (2017) with added queries pertinent to training in Europe was sent to 1450 residents in two iterations. These included site-specific training, volume of experience, barriers to training, institutional support, and preferences for further education. Responses to individual statements were given on a 1 to 5 Likert-type scale. The answers were reported by junior (≤3 years of training) and senior years of training (year of training 4/5/6 and junior staff). Descriptive statistics were used to describe frequencies.

RESULTS

Residents from 21 European countries participated, 445 (31%) responded. 205 (47%) were senior residents. 60% residents consider that performing BT independently at the end of residency is very or somewhat important. Confidence in joining a brachytherapy practice at the end of residency was high or somewhat high in 34% of senior residents. They reported as barriers to achieving independence in BT to be lack of appropriate didactic/procedural training from supervisors (47%) and decreased case load (31%). 68% reported their program lacks a formal BT curriculum and standardized training assessment.

CONCLUSIONS

Residents in Europe, feel independent BT practice is very or somewhat important, but do not feel confident they will achieve this goal. To address this gap, efforts are needed to develop and implement a formal and comprehensive BT curriculum with easy access to trained instructors.

System-level capacity of high dose rate (HDR) brachytherapy for management of cervical cancer in an upper middle-income country: a case study from Brazil

BACKGROUND

Ensuring optimal access to radiotherapy (RT) facilities is challenging for many countries. External beam RT and brachytherapy (BCT) are required to treat advanced cervical cancer. In this analysis, we evaluate the system-level capacity of brachytherapy in Brazil and its relationship with access to complete cervix cancer radiation treatment with both external beam radiotherapy and BCT.

METHODOLOGY

We used official government reports to compile data on BCT and Linear accelerator (LINAC) numbers, geographic distribution and coverage, cervical cancer annual incidence, and prevalence in Brazil. We also evaluated changes in national BCT capacity between 2001 and 2021. The 2020 relationship between cervical cancer cases for RT per BCT unit, LINAC per BCT unit, and the LINAC supply for each Brazilian state and region were evaluated. For comparison, the LINAC per BCT unit ratio in Brazil was compared with Europe using International Atomic Energy Agency data.

RESULTS

85% (23/27) of Brazilian states have at least one brachytherapy unit; nationally, there are 117 cervical cancer cases for RT per BCT unit. Compared with the benchmark of 200 cervical cancer cases per BCT device per year, there are enough BCT units to fill capacity in Brazil nationally and regionally. The ratio of total cervix cancer cases per BCT unit decreased substantially over time from 142 in 2013 to 117 in 2021 (p<0.0001). Nationally, there are 252 LINAC units in the public system with a ratio of 1,985 new cancer cases/LINAC. Brazilian regions have a LINAC shortage ranging from 15 to 141 units. There were 2.55 LINACs per BCT unit in Brazil, compared with 3.25 in Europe (p=0.012).

CONCLUSION

Over 20 years, BCT capacity in Brazil has increased to meet the cervical cancer demand. However, the LINAC shortage has persisted over the decades, impacting the access to complete treatment and possibly the oncological outcomes. These data can help organize the patient treatment flow, avoid treatment delays, and improve survival.

Gynecological intrauterine brachytherapy training for radiation therapists: The development and implementation of a training program

PURPOSE

Gynecological brachytherapy (GynBT) is an important part of gynecological cancer management. At Olivia Newton-John Cancer Wellness & Research Centre (ONJCWRC), Melbourne, Australia, radiation therapists (RTs) are integral to the MRI adaptive GynBT program workflow. However, there is limited GynBT training available for RTs in Australia. A GynBT training program has been developed at ONJCWRC to meet this need and support RTs in becoming competent, proficient and confident in the various roles in GynBT. This is a preliminary report on the development and implementation of a credentialing program, providing a structured approach to GynBT training of RTs.

METHODS AND MATERIALS

A credentialing program was designed with modules and competency assessments to ensure efficiency and proficiency of RTs in the GynBT workflow. The program includes theoretical modules in anatomy, international GynBT guidelines, radiation safety and local protocols; and practical modules in equipment, ultrasound for GynBT, operating theatre procedures, MRI, contouring, applicator reconstruction, planning, quality assurance and treatment delivery. Learning strategies include self-directed learning, tutorials, practical sessions, and third-party courses. The program concludes with an exit examination assessing major competencies.

RESULTS

The program was implemented in April 2018 with three RTs completing the program and passing the exit examination on first attempt. On post-program survey, the RTs felt the program was comprehensive, helping to build their confidence, and proficiency in GynBT.

CONCLUSIONS

A GynBT RT credentialing program was successfully developed and implemented to improve the quality of training at ONJCWRC. This program is mandatory for RTs joining the GynBT team. This program can provide a framework for implementation of GynBT training in other centers.

Brachytherapy infrastructure in sub-Saharan Africa and quest for cervical cancer elimination

Purpose

Sub-Saharan Africa has the highest burden of cervical cancer in the world. The African continent has only 5% of the world's cancer care resources, and brachytherapy is an important part of treatment of cervical cancer. This study explored the availability of brachytherapy units in Africa.

Material and methods

We used publicly available data on cervical cancer and brachytherapy from GLOBOCAN 2018 database hosted by IARC and Directory of Radiotherapy Centers (DIRAC) presented by IAEA, respectively. Number of brachytherapy units per 1,000 new cases was calculated as an index for comparison between groups.

Results

There are 101 brachytherapy units in 20 African countries, accounting for 3% (101/3,375) of total global units. Sub-Saharan Africa accounts for half of these units (50/101). Egypt has the highest number of units per 1,000 new cases (23.7 units/1,000 new cases), while Nigeria has the least with 0.13 units per 1,000 new cases. No country in central African region has a brachytherapy unit. More than 70% of brachytherapy units are located in five countries (Algeria, Kenya, Egypt, Morocco, and South Africa).

Conclusions

In order to treat 90 percent of invasive cervical cancer on the continent, Africa needs a continental political action plan and massive investment in brachytherapy equipment over the next ten years.

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.

Global challenges of radiotherapy for the treatment of locally advanced cervical cancer

Cervical cancer represents a significant portion of the global cancer burden for women, with low- and middle-income countries carrying the bulk of this burden. Additionally, underserved populations in countries with sufficient resources may have a higher incidence of cervical cancer and poorer outcomes. Concurrent chemoradiotherapy is the standard-of-care treatment for locally advanced cervical cancer, which includes patients with stage IB3 to IVA disease, and it is effective for many patients; however, cervical cancer-related mortality remains high. The critical nature of cervical cancer treatment is underscored by the recent launch of the World Health Organization global initiative to accelerate the elimination of cervical cancer using a triple-intervention strategy of increased vaccination, screening, and treatment. The initiative calls for 90% of all patients diagnosed with cervical cancer to receive the appropriate treatment, but to reach this global goal there are significant barriers related to radiotherapy that must be addressed. We discuss and review evidence of the lack of adherence to guideline-recommended treatment, brachytherapy underutilization, limited access to radiotherapy in low- and middle-income countries, as well as regional limitations within high-income countries, as the major barriers to radiotherapy treatment for locally advanced cervical cancer. We further review ways these barriers are currently being addressed and, in some cases, make additional recommendations to address these issues. Finally, despite receiving recommended treatments, many patients with locally advanced cervical cancer have a poor prognosis. With effective administration of current standards of care, the global community will be able to shift focus to advancing treatment efficacy for these patients. We review several types of therapies under clinical investigation that are additions to concurrent chemoradiotherapy, including immune checkpoint inhibitors, antiangiogenic agents, DNA repair inhibitors, human papillomavirus vaccines, and radiosensitizing nanoparticles.

Education in gynecological brachytherapy

Brachytherapy is an essential component in the curative treatment of many gynecological malignancies. In the past decade, advances in magnetic resonance imaging and the ability to adapt and customize treatment with hybrid interstitial applicators have led to improved clinical outcomes with decreased toxicity. Unfortunately, there has been a shift in clinical practice away from the use of brachytherapy in the United States. The decline in brachytherapy is multifactorial, but includes both a lack of exposure to clinical cases and an absence of standardized brachytherapy training for residents. In other medical specialties, a clear relationship has been established between clinical case volumes and patient outcomes, especially for procedural-based medicine. In surgical residencies, simulation-based medical education (SBME) is a required component of the program to allow for some autonomy before operating on a patient. Within radiation oncology, there is limited but growing experience with SBME for training residents and faculty in gynecological brachytherapy. This review includes single institutional, multi-institutional and national initiatives using creative strategies to teach the components of gynecological brachytherapy. These efforts have measured success in various forms; the majority serve to improve the confidence of the learners, and many have also demonstrated improved competence from the training as well. The American Brachytherapy Society launched the 300 in 10 initiative in 2020 with a plan of training 30 competent brachytherapists per year over a 10 year period and has made great strides with a formal mentorship program as well as externships available to senior residents interested in starting brachytherapy programs. Moving forward, these curricula could be expanded to provide standardized brachytherapy training for all residents. SBME could also play a role in initial certification and maintenance of certification. Given the burden of disease, it would be valuable to develop similar training for providers in low and middle income countries.

Radiotherapy resources in Africa: an International Atomic Energy Agency update and analysis of projected needs

The number of patients with cancer in Africa has been predicted to increase from 844 279 in 2012 to more than 1·5 million in 2030. However, many countries in Africa still lack access to radiotherapy as a part of comprehensive cancer care. The objective of this analysis is to present an updated overview of radiotherapy resources in Africa and to analyse the gaps and needs of the continent for 2030 in the context of the UN Sustainable Development Goals. Data from 54 African countries on teletherapy megavoltage units and brachytherapy afterloaders were extracted from the Directory for Radiotherapy Centres, an electronic, centralised, and continuously updated database of radiotherapy centres. Cancer incidence and future predictions were taken from the GLOBOCAN 2018 database of the International Agency for Research on Cancer. Radiotherapy need was estimated using a 64% radiotherapy utilisation rate, while assuming a machine throughput of 500 patients per year. As of March, 2020, 28 (52%) of 54 countries had access to external beam radiotherapy, 21 (39%) had brachytherapy capacity, and no country had a capacity that matched the estimated treatment need. Median income was an important predictor of the availability of megavoltage machines: US$1883 (IQR 914-3269) in countries without any machines versus $4485 (3079-12480) in countries with at least one megavoltage machine (p=0·0003). If radiotherapy expansion continues at the rate observed over the past 7 years, it is unlikely that the continent will meet its radiotherapy needs. This access gap might impact the ability to achieve the Sustainable Development Goals, particularly the target to reduce preventable, premature mortality by a third, and meet the target of the cervical cancer elimination strategy of 90% with access to treatment. Urgent, novel initiatives in financing and human capacity building are needed to change the trajectory and provide comprehensive cancer care to patients in Africa in the next decade.

Practical brachytherapy solutions to an age-old quandary

•

Age should not be a limiting factor for brachytherapy in patients with localised cancer or for palliation in metastatic disease.

•

In tumour streams where brachytherapy forms part of the curative management, it should not be omitted in elderly patients who are medically fit for treatment.

•

Treatment decisions should factor in patient preferences, the relative merits of different therapeutic approaches and maintaining minimal impact on quality of life.

Cancer is predominantly a disease of the elderly and as population life expectancy increases, so will the incidence of malignant disease. Elderly patients often have other comorbidities and social complexities, increasing the support required to safely deliver all treatment modalities. Brachytherapy is a relatively simple technique by which radiation therapy can be delivered. It offers dosimetric advantages through a highly conformal dose distribution thereby limiting radiation exposure to normal tissues reducing toxicity. Requiring fewer hospital visits, it also offers practical and logistical advantages to the elderly population and in many cases can be performed without the need for general anaesthesia. In tumour streams where brachytherapy forms part of the curative management, it should not be omitted in elderly patients who are medically fit for treatment. In the palliative setting, brachytherapy often offers an excellent means for achieving either local tumour and/or symptom control and should be actively considered in the therapeutic armamentarium of the oncologist in this context.