Estimation of the Optimal Brachytherapy Utilization Rate in the Treatment of Gynecological Cancers and Comparison With Patterns of Care

Disparities in brachytherapy utilization in cervical cancer in the United States: A comprehensive literature review

Brachytherapy (BT) is an integral component of treatment for patients with locally advanced cervical cancer, significantly improving local control and overall survival. There is an overall trend of decreased utilization of BT in United States (US) in the last few decades with around 50% of patients being treated without BT. The cause of decreased utilization is multifactorial including physician comfort, facility volume, low reimbursements rates and costs of starting and maintaining a brachytherapy program. This decrease coincides with an increase in the use of newer advanced techniques like intensity modulated radiation therapy (IMRT) and stereotactic body radiation therapy (SBRT) boost resulting in inferior oncological outcomes and increased toxicity. Moreover, racial and socioeconomic disparities in BT utilization have been widely reported in the US. Various factors including age, race, socio-economic status, location, facility type, facility volume and insurance status result in limited access to brachytherapy, which jeopardizes oncologic outcomes. This comprehensive review discusses the BT utilization in the US, examines the impact of race and socioeconomic factors on BT utilization, and highlights its impact on outcomes.

Radiotherapy resources in Latin America and the Caribbean: a review of current and projected needs based on International Atomic Energy Agency data

The inequitable access to radiotherapy globally is a complex undertaking that will require sustained work identifying gaps and mobilising efforts to resolve. The purpose of this review is to identify gaps and needs in radiotherapy in Latin America and the Caribbean. Data from 41 countries in Latin America and the Caribbean on teletherapy megavoltage units and brachytherapy resources were extracted from the International Atomic Energy Agency (IAEA) Directory of Radiotherapy Centers. These data were then matched to open-source data from GLOBOCAN and World Bank Data which included data on population size, gross national income per capita, cancer incidence, and mortality. These data were matched to current and projected cancer incidence and mortality (as estimated by the Global Cancer Observatory in 2020) to calculate current and projected gaps in external beam radiotherapy facilities. For brachytherapy, the analysis was focused on cervical cancer and included high dose rate and low dose rate machines. As of Oct 22, 2022, external beam radiotherapy was available in 32 (78%) of 41 countries, representing 742 radiotherapy centres and 1122 megavoltage units. Average coverage was 63%. LINACs accounted for 85% (955 of 1122) of megavoltage units and Cobalt-60 capacity decreased to 12% compared with in 2018. Median megavoltage units per 1000 cancer cases were 0·8 (IQR 0·54-1·03). Most countries clustered in the same range of gross national income per capita for teletherapy units per 1000 cases at a median of US$9380. The current deficit in megavoltage units is estimated at 668 units and is projected to be 2455 units by 2030. 28 (68%) of 41 countries had 279 installed brachytherapy services, both high dose rate and low dose rate, which could treat 108 420 patients with cervical cancer per year and meet the current needs, albeit with inequitable distribution of resources. Overall, this review indicated a 15% improvement in the current external beam radiotherapy capacity in Latin America and the Caribbean compared with 2018. However, there is still a current shortage of at least 668 extra units. By 2030, the need for megavoltage units will be double the current capacity. There is inequitable distribution of brachytherapy resources across the region primarily in the Caribbean. Adoption of hypofractionation can help overcome machine shortage; however, it will present technical challenges that need to be taken into account. Rays of Hope, is a novel IAEA initiative that is designed to mobilise global efforts to address radiotherapy gaps while ensuring the highest return on investment.

Leveling Up the Access to Radiation Therapy in Latin America: Economic Analysis of Investment, Equity, and Inclusion Opportunities Up to 2030

PURPOSE

Latin America faces a shortage in radiation therapy (RT) units and qualified personnel for timely and high-quality treatment of patients with cancer. Investing in equitable and inclusive access to RT over the next decade would prevent thousands of deaths. Measuring the investment gap and payoff is necessary for stakeholder discussions and capacity planning efforts.

METHODS AND MATERIALS

Data were collected from the International Atomic Energy Agency's Directory of Radiotherapy Centers, industry stakeholders, and individual surveys sent to national scientific societies. Nationwide data on available devices and personnel were compiled. The 10 most common cancers in 2020 with RT indication and their respective incidence rates were considered for gap calculations. The gross 2-year financial return on investment was calculated based on an average monthly salary across Latin America. A 10-year cost projection was calculated according to the estimated population dynamics for the period until 2030.

RESULTS

Eleven countries were included in the study, accounting for 557,213,447 people in 2020 and 561 RT facilities. Approximately 1,065,684 new cancer cases were diagnosed, and a mean density of 768,469 (standard deviation ±392,778) people per available unit was found. By projecting the currently available treatment fractions to determine those required in 2030, it was found that 62.3% and 130.8% increases in external beam RT and brachytherapy units are needed from the baseline, respectively. An overall regional investment of approximately United States (US) $349,650,480 in 2020 would have covered the existing demand. An investment of US $872,889,949 will be necessary by 2030, with the expectation of a 2-year posttreatment gross return on investment of more than US $2.1 billion from patients treated in 2030 only.

CONCLUSIONS

Investment in RT services is lagging in Latin America in terms of the population's needs. An accelerated outlay could save additional lives during the next decade, create a self-sustaining system, and reduce region-wide inequities in cancer care access. Cash flow analyses are warranted to tailor precise national-level intervention strategies.

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.

A questionnaire-based survey on 3D image-guided brachytherapy for cervical cancer in Japan: advances and obstacles

The purpose of this study is to survey the current patterns of practice, and barriers to implementation, of 3D image-guided brachytherapy (3D-IGBT) for cervical cancer in Japan. A 30-item questionnaire was sent to 171 Japanese facilities where high-dose-rate brachytherapy devices were available in 2012. In total, 135 responses were returned for analysis. Fifty-one facilities had acquired some sort of 3D imaging modality with applicator insertion, and computed tomography (CT) and magnetic resonance imaging (MRI) were used in 51 and 3 of the facilities, respectively. For actual treatment planning, X-ray films, CT and MRI were used in 113, 20 and 2 facilities, respectively. Among 43 facilities where X-ray films and CT or MRI were acquired with an applicator, 29 still used X-ray films for actual treatment planning, mainly because of limited time and/or staffing. In a follow-up survey 2.5 years later, respondents included 38 facilities that originally used X-ray films alone but had indicated plans to adopt 3D-IGBT. Of these, 21 had indeed adopted CT imaging with applicator insertion. In conclusion, 3D-IGBT (mainly CT) was implemented in 22 facilities (16%) and will be installed in 72 (53%) facilities in the future. Limited time and staffing were major impediments.

Patterns of care study of brachytherapy in New South Wales: malignancies of the uterine corpus

Purpose

There are limited data at a population level on adjuvant brachytherapy (BT) practice for uterine corpus malignancies. The aims of the current study were to describe BT practice for this disease in New South Wales (NSW), to assess quality of BT, and to determine if a caseload effect on quality exists.

Material and methods

Patient, tumour, and treatment related data were collected from all nine NSW radiation oncology departments that treated patients with BT. Included patients had malignancy of the uterine corpus with treatment including BT. Brachytherapy quality was assessed using published quality benchmarks. Higher gynaecological BT caseload departments were compared with lower caseload departments.

Results

One hundred sixty-three NSW residents with gynaecological cancer were treated with BT. The four higher gynaecological BT caseload departments treated a median of 25.5 NSW residents (range 22-38), compared to median 10 (range 3-18) in the five lower caseload departments. Seventy-five patients underwent BT for uterine malignancies. Most patients had early stage endometrioid disease and were treated adjuvantly with intravaginal cylinders using high-dose-rate BT. Doses were in accordance with guideline recommendations in 83% of cases, and BT was appropriately indicated in 76% of cases. Higher caseload departments were more likely to treat with guideline doses (96% vs. 53%, p < 0.001) but there was no difference in compliance rate with treatment indications (p = 0.75).

Conclusions

Brachytherapy patients, techniques, and numbers/unit for uterine corpus malignancies were similar in NSW compared to the USA but more dispersed than in Western Europe. Doses prescribed may not be optimal in lower gynaecological BT caseload departments – the significance of this represents an area in which more research is needed.

Dosimetric feasibility of stereotactic body radiation therapy as an alternative to brachytherapy for definitive treatment of medically inoperable early stage endometrial cancer

PURPOSE

This study was designed to evaluate the dosimetric feasibility of definitive stereotactic body radiation therapy (SBRT) for the treatment of medically inoperable early stage endometrial cancer.

METHODS

CT simulation scans from 10 medically inoperable early stage endometrial cancer patients previously treated with high dose-rate (HDR) intracavitary brachytherapy were used to generate Helical Tomotherapy (HT) plans using the IMRT mode with clinical target volumes (CTVs) that included the uterus plus cervix. A prescription dose of 34 Gy in 4 fractions was used. The SBRT dosimetry was compared to the 10 prior intracavitary brachytherapy plans normalized to a standard dose. Organs at risk (OARs) evaluated were the bladder, rectum, sigmoid, femoral heads, and other bowel, including both large and small bowel. The simulation CT and daily image guidance for 4 patients treated with this technique were evaluated to assess for interfraction variation in the uterine position and effects on dosimetry.

RESULTS

Compared to intracavitary brachytherapy, HT SBRT produced significantly greater overall target coverage to the uterus, boost CTV, and PTV, with exception of the V150% of the uterus. HT SBRT significantly increased dose to the rectum, bowel, and femoral heads compared to intracavitary brachytherapy, though not outside of dose tolerance limits. Review of daily image guidance for patients treated with this technique demonstrated good reproducibility with a mean overlap index of 0.87 (range, 0.74 - 0.99).

CONCLUSIONS

Definitive SBRT for medically inoperable early stage endometrial cancer appears to be a feasible treatment option. Future studies are warranted to evaluate long-term clinical outcomes with this technique, compared to HDR intracavitary brachytherapy.

Patterns of care study of brachytherapy in New South Wales: cervical cancer treatment quality depends on caseload

PURPOSE

We previously conducted modelling and a patterns of care study (POCS) that showed gynaecological brachytherapy (BT) was underutilized in New South Wales (NSW), the USA and Western Europe. The aim of the current study was to assess the quality of cervical BT in NSW, and to determine if caseload affects quality of treatment delivery.

MATERIAL AND METHODS

All nine NSW radiation oncology departments that treated patients with cervical BT in 2003 were visited. Patient, tumour and treatment related data were collected. Quality of BT was assessed using published quality benchmarks. Higher and lower caseload departments were compared.

RESULTS

The four higher cervical BT caseload departments treated 11-15 NSW residents in 2003, compared to 1-8 patients for the lower caseload departments. Cervix cancer patients treated at the higher caseload departments were more likely to be treated to a point A dose ≥ 80 Gy (58% vs. 14%, p = 0.001), and to have treatment completed within 8 weeks (66% vs. 35%, p = 0.02). Despite higher point A doses, there was no significant difference in proportions achieving lower than recommended rectal or bladder doses, implying better BT insertions in higher caseload departments.

CONCLUSIONS

Cervical BT in NSW was dispersed amongst a large number of departments and was frequently of sub-optimal quality. Higher quality BT was achieved in departments treating at least 10 patients per year. It is likely that improved outcomes will be achievable if at least 10 patients are treated per department per year.

Intensity modulated proton beam radiation for brachytherapy in patients with cervical carcinoma

PURPOSE

To evaluate intensity modulated proton therapy (IMPT) in patients with cervical cancer in terms of coverage, conformity, and dose-volume histogram (DVH) parameters correlated with recommendations from magnetic resonance imaging (MRI)-guided brachytherapy.

METHODS AND MATERIALS

Eleven patients with histologically proven cervical cancer underwent primary chemoradiation for the pelvic lymph nodes, the uterus, the cervix, and the parametric region, with a symmetric margin of 1 cm. The prescription was for 50.4 Gy, with 1.8 Gy per fraction. The prescribed dose to the parametria was 2.12 Gy up to 59.36 Gy in 28 fractions as a simultaneous boost. For several reasons, the patients were unable to undergo brachytherapy. As an alternative, IMPT was planned with 5 fractions of 6 Gy to the cervix, including the macroscopic tumor with an MRI-guided target definition, with an isotropic margin of 5 mm for planning target volume (PTV) definition. Groupe-Europeen de Curietherapie and European society for Radiotherapy and Oncology (GEC-ESTRO) criteria were used for DVH evaluation. Reference comparison plans were optimized for volumetric modulated rapid arc (VMAT) therapy with the RapidArc (RA).

RESULTS

The dose to the high-risk volume was calculated with α/β = 10 with 89.6 Gy. For IMPT, the clinical target volume showed a mean dose of 38.2 ± 5.0 Gy (35.0 ±1.8 Gy for RA). The D98% was 31.9 ± 2.6 Gy (RA: 30.8 ± 1.0 Gy). With regard to the organs at risk, the 2Gy Equivalent Dose (EQD2) (α/β = 3) to 2 cm(3) of the rectal wall, sigmoid wall, and bladder wall was 62.2 ± 6.4 Gy, 57.8 ± 6.1 Gy, and 80.6 ± 8.7 Gy (for RA: 75.3 ± 6.1 Gy, 66.9 ± 6.9 Gy, and 89.0 ± 7.2 Gy, respectively). For the IMPT boost plans in combination with external beam radiation therapy, all DVH parameters correlated with <5% risk for grades 2 to 4 late gastrointestinal and genitourinary toxicity.

CONCLUSION

In patients who are not eligible for brachytherapy, IMPT as a boost technique additionally to external beam radiation therapy provides good target coverage and conformity and superior DVH parameters, compared with recommendations to MRI-guided brachytherapy. For selected patients, IMPT might be a valid alternative to brachytherapy and also superior to reference VMAT plans.