What is the evidence for the clinical value of SBRT in cancer of the cervix?

Phase I/II study of stereotactic body radiotherapy boost in patients with cervical cancer ineligible for intracavitary brachytherapy

PURPOSE

Stereotactic body radiotherapy (SBRT) boost is a promising treatment for cervical cancer patients who are ineligible for intracavitary brachytherapy (ICBT). The aim of this multicenter, single-arm, phase I/II study was to prospectively evaluate the efficacy and toxicity of SBRT boost.

MATERIALS AND METHODS

ICBT-ineligible patients with untreated cervical cancer were enrolled. Patients underwent whole-pelvic radiotherapy (45 Gy in 25 fractions) with SBRT boost to the primary lesion. In the phase I dose-escalation cohort (3 + 3 design), patients were treated with SBRT boost of 21 or 22.5 Gy in three fractions. Although dose-limiting toxicity was not confirmed, a dose of 21 Gy was selected for the phase II cohort because it was difficult to reproduce the pelvic organs position in two patients during the phase I trial. The primary endpoint was 2-year progression-free survival.

RESULTS

Twenty-one patients (phase I, n = 3; phase II, n = 18) were enrolled between April 2016 and October 2020; 17 (81%) had clinical stage III-IV (with para-aortic lymph node metastases) disease. The median (range) follow-up was 40 (10-84) months. The initial response was complete response in 20 patients and partial response in one patient. The 2-year locoregional control, progression-free survival, and overall survival rates were 84%, 67%, and 81%, respectively. Grade ≥ 3 toxicity was confirmed in one patient each in the acute (diarrhea) and late (urinary tract obstruction) phases.

CONCLUSION

These findings suggested that a SBRT boost is more effective than the conventional EBRT boost and can be an important treatment option for ICBT-ineligible patients with cervical cancer.

STUDY REGISTRATION

This study was registered at the University Hospital Medical Information Network Clinical Trials Registry (UMIN000036845).

Brachytherapy Versus Stereotactic Body Radiotherapy for Cervical Cancer Boost: A Dosimetric Comparison

BACKGROUND

The standard treatment for locally advanced cervical cancer involves chemo-radiation followed by brachytherapy. However, some patients are unable to undergo brachytherapy intensification. Recent advancements in radiation technology have provided several techniques, with stereotactic body radiation therapy (SBRT) theoretically able to mimic the dose distribution of brachytherapy with a high dose gradient.

METHODS

We analyzed 20 high-dose-rate intra-cavity brachytherapy plans for women with cervical cancer and simulated an adjunctive stereotactic radiotherapy plan at the same doses used for brachytherapy (21 Gray [Gy] in three fractions). No planning tumoral volume (PTV) margin was added for SBRT dosimetry. We used the dose constraints for brachytherapy from the EMBRACE trial and the dose constraints for SBRT in three fractions. Dose distribution, maximum dose points on target volumes, bladder, rectum, and dose-volume histograms were compared between the two techniques.

RESULTS

The mean volume of the high-risk clinical tumoral volume (CTV) was 64 cm3, and the mean volume of the intermediate-risk CTV was 93 cm3. The mean minimum dose received by 90% of the high-risk CTV (D90 CTV HR) was 17 Gy for brachytherapy versus 8.3 Gy for SBRT. The average minimum dose received by 90% of the intermediate-risk CTV (D90 CTV IR) was 7.5 Gy for brachytherapy versus 8.9 Gy for SBRT. The mean minimum dose delivered to 2cc of the bladder was 74.6 Gy for brachytherapy versus 84.7 Gy for SBRT. The mean minimum dose delivered to 2cc of the rectum was 71.8 Gy for brachytherapy versus 74.7 Gy for SBRT.

CONCLUSION

We confirmed the dosimetric superiority of brachytherapy over SBRT in terms of target volume coverage and organ-at-risk sparing. Therefore, pending the results of further clinical studies, no current radiotherapy technique can replace brachytherapy for cervical cancer boost after external radiotherapy.

Brachytherapy for Pediatric Patients at Gustave Roussy Cancer Campus: A Model of International Cooperation for Highly Specialized Treatments

PURPOSE

Childhood cancer is rare, and treatment is frequently associated with long-term morbidity. Disparities in survival and long-term side effects encourage the establishment of networks to increase access to complex organ-conservative strategies, such as brachytherapy. We report our experience of an international cooperation model in childhood cancers.

METHODS AND MATERIALS

We examined the outcome of all children referred to our center from national or international networks to be treated according to a multimodal organ-conservative approach, including brachytherapy.

RESULTS

We identified 305 patients whose median age at diagnosis was 2.2 years (range, 1.4 months to 17.2 years). Among these patients, 99 (32.4%) were treated between 2015 and 2020; 172 (56.4%) were referred from national centers; and 133 (43.6%) were international patients from 31 countries (mainly Europe). Also, 263 patients were referred for primary treatment and 42 patients were referred for salvage treatment. Genitourinary tumors were the most frequent sites, with 56.4% bladder/prostate rhabdomyosarcoma and 28.5% gynecologic tumors. In addition to brachytherapy, local treatment consisted of partial tumor resection in 207 patients (67.9%), and 39 patients (13%) had additional external radiation therapy. Median follow-up was 58 months (range, 1 month to 48 years), 93 months for national patients, and 37 months for international patients (P < .0001). Five-year local control, disease-free survival, and overall survival rates were 90.8% (95% confidence interval [CI], 87.3%-94.4%), 84.4% (95% CI, 80.1%-89.0%), and 93.3% (95% CI, 90.1%-96.5%), respectively. Patients referred for salvage treatment had poorer disease-free survival (P < .01). Implementation of image guided pulse-dose-rate brachytherapy was associated with better local control among patients with rhabdomyosarcoma referred for primary treatment (hazard ratio, 9.72; 95% CI, 1.24-71.0). At last follow-up, 16.7% patients had long-term severe treatment-related complications, and 2 patients (0.7%) had developed second malignancy.

CONCLUSIONS

This retrospective series shows the feasibility of a multinational referral network for brachytherapy allowing high patient numbers in rare pediatric cancers. High local control probability and acceptable late severe complication probability could be achieved despite very challenging situations. This cooperation model could serve as a basis for generating international reference networks for high-tech radiation such as brachytherapy to increase treatment care opportunities and cure probability.

The Role of Interstitial Brachytherapy for Breast Cancer Treatment: An Overview of Indications, Applications, and Technical Notes

Simple Summary

Breast cancer is the most common cancer in the female population. Adjuvant radiotherapy has become increasingly important as conservative treatment. Muticatheter interstitial brachytherapy is a type of radiation technique wherein the radioactive sources are directly implanted into or close to the target tissue and may be considered an extremely precise, versatile, and variable radiation technique. Literature data support muticatheter interstitial brachytherapy as the only method with strong scientific evidence to perform partial breast irradiation and reirradiation after previous conservative surgery and external beam radiotherapy. The aim of our work is to provide a comprehensive view of the use of interstitial brachytherapy, with particular focus on the implant description, limits, and advantages of the technique.

Abstract

Breast cancer represents the second leading cause of cancer-related death in the female population, despite continuing advances in treatment options that have significantly accelerated in recent years. Conservative treatments have radically changed the concept of healing, also focusing on the psychological aspect of oncological treatments. In this scenario, radiotherapy plays a key role. Brachytherapy is an extremely versatile radiation technique that can be used in various settings for breast cancer treatment. Although it is invasive, technically complex, and requires a long learning curve, the dosimetric advantages and sparing of organs at risk are unequivocal. Literature data support muticatheter interstitial brachytherapy as the only method with strong scientific evidence to perform partial breast irradiation and reirradiation after previous conservative surgery and external beam radiotherapy, with longer follow-up than new, emerging radiation techniques, whose effectiveness is proven by over 20 years of experience. The aim of our work is to provide a comprehensive view of the use of interstitial brachytherapy to perform breast lumpectomy boost, breast-conserving accelerated partial breast irradiation, and salvage reirradiation for ipsilateral breast recurrence, with particular focus on the implant description, limits, and advantages of the technique.

Gynecologic radiation therapy in low and middle income countries during the COVID-19 pandemic

The COVID-19 pandemic has forever affected healthcare and posed an incredible challenge to our society to care for our sick. Patients with cancer were found early on to have higher rates of complications with COVID-19. Radiation therapy is an integral part of treatment for many types of gynecologic cancer and adaptation on its utilization during the pandemic varied across the globe. In this review, we detail certain guidelines for the use of radiation in gynecologic cancers during the pandemic as well as real world accounts of how different countries adapted to these guidelines or created their own based on individualized resources, staffing, government restrictions, and societal norms. Critically, this review demonstrates the breadth of fractionation schemes and technologies used when resources were limited but highlights the importance of long term follow-up for many of our patients during this time.

The state of gynecologic radiation therapy in low- and middle-income countries

A disproportionate burden of gynecologic malignancies occurs in low- and middle-income countries. Radiation therapy is an integral component of treatment for gynecologic malignancies both from a curative (locally advanced cervical cancer) and palliative (bleeding cervical or pelvic mass) standpoint. Critical to understanding how better to serve patients in this regard is understanding both the extent of disease epidemiology and the radiotherapy infrastructure to treat these diseases. In this review, we explore various geographic regions and how they address a unique set of challenges specific to the peoples and culture of the region. We identify common threads across regions, including sparse distribution of radiation equipment, geographic access, and specialized training. We also highlight examples of success in the use of telemedicine and cross-cultural partnerships to help bolster access to training to ensure increased access to adequate and appropriate treatment of gynecologic malignancies.

Is the CyberKnife radiosurgery system effective and safe for patients? An umbrella review of the evidence

Background: The CyberKnife system combines real-time image guidance and a dynamic tracking system to implement frameless radiotherapy. This umbrella review is aimed to evaluate the effectiveness and safety of CyberKnife. Methods: A comprehensive search of health technology assessments and systematic reviews was performed among the Embase, PubMed and other grey databases until July 2020. Treatment outcomes were extracted, and the quality of included studies were assessed using AMSTAR-2. Results: Nineteen studies were eligible. CyberKnife not only had a wide range of applications, long overall survival and great local control, but also had a limited toxicity and good cost-effectiveness compared with other radiotherapy equipment. Conclusion: Despite the relatively low quality of the evidence, our findings can still provide a decision reference for policymakers.

Clinical Implication of Simultaneous Intensity-modulated Radiotherapy Boost to Tumor Bed for Cervical Cancer with Full-thickness Stromal Invasion

OBJECTIVE

The objective of this study was to retrospectively explore the clinical implications of simultaneous intensity-modulated radiotherapy (IMRT) boost to the tumor bed in cervical cancer with full-thickness stromal invasion (FTSI).

PATIENTS AND METHODS

Patients diagnosed with the International Federation of Gynecology and Obstetrics (FIGO) 2009 stage IB and IIA cervical cancer with confirmed FTSI were included. Patients received pelvic IMRT from a dose of 50.4 Gy in 28 fractions with (or without) a simultaneous integrated boost (SIB) to 58.8 Gy in 28 fractions for the tumor bed. The progression-free survival (PFS), overall survival (OS), and pelvic-PFS (p-PFS) were analyzed using the Kaplan-Meier method, and independent prognostic factors were explored by Cox regression analyses.

RESULTS

Patients without a tumor bed boost had a poor prognosis. The 5-year OS was 81.3% versus 58.3% and the 5-year PFS rates were 75.0% versus 57.6% (boost vs non-boost). The FIGO stage, pathology, adjuvant chemotherapy, and tumor bed boost were independent factors affecting both the 5-year OS and PFS. Subgroup analysis showed that the SIB group had a higher 5-year OS, PFS, and p-PFS for different stages, lymph node status, and risk groups than the non-SIB group. Recurrence occurred in 268 of 910 (29.5%) patients without SIB and 49 of 293 (16.7%) with SIB. Among patients with recurrence, 113 of 282 (40.1%) in the non-boost group compared with 14 of 51 (23.0%) patients in the boost group had a pelvic recurrence. Tumor bed boost resulted in an increase in the mean radiation dose to the intestine, rectum, and bladder, although there were no differences in the rates of acute and late toxicities between the 2 groups.

CONCLUSION

Tumor bed boost by external beam radiotherapy (EBRT) is an effective and safe method for patients with FTSI and risk factors. Compared with the standard prophylactic radiation, tumor bed boost by EBRT was not associated with increased acute and late toxicities.

Online Magnetic Resonance-Guided Radiotherapy (oMRgRT) for Gynecological Cancers

Radiation therapy (RT) is increasingly being used in gynecological cancer management. RT delivered with curative or palliative intent can be administered alone or combined with chemotherapy or surgery. Advanced treatment planning and delivery techniques such as intensity-modulated radiation therapy, including volumetric modulated arc therapy, and image-guided adaptive brachytherapy allow for highly conformal radiation dose delivery leading to improved tumor control rates and less treatment toxicity. Quality on-board imaging that provides accurate visualization of target and surrounding organs at risk is a critical feature of these advanced techniques. As soft tissue contrast resolution is superior with magnetic resonance imaging (MRI) compared to other imaging modalities, MRI has been used increasingly to delineate tumor from adjacent soft tissues and organs at risk from initial diagnosis to tumor response evaluation. Gynecological cancers often have poor contrast resolution compared to the surrounding tissues on computed tomography scan, and consequently the benefit of MRI is high. One example is in management of locally advanced cervix cancer where adaptive MRI guidance has been broadly implemented for adaptive brachytherapy. The role of MRI for external beam RT is also steadily increasing. MRI information is being used for treatment planning, predicting, and monitoring position shifts and accounting for tissue deformation and target regression during treatment. The recent clinical introduction of online MRI-guided radiation therapy (oMRgRT) could be the next step in high-precision RT. This technology provides a tool to take full advantage of MRI not only at the time of initial treatment planning but as well as for daily position verification and online plan adaptation. Cervical, endometrial, vaginal, and oligometastatic ovarian cancers are being treated on MRI linear accelerator systems throughout the world. This review summarizes the current state, early experience, ongoing trials, and future directions of oMRgRT in the management of gynecological cancers.

Image-Guided Brachytherapy for Salvage Reirradiation: A Systematic Review

Simple Summary

Local recurrence in gynecological malignancies occurring in a previously irradiated field is a difficult clinical issue. Curative-intent treatment is salvage surgery and is associated with non-negligible peri-operative morbidity and has a substantial impact on long-term quality of life. Reirradiation, using three-dimensional image-guided brachytherapy (3D-IGBT), might be a suitable alternative, especially in non-operable patients. The aim of this review is to report outcomes and toxicities of reirradiation 3D-IGBT in this context. 3D-IGBT appears to be a feasible alternative to salvage surgery in inoperable patients, with an acceptable outcome for patients who have no other curative therapeutic options, however long-term toxicities were high in some studies. Each case should be referred to highly experienced expert centers.

Abstract

Background: Local recurrence in gynecological malignancies occurring in a previously irradiated field is a challenging clinical issue. The most frequent curative-intent treatment is salvage surgery. Reirradiation, using three-dimensional image-guided brachytherapy (3D-IGBT), might be a suitable alternative. We reviewed recent literature concerning 3D-IGBT for reirradiation in the context of local recurrences from gynecological malignancies. Methods: We conducted a large-scale literature research, and 15 original studies, responding to our research criteria, were finally selected. Results: Local control rates ranged from 44% to 71.4% at 2–5 years, and overall survival rates ranged from 39.5% to 78% at 2–5 years. Grade ≥3 toxicities ranged from 1.7% to 50%, with only one study reporting a grade 5 event. Results in terms of outcome and toxicities were highly variable depending on studies. Several studies suggested that local control could be improved with 2 Gy equivalent doses >40 Gy. Conclusion: IGBT appears to be a feasible alternative to salvage surgery in inoperable patients or patients refusing surgery, with an acceptable outcome for patients who have no other curative therapeutic options, however at a high cost of long-term grade ≥3 toxicities in some studies. We recommend that patients with local recurrence from gynecologic neoplasm occurring in previously irradiated fields should be referred to highly experienced expert centers. Centralization of data and large-scale multicentric international prospective trials are warranted. Efforts should be made to improve local control while limiting the risk of toxicities.

[Can stereotactic body radiotherapy replace brachytherapy for locally advanced cervical cancer? French society for radiation oncology statement]

Brachytherapy is part of the treatment of locally advanced cervical cancers, accounting for about half of the total delivered dose. The benefit of dose escalation is the most important in advanced cases or if the tumor has responded poorly. The use of interstitial implantations makes it possible to reach doses of the order of 85 to 90Gy (including external beam radiotherapy contribution) in most patients, through image-guided approaches. Brachytherapy delivery is one of the quality criteria for patient care. To date, no data allow us to consider as an alternative the use of external boost through intensity-modulated or stereotactic body radiotherapy. Indeed, the doses delivered to the tumor and the capacity to spare normal tissues remains lower, as compared to what is permitted by brachytherapy. It is therefore appropriate for centers that do not have access to the technique to establish networks with centers where brachytherapy is performed, to allow each patient to have access to the technique. It is also necessary to promote brachytherapy teaching. The issue of reimbursement will be crucial in the coming years to maintain expertise that is today insufficiently valued in its financial aspects, but has a very high added value for patients.

Disease Site-Specific Guidelines for Curative Radiation Treatment During 'Limited Surgery' and 'Hospital Avoidance': A Radiation Oncology Perspective From the Epicenter of COVID-19 Pandemic

The COVID-19 pandemic has resulted in an unprecedented situation where the standard of care (SOC) management for cancers has been altered significantly. Patients with potentially curable cancers are at risk of not receiving timely SOC multidisciplinary treatments, such as surgery, chemotherapy, radiation therapy, or combination treatments. Hospital resources are in such high demand for COVID-19 patients that procedures, such as surgery, dentistry, interventional radiology, and other ancillary services, are not available for cancer patients. Our tertiary care center is considered the center of the epicenter in the USA. As a result, all non-emergent surgeries have been suspended in order to provide hospital beds and other resources for COVID-19 patients.

Additionally, ambulatory efforts to avoid treatment-related morbidity are critical for keeping patients out of emergency departments and hospitals. In this review article, we discuss evidence-based radiation therapy approaches for curable cancer patients during the COVID-19 pandemic. We focus on three scenarios of cancer care: 1) radiation therapy as an alternative to surgery when immediate surgery is not possible, 2) radiation therapy as a ‘bridge’ to surgery, and 3) radiation options definitively or postoperatively, given the risk of hospitalization with high-dose chemotherapy. 

Brachytherapy: An overview for clinicians

Brachytherapy is a specific form of radiotherapy consisting of the precise placement of radioactive sources directly into or next to the tumor. This technique is indicated for patients affected by various types of cancers. It is an optimal tool for delivering very high doses to the tumor focally while minimizing the probability of normal tissue complications. Physicians from a wide range of specialties may be involved in either the referral to or the placement of brachytherapy. Many patients require brachytherapy as either primary treatment or as part of their oncologic care. On the basis of high-level evidence from randomized controlled trials, brachytherapy is mainly indicated: 1) as standard in combination with chemoradiation in patients with locally advanced cervical cancer; 2) in surgically treated patients with uterine endometrial cancer for decreasing the risk of vaginal vault recurrence; 3) in patients with high-risk prostate cancer to perform dose escalation and improve progression-free survival; and 4) in patients with breast cancer as adjuvant, accelerated partial breast irradiation or to boost the tumor bed. In this review, the authors discuss the clinical relevance of brachytherapy with a focus on indications, levels of evidence, and results in the overall context of radiation use for patients with cancer.