The role of para-aortic nodal irradiation in cervical cancer

Study protocol of Elective Para-aortic and pelvic versus Pelvic only Irradiation in pelvic node positive Cervical cancer: a multicentric open labelled phase III randomised controlled trial (EPIC Study)

INTRODUCTION

The revision of International Federation of Gynaecology and Obstetrics staging in 2018 with recommendations to include cross-sectional imaging and a separate stage for node positive disease have opened a lot of uncertainties in implementing the correct treatment approach in these patients. While studies have suggested higher chances of occult para-aortic lymph node (PALN) even with advanced imaging, especially in pelvic node positive disease which tend to recur after pelvic radiation therapy. This study intends to study these patients and isolate the subset who will benefit most from elective PALN irradiation.

METHODS AND ANALYSIS

This is an ongoing multicentric phase III randomised controlled trial with a sample size of 274 subjects in two arms (137 in each arm) to determine the superiority of limited elective para-aortic irradiation compared with no irradiation. Arm one includes radiation to the lower PALN and pelvis; Arm two includes radiation to the pelvis. Concurrent chemotherapy followed by brachytherapy is standard in both arms. Patients with cervical cancer and radiologically positive pelvic LNs aged>18 years and<70 years are screened for the study. The primary endpoint of this study is 3-year disease-free survival. The secondary endpoints include 3-year para-aortic recurrence-free survival, 3-year distant metastasis-free survival, 3-year overall survival, acute and late toxicity, quality of life. Translational study to evaluate systemic immune response by FAPI-PETCT (fibroblast activator protein inhibitor positron emission tomography) and assessment of p16, L1 cell adhesion molecule (L1CAM) and protein death ligand-1 (PDL-1) expression by immunohistochemistry.

ETHICS AND DISSEMINATION

The study has been approved by the institutional ethics committee and will be routinely monitored according to standard guidelines. The results of the study will be published in peer-reviewed scientific journals, presented at conferences and submitted to regulatory authorities.

TRIAL REGISTRATION NUMBER

The study was registered on 17 January 2022 under CTRI/2022/01/039495 (http://ctri.nic.in).

The Evolving Role of Novel Imaging Techniques for Radiotherapy Planning

The ability to visualise cancer with imaging has been crucial to the evolution of modern radiotherapy (RT) planning and delivery. And as evolving RT technologies deliver increasingly precise treatment, the importance of accurate identification and delineation of disease assumes ever greater significance. However, innovation in imaging technology has matched that seen with RT delivery platforms, and novel imaging techniques are a focus of much research activity. How these imaging modalities may alter and improve the diagnosis and staging of cancer is an important question, but already well served by the literature. What is less clear is how novel imaging techniques may influence and improve practical and technical aspects of RT planning and delivery. In this review, current gold standard approaches to integration of imaging, and potential future applications of bleeding-edge imaging technology into RT planning pathways are explored.

Imaging evaluation of para-aortic lymph nodes in cervical cancer

BACKGROUND

In recent years, much literature has reported the diagnostic value of computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET)-CT in para-aortic lymph node metastasis of cervical cancer.

PURPOSE

To compare and analyze the para-aortic lymph node presentations found in cervical cancer on different images in order to determine the best precise imaging method for identifying metastatic lymph nodes.

MATERIAL AND METHODS

PubMed, Web of Science, MEDLINE, and other databases were searched for the non-invasive detection of metastatic lymph nodes for a comprehensive comparison.

RESULTS

Positive lymph nodes on CT are significantly related to the following factors: short axis ≥10 mm; and round or central necrosis. Positive lymph nodes on MRI are significantly related to the following factors: short axis ≥8 mm; inhomogeneous signal intensity; morphology: round, irregular edge, extracapsular invasion, central necrosis, loss of lymph node structure, burrs, or lobes; and ADC value decreases, combined with local actuality. On PET-CT examination, when the short axis of the lymph node is >5 mm, the SUV is >2.5, or the FDG uptake is greater than that of the surrounding tissue, it is a metastatic lymph node.

CONCLUSION

In conclusion, different imaging techniques show metastatic lymph nodes in different ways. Combining the patient's medical history with the symptoms of the aforementioned lymph nodes, together with one or more imaging techniques, is important to diagnose para-aortic lymph nodes in cervical cancer.

Correlating Quantitative Para-Aortic Lymph Node Computed Tomography Parameters With Fluorodeoxyglucose Positron Emission Tomography for Cervical Cancer Staging: Possible Solution for Resource Constrained Countries

OBJECTIVE

The aim of the study was to determine the most accurate quantitative morphological parameters on computed tomography (CT) that correlate with fluorodeoxyglucose (FDG)-avid para-aortic nodes (PANs) in patients with cervical cancer.

METHODS

A single-institution retrospective evaluation was performed of women with cervical cancer who underwent pretreatment positron emission tomography (PET)/CT and radiotherapy therapy planning CT between 2009 and 2020. A node-by-node correlation between pretreatment CT and PET/CT was performed for the reference standard of FDG avidity for short- and long-axis diameters, volume, and long-/short-axis ratio (L/S). The FDG-avid PANs were defined as PET-positive and non-FDG-avid PANs from patients without PET-determined PAN metastasis were defined as PET negative. Area under the receiver operator curve was calculated to access diagnostic accuracy of the different quantitative parameters.

RESULTS

A total of 94 women (mean age ± standard deviation, 52 ± 13 years) with cervical cancer were included. Forty-seven patients had PET-positive PANs (181 PET-positive PANs) and 47 patients had no PET-positive PANs (141 PET-negative PANs). The area under the receiver operator curve for volume (0.945) was greater (P < 0.001) than that of short axis (0.895), long axis (0.885), and L/S (0.583). At a specificity set point of 0.90 (127/141 PANs), the cutoff for volume was 0.443 cm3 or greater (0.85 sensitivity [154/181 PANs]; 95% confidence interval, 0.83-0.93) and for short-axis diameter was 5.9 mm or greater (0.75 sensitivity [135/181 PANs]; 95% confidence interval, 0.68-0.81).

CONCLUSIONS

Para-aortic lymph node volume demonstrated that improved node-by-node correlation between CT and PET/CT compared with short-axis diameter, long-axis diameter, and L/S and is an alternative to improve detection of PAN suspicious of metastatic diseases in locations without access to PET/CT.

Risk factors for nodal failure after radiochemotherapy and image guided brachytherapy in locally advanced cervical cancer: An EMBRACE analysis

OBJECTIVE

To assess risk factors for nodal failure (NF) after definitive (chemo)radiotherapy and image-guided brachytherapy for locally advanced cervical cancer (LACC) for patients treated in the EMBRACE I study.

MATERIALS AND METHODS

Data for pelvic NF and para-aortic (PAO) NF (NF_PAO) were analysed. After multiple imputation, univariable and multivariable Cox-regression was performed for clinical and treatment-related variables. For patients with affected pelvic nodes but no PAO nodes at diagnosis, additional analyses were performed for two subgroups: 1. 'small pelvis' nodes in internal and external iliac, obturator, parametrial, presacral and/or common iliac (CI) region and 2. any CI nodes (subgroup of 1).

RESULTS

1338 patients with 152 NF and 104 NF_PAO events were analysed with a median follow-up of 34.2 months (IQR 16.4-52.7). For the entire group, larger tumour width, nodal risk groups (in particular any CI nodes without PAO nodes), local failure, and lower Hb-nadir increased the risk of NF. Elective PAO-irradiation was independently associated with a decreased risk of NF_PAO (HR 0.53, 95%-CI 0.28-1.00, p = 0.05). For subgroup 1, having 'any CI nodes without PAO nodes' and local failure significantly increased NF risk. Additionally, elective PAO-irradiation was associated with less risk of NF_PAO (HR 0.38, 95%-CI 0.17-0.86, p = 0.02). For subgroup 2 only local failure was associated with higher risk of NF.

CONCLUSION

In this patient cohort, nodal disease and tumour width at diagnosis, as well as local failure, are risk factors for NF after definitive treatment. Having either 'any PAO nodes' (with or without pelvic nodes) or 'any CI nodes' (without PAO nodes) are stronger risk factors than involvement of nodes in the small pelvis alone. Elective PAO-irradiation was associated with significantly less NF_PAO, particularly in patients with nodal disease in the 'small pelvis' and/or CI region at time of diagnosis.

Para-aortic lymph node involvement in cervical cancer: Implications for staging, outcome and treatment

Locally advanced cervical cancer with the involvement of para-aortic lymph nodes (PALN) is a common occurrence in low-income and low-middle-income countries. With the incorporation of PALN in the recent FIGO staging, therapeutic management becomes crucial. There are varied presentations of this group which may range from microscopic involvement to extensive lymphadenopathy. Various imaging modalities have been studied to accurately diagnose PALN metastases without surgical intervention, while some investigators have studied the survival benefit of para-aortic lymph node dissection for accurate staging and guiding extent of radiation. With recent advances in radiation therapy, its application to treat bulky nodal metastases and the role of prophylactic irradiation have been reported. In this review, the available evidence and the scope of further interventions is presented.