More accurate definition of clinical target volume based on the measurement of microscopic extensions of the primary tumor toward the uterus body in international federation of gynecology and obstetrics Ib-IIa squamous cell carcinoma of the cervix

Exclusion of non-Involved uterus from the target volume (EXIT-trial): An individualized treatment for locally advanced cervical cancer using modern radiotherapy and imaging techniques followed by completion surgery

Background and purpose

Chemoradiotherapy followed by brachytherapy is the standard of care for locally advanced cervical cancer (LACC). In this study, we postulate that omitting an iconographical unaffected uterus (+12 mm distance from the tumour) from the treatment volume is safe and that no tumour will be found in the non-targeted uterus (NTU) leading to reduction of high-dose volumes of surrounding organs at risk (OARs).

Material and Methods

In this single-arm phase 2 study, two sets of target volumes were delineated: one standard-volume (whole uterus) and an EXIT-volume (exclusion of non-tumour-bearing parts of the uterus with a minimum 12 mm margin from the tumour). All patients underwent chemoradiotherapy targeting the EXIT-volume, followed by completion hysterectomy. In 15 patients, a plan comparison between two treatment plans (PTV vs PTV_EXIT) was performed. The primary endpoint was the pathological absence of tumour involvement in the non-targeted uterus (NTU). Secondary endpoints included dosimetric impact of target volume reduction on OARs, acute and chronic toxicity, overall survival (OS), locoregional recurrence-free survival (LRFS), and progression-free survival (PFS).

Results

In all 21 (FIGO stage I: 2; II: 14;III: 3; IV: 2) patients the NTU was pathologically negative. Ssignificant reductions in Dmean in bladder, sigmoid and rectum; V15Gy in sigmoid and rectum, V30Gy in bladder, sigmoid and rectum; V40Gy and V45Gy in bladder, bowel bag, sigmoid and rectum; V50Gy in rectum were achieved. Median follow-up was 54 months (range 7-79 months). Acute toxicity was mainly grade 2 and 5 % grade 3 urinary. The 3y- OS, PFS and LRFS were respectively 76,2%, 64,9% and 81 %.

Conclusion

MRI-based exclusion of the non-tumour-bearing parts of the uterus at a minimum distance of 12 mm from the tumour out of the target volume in LACC can be done without risk of residual disease in the NTU, leading to a significant reduction of the volume of surrounding OARS treated to high doses.

Retrospective analysis of local recurrence pattern by computed tomography image-guided intracavitary and interstitial brachytherapy for locally advanced cervical cancer in a single Japanese institution

PURPOSE

The purpose of this study was to investigate the treatment results with focus on local control (LC) by computed tomography (CT)-guided intracavity brachytherapy and interstitial brachytherapy (ICBT/ISBT) for locally advanced cervical cancer (LACC).

METHODS AND MATERIALS

Patients with LACC undergoing ICBT/ISBT at least once in our institution between January 2017 and June 2019 were analyzed retrospectively. The primary endpoint was local control (LC), and the secondary endpoints were progression-free survival (PFS), overall survival (OS), and late toxicities. Differences between patient subgroups for prognostic factors in LC, PFS, and OS were analyzed using the log-rank test. The recurrence patterns of LC were also investigated.

RESULTS

Forty-four patients were included in the present study. The median high-risk clinical target volume (HR-CTV) at the initial brachytherapy was 48.2 cc. The median total dose of HR-CTV D90 (EQD2) was 70.7 Gy. The median followup period was 39.4 months. The 3-year LC, PFS and OS rates in all patients were 88.2%, 56.6%, and 65.4% (95% CI 50.3-78.0%), respectively. Corpus invasion and large HR-CTV (70 cc or more) were significant prognostic factors in LC, PFS, and OS. Marginal recurrences at the fundus of the uterus were detected in 3 of 5 patients in whom local recurrence was observed. Late toxicities of Grade 3 or higher were detected in 3 patients (6.8%).

CONCLUSIONS

Favorable LC was achieved by performing CT-guided ICBT/ISBT for LACC. The brachytherapy strategy for patients with corpus invasion or large HR-CTV may need to be reconsidered.

Clinicopathologic analysis of microscopic tumor extension in glioma for external beam radiotherapy planning

BACKGROUND

There is no consensus regarding the clinical target volume (CTV) margins in radiotherapy for glioma. In this study, we aimed to perform a complete macropathologic analysis examining microscopic tumor extension (ME) to more accurately define the CTV in glioma.

METHODS

Thirty-eight supra-total resection specimens of glioma patients were examined on histologic sections. The ME distance, defined as the maximum linear distance from the tumor border to the invasive tumor cells, was measured at each section. We defined the CTV based on the relationships between ME distance and clinicopathologic features.

RESULTS

Between February 2016 and July 2020, a total of 814 slides were examined, corresponding to 162 slides for low-grade glioma (LGG) and 652 slides for high-grade glioma (HGG). The ME value was 0.69 ± 0.43 cm for LGG and 1.29 ± 0.54 cm for HGG (P < 0.001). After multivariate analysis, tumor grade, O⁶-methylguanine-DNA-methyltransferase promoter methylated status (MGMT_m), isocitrate dehydrogenase wild-type status (IDH_wt), and 1p/19q non-co-deleted status (non-codel) were positively correlated with ME distance (all P < 0.05). We defined the CTV of glioma based on tumor grade. To take into account approximately 95% of the ME, a margin of 1.00 cm, 1.50 cm, and 2.00 cm were chosen for grade II, grade III, and grade IV glioma, respectively. Paired analysis of molecularly defined patients confirmed that tumors that had all three molecular alterations (i.e., MGMT_m/IDH_wt/non-codel) were the most aggressive subgroups (all P < 0.05). For these patients, the margin could be up to 1.50 cm, 2.00 cm, and 2.50 cm for grade II, grade III, and grade IV glioma, respectively, to cover the subclinical lesions in 95% of cases.

CONCLUSIONS

The ME was different between the grades of gliomas. It may be reasonable to recommend 1.00 cm, 1.50 cm, and 2.00 cm CTV margins for grade II, grade III, and grade IV glioma, respectively. Considering the highly aggressive nature of MGMT_m/IDH_wt/non-codel tumors, for these patients, the margin could be further expanded by 0.5 cm. These recommendations would encompass microscopic disease extension in 95% of cases.

TRIAL REGISTRATION

The trial was registered with Chinese Clinical Trial Registry ( ChiCTR2100049376 ).

Prospective validation of craniocaudal tumour size on MR imaging compared to histoPAthology in patients with uterine cervical cancer: The MPAC study

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Tumour extension on MRI was compared with histopathology using three methods.

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MRI visualises tumour extension within a margin of 10 mm compared to microscopy.

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The major source of measurement uncertainty is post-surgical change of organ.

Purpose

To determine the accuracy of MRI in detecting craniocaudal tumour extension, compared to histopathology, of the hysterectomy specimen in patients with early-stage uterine cervical cancer. Three complementary methods were investigated.

Materials and methods

Thirty-four patients with early-stage cervical cancer had pre-operative MRI, followed by radical hysterectomy or trachelectomy. 1) craniocaudal tumour extension was measured on MRI by two radiologists and compared to microscopy by a pathologist, 2) to compensate for changes in uterine shape between pre-operative MRI and the surgical specimen, craniocaudal tumour extensions were directly compared and appreciated as being a part of a 3-dimensional tumour by a radiation oncologist and resident, and 3) tumour size on MRI was compared macroscopically after digital non-rigid registration of the uterus, uterine cavity and tumour of both modalities.

Results

The craniocaudal tumour extension measured on histopathology minus MRI gives: 1) on average +3 mm difference when measured by a radiologist compared to the microscopic extension (range −13 to +15 mm), 2) −0.2 mm (range −11 to +6.0 mm) when evaluated on MRI by a radiation oncologist compared to the macroscopic tumour; 3) after non-rigid organ registration, a margin of 10 mm around the tumour on MRI would be needed to cover 95% of the tumour in 90% of the patients.

Conclusions

Results indicate that microscopic tumour extension towards the uterine fundus is within a margin of 10 mm around the visible tumour on MRI. The major source of measurement uncertainty is post-surgical change of organ shape and form.