MRI-guided treatment-planning optimisation in intracavitary or combined intracavitary/interstitial PDR brachytherapy using tandem ovoid applicators in locally advanced cervical cancer

doi:10.1016/j.radonc.2009.08.014

Radiotherapy and Oncology

Volume 93, Issue 2, November 2009, Pages 322-330

https://doi.org/10.1016/j.radonc.2009.08.014 Get rights and content

Abstract

Purpose

To study the impact of MRI-guided treatment planning on dose/volume parameters in pulsed dose rate (PDR) brachytherapy (BT) for cervical cancer. Additionally, we investigated the potential benefit of an intracavitary/interstitial (IC/IS) modification of the classical tandem ovoid applicator.

Material and methods

For 24 patients we compared Standard PDR BT plans, Scaled Standard plans and MRI-guided Optimised plans. The total EBRT/BT prescribed dose to Manchester point A or to 90% of the HR-CTV (D90 HR-CTV) [1] expressed in EQD₂ was 80 Gy_αβ10 in 17 patients (Period I) and 84 Gy_αβ10 in 7 patients (Period II). The constraints to 2 cm³ of the OAR were 90 Gy_αβ3 for bladder and 75 Gy_αβ3 for rectum, sigmoid and bowel. Most cases were treated with a traditional intracavitary tandem ovoid applicator. In 6 patients we used a newly designed combined IC/IS modification for the second PDR fraction and investigated the benefit of the interstitial part.

Results

The average gain of MRI-guided optimisation expressed in D90 HR-CTV was 4 ± 9 Gy_αβ10 (p < 0.001) and 10 ± 7 Gy_αβ10 (p = 0.003) in the two periods. The dose to 2 cm³ of the OAR met the constraints. In the group that was treated with the combined IC/IS approach, we could increase the D90 HR-CTV for the second PDR fraction with 5.4 ± 4.2 Gy_αβ10 (p = 0.005) and the D100 with 4.8 ± 3.1 Gy_αβ10 (p = 0.07).

Conclusions

Three-dimensional MRI-guided treatment planning and optimisation improves the DVH parameters compared to conventional planning strategies. Additional improvement can be achieved by using a combined IC/IS approach.

Section snippets

Diagnostic workup, treatment protocols and dose calculation for EBRT and BT

Diagnosis of cervical cancer was based on clinical investigation, gynaecological investigation under anaesthesia with cystoscopy and biopsy, MR imaging of the pelvic region and the retroperitoneal space, as well as whole body FDG-PET on indication. The analysis includes 24 patients with pathologically proven cervical cancer treated between February 2006 and December 2007. All patients had FIGO stage IB2 to IVA tumours. Treatment was performed according to our institutional protocol with a

Results

The dose–volume parameters derived for all patients and for three different treatment plans are listed in Table 1. The differences in treated volumes between the Standard and the Optimised plans were limited on average with not more than 5 cm³ for VPD and 2 cm³ for V2PD. However, in individual cases a difference of up to 30% was seen. Between the Scaled Standard and Optimised plans, differences were more pronounced but did not exceed 14 cm³ for VPD and 6 cm³ for V2PD. The average HR-CTV sizes

Discussion

In Utrecht BT for cervical cancer is delivered using tandem ovoid applicators with treatment planning having been traditionally performed according to the ICRU 38 guidelines [8]. Treatment plans were generated using standard loading patterns. Dose was prescribed to the Manchester point A and was reduced, if the dose to ICRU bladder and/or rectum point exceeded our institutional constraints. The dilemma of this strategy is that the OAR-related dose reduction decreases the tumour dose and

Conclusion

Performing MRI-guided adaptive BT for cervical cancer is feasible in our department with an advantage in dose–volume relationships over our traditional treatment-planning strategy. By comparing our data with the results from other groups, we could demonstrate that we reach similar dose levels in target volumes and OAR. These findings suggest that 3D MRI-guided adaptive BT treatment planning according to the GEC ESTRO recommendations brings different treatment strategies together. The guidelines

References (36)

C. Haie-Meder et al.
Recommendations from gynaecological (GYN) GEC-ESTRO working group (I): concepts and terms in 3D image based 3D treatment planning in cervix cancer brachytherapy with emphasis on MRI assessment of GTV and CTV
Radiother Oncol
(2005)
M.D. Logsdon et al.
Figo IIIB squamous cell carcinoma of the cervix: an analysis of prognostic factors emphasizing the balance between external beam and intracavitary radiation therapy
Int J Radiat Oncol Biol Phys
(1999)
J.S. Haas et al.
Dosimetric comparison of the Fletcher family of gynaecologic colpostats 1950–1980
Int J Radiat Oncol Biol Phys
(1985)
P.W. Grigsby et al.
Perez CA Source configuration and dose rates for the Selectron afterloading equipment for gynaecologic applicators
Int J Radiat Oncol Biol Phys
(1992)
F. van den Bergh et al.
The use of a transverse CT image for the estimation of the dose given to the rectum in intracavitary brachytherapy for carcinoma of the cervix
Radiother Oncol
(1998)
N. Wachter-Gerstner et al.
Bladder and rectum dose defined from MRI based treatment planning for cervix cancer brachytherapy: comparison of dose–volume histograms for organ contours and organ wall, comparison with ICRU rectum and bladder reference point
Radiother Oncol
(2003)
N. Wachter-Gerstner et al.
The impact of sectional imaging on dose escalation in endocavitary HDR-brachytherapy of cervical cancer: results of a prospective comparative trial
Radiother Oncol
(2003)
R.Y. Kim et al.
Radiography-based treatment planning compared with computed tomography (CT)-based treatment planning for intracavitary brachytherapy in cancer of the cervix: analysis of dose–volume histograms
Brachytherapy
(2003)
C.E. Pelloski et al.
Comparison between CT-based volumetric calculations and ICRU reference-point estimates of radiation doses delivered to bladder and rectum during intracavitary radiotherapy for cervical cancer
Int J Radiat Oncol Biol Phys
(2005)
R.Y. Kim et al.
Image-based three-dimensional treatment planning of intracavitary brachytherapy for cancer of the cervix: dose–volume histograms of the bladder, rectum, sigmoid colon, and small bowel
Brachytherapy
(2007)

R. Pötter et al.

Recommendations from gynaecological (GYN) GEC ESTRO working group (II): concepts and terms in 3D image-based treatment planning in cervix cancer brachytherapy-3D dose–volume parameters and aspects of 3D image-based anatomy, radiation physics, radiobiology

Radiother Oncol

(2006)

S. Nag et al.

Proposed guidelines for image-based intracavitary brachytherapy for cervical carcinoma: report from Image-Guided Brachytherapy Working Group

Int J Radiat Oncol Biol Phys

(2004)

C. Kirisits et al.

The Vienna applicator for combined intracavitary and interstitial brachytherapy of cervical cancer: design, application, treatment planning, and dosimetric results

Int J Radiat Oncol Biol Phys

(2006)

C. Kirisits et al.

Dose and volume parameters for MRI-based treatment planning in intracavitary brachytherapy for cervical cancer

Int J Radiat Oncol Biol Phys

(2005)

J.C. Dimopoulos et al.

The Vienna applicator for combined intracavitary and interstitial brachytherapy of cervical cancer: clinical feasibility and preliminary results

Int J Radiat Oncol Biol Phys

(2006)

R. Pötter et al.

Clinical impact of MRI assisted dose–volume adaptation and dose escalation in brachytherapy of locally advanced cervix cancer

Radiother Oncol

(2007)

L. Van de Bunt et al.

Conventional, conformal, and intensity-modulated radiation therapy treatment planning of external beam radiotherapy for cervical cancer: the impact of tumor regression

Int J Radiat Oncol Biol Phys

(2006)

A. Taylor et al.

Mapping pelvic lymph nodes: guidelines for delineation in intensity-modulated radiotherapy

Int J Radiat Oncol Biol Phys

(2005)

Cited by (109)

Prospective validation of a machine learning model for applicator and hybrid interstitial needle selection in high-dose-rate (HDR) cervical brachytherapy
2024, Brachytherapy
To Demonstrate the clinical validation of a machine learning (ML) model for applicator and interstitial needle prediction in gynecologic brachytherapy through a prospective clinical study in a single institution.
The study included cervical cancer patients receiving high-dose-rate brachytherapy using intracavitary (IC) or hybrid interstitial (IC/IS) applicators. For each patient, the primary radiation oncologist contoured the high-risk clinical target volume on a pre-brachytherapy MRI, indicated the approximate applicator location, and made a clinical determination of the first fraction applicator. A pre-trained ML model predicted the applicator and IC/IS needle arrangement using tumor geometry. Following the first fraction, ML and radiation oncologist predictions were compared and a replanning study determined the applicator providing optimal organ-at-risk (OAR) dosimetry. The ML-predicted applicator and needle arrangement and the clinical determination were compared to this dosimetric ground truth.
Ten patients were accrued from December 2020 to October 2022. Compared to the dosimetrically optimal applicator, both the radiation oncologist and ML had an accuracy of 70%. ML demonstrated better identification of patients requiring IC/IS applicators and provided balanced IC and IC/IS predictions. The needle selection model achieved an average accuracy of 82.5%. ML-predicted needle arrangements matched or improved plan quality when compared to clinically selected arrangements. Overall, ML predictions led to an average total improvement of 2.0 Gy to OAR doses over three treatment fractions when compared to clinical predictions.
In the context of a single institution study, the presented ML model demonstrates valuable decision-support for the applicator and needle selection process with the potential to provide improved dosimetry. Future work will include a multi-center study to assess generalizability.
Basic principles in gynecologic radiotherapy
2023, DiSaia and Creasman Clinical Gynecologic Oncology
A basic understanding of the principles of radiation oncology is essential to gynecologic oncologists. Radiation therapy is used in the curative treatment of locoregionally advanced cervical and vaginal carcinoma. It is often an adjuvant therapy prescribed for uterine or vulvar carcinoma and in inoperable patients may be the only definitive therapy available. Lastly, it can be used for the palliative treatment of gynecologic carcinomas.
The Kelowna template for combined intracavitary and interstitial brachytherapy for gynecologic malignancies: Design, application, treatment planning, dosimetric and treatment outcomes
2022, Brachytherapy
We report the feasibility, experience, and early outcomes of the combined intracavitary and interstitial dedicated applicator using the Kelowna GYN template (Varian, Palo Alto, CA).
The Kelowna GYN template is CT compatible and used for the treatment of gynecologic cancers. In cases with patients that have an intact uterus, a modified applicator system using the Kelowna GYN template and a 3D printed adapter piece allows for compatibility with an intrautaerine tandem.
We reviewed the treatment course of 23 patients comprising of 86 fractions of HDR treatment. Median D90 for cervical tumors (n = 7) was 82.4 Gy (range 77.7–92.6); for postoperative cervical tumors (n = 2) was 73.9 Gy (range 72.0–5.8); for vaginal tumors (n = 4) was 85.8 Gy (range 79.8–88.1); for recurrent endometrial (n = 10) was 86.9 Gy (range 74.8–103.2). Median EQD2 D2cc for bladder was 72.4 Gy (range 47.7–99.4), for rectum was 61.2 Gy (range 52.4–80.6), and for sigmoid colon of 50.5 Gy (44.3–66.9). At a median follow-up of 12 months, 2 patients had a local recurrence. Two patients had distant recurrence: one with carcinomatosis at 6 months, and one with pulmonary metastases at 3 months. No patients had late grade three toxicities.
Our single institutional experience supports the use of the Kelowna template as a robust system as a combined IC-IS applicator resulting in versatile and reproducible implants for a variety of gynecologic malignancies.
Clinical outcome of combined intracavitary / interstitial brachytherapy using a hybrid applicator in locally advanced cervical cancer
2022, Gynecologic Oncology
The aim of this study was to evaluate the clinical outcome in locally advanced cervical cancer (LACC) after image-guided adaptive brachytherapy (IGABT) with combined intracavitary and interstitial (IC/IS) techniques using the hybrid Venezia applicator (Elekta AB, Sweden).
LACC patients (UICC Stage IIB – IVB) treated with radiochemotherapy followed by IGABT with the hybrid IC/IS Venezia applicator at a single institution were retrospectively analyzed. Treatment comprised EBRT of the pelvis with 45 Gy and concomitant weekly cisplatin chemotherapy (40 mg/m²) followed by MRI-based IGABT. Dosimetry, oncological outcome and toxicity were investigated.
Forty-six patients underwent a total of 184 fractions of IGABT between 2017 and 2020. Median follow-up was 24 months. Combined IC/IS techniques were used in 40 patients (87%). The median HRCTV volume was 31.2 cm³ and the median HRCTV D_90% was 92.3 Gy (EQD2₁₀). The median D_2cm³ was 74.8 Gy for bladder, 57.9 Gy for rectum, 60.0 Gy for sigmoid and 52.2 Gy for bowel (EQD2₃). The 3-yr actuarial rates were 97.6% for local control, 97.6% for pelvic control, 59.9% for distant metastasis-free survival and 81.6% for overall survival. The crude rate for G2 and G3 late toxicity was 21.7% and 4.3%.
IGABT with the hybrid Venezia applicator and a pronounced use of a combined IC/IS technique achieved high target doses, while maintaining low doses to organs at risk, leading to excellent local control and overall survival rates with acceptable toxicity.
Characterization of combined intracavitary/interstitial brachytherapy including oblique needles in locally advanced cervix cancer
2021, Brachytherapy
To characterize and report on dosimetric outcomes of image guided adaptive brachytherapy (IGABT) using intracavitary and interstitial (IC/IS) applicators including oblique needles (O-needles) in locally advanced cervical cancer (LACC).
Twenty LACC patients treated with radio-chemotherapy and offered IC/IS-IGABT including O-needles were analyzed. An in-house 3D-printed vaginal template was used to steer the needles parallel and obliquely in relation to the tandem, supplemented with free-hand needles if needed. Implant characteristics and loading patterns were analyzed. Using the equivalent dose in 2Gy-fractions (EQD2) concept, cumulative (EBRT+BT) V85, V75, V60Gy, targets/OARs doses and high dose volumes (150%, 200% and 300% (100% = 85 Gy EQD2₁₀)) were evaluated.
Median(range) tumor width at diagnosis was 5.5(3.6; 7.5)cm; CTV_HR volume was 45(23; 136)cm³ with maximum distance from tandem to CTV_HR border of 3.4(2.5; 4.8)cm. T-stage distribution was IIB/III/IVA in 6(30%)/9(45%)/5(25%) of patients. At BT, 13(65%) patients had distal parametrial/pelvic wall infiltration. Median(range) number of needles per patient was 11(8–18). Average distribution of intrauterine, vaginal and interstitial dwell times were 31%, 25% and 44%, respectively. Median(range) dwell-time per dwell position was 11(2–127)% of average point-A based standard loading. Median V_85Gy/V_150%/V_200%/V_300% were 85(38; 171)/41(21; 93)/22(12; 41)/7(4; 19) cm³; CTV_HR D_90% was 93(83; 97)Gy EQD2₁₀; bladder/rectum/sigmoid/bowel D_2cm3 were 78(64; 104)/65(52; 76)/59(53; 69)/61(47; 76)Gy EQD2₃.
The use of O-needles in patients with large and/or unfavorable tumors resulted in excellent target coverage and OARs sparing. Intrauterine and vaginal loadings were reduced compared to standard loading and almost half of the loading was shifted into IS needles. This was achieved with gentle loading in the majority of dwell positions.
MRI-guided brachytherapy for locally advanced cervical cancer: Program initiation, learning curve and dose delivery results in Kuopio University Hospital
2021, Brachytherapy
Image guided adaptive brachytherapy, the standard treatment for locally advanced cervical cancer (LACC), is a complex medical procedure that requires an experienced multidisciplinary team. The aims of this analysis were to assess (1) the learning curve of brachytherapy team, (2) dose-volume parameters, (3) the use of an interstitial component, and (4) the overall treatment time (OTT).
Our study cohort comprised 117 LACC patients treated in Kuopio University Hospital with magnetic resonance imaging guided intracavitary (IC) or combined intracavitary/interstitial (IC/IS) high dose rate brachytherapy during 2009-2018. Target volumes and organs at risk (OAR) were contoured according to ICRU/GEC-ESTRO recommendations. Treatment plans were optimized individually without using standard loading patterns.
Mean dose to 90% of the high-risk clinical target volume (HR-CTV D90) improved after the first 15 patients, however the team's learning curve to reliably fulfill the main planning aim (PA) of 85 Gy required a total 43 patients and more than 10 patients annually. Significant difference was detected between IC and IC/IS brachytherapy in achieving the PA of HR-CTV D90. Especially, HR-CTV volumes >30 cm³ benefitted from IS needles. Needle insertion did not cause serious complications. With the brachytherapy program, the OTT of patients from outside institutions was reduced to the same level as our own patients.
Brachytherapy requires good experience of multidisciplinary team and the continuous development of the program to fulfill PA and to avoid OTT prolongation. The use of IS needles is safe and improves the fulfillment of PA to target volume.

View all citing articles on Scopus

View full text

Cervix cancer brachytherapyMRI-guided treatment-planning optimisation in intracavitary or combined intracavitary/interstitial PDR brachytherapy using tandem ovoid applicators in locally advanced cervical cancer

Abstract

Purpose

Material and methods

Results

Conclusions

Section snippets

Diagnostic workup, treatment protocols and dose calculation for EBRT and BT

Results

Discussion

Conclusion

Radiother Oncol

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Radiother Oncol

Radiother Oncol

Radiother Oncol

Brachytherapy

Int J Radiat Oncol Biol Phys

Brachytherapy

Radiother Oncol

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Radiother Oncol

Int J Radiat Oncol Biol Phys

Int J Radiat Oncol Biol Phys

Cervix cancer brachytherapy
MRI-guided treatment-planning optimisation in intracavitary or combined intracavitary/interstitial PDR brachytherapy using tandem ovoid applicators in locally advanced cervical cancer