The vaginal cylinder: Misunderstood, misused, or trivial? An in-depth dosimetric and multiinstitutional outcome investigation

Guy, Christopher L.; Fields, Emma C.; Quinn, Bridget A.; Fisher, Christine M.; Ladbury, Colton; Romano, Kara D.; Todor, Dorin

doi:10.1016/j.brachy.2019.08.007

Cited by 11 publications

(20 citation statements)

References 33 publications

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“…In a study including 304 EC patients treated with BT, there was a significant association between cylinder diameter and vaginal stenosis (10). In a recently published study, an increased stenosis rate was associated with a deeper prescription point ( p = 0.005) and longer treatment length ( p = 0.01) [ 26 ]. Since 2003 the patients in our hospital have been treated with a larger cylinder diameter, usually of 3.5 m and with a treatment source length of 2.5 cm, and patients are strongly encouraged to use vaginal dilators which could explain the low rate of G2 complications.…”

Section: Discussionmentioning

confidence: 99%

EQD2 Analyses of Vaginal Complications in Exclusive Brachytherapy for Postoperative Endometrial Carcinoma

Zhang

Fornes

Gomez

et al. 2020

Cancers

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Background: To evaluate whether EQD2(α/β = 3Gy) at 2 cm3 of the most exposed area of the vagina is related to late vaginal toxicity in postoperative endometrial cancer (PEC) patients (p) treated with exclusive brachytherapy (BT). Methods: From 2014 to 2017, 43p were included in this study. BT was administered: 3-fractions of 6Gy in 37p and 2-fractions of 7.5Gy in 6p. The dose was prescribed at a depth of 5 mm from the applicator surface with dose-point optimization based on distance. The active treatment length was 2.5 cm. CTV-D90 and the dose to the most exposed 2 cm3 of the vagina was calculated for each patient. Late toxicity of the bladder and rectum was assessed using Radiation Therapy Oncology Group (RTOG) criteria, and vaginal toxicity by objective Late Effects Normal Tissue Task Force (LENT)-Subjective, Objective, Management, Analytic (SOMA) (LENT-SOMA) criteria. Statistics: frequency tables, mean, median, range, standard deviation, and box plot. Results: The median follow-up was 51 months (12–68). 20 p (46.5%) and 2 p (4.7%) developed G1 and G2 vaginal complications, respectively. Only 1/2 p-G2 receiving EQD2(α/β = 3Gy) at 2 cm3 >68Gy presented vaginal shortening and 18/20 p-G1 received doses < 68Gy. Conclusions: PECp receiving exclusive brachytherapy with doses < 68Gy EQD2(α/β = 3Gy) at 2 cm2 of the vagina presented only G0–G1 vaginal toxicity, except for one with bleeding telangiectasias. Larger prospective studies are necessary to confirm the present results.

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Section: Discussionmentioning

confidence: 99%

EQD2 Analyses of Vaginal Complications in Exclusive Brachytherapy for Postoperative Endometrial Carcinoma

Zhang

Fornes

Gomez

et al. 2020

Cancers

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“…Kloetzer et al observed no difference in survival or vaginal recurrence treating only proximal half of the vagina [17]. Surprisingly, one analysis found that overall recurrence was correlated with increased prescription length, though this was not discussed in the paper, and it was most likely due to differences in disease [14]. We found a significant difference in vaginal cuff recurrence between patients treated with an AL of 1 and 2 cm (5-year recurrence rates of 11.5% and 0.9%, respectively).…”

Section: Discussionmentioning

confidence: 98%

“…The length of vagina irradiation is known to be associated with vaginal shortening and stenosis [13,35]. A recent analysis showed stenosis rates of 5% and 31%, with prescription lengths of 2.5 cm and 5.0 cm, respectively [14]. This same analysis found that stenosis rates correlated significantly with prescription depth (4% vs. 21% at the surface and 5 mm, respectively), but not with cylinder diameter, which, unlike prescription point and length, physicians tend to alter based on individual anatomy.…”

Section: Discussionmentioning

confidence: 99%

“…Wide practice variances are often due to a lack of data. However, length of vaginal irradiation as well as volume have been known to be associated with vaginal shortening and stenosis for decades [13][14][15][16]. Less described in the literature is a relationship between the length of vagina irradiation and vaginal recurrence [14,17].…”

Section: Purposementioning

confidence: 99%

“…However, length of vaginal irradiation as well as volume have been known to be associated with vaginal shortening and stenosis for decades [13][14][15][16]. Less described in the literature is a relationship between the length of vagina irradiation and vaginal recurrence [14,17]. The common prescription depth of 5 mm, though potentially more toxic than prescribing to the surface, can be justified by location of vaginal lymphatics [8,18,19].…”

Section: Purposementioning

confidence: 99%

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Vaginal cuff brachytherapy: do we need to treat to more than a two-centimeter active length?

Jensen¹,

Barry²,

Eldredge-Hindy³

et al. 2021

jcb

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Purpose: American Brachytherapy Society (ABS) guidelines recommend using a 3-5 cm active length (AL) when treating vaginal cuff (VC) in adjuvant setting of endometrial cancer (EC). The purpose of this study was to evaluate local control and toxicity, using an AL of 1 or 2 cm and immobilization with a traditional table-mounted (stand) or patient-mounted (suspenders) device.Material and methods: Between 2005 and 2019, 247 patients with EC were treated with adjuvant high-dose-rate vaginal cuff (HDR-VC) brachytherapy with or without external beam radiation (EBRT). Treatment was prescribed to a 0.5 cm depth, with an AL of 1 or 2 cm, using stand or suspenders. VC boost after EBRT was typically administered with 2 fractions of 5.5 Gy, while VC brachytherapy alone was typically applied with 3 fractions of 7 Gy or 5 fractions of 5.5 Gy.Results: The combination of suspender immobilization and an AL of 2 cm (n = 126, 51%) resulted in 5-year local control of 100%. An AL of 2 cm compared to 1 cm correlated with better local control (99.1% vs. 88.5%, p = 0.0479). Regarding immobilization, suspenders correlated with improved local control compared to stand (100% vs. 86.7%, p = 0.0038). Immobilization technique was significantly correlated with AL (p < 0.0001). Only 5 (2.0%) patients experienced grade ≥ 3 toxicity, all of whom received EBRT.Conclusions: In the present series, an AL of 2 cm provided excellent local control, while 1 cm was inadequate. Suspender immobilization was a practical alternative to stand immobilization in HDR brachytherapy of the vaginal cuff.

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The effect of vaginal cylinder inhomogeneity on the HDR brachytherapy dose calculations using Monte Carlo simulations

Meftahi,

Song

2023

J Applied Clin Med Phys

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PurposeTo analytically assess the heterogeneity effect of vaginal cylinders (VC) made of high‐density plastics on dose calculations, considering the prescription point (surface or 5 mm beyond the surface), and benchmark the accuracy of a commercial model‐based dose calculation (MBDC) algorithm using Monte Carlo (MC) simulations.Methods and materialsThe GEANT4 MC code was used to simulate a commercial 192Ir HDR source and VC, with diameters ranging from 20 to 35 mm, inside a virtual water phantom. Standard plans were generated from a commercial treatment planning system [TPS—BrachyVision ACUROS (BV)] optimized for a treatment length of 5 cm through two dose calculation approaches: (1) assuming all the environment as water (i.e., Dw,w‐MC & Dw,w‐TG43) and (2) accounting for the heterogeneity of VC applicators (i.e., Dw,w‐App‐MC & Dw,w‐App‐MBDC). The compared isodose lines, and dose & energy difference maps were extracted for analysis. In addition, the dose difference on the peripheral surface, along the applicator and at middle of treatment length, as well as apical tip was evaluated.ResultsThe Dw,w‐App‐MC results indicated that the VC heterogeneity can cause a dose reduction of (up to) % 6.8 on average (for all sizes) on the peripheral surface, translating to 1 mm shrinkage of the isodose lines compared to Dw,w‐MC. In addition, the results denoted that BV overestimates the dose on the peripheral surface and apical tip of about 3.7% and 17.9%, respectively, (i.e., Dw,w‐App‐MBDC vs Dw,w‐App‐MC) when prescribing to the surface. However, the difference between the two were negligible at the prescription point when prescribing to 5 mm beyond the surface.ConclusionThe VCs’ heterogeneity could cause dose reduction when prescribing dose to the surface of the applicator, and hence increases the level of uncertainty. Thus, reviewing the TG43 results, in addition to ACUROS, becomes prudent, when evaluating the surface coverage at the apex.

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The vaginal cylinder: Misunderstood, misused, or trivial? An in-depth dosimetric and multiinstitutional outcome investigation

Cited by 11 publications

References 33 publications

EQD2 Analyses of Vaginal Complications in Exclusive Brachytherapy for Postoperative Endometrial Carcinoma

EQD2 Analyses of Vaginal Complications in Exclusive Brachytherapy for Postoperative Endometrial Carcinoma

Vaginal cuff brachytherapy: do we need to treat to more than a two-centimeter active length?

The effect of vaginal cylinder inhomogeneity on the HDR brachytherapy dose calculations using Monte Carlo simulations

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