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3D Printed Rigid Bolus Versus Silicone Bolus for Treatment of Tumors Involving the Skin: A Comparative Study

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT04176900
Recruitment Status : Unknown
Verified February 2020 by Lara Best, MD, FRCPC, MMEd, Nova Scotia Cancer Centre.
Recruitment status was:  Not yet recruiting
First Posted : November 25, 2019
Last Update Posted : February 26, 2020
Information provided by (Responsible Party):
Lara Best, MD, FRCPC, MMEd, Nova Scotia Cancer Centre

Tracking Information
First Submitted Date  ICMJE November 22, 2019
First Posted Date  ICMJE November 25, 2019
Last Update Posted Date February 26, 2020
Estimated Study Start Date  ICMJE March 2020
Estimated Primary Completion Date December 31, 2021   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures  ICMJE
 (submitted: November 22, 2019)
  • Air Gap measurement [ Time Frame: 6 weeks ]
    Measurement of the gap between the bolus and the surface of the patient
  • Planned versus expected radiation duse [ Time Frame: 6 weeks ]
    Comparison of the planned radiation dose at skin, and that measured during radiation therapy treatment
Original Primary Outcome Measures  ICMJE Same as current
Change History
Current Secondary Outcome Measures  ICMJE
 (submitted: November 22, 2019)
  • Ease of Use [ Time Frame: 6 weeks ]
    Time required to place bolus in proper location prior to each radiation therapy treatment
  • Radiation Therapist ease of use [ Time Frame: 6 weeks ]
    Radiation therapists asked to rate ease of use for each type of bolus
  • Challenges with Bolus Use [ Time Frame: 6 weeks ]
    Comparison of the number of times each bolus could not be adequately applied prior to radiation therapy treatment
  • Patient Reported Outcomes [ Time Frame: 6 weeks ]
    Patients asked about comfort associated with each bolus, their preference between the two, and any other feedback on the boluses
  • Fabrication time [ Time Frame: 2 weeks ]
    Comparison of average fabrication time for each type of bolus
  • Successful fabrication [ Time Frame: 2 weeks ]
    Comparison of percentage of cases for which an acceptable bolus could be created for each type of bolus
Original Secondary Outcome Measures  ICMJE Same as current
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
Descriptive Information
Brief Title  ICMJE 3D Printed Rigid Bolus Versus Silicone Bolus for Treatment of Tumors Involving the Skin: A Comparative Study
Official Title  ICMJE 3D Printed Rigid Bolus Versus Silicone Bolus: A Comparative Study
Brief Summary This study compares two types of 3D-printed skin bolus (rigid and flexible) used to optimize the treatment of tumors/cancers involving the skin. Each patient will have both types of bolus made, with each will be used on alternating days. The goal is to determine if one type of bolus provides a better fit and thus radiotherapy plan, the ease of use of each type of bolus, and patient reported feedback.
Detailed Description

Need for Skin Bolus during Radiotherapy for Cancers that Involve the Skin Using standard megavoltage (MV) radiotherapy to treat tumors that involve the skin is technically challenging as without modification, the high-energy radiotherapy machines under-dose the superficial tissue. This is a problem, as this may lead to an inadequate radiation dose being delivered to the skin, thus compromising tumor control. To compensate for this, a flexible polymer material ("bolus") measuring 5-10mm in thickness is placed over the skin during radiotherapy.

There are many types of boluses used internationally from rubber to candle wax slabs. The bolus allows the radiation dose to build up so that a sufficient dose is deposited at the skin. Use of bolus for cancers involving the skin is considered the standard of care when using conventional MV radiotherapy.

Challenges of Using Conventional Bolus Many standard boluses are slightly flexible, but are not able to follow significant changes in the underlying contours. When a bolus is not able to follow an individual's unique 'peaks and valleys' in contour, it can lead to air gaps between the bolus and the skin. An air gap, which is easily seen during imaging, can also vary on a day-to-day basis due to slight changes in positioning of the bolus prior to radiotherapy treatment. The varying air gaps can affect how much radiation dose is getting to the skin, and can potentially lead to under-dosing of the cancer cells in the skin. Even small air gaps (i.e. 5mm in thickness), can cause a 5% error in dose, which exceeds the safe tolerance for treatment.

Areas where this can be a problem are where the patient's anatomy undergoes significant topographical changes in a small area. Examples of this include the ear, nose, top of head. Patients with metastatic cancer can also have large lymph nodes or masses that are growing towards the skin that can be difficult to accommodate with standard bolus materials.

3D-Printed Bolus One method to overcome challenging anatomy for cases that require skin bolus for radiotherapy is the use of 3D-printed bolus. This technology uses data acquired from a CT scan of the affected area. The patients contour can then be used to create an individualized bolus that matches the patient contour for the treatment field. This technology has been demonstrated to improve fit (less air gaps) and decreased radiotherapy treatment time. The bolus used in this study was rigid.

Trial design and Rationale Other than the chestwall study, the literature on 3D-printed bolus for radiotherapy has focused on the dosimetry and feasibility of using this technology. However, it is used in an ad hoc method in many centers, using various workflows. There are no studies examining which type of bolus provides the best radiotherapy plan, is the easiest to use at the radiation therapy machines or which is preferred by patients.

To fill this gap, this study will aim to answer a few questions. It will compare the use of rigid 3D-printed bolus (most commonly used and reported in the literature) versus a flexible silicone 3D-printed bolus. Both types of bolus will be used to treat patients with cancers involving the skin. This will allow comparison of radiotherapy plans for each patient between the two types of bolus where each subject is his/her own control. The study will also collect data about real-time set-up using each bolus and feedback from radiation therapists (deliver radiation treatments) about the ease of use of each. Lastly, patients will complete a short survey to provide feedback about comfort with use of each type of bolus and to determine if one type of bolus is favored over the other.

This data will be instrumental is determining the standard of care of the use of 3D-printed bolus as it will assess two types of bolus in three domains: ability to help generate an adequate radiotherapy plan, ease of use by the specialists that deliver the radiotherapy (radiation therapists) and patient reported feedback.

Study Type  ICMJE Interventional
Study Phase  ICMJE Not Applicable
Study Design  ICMJE Allocation: N/A
Intervention Model: Single Group Assignment
Intervention Model Description:
All patients will have both the rigid and flexible 3D printed boluses made. Each will be used on alternate days during radiation therapy treatments.
Masking: None (Open Label)
Primary Purpose: Other
Condition  ICMJE
  • Skin Neoplasm Malignant
  • Skin Cancer
Intervention  ICMJE
  • Other: Ingeo Biopolymer (PLA)
    Biopolymer used for 3D-printing of rigid bolus
    Other Name: 3D-Fuel PLA
  • Other: Ecoflex 030
    Polymer used for the 3D-printed flexible bolus
    Other Names:
    • Body Double & Body Double SILK
    • Dragon Skin Series & F/X Pro
    • Encapso K
    • Equinox Series
    • EZ Brush Silicone
    • EZ-Spray Silicone Series
    • Mold Max Series
    • Mold Star Series
    • OOMOO Series
    • PoYo Putty 40
    • Psycho Paint
    • Rebound Series
    • Rubber Glass
    • Silicone 1515, 1603, 3030, 1708
    • Skin Tite
    • Smooth-Sil Series
    • Solaris
    • SomaFoama Series
    • SORTA-Clear Series
Study Arms  ICMJE Experimental: Alternating 3D boluses
Both rigid and flexible 3D printed boluses made for each patient. Each is used on alternate days during radiation therapy.
  • Other: Ingeo Biopolymer (PLA)
  • Other: Ecoflex 030
Publications *

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
Recruitment Information
Recruitment Status  ICMJE Unknown status
Estimated Enrollment  ICMJE
 (submitted: November 22, 2019)
Original Estimated Enrollment  ICMJE Same as current
Estimated Study Completion Date  ICMJE March 30, 2022
Estimated Primary Completion Date December 31, 2021   (Final data collection date for primary outcome measure)
Eligibility Criteria  ICMJE

Inclusion Criteria:

  • Pathologically (histologically or cytologically) proven diagnosis of a primary skin cancer or metastatic cancer with involvement of the skin or underlying soft tissues
  • Being treated with radiation therapy that requires the use of bolus to ensure adequate radiotherapy dose to the skin in the affected area
  • Planned for palliative or curative intent radiotherapy using megavoltage (MV) photons
  • Site of involvement has significant contour change, leading to anticipated challenges using conventional bolus material
  • Patient must be competent and able to complete informed consent
  • Age ≥ 18
  • Women of childbearing potential must be proven to not be pregnant or breast feeding

Exclusion Criteria:

  • Patient being treated with a radiotherapy technique that does not require bolus
  • Patient being treated with a radiotherapy technique other than MV photons (i.e. electrons, brachytherapy, kilovoltage (kV) photons)
  • Patient of childbearing potential who is pregnant, actively trying to become pregnant or breast feeding
  • Allergy to silicone or other components of either the 3D printed rigid or flexible bolus.
  • Size of the bolus required for treatment exceeds 25cm in maximum diameter
Sex/Gender  ICMJE
Sexes Eligible for Study: All
Ages  ICMJE 18 Years and older   (Adult, Older Adult)
Accepts Healthy Volunteers  ICMJE Yes
Contacts  ICMJE Contact information is only displayed when the study is recruiting subjects
Listed Location Countries  ICMJE Not Provided
Removed Location Countries  
Administrative Information
NCT Number  ICMJE NCT04176900
Other Study ID Numbers  ICMJE 15441
Has Data Monitoring Committee Yes
U.S. FDA-regulated Product
Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Product Manufactured in and Exported from the U.S.: No
IPD Sharing Statement  ICMJE
Plan to Share IPD: No
Current Responsible Party Lara Best, MD, FRCPC, MMEd, Nova Scotia Cancer Centre
Original Responsible Party Same as current
Current Study Sponsor  ICMJE Nova Scotia Cancer Centre
Original Study Sponsor  ICMJE Same as current
Collaborators  ICMJE Not Provided
Investigators  ICMJE
Principal Investigator: Lara R Best, MD, FRCPC Nova Scotia Cancer Centre
PRS Account Nova Scotia Cancer Centre
Verification Date February 2020

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP