Simultaneous Integrated Boost With Volumetric Arc Radiotherapy in Patients With Breast Cancer
Condition: Breast Cancer
MeSH terms: Breast Neoplasms
Study type: Interventional
Phase: Phase 2

Summary: 
      The study will include 27 patients to study the dosimetric data and acute toxicity. Patients
      will be treated by SIB intensity modulated radiotherapy (IMRT) boost to the cavity.The dose
      to be delivered will be a hypo fractionated regimen of 34Gy/10#/2weeks to the whole breast
      and 40Gy/10#/2weeks to the tumour bed. The dose to the target and to the OAR will be
      observed. The acute toxicity and cosmesis will be assessed.
    

Detailed description: 
      Aim To study the dose to the target and OARs with SIB-IMRT in patients with breast cancer.

      Objectives: To study

        1. Dose distribution, target coverage and dose homogeneity in the diseased breast.

        2. Dose to the OARs.

        3. Acute toxicities.

        4. Cosmetic outcome. Materials and methods Patients: Total 27 patients post BCS will be
           included in the study. 4D computed tomography simulation and image acquisition: All the
           patients will undergo a standard free breathing with virtual CT breast simulationin
           supine position on a breast board or wing board with ipsilateral arm abducted above
           head. The other side arm will be kept on side. Three skin markings will be placed along
           with the fiducials below the breast folds for reproducibility and the localizationtion
           of tumor bed. The 4DCT images with recording the respiratory signals will be acquired
           with thickness of 3mm with a 16 slice Brilliance 85cms bore CT scanner (Philips medical
           system, Inc., Cleveland, OH, USA). The signals will be sent to the scanner to label a
           time tag on each CT image. 4D software (GE Healthcare, Waukesha, WT, USA) will sort the
           reconstructed 4DCT image into ten separate phases on basis of these tags, with 0%
           corresponding to end-inhalation (CT0) and 50% corresponding to end-exhalation CT50. The
           constructed 4DCT sets will be transferred to eclipse treatment planning system (TPS),
           (Eclipse 10, Varian medical system, Palo alto, CA, USA) for structure delineation. The
           10 to 90% phase of 4DCT images will be registered on 50% phase images, which will serve
           as basic phase image. The delineation of the tumor cavity and contouring of the organs
           at risk will be done by using standard RTOG guidelines for contouring breast cancer
           cases on Maximum intensity phase (MIP) CT. The tumor cavity will be delineated with the
           help of surgical clips (if put by the surgeon during lumpectomy), mammography films and
           by the clinical examination done before surgery to assess the location of tumor in the
           affected breast. The scar will be adequately covered. The organs at risk contoured will
           be heart, bilateral lungs, contralateral breast, esophagus, spinal cord, bilateral
           humerus head, left anterior descending(LAD) artery and right coronary artery. The
           diseased breast contoured will be clinical target volume (CTV). A margin of 5mm will be
           added for setup error and motion for the planning treatment volume (PTV) breast. A
           Margin of 5mm will be added to cavity to form PTV SIB.

      Target coverage and dose homogeneity: target implies to the tumor bed which has been
      delineated with the help of surgical clips, mammography and clinical examination and history.
      It has to be covered adequately and the dose has to be homogenized without the presence of
      any cold spot or hotspot. The criteria to ensure the dose distribution appropriately will
      beas: PTV: D98 > 95% and D2 < 107%; PTV SIB: D98 > 95% and D2 < 107%. Dose to the OARs: OARs
      will include: heart, ipsilateral lung, contralateral lung, opposite breast, oesophagus,
      spinal cord and LAD. The dose constraints will be different to the laterality of the disease
      since the location of organs differs.

      Treatment:Patients will be treated with a dose of 34 Gy/10#/2wk to the PTV and 40Gy/10#/2 Wk
      to the PTV SIB with IGRT using Rapid arc technique. Acute toxicities will be assessed at the
      time of completion of treatment andat 1 month and 3 months after treatment. Cosmetic outcome
      will be assessed at 1, 3 and at 6 months of followup.

      Assessment of toxicity will be done as per RTOG scores and LENT SOMA scale Toxicity Grade0
      Grade1 Grade2 Grade3 Grade4 Skin No change over baseline Follicular, faint/ dull erythema/
      epilation/dry desquamation/ decreased sweating Tender or bright erythema, patchy moist
      desquamation/ moderate edema Confluent, moist desquamation other than skin folds, pitting
      edema Ulceration, haemorrhage, necrosis Subcutaneous tissue None Slight induration (fibrosis)
      and loss of subcutaneous fat Moderate fibrosis but asymptomatic Slight field contracture <10%
      linear reduction Severe induration and loss of subcutaneous tissue Field contracture >10%
      linear measurement Necrosis

      Pigmentary change :

      0 = None

      1 = Transitory , slight 2 = Permanent , marked

      Breast edema :

      0 = None 1 = Asymptomatic 2 = Symptomatic 3 = Secondary dysfunction Cosmetic assessment
      Sample size calculation

      The purpose of the trial is to reject the experimental treatment from further study if it
      were insufficiently active, and to accept it for further study if it were active. The study
      is designed as a phase II trial with the following assumptions:

        -  the inactivity cut-off is chosen equal to 11%, the activity cut-off equal to 36%. Hence
           the hypotheses of interest are H0: r ≤ 11% against HA: r ≥ 36%, where r is the
           proportion of patients with grade 2 skin toxicity

        -  the type I error rate (alpha, probability of accepting an overly toxic treatment, a
           false positive outcome) is set to 5%

        -  the type II error rate (beta, probability of rejecting an acceptably toxic treatment, a
           false negative outcome) is set to 10% - i.e., the power is equal to 90% Under these
           assumptions, the design consists of treating 27 evaluable patients, and if at most 5
           patients have grade 2 skin toxicity, the treatment is considered acceptable (5/27=19%)

        -  if at least 6 patients have grade 2 skin toxicity, the treatment is considered too toxic
           (6/27=22%)

      Statistical analysis The principle end point of the study will be an analysis of dosimetric
      parameters and acute radiation toxicities. Secondary end point will be cosmetic score
      analysis and local control. Skin, subcutaneous toxicity and cosmetic assessment will be done
      before treatment and then in regular follow up of the study. Descriptive statistics including
      mean and standard deviation will be obtained for all variables. p values of <0.05 will be
      taken as significant. All tests would be performed using SPSS (Statistical Package for the
      Social Sciences) v.12.0.
    

Intervention name(s): Radiotherapy
Intervention type(s): Radiation
Intervention description(s): 34 Gy/10#/2wk to the PTV and 40Gy/10#/2 Wk to the PTV SIB with IGRT using Rapid arc technique.
Intervention model: Single Group Assignment
Intervention model description: To be treated with hypofractionated radiotherapy of 34Gy in 10 fractions to whole breast and 40Gy in 10fractions to the tumor bed
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Hypofractioned radiotherapy; Simultaneous integrated boost