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Clinical Oncology AssignmentDirections: Divide the following anatomical areas amongst your group members and complete the following assignment. For groups with 4 members you may choose 2 primary tumors in the same area (head and neck, chest, or pelvis) but they should not be the same tumor site.

Primary Head and Neck with lymph nodes Primary Lung/Mediastinum or Breast/chest wall with lymph nodes Primary Pelvis (any tumor found below L4-L5) with lymph nodes

Find a case in your clinic that you have worked on, or are working on, to research and answer the corresponding questions (Note: this can be a case that your clinical instructor is planning or planned but you observed/participated). Please include any references and helpful screenshots to describe your rationale and to explain the treatment plan design and process.

Questions: 1. How was this patient positioned for simulation? What positioning devices/accessories

were used, how and why? (5 points)a. This patient was simulated with a pillow and large angle for head support.

Immobilization was achieved for the lower body by using a leg immobilizer sponge and rubber band around the feet.

b. Leg immobilizer sponge:

2. Discuss the target dose as defined by your physician and the rationale behind the total dose and fractionation regimen. Include any references or current research to help answer the question. (5 points)

a. This patient was prescribed a dose of 45Gy to the whole pelvis, with a cone down boost of 34.2Gy to the prostate and seminal vesicle only. There are several studies from the Radiation Therapy Oncology Group (RTOG) that study the effect of dose escalation along with the determination of pelvis nodal volumes to treat in high risk prostate patients. A Phase III Trial from the RTOG Group 94131 concludes that “whole pelvis radiation therapy with neoadjuvant and concurrent hormonal therapy (NCHT) improves progression free survival compared with prostate-only radiation therapy and NCHT.”

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3. What specific avoidance structures were contoured? Include a screen shot of your contoured target and organs at risk. Create and embed a table of OAR tolerance doses based on your physician prescription and include any associated QUANTEC values. List the contraindications if tolerance doses were to be exceeded. (20 points)

a.OAR QUANTEC Value2 Achieved Value ToxicityRectum V75<15% 12.57% Grade 3+Bladder V65<50% 30.94% Grade 3+Hips V50<5% (RTOG GU

Consensus)0.34% Hip fracture

Small Bowel V45<195cc 34.82cc Grade 3+b. Grade 3+ toxicity as defined by the RTOG and European Organization for

Research and Treatment of Cancer3:i. Lower GI/Pelvis: diarrhea requiring parenteral support, severe mucus or

bloody discharge, abdominal distentionii. Genitourinary: nocturia, increased frequency and urgency of hourly or

greater, dysuria, bladder spams requiring regular narcotics, hematuria

c.

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4. Identify any involved lymph nodes in your treatment region. Embed a screen shot of the nodal regions with corresponding labels. (15 points)

a. The most common lymph node drainage for prostate cancer includes: presacral, internal and external iliac, and obturator lymph nodes. Please see the images below to map out nodal volumes. The treatment planning CT depicts the nodal volumes in a teal colorwash. The subsequent images are from the RTOG contouring atlas, which is an accepted standard for drawing pelvis nodal volumes in prostate patients.

b. Treatment Planning CT- (nodes: teal colorwash)

c. RTOG Atlas Images4

i. Presacral and Internal/External Iliac:

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ii. Obturator:

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5. Use your IMAIOS Subscription: http://www.imaios.com/en and other anatomy references to describe the anatomical “boundaries” (physical limits) of the area treated. Embed a diagram and/or screen shot of your CT data to point out the boundaries. (20 points)

a. According to the RTOG contouring atlas, there are several landmarks of where to start and stop drawing volumes for pelvis lymph nodes. The superior border includes the presacral lymph nodes and the splitting of the common iliac vessels to form the internal and external iliac. This is commonly seen at the L5/S1 vertebral space. The lateral extent of the volumes includes a 7mm margin surrounding the vessels without entering bone, bowel or bladder.4 The inferior border of the treatment field will be the inferior portion of the prostate gland including whatever treatment margin specified by the doctor. With regards to bony anatomy, the inferior border will lie close to the inferior portion of the pubic symphysis.

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6. Describe, in detail, the radiation treatment technique used to treat this anatomical region. (20 points)

Examples: Technique type (VMAT, IMRT, Conformal), VMAT-Number of arcs, their direction, collimator rotations, number of degrees. Beam angles, couch rotations, field design, wedges, use of split fields, etc. Include all specific setup information to describe your process. Include any screen shots to help describe your plan design.

a. This patient was treated with two treatment plans both using a VMAT planning technique. The first plan included the pelvis and prostate treatment to 45Gy, during which time 4 CT’s were obtained to complete an adaptive planning process. My clinical site does a unique type of planning for prostate patients where they fuse the 4 CT’s while the patient is under treatment for the initial prescription. The dosimetrists then contour the prostate, seminal vesicles, rectum, and bladder to track motion. With these fusions, the dosimetrists create average contours of the rectum and bladder to use for the boost planning, and tighten the treatment margin of the PTV surrounding the prostate and seminal vesicles. Then a second plan was created boosting the prostate and seminal vesicle an additional 3420cGy to bring the total treatment dose of the prostate to 7920cGy. The second plan was a VMAT plan with 2 treatment arcs (clockwise and counterclockwise). The arcs spanned 180° each for treatment and had a 5° opposing collimator on each arc. The reasoning for the collimator angle is attributed to minimizing leaf leakage. By turning the collimator, the leaves open and close in a different plane across the body minimizing low dose leakage in the

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plan. This knowledge was obtained in a webinar stating it was more evident to experience leaf leakage with Varian machines, but as a good practice our clinic tries to add the opposing collimator angles even with Elekta equipment.

b. The picture below depicts the two arcs that travel 180° around the patient:

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c. Leaf segments for the clockwise arc during whole pelvis treatment:

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d. Leaf segments for prostate and seminal vesicle boost plan:

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e. Final isodose lines (bolded red: 4500cGy, bright green: 7920cGy)

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7. Include a final DVH of your treatment plan with appropriate labels and discuss your ability to meet the target and OAR tolerance guidelines. (15 Points)

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a. Objectives used for optimization and critical structures to avoid are included on the following scorecard. All objectives “pass” the constraints for treatment planning except two of the rectal constraints. They are listed as “ok” because they meet the current institution’s constraint, but they do not meet a set of more conservative values that are in the process of being established at my facility. In reviewing the plan, the physician was willing to accept these values to maintain adequate coverage of the treatment volume.

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References:1. Roach M, Desilvio M, Lawton C, et al. Phase III Trial Comparing Whole-Pelvic Versus Prostate-Only Radiotherapy and

Neoadjuvant Versus Adjuvant Combined Androgen Suppression: Radiation Therapy Oncology Group 9413. Journal of Clinical Oncology. 2003;21(10):1904-1911. doi:10.1200/jco.2003.05.004.

2. Radiation Oncology/Toxicity/QUANTEC. Wikibooks. https://en.wikibooks.org/wiki/Radiation_Oncology/Toxicity/QUANTEC. Accessed February 19, 2018.

3. Cox JD, Stetz J, Pajak TF. Toxicity criteria of the Radiation Therapy Oncology Group (RTOG) and the European organization for research and treatment of cancer (EORTC). Int J Radiat Oncol Biol Phys. 1995;31(5):1341-1346. doi:10.1016/0360-3016(95)00060-c.

4. Lawton C. Pelvic Nodal Consensus CTV Contours: High Risk/ Locally Advanced Adenocarcinoma of the Prostate. Prostate Pelvic Lymph Nodes. https://www.rtog.org/CoreLab/ContouringAtlases/ProstatePelvicLymphNodes.aspx. Accessed February 19, 2018.