Phyllodes tumour of the breast is a rare fibroepithelial tumour, composed of an epithelial and a cellular stromal component. This presentation was made by Dr. Abiola Adewale, a radiation and clinical oncologist at ASI Ukpo Cancer Centre, Calabar, as part of a webinar series for ARCON Nigeria (Association of Radiation and Clinical Oncologists of Nigeria), April 2022.

1. RADIOTHERAPY TREATMENT
PLANNING INTRACIES IN
MALIGNANT PHYLLODES
Dr. Abiola Adewale, FWACS, MPhil
Radiation and Clinical Oncologist

2. CONTENTS
• Introduction
• Treatment Options
• Indications for RT
• Target Delineation
• Workup
• Anatomy/Imaging
• Contours
• Positioning
• Treatment Delivery 2

3. INTRODUCTION
• Phyllodes tumour of the breast is a rare
fibroepithelial tumour, composed of an
epithelial and a cellular stromal
component.
• It represents about 1% of all neoplasms.
Phyllodes tumours have an inherent
recurrence and/or metastatic potential.
3

4. TREATMENTOPTIONSFORPHYLLODES
•Surgery
•Radiotherapy
•Chemotherapy(?)
4

5. INDICATIONS FOR RT
• Positive surgical margin
• Large tumour
5

6. SCENARIOS FOR RT
• Early disease
• Wide local excision or lumpectomy
• Late disease
• Mastectomy
• Post-reconstruction
• Immediate reconstruction
• Delayed reconstruction
6

7. EARLY DISEASE
• Whole Breast Radiotherapy (WBRT) and boost to
the lumpectomy cavity
• Workup: Thorough history, physical examination,
adequate imaging studies and pathological
examination.
• Imaging: Mammography or Breast MRI, Chest CT
scan
7

8. POSITIONING- EARLYDISEASE
• Patient in supine position
• Same position during simulation and treatment
• Immobilization: Pt should be immobilized with a
breast board, arms above the head, neutral head
position.
• CT should encompass the entire breast with a
generous margin. Pt. will be scanned from the
chin to the upper abdomen, with CT slice
thickness of <3 mm.
8

9. CONTOURS- EARLYDISEASE
• Target volume includes breast tissue and
lumpectomy cavity.
• Delineation of OARs - heart, lungs, thyroid
• Breast tissue: To include all visible glandular
tissues, as well as tissues encompassed in a wire
or any pendulous tissue.
• In patients with tissue folds, use bony landmarks
to ensure all glandular tissue is included in the
volume.
9

10. CONTOURS- EARLYDISEASE
• Lumpectomy cavity: This should include all
visible post-surgical changes and clips, if the
surgeon had placed it.
• Mammogram or Breast MRI + Breast US can help
in identifying the post-surgical changes.
• Lumpectomy PTV: 0.5 – 1 cm margin
10

11. OARs- EARLYDISEASE
• Heart should be contoured for all patients, esp.
for those with left sided breast disease.
• Heart contour starts just below the pulmonary
vessels.
• Both lungs should be contoured.
11

12. TARGETVOLUMEDELINEATION
Breast:
• Cranial Border: Below the head of the clavicle, at the
insertion of the 2nd rib.
• Caudal Border: At loss of breast tissue
• Medial Border: At the edge of the sternum, and should
not cross the midline.
• Lateral Border: Midaxillary line
• Anterior Border: Skin or few mm from surface of skin
• Posterior Border: Pectoralis muscle
• Target volume should NOT include pectoralis muscle or
the ribs.
12

13. Fig: Delineation of whole breast with lumpectomy cavity 13

14. Fig: Isodose lines for conserved breast with lumpectomy cavity 14

15. LATE DISEASE
• Prescription Point: Chestwall and lymph nodes
• Workup: Thorough history, physical examination,
adequate imaging studies and pathological
examination.
• Imaging: Mammography or Breast MRI, Chest CT
scan
15

16. POSITIONING– LATEDISEASE
• Patient in supine position
• Same position during simulation and treatment
• Immobilization: Breast board, arms above the
head, neutral head position.
• CT: From cricoid through 5cm below the
contralateral breast. Entire lung MUST be
included. 16

17. CONTOURS– LATEDISEASE
• Cranial Border: Clavicle Head
• Caudal Border: Clinical Ref + loss of CT apparent
contralateral breast
• Anterior: Skin
• Posterior: Rib-pleural interface. Must include pectoralis
muscles, chestwall muscles, ribs
• Lateral: Clinical Ref / Mid-axillary line. May exclude
lattismus dorsi muscle
• Medial: Sternal-rib junction
17

18. LYMPH NODES– LATEDISEASE
• Delineation of lymph nodes: According to RTOG
guidelines.
• Ipsilateral levels:
• 1-3 lymph nodes,
• Ipsilateral supraclavicular nodes
• Ipsilateral internal mammary lymph nodes
18

20. OARs- LATEDISEASE
• OARs: Heart should be contoured for all
patients, esp. for those with left sided breast
disease.
• Heart contour starts just below the pulmonary
vessels.
• Both entire lungs should be contoured.
20

21. TARGETVOLUMEDELINEATION–LATEDISEASE
• CTV: Breast tissue or chest wall as defined by RTOG
Breast Cancer Atlas 1 , ipsilateral regional lymph
nodes 2, interconnecting lymphatic drainage routes,
and chest wall musculature/skin determined to be at
risk for microscopic disease.
• PTV: A margin of 3–5 mm medially, 5–10 mm
laterally, 3–5 mm posteriorly, and 5–10 mm
superiorly, inferiorly, and anteriorly (to include the
skin surface) will be added to the CTV. The amount
of lung can be trimmed per physician discretion. 21

22. Fig:CoronalView- Red: PTV LightOrange:CTV
22

23. TREATMENTDELIVERY
RT Options: Conventional (3D-CRT), IMRT or VMAT
Fig: Dose Volume Histograms of IMRT vs 3D-CRT treatment plans,
showing better OAR sparing for IMRT

24. TREATMENTGUIDELINES
• Prescribed Dose: 45 – 50.4 Gy / 25-28#
• Hypofractionation: 40 – 42.5 Gy / 15-16#
• Boost: 10 -16 Gy / 4-8# using electrons, photons or brachy
24

25. RECONSTRUCTEDBREASTRT
• Patients who undergo mastectomy for the
treatment of breast cancer often consider both
postmastectomy radiotherapy (PMRT) and
breast reconstruction.
• Patients desiring reconstruction must choose
between involving implants or relying
exclusively on autologous tissues.
• Not all patients are candidates for both.
25

26. 26
Fig: Sequencing Options
of Reconstruction Process
TE: Tissue Expander

27. IMMEDIATEvsDELAYEDRECONSTRUCTION
• In as much as immediate breast reconstruction would
bring better psychosocial wellbeing and less distress
associated with mastectomy, there is still an associated
nontrivial rate of complications and reconstruction
failures.
• Immediate reconstruction may create technical
challenges in delivering RT that can result in
unfavourable compromises between target coverage
and normal tissue dose.
• Introduces the possibilities of delays in RT or
chemotherapy because of complications.
27

28. 28

29. 29
Pros
Cons

30. 30

31. 31
Pros
Cons

32. 32
Fig: Isodose line distributions of a patient with bilateral implant immediate
reconstruction that was treated with IMRT plan. The 50 Gy IDL (yellow) is
conformal to the chest wall and internal mammary node.

33. POSSIBLESIDE EFFECTS
• Early:
• Skin reactions
• Swelling of breast
• Pain in breast or chest area
• Hair loss in axilla
• Sore throat
• Fatigue
• Lymphedema
• Late:
• Fibrosis
• Hardening of tissue
• Effects on heart/lungs, e.g. ischemic heart dx. 33

34. RECOMMENDATION
• Earlier inclusion of radiation oncologists in
the overall treatment planning process of
ca. breast patients to guide decision of
reconstruction.
• A Multidisciplinary Tumour Board
involving surgeons, reconstructive
surgeons and radiation and clinical
oncologists is recommended. 34

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ASI UKPO COMPREHENSIVE CANCER CENTRE
4 Mary Slessor Avenue, Calabar, Nigeria.
Tel: +234 809 966 1668. Email: oncologyfrontdesk@asiukpo.com