Intensity-Modulated Radiotherapy to Bilateral Lower Limbs: A Case Study

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1 Intensity-Modulated adiotherapy to Bilateral ower imbs: A Case Study Emma Fitzgerald; Paul Fenton; Jim Frantzis Epworth adiation Oncology, Melbourne, Australia Disclaimer: Patient consent was obtained. Warning: Graphic images are included. Introduction In Australia 80% of all newly diagnosed cancers are skin 1. 3 main types: - Melanoma - Basal Cell Carcinoma (BCC) - Squamous Cell Carcinoma (SCC) BCC & SCC are the most common skin cancers with 434,000 patients treated annually 1-3. Case Study A 71 year old female presented with Hyperkeratosis & painful superficial skin cancers on both lower limbs (Figure 1). The lesions were classical BCC and ulcerated SCC. History: - Bowen s disease - Multiple superficial skin cancers - Surgeries & skin grafts - Topical Chemotherapy Treatment modalities 1 : - adiation Therapy (T) - Topical Chemotherapy - Surgery Intensity-Modulated adiation Therapy () when compared to conformal techniques can reduce toxicity to surrounding tissues without compromising target coverage through concave dose distributions 4-5. Treatment: - Surgery; - Considered ineffective - esult in extensive skin grafting - Topical Chemotherapy; - Patient declined (previous severe reaction) - Superficial T; - High risk of chronic non-healing ulcers - ; - Effectively treat planning target volume (PTV) - Optimised dose to normal tissue structures Figure 1: Mixed BCC/SCC pre-t

2 Method Prescription, Stabilisation & Volumes (Figures 2-4): - 60Gy in 2Gy daily fractions - Feet first in Vacfix. egs abducted & treated separately. - PTV excluded posterior aspect of limbs to reduce the risk of gross oedema. - PTV: 2 mm SUP/INF expansion of the PTV - Normal Tissue: eg cropped from PTV by 5 mm Area to receive ~ <D50% ed = PTV Green = Normal Tissue Figure 2: Field arrangement and PTVs. Planning: - Eclipse version 10 treatment planning system - Anisotropic Analytical Calculation Algorithm (AAA) - 6 fields per limb avoiding the contralateral limb (Figure 2) cm bolus over anterior surface of each limb - Planned according to ICU guidelines (+7%, -5%) - 3-Dimensional Conformal adiotherapy () plan created for retrospective comparison with. Proximal Daily Isocentre Verification: - kv/kv orthogonal paired images anterior obliques - Online zero-action threshold Ant Post Skin Toxicity: - Measured against the National Cancer Institute: Common Terminology Criteria for Adverse Events (NCI: CTAE v3) 6 - G0 = Normal - G1 = Faint Erythema/Dry Desquamation - G2 = Patchy Moist Desquamation - G3 = Moist Desquamation - G4 = Skin Necrosis or Ulceration Figure 3: Stabilization and Tattoos. PTV Distal Figure 4: Structures

3 Figure 5: Dose Colourwash at Central Axis. ange 95% - Max. Figure 6: Dose Colourwash at Upper evel. ange 95% - Max. Figure 7: Dose Colourwash at ower evel. ange 95% - Max. esults Dosimetry (Figures 5-9): - ICU Guidelines achieved (57Gy Gy) - eft eg (D98% = 57Gy & D2% = 63Gy) - ight eg (D98% = 56Gy & D2% = 64Gy) - Homogenous and conformal dosimetry achieved - Dose to posterior aspect of each limb minimised - Normal Tissue mean dose 34Gy () & 33Gy () Dosimetry: - PTV coverage compromised (Figures 5-7) - eft eg (D98% = 56Gy & D2% = 63Gy) - ight eg (D98% = 57Gy & D2% = 63Gy) - Posterior aspect of each limb irradiated (Figures 8 & 9) - Normal Tissue mean dose 49Gy () & 58Gy () Side Effects: - Pain present prior to & throughout T. - Managed with pain relief - Oxycontin bi-daily & Endone as required - Skin reached G3 (Moist Desquamation) at week 4. - Hospitalised for management. - eceived at least Bi-Daily silicon based dressings Figure 8: Dose Colourwash at Central Axis. ange 50% - Max. Figure 9: Dose Colourwash at Central Axis. ange 10% - Max.

4 Figure 10: Simulation G0 Figure 11: Week 3 G1/G2 Figure 12: Week 4 G3 Figure 13: Week 6 G3 Figure 14: Discussion The results demonstrated that the plans were not capable of achieving the equivalent level or better homogeneity and PTV coverage when compared with. Figures demonstrate the progression of skin toxicities. At week 4, skin reaction reached a peak of G3 (Moist Desquamation) due to the radical treatment and bolus providing 100% dose to the skin (Figures 12 & 13). The healing process was affected by the patient s co-morbidities of diffuse atheromatous and poor circulation. The patient was admitted to hospital during week 4 for continual skin care and pain management. The patient s 6 week post T follow up showed complete resolution of skin toxicity (G0) (Figure 14). A small cancerous nodule remained on her left leg (within the treatment area) that will be surgically excised at later date. Figure 15: Skin eaction observed over adiation Therapy course against the NCI: CTAE Grading System.

5 Conclusion This case study presented a complex radiotherapy approach for treating skin cancer encompassing the limbs. For this patient was the most advantageous option and resulted in favourable dosimetric results. Furthermore, the skin reaction reached G3 (Moist Desquamation) as a result of the radical treatment, co-morbidities and use of bolus. The skin had resolved by the 6 week post-t follow up (Figures 16-18) and treatment was well tolerated. This case study has demonstrated the feasibility and effectiveness of for skin cancers of the limbs for patients with similar history and background. eferences Figure 16: 1. Cancer Council Australia. Skin Cancer. etrieved December 21 st, 2012 from 2. Adam I, ubin M, Elbert H, Chen M and atner D. Basal-Cell Carcinoma. N Engl J Med 2005; 353: Wong C, Strange, ear J. Basal cell carcinoma. British Medical Journal 2003; 327: Alektiar K, Brennan M, Healey J and Singer S. Impact of Intensity-Modulated adiation Therapy on ocal Control in Primary Soft-Tissue Sarcoma of the Extremity. Journal of Clinical Oncology; 26: Hong, Alektiar KM, Hunt M, et al: Intensity Modulated adiotherapy for Soft Tissue Sarcoma of the Thigh. Int J adiat Oncol Biol Phys 59: , Cancer Therapy Evaluation Program. Common Terminology Criteria for Adverse Events v3.0 (CTCAE). etrieved December 21 st from ight eg eft eg Figure 17: Special Acknowledgments Margaret Hjorth Sarah Gonzales Christopher James Dr. Wes Miles And all the team at Epworth adiation Oncology. Figure 18: