680 likes | 918 Views
Challenges in Optimal Delivery of Radiation in Head and Neck Cancers Dr. J P Agarwal Associate Professor Department of Radiation Oncology Tata Memorial Hospital, India. TMH ESTRO EBM 2005. Head and Neck Squamous Cell Carcinoma.
E N D
Challenges in Optimal Delivery of Radiation in Head and Neck Cancers Dr. J P Agarwal Associate Professor Department of Radiation Oncology Tata Memorial Hospital, India TMH ESTRO EBM 2005
Head and Neck Squamous Cell Carcinoma Accounts for about 4,50,000 cases worldwide* 20% of cancer burden - 1,50,000 new cases in 2000 in India* TMH - 25% of all new cases annually > 75 % present with advanced disease *Globocan,2002 IARC
General Management Guidelines for H & N Cancers • Aim • Highest loco- regional control • Anatomical with functional preservation • Stage I / II Single modality ( Surgery or RT ) • Stage III / IV Combined modality Surgery + RT (in most patients) Chemotherapy + RT in selected patients • When different modalities available, one with maximum chance of cure should be used • When different modalities have same results, one offering better quality of life, with organ, function preservation and good cosmetic results should be used
Head And Neck Radiotherapy A Challenge for The Radiation Oncologist • Tumor • Very Close proximity Of Tumor and Critical structures • Total Dose Delivery Limited by Tolerance of Normal structures • Dosimetric Challenges Due to Varying Contour/Tissue Heterogeneity • Patient • Compromised Tolerance To Treatment • Poor Nutritional Status and Weight Loss • Inadequate oral Intake • Treatment Induced Mucositis
The Goal Optimal Dose Delivery …With Minimum Acute And Long Term Toxicity
Evolution Of Head And Neck Radiotherapy 1970-2005 Escalation Of Doses Through Precise Immobilization Tissue Compensation/Customized Blocks Better Skin Sparing (Megavoltage) Integration of brachytherapy 3DCRT /SRT/ IMRT
Key Issues In Head And Neck Radiotherapy • Set up Uncertainties • Target Volume Delineation • Precise Treatment Planning & Delivery • Locoregional control & Overall Survival • Overall Treatment Time • Nutritional support & Quality of Life
The changing paradigm Wide field radiation Conformal radiation Clinical motivation for high-precision techniques More conformality = Better sparing
Key Issues In Head And Neck Radiotherapy • Set up Uncertainties • Target Volume Delineation • Precise Treatment Planning & Delivery • Overall Treatment time • Locoregional control • Overall Survival. • Nutritional status & Quality of life
Conformal Radiotherapy ……The Need For Higher Accuracy • Immobilization Devices used • Head Rest alone • POP with Head Rest • Mouth Bite, Nasion & Chin support • Thermoplastic Moulds • Varying levels of level of Uncertainty • Set up errors 5 mm-1 cm.
Head and Neck Immobilization devices 3 Clamp 4 Clamp 5 Clamp Random Errors with different Fixation devices Radiotherapy Oncology,2001
Verification Of Patient Positioning • Incorporation of EPID. • Cone beam CT • Correction Software • IGRT
Systemic & Random Errors Radiotherapy And Oncology 2001.
Immobilization and Set Up Uncertainties Needs with the changing Paradigm Permissible Errors with State of Art equipment: Recommendations for Good Clinical Practice
Guidelines for patient positioning in head and neck cancer Setup the patient with neutral neck position. minimizes intra-fraction patient motion Use a customized head and neck support and face mask for each patient. improves accuracy of field matching (Neck and LAN fields) Index immobilization apparatus to the treatment table. Improves treatment setup efficiency and accuracy Use active patient position monitoring system (LED camera System) Improves setup accuracy and reproducibility, and minimizes intra-fraction patient motion These strategies can reduce the setup random errors to less than 2 mm for upper neck.
Tackling The Time…The Fourth Dimension Range:7mm Asselen et al IJROBP:56:2004
Key Issues In Head And Neck Radiotherapy • Set up Uncertainties • Target Volume Delineation • Precise Treatment Planning & Delivery • Locoregional control & Overall Survival • Overall Treatment Time • Nutritional support & Quality of Life
Challenges In Planning Radiation Treatment Shoot The Tumor….Save The Man
Guidelines For Target Volume Delineation 7 Different Groups……Variations in the Target Volume Delineation Novak et al, Vijjers et al, Som et al, Gregoire et al, Palazzi et al, Van Triest et al, Gregoire et al Implications on Target Volume Delineation
Heterogeneity In Target Volume Delineation Sanguinetti et al IJROBP,2004
Imaging for target volume delineation Does Fusion Help ?
Variations In Target Coverage with CT/ MRI Where Do we Stand?.....Where Do we Go? Emami et al IJROBP,2003
Variations In Target Coverage with CT/ MRI fusion In Nasopharyngeal Primary MRI & CT are complementary Emami et al IJROBP,2003
PET CT Fusion And Effect On PTV Reduction In size of PTV at Primary Primary GTV CT/GTV PET = 3 Node Node PET/Node CT= 0.7 Heron et al IJROBP,2004
Integration Of Biological Imaging In Target Volume Delineation Ling et al IJROBP:47:2001
Key Issues In Head And Neck Radiotherapy • Set up Uncertainties • Target Volume Delineation • Precise Treatment Planning & Delivery • Locoregional control & Overall Survival • Overall Treatment Time • Nutritional support & Quality of Life
Variation of Neck Contour at Different Levels causes Under and Overdosage….
Heterogeneities within the H & N pose difficulty in treatment planning delivery Soft Tissue Varying Contour & Tissue Heterogeneities Bone Air Sinuses
Evaluation on 13 patients • Mean time to rescanning 37 days • Results of Replanning • Reduction of dose to CTV &PTV (upto 8 Gy underdosage. • Over dosage to the Spinal Cord (Spinal Cord D Max exceeded 45 Gy in 92% patients). • Recommendations • Should be undertaken in patients having significant weight loss during chemoradiotherapy. ASTRO ,2004
Key Issues In Head And Neck Radiotherapy • Set up Uncertainties • Target Volume Delineation • Precise Treatment Planning & Delivery • Locoregional control & Overall Survival • Overall Treatment Time • Nutritional support & Quality of Life
Improving Efficacy of Irradiation • Dose escalation • Altered Fractionation Schemes • Chemoradiotherapy • Biological Therapy And Molecular Targetting
Higher doses up to 70 Gy are related with better locoregional control ,however with enhanced acute and long term complications Tata Memorial Hospital Dinshaw et al (in press)
Aids In Escalating Dose • Altering The Physical Dose • Tissue Compensators • Wedges • Integration of Brachytherapy/3DCRT/SRS Boost. • Altering The Biological Dose • Altered Fractionation Schedules. • Chemoradiotherapy Schedules
Attempts in precise dose delivery with minimal toxicity Conformal RT/ 3DCRT/ IMRT/IMPT Conventional 3-D CRT IMRT IMPT
Averaged End Point doses for T1/T2 tumors Averaged End Point doses for T3/T4 tumors IJROBP,2004
15 Randomized Trials of Varied Fractionation (1970-1998) 7073 patients 3% Increase In absolute Survival 7% Increase in locoregional control Maximum Benefit in Hyper fractionated RT with Increased Total Dose
ChemoRadiotherapy • Absolute benefit of CT – 5% at 5yrs • Higher For Platinum Based Regimens. • No Benefit of NACT (MACH- NC update) • However NACT may still have a role in organ and function preservation as in Laryngeal tumors
Can this depiction of enhanced tumor control translated into the clinics?
Fractionation IMPACT (Intergroup Merger of Patient Data from Altered Or Conventional Treatment Schedule) EORTC 22791,22811,22851, PMH Trial, CHART
Comparison of toxicity profile Conventional Vs Altered Fractionation Trotti et al IJROBP,2000
Toxicity Profile with Chemoradiotherapy Trotti et al IJROBP,2000
Key Issues In Head And Neck Radiotherapy • Set up Uncertainties • Target Volume Delineation • Precise Treatment Planning & Delivery • Locoregional control & Overall Survival • Overall Treatment Time • Nutritional support & Quality of Life
Effect of Interruptions on Local control • 0.9 Gy loss Per day of Interruption. • 0.7-1.4% decrease in probability of local control for every missed day • 14-20% decrease in locoregional control for a gap of 7 days
Importance of the Time interval between surgery and postoperative radiation therapy in the combined management of head and neck cancers N= 22 PORT within 7 weeks / later LRC 70% (PORT within 7 weeks) 27%(PORT more than 7 weeks) Bhadrasain V,IJROBP,1979
Effect of delay in PORT on survival Bastit et al, IJROBP,2001