Pulmonary Stereotactic Ablative Radiotherapy: Current
Implementation and Future Directions CTOP Conference 2014 Philip
Schaner M.D., Ph.D Slide 2 I have no conflicts of interest to
report Slide 3 Definition of Stereotactic Body Radiotherapy Method
of delivering external beam radiotherapy (EBRT) Particles (proton)
or photon Dose per Fraction: at least equivalent to radical doses
in conventional fractionation: 5 34 gray (Gy) [ Conventional
Fractionation: 1.8 2 Gy] Accurately delivers EBRT with a high
degree of conformality Spatial and Temporal resolution of target
and organs at risk Maintenance of high spatial targeting accuracy
throughout the entire treatment Immobilization High frequency
position monitoring through integrated image guidance Respiratory
Motion Management Few fractions: 1 - 10 Nomenclature: Stereotactic
ablative radiotherapy (SABR) Stereotactic body radiotherapy (SBRT)
Slide 4 SBRT LUNG Slide 5 Subset of NSCLC appropriate for SBRT
Stage I subset: typically < 5 cm in maximal dimension Not
invading outside the chest (can be touching pleura) Not invading
into lobar bronchus Minimal associated lung collapse Mass well
delineated Slide 6 Subset of NSCLC appropriate for SBRT Mass too
large, invading into nearby structures Primary acceptable but nodal
disease present Slide 7 Treatment Planning Highly conformal dose
distribution with rapid dose fall off Maximally spare adjacent
organs Low dose spill High dose spill Slide 8 Accurate Delivery
Target localization Lung cancer is a moving target. Slide 9 4D
Treatment Delivery Patient Breaths Normally Control when XRT is on
Slide 10 Multi-institutional Phase II Data: RTOG 0236 Inclusion:
NSCLC T1 or T2, N0,M0 Peripheral: > 2 cm from proximal bronchial
tree Medically inoperable: FEV1 Treatment of oligometastatic
disease: Stage IV cancer with 5 metastatic lesions Inclusion: Any
primary tumor except germ cell, leukemia, lymphoma Max cumulative
tumor diameter < 7 cm Extrathoracic disease allowed: low burden,
potentially treatable with 1 st or 2 nd line standard therapy
Adequate lung function: FEV1 >40%, DCLO >40% Methodology:
Dose escalation to 20 Gy x 3 fractions (60 Gy) Accrual: 38 pts
=> 63 lesions Rusthoven et al. JCO 2009 Clinical
Multi-institutional phase I/II trial of stereotactic body radiation
therapy for lung metastases Slide 13 Results: Local control: 2 yr =
96% Patient characteristics Clinical Rusthoven et al. JCO 2009
Toxicity: Grade 3: 8% Grade 4-5: 0% Slide 14 Areas of Investigation
What is the appropriate SABR dose for peripheral lesions? Slide 15
Areas of Investigation RTOG 0915 interim outcomes: N=94 Median FU
20.6 months No significant difference with respect to toxicity in
both arms: 9.8% 34 Gy vs 13.3% 48 Gy > Gr 3 toxicities. Local
Control at 1 yr 97% both arms. Winner? Need longer term follow up
Local Failure increases over time in many series, one year is not
enough follow up. Slide 16 What is the appropriate SABR dose for
centrally located lesions? Areas of Investigation Slide 17
Measuring SABR against Surgery Stage IA NSCLC Peripheral lesion ARM
1: Anatomical surgical resection with LN dsxn ARM 2: SABR 20 Gy x 3
12 Gy x 5 FOLLOWUPFOLLOWUP ROSEL Trial (Netherlands) Terminated due
to poor accrual Areas of Investigation Slide 18 Measuring SABR
against Surgery Stage I NSCLC < 4 cm Good surgical candidate
FEV1 > 40% pred DLCO > 40% pred Post-op predicted FEV1 >
30% ARM 1: Lobectomy or pneumonectomy ARM 2: SABR using Cyberknife
Peripheral: 20 Gy x 4 Central: 15 Gy x 4 FOLLOWUPFOLLOWUP Lung
Cancer STARS trial: phase III, endpoint 3 yr OS Areas of
Investigation Slide 19 Measuring SABR against Surgery Histological
confirmation NSCLC and confirmation N2/N3 negative lymph nodes T
< 3 cm Peripheral High risk for surgery Major FEV1 50% pred DLCO
50% pred Minor Age 75 years FEV1 51-60% pred DLCO 51-60% pred ARM
1: Sublobar Resection Brachytherapy (SR) ARM 2: Stereotactic Body
Radiation Therapy (SBRT) 18 Gy X 3 = 54 Gy FOLLOWUPFOLLOWUP ACOSOG
Z4099/RTOG 1021 Phase III Trial Opened June 2011 Areas of
Investigation Slide 20 Combining radiofrequency ablation with SABR
UNM: RFA combined with SABR for large lung tumors T2-4N0 > 3 cm;
N1-3 if M1 eligible 40 Gy/5 fractions escalating to 50 Gy/5
fractions f/b RFA procedure Areas of Investigation Using SBRT as a
boost for Stage II/III NSCLC U Kentucky: Stage IIA selected III-B
59.4 Gy chemoradiotherapy => if residual disease: boost 10 Gy x
2 (peripheral) Proton vs Photon SBRT SBRT combined with
chemotherapy Maintenance chemotherapy vs consolidative SBRT for
Stage IV NSCLC UTSW: 1 st line chemo (no biologics) => up to six
discrete extracranial lesions U Kentucky: T1-T3N0 NSLC => SBRT
then adjuvant cisplatin + docetaxel or pemetrexed Slide 21
Questions.
