Individualized higher dose of 70–75 Gy using five-fraction robotic stereotactic radiotherapy for non-small-cell lung cancer: A feasibility study

Figures & data

Figure 1. Dose volume comparison: seven-beam configuration versus the CyberKnife. V(CK) is the volume receiving a given percentage dose level for the CyberKnife plan and V is the volume receiving this level with either the seven-beam configuration (blue curve) or the single-arc plan (red). The isodose line range for our patients was 60 to 84%. V/V(CK) is seen to be ∼1.00 for the dose level 70–80%. The dose volume for 7B/CK includes nearly five times more adjacent tissue than CK. (From reference [39]).

Table I.  Patient data. The column headers represent the following: Pt #: patient number;1st Rx: date of first treatment; Sex; Age; Loc: location of tumor; Dia: tumor diameter in centimeters; dose: total dose in Gy; Fx: number of fractions; V₁₅: cc of lung irradiated with 15 Gy, total volume of both lungs minus the planning treatment volume; IDL: isodose level use to treat tumor; BED₂₀: biological equivalent dose delivered if α/β is 20 Gy; Fiducials: number of fiducials placed in tumor; Beams: total number of beams used to deliver dose; Paths: number of paths used to deliver dose; P/M: whether primary and/or metastatic tumor treated; Cell: cell type (adeno - adenocarcinoma, NSCLC - non-small cell lung cancer, BAC - bronchial alveolar cell carcinoma, Neuro end – neuro-endocrine carcinoma, Squamous – squamous cell carcinoma); Results: results of irradiation (LC – local control, DM – distant metastasis, RR – regional recurrence, Bx – biopsy); Stage: stage of NSCLC at diagnosis and treatment. Tumor effects are the same, but late complications are much less common with 5 fractions.

Pt. #	1st Rx	Sex	Age	Loc.	Dia.	Dose	Fx	V15	IDL	BED20	Fiducials	Beams	Paths	P/M	Cell	Results	Stage	Treatment before CyberKnife & comments
93	12/5/2006	F	71	LUL	2.5	67	5	N/A	60	157	1	158	3	P	Adeno	LC/DM	IV	S/P breast cancer (1st Rx: 15 Gy × 1F-13 Gy × 4F). SUV 5.3. Expired 5/3/09. DM
97	12/27/2006	F	84	RUL	1.8	67.5	5	N/A	65	159	1	113	3	P	NSCLC	LC/DM	IV	2/4/2010 LC brain metastases. LC
100	3/12/2007	M	65	LUL	2.3	67.5	5	N/A	68	159	1	125	2	P	Squamous	LC/DM	IV	S/P CNS CK 6.16.07. Expired 3 mo. due to CNS metastases
138	12/1/2008	M	66	RML	2.5	70	5	N/A	65	168	2	90	3	P	Adeno	LC/RR	IIA	T1b N2 M0 metastases to sub-carina. 2/11/2010 CR RUL, S/P IMRT med.
148	2/25/2009	F	81	RUL	1	70	5	152	70	168	1	75	3	P	NSCLC	LC	IB	SUV+19. 1/5/2010 CR. Clear cell carcinoma of thyroid 12 yrs ago
149	3/10/2009	F	71	LUL	1.6	70	5	271	65	168	1	91	3	P	BAC	LC	IA	SUV 2.7, T1 COPD
151	3/25/2009	F	71	RUL	2.6	70	5	768	64	168	1	82	3	P	NSCLC	LC	IIB	T2 N1 M0. CR 6/1/2009
153	4/17/2009	F	60	RLL	3.1	75	5	254	64	187	1	90	3	P	BAC	LC/Bx	IA	Negative biopsy. 2/19/2010 PET negative
158	5/18/2009	F	66	LLL	2.8	70	5	N/A	64	168	1	122	3	P	Adeno	LC	III	T2 N2 M0. S/P chemo., paralysis of right hemidiaphragm
162	8/24/2009	M	81	RUL	1.7	70	5	N/A	79	168	0	45	1	P	Neuro endo	LC	IA	V10 right: 14% / both lungs: 8.5%. Carcinoid isocentric Rx
166	9/2/2009	M	88	RLL	3	75	5	N/A	81	187	1	127	3	P	NSCLC	LC/Bx	IIB	T2 N1 M0. Expired from CHF 3 mo. P/C CK negative biopsy. Refused surgery
167	9/14/2009	F	88	RLL	3.1	70	5	488	60	168	0	109	1	P	Adeno	LC	IA	SUV 3.2. 1/25/2010: RLL 50% reduction SUV →1.6
175	10/21/2009	F	77	RUL	2	70	5	358	62	168	0	108	1	P	Adeno	LC	IA	Moderately differentiated
176	10/22/2009	M	67	RUL	3.4	70	5	490	60	168	1	133	1	P	NSCLC	LC	IV	S/P RT larynx 12/2008, SUV 11.4
179	1/11/2010	M	76	RUL	2.8	70	5	396	78	168	1	146	2	P	Adeno	LC	IIIA	S/P 4 Carbo-Tax IMRT med., chemo., CK
180	1/11/2010	M	80	LUL	2	75	5	501	75	187	1	110	2	P	NSCLC	LC	IA	S/P prostate cancer. Bx poorly diff. carcinoma, SUV 4.1, TTF1 + PSA - rib met. 4/14/10
180d	11/18/2009	M	92	RUL	2.6	75	5	346	68	187	1	113	1	P	Adeno	LC	II	T2 N1 M0, SUV 14.3. 2/10/10 PET SUV →3, GTV 4 cm →3
180w	1/12/2010	M	77	LLL	2.2	70	5	330	60	168	1	101	1	P	NSCLC	LC	IA	S/P squamous cell laryngeal carcinoma. Rx External Beam CR. Met?
181	1/26/2010	M	69	RUL	2.3	70	5	595	68	168	1	134	2	P	Neuro endo	LC	IV	T1/T2 N3 M1. S/P chemo., COPD. Carcinoma with neuroendocrine differentiation

Figures 2. In lung tumor patients treated by high ablative doses, fibrotic or ground glass changes matching the high-dose isodose distribution were considered to represent pneumonitis or treatment effects as opposed to disease progression. This image series shows gradually improving characteristic changes following 15 Gy × 5 fractions = 75 Gy₁₀: (1) Planning CT scan, April 2009; (2) CyberKnife ablation at 90 days; (3) August 2009 follow-up CT scan; (4) November 2009 follow-up; and (5) February 2010 follow-up.

Table II.  Comparison of 5-fraction and 3-fraction SBRT for lung tumors α/β 20 Gy.

Schedule fractions × Gy	Total dose (Gy)	Tumor BED α/β = 20 Gy	EQD in 2-Gy fractions α/β = 20 Gy	Late BED Gy3 α/β = 3 Gy	EQD in 2-Gy fractions & NTD
5F × 14	70	119	109	396	238
5F × 15	75	131.3	119.3	450	270
5F × 16	80	144	130.9	506.7	304
5F × 17	85	157.3	143	566.7	340.9
5F × 18	90	171	155.5	630	378
3F × 20	60	120	109	460	276
3F × 21	63	129.2	117.5	504	302
3F × 22	66	138.6	126	550	302
3F × 23	69	148.4	134	598	259.8
3F × 24	72	159	143.6	648	388

BED: Biological equivalent dose. EQD: Equivalent dose. NTD: Normalized total dose

Brown WT, Perman M, Wu X, Yang J, Schwade JG. Image-guided robotic stereotactic radiosurgery for treatment of lung tumors. Robotic Radiosurgery, RF Mould, RA Schulz, RD Bucholz, GJ Gagnon, PC Gerszten, JJ Kresl, PC Levendag. CyberKnife Society Press, Sunnyvale, CA 2005; 1: 255–268

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