Percutaneous CT-guided thermal ablation as salvage therapy for recurrent non-small cell lung cancer after external beam radiotherapy: A retrospective study

Figures & data

Table 1. Subject, tumour and imaging characteristics, and outcomes of patients receiving thermal ablation for non-small cell lung cancer local recurrence after radiotherapy.

Characteristic	N	%
Patients (n)	12
Male	8	67
Female	4	23
Mean age ± SD	71 ± 7
Initial tumour stage
I	5	42
II	6	50
III	1	8
Dose range of previous radiotherapy (Gy)	50–63
Median survival (months)	35 (95% CI: 12, 58)
Median TTLP (months)	14 (95% CI: 8, 19)
Recurrence after 1 ablation	6/12	50
Recurrence after 2 ablations	1/5	20

TTLP, time to local progression; CI, confidence interval.

Table 2. Treatment characteristics of patients receiving thermal ablation for NSCLC local recurrence after radiotherapy.

Patient	Location of lesion	Histology+	Post-XRT time to recurrence‡ (months)	Chemotherapy§	Modality (ablation session)	Size of lesion	No. of ablations (total duration, min)	Max power used (W)	PTX post-ablation	ICC required	Follow-up period (months)	Modified RECIST outcome	Status
1	RUL inner	Adenoca	15	Yes	RFA (1)	18	1 (18)	200*	Yes	Yes	15	Progression	Deceased
					RFA (2)	25	1 (21)	200*	No	–	9	Stable
2	LUL (lingula) both	SCC	6	No	RFA (1)	33	4 (48)	150*	No	–	6	Progression	Alive
					RFA (2)	52	3 (34)	150*	No	–	25	Complete
3	LUL outer	Adenoca	20	No	MWA (1)	19	2 (5)	100	No	–	10	Progression	Alive
					MWA (2)	17	2 (4)	80	No	–	32	Complete
4	RUL outer	Adenoca	19	No	MWA (1)	37	3 (5.75)	100	No	–	10	Stable	Deceased
5	LLL inner	SCC	37	No	MWA (1)	24	2 (20)	45	Yes	No	31	Stable	Deceased
6	RUL outer	Adenoca	7	No	MWA (1)	29	1 (4)	120	Yes	No	12	Stable	Deceased
7	LLL both	SCC	11	No	MWA (1)	61	2 (9)	100	Yes	Yes	13	Stable	Deceased
8	RUL both	SCC	10	Yes	MWA (1)	47	4 (10)	140	No	–	7	Progression	Deceased
9	LUL both	SCC	13	No	MWA (1)	50	5 (14)	100	No	–	8	Progression	Alive
					MWA (2)	37	1 (3)	80	No	–	11	Progression
10	RUL outer	Adenoca	10	No	MWA (1)	24	1 (4)	100	No	–	10	Complete	Alive
11	RUL both	Adenoca	9	No	MWA (1)	34	2 (3)	80	Yes	No	5	Stable	Deceased
12	RUL outer	SCC	9	No	MWA (1)	33	2 (7.5)	100	No	–	11	Progression	Alive
					MWA (2)	41	2 (6)	100	No	–	7	Partial
Total									5/17 (29%)	2/17 (12%)

+Recurrent tumours after initial ablation, which were subsequently re-ablated were assigned to their previous histology.

‡Time to local recurrence after radiation therapy in months.

§Adjunct chemotherapy to radiotherapy prior to ablation.

*These radiofrequency ablations used impedance-based technology, and wattage was not selected by the operator, rather it was dependent on the machine.

XRT, radiation therapy; PTX, pneumothorax; ICC, intercostal catheter; CTCAE, common terminology criteria for adverse events; RECIST, response evaluation criteria in solid tumours; RFA, radiofrequency ablation; MWA, microwave ablation; RUL, right upper lobe; LUL, left upper lobe; LLL, left lower lobe; Both, both inner and outer halves involved; Adenoca, adenocarcinoma; SCC, squamous cell carcinoma.

Figure 1. Kaplan–Meier curve of time to local progression (TTLP) for recurrent non-small cell lung caner (NSCLC) treated with thermal ablation in patients previously receiving radiation therapy (n = 17). The median TTLP is 14 months (95% CI: 8, 19).

Figure 2. A 55-year-old patient with recurrence of right upper lobe (RUL) non-small cell lung cancer (NSCLC) after 60 Gy of radical external beam radiation. (a) Axial CT lung window shows lobulated RUL mass. (b) Central position of microwave antenna within the tumour. (c) Axial CT scan 24 h after MWA shows surrounding ground-glass opacity (GGO) around tumour (arrows); medial lack of GGO at level of dashed arrows. (d) Volumetric comparison between 3 months post-ablation scan and 6 months post-ablation scan showing reduction in size by 30%, qualifying as partial response under RECIST criteria.

Figure 3. A 55-year-old patient with recurrence of right right upper lobe (RUL) non-small cell lung cancer (NSCLC) after 60 Gy of radical external beam radiation, treated with MWA. Residual avidity on FDG-PET scan 6 months post-ablation (see Figure 1Cb). (a) CT-guided core biopsy RUL lesion. (b) CT-guided microwave re-ablation 12 months after initial ablation (c) Axial CT scan 24 h after re-ablation shows large circumferential area of GGO and partial atelectasis. (d) CT scan 6 months after re-ablation shows cavitating non-enhancing ablation site.

Figure 4. A 56-year-old patient with right upper lobe (RUL) non-small cell lung cancer (NSCLC) with FDG-PET scan series. (a) After 30 cycles x 2 Gy of radical external beam radiotherapy. (b) Six months after MWA shows residual inferior FDG uptake, best appreciated on the coronal MIP. (c) welve months after MWA shows enlarging RUL mass with increasing FDG uptake. (d) Six months after re-MWA shows shrinking focus with no residual FDG uptake.