Precision oncology: The role of minimally-invasive ablation therapy in the management of solid organ tumors

Table 1 Overview of minimally invasive ablation techniques

Technique	Mechanism	Frequency range	Max temperature	Tumor types treated	Strengths	Limitations	Common complications
Radiofrequency ablation	High-frequency currents to induce coagulative necrosis	460-500 KHz	100 °C	Adrenal gland, bone, breast, kidney, liver, lung, pancreas, thyroid	Oldest technique, low cost, minimal equipment	Requires conductivity, heat sink, less effective over time	Bleeding, pain, infection, tumor seeding, skin burns, post-RFA syndrome
Microwave ablation	Electromagnetic waves to induce coagulative necrosis	300 MHz-300 GHz	150 °C	Adrenal gland, bone, breast, kidney, liver, lung, prostate, spleen, uterus	Higher temps quickly, no conductivity needed, multiple probes for larger ablation	Cables can burn patient, requires cooling, less precise	Bleeding, pain, infection, tumor seeding, skin burns, post-ablation syndrome
Cryoablation	Extreme cold to induce cell death	N/A (cryogenic gases)	-196 °C	Bone, breast, kidney, liver, lung, prostate, skin	No heat, vessel occlusion, minimal damage to nearby tissues, multiple probes for larger ablation	Specialized gases needed, safety hazard with compressed gases	Infection, pain, bleeding, cryoshock, cryoreaction
High-intensity focused ultrasound	High-intensity ultrasound to generate localized heat and necrosis	0.8-3.5 MHz	Exceeds 60 °C rapidly	Bone, breast, desmoid, kidney, liver, pancreas, prostate, uterus	Non-invasive, high precision, lower risk of off-target damage	Requires anesthetics, affected by tissue echogenicity	Skin burn, pain, fistula, local edema, hyperpigmentation
Histotripsy	Cavitation bubbles to mechanically disintegrate tumors	250 KHz-6 MHz	N/A	Brain, breast, kidney, liver, muscle, pancreas, prostate, skin, thymus	Non-invasive, non-thermal, high precision, lowest risk of off-target damage	Requires anesthetics, affected by tissue echogenicity, experimental, low clinical data	Immune-mediated responses

N/A: Not applicable; RFA: Radiofrequency ablation.

Table 2 Clinical indications and outcomes for ablation techniques

Tumor type	Ablation technique	Indications	Response rate	1-year PFS	1-year OS
Hepatocellular carcinoma	RFA, MWA, CA, HIFU, histotripsy	Solitary tumors < 3 cm (RFA), recurrent or aggressive disease, association with vasculature/biliary system	91.8% (RFA), 98.8% (MWA), 94% (CA), 90% (HIFU), 100% (histotripsy, preliminary)	75% (RFA), 87.6% (MWA), 84.4% (CA), 63.6% (HIFU), limited data (histotripsy)	93.3% (RFA), 95.9% (MWA), 100% (CA), 59.48% (HIFU), limited data (histotripsy)
Non-small cell lung cancer	RFA, MWA, CA	Early-stage non-surgical candidates, medically inoperable elderly patients, metastatic	79.5% (RFA), 100% technical success (MWA), 100% (CA), limited data (HIFU, histotripsy)	54% (RFA), 93.7% (MWA), 100% (CA), limited data (HIFU, histotripsy)	100% (RFA), 99% (MWA), 97.5% (CA), limited data (HIFU, histotripsy)
Renal cell carcinoma	RFA, MWA, CA, HIFU, histotripsy	Stage T1a and T1b, high-risk patients, oligometastatic	95.5% technical success (RFA), high (MWA), 92.6% technical success (CA), limited data (HIFU, histotripsy)	> 97% (RFA), 100% (MWA), 95.6% (CA), limited data (HIFU, histotripsy)	> 97% (RFA), 99% (MWA), 98% (CA), limited data (HIFU, histotripsy)
Desmoid tumors	RFA, MWA, CA, HIFU, histotripsy	Combination with chemotherapy, difficult anatomical locations, recurrence management	88.9% (MWA), 80% (CA), 47.3% (HIFU), limited data (RFA, histotripsy)	85.1% (CA), limited data (RFA, MWA, HIFU, histotripsy)	69.3% (HIFU, 5-year), limited data (RFA, MWA, CA, histotripsy)

PFS: Progression-free survival; OS: Overall survival; RFA: Radiofrequency ablation; MWA: Microwave ablation; CA: Cryoablation; HIFU: High-intensity focused ultrasound.

Table 3 Analysis of ablation techniques in specific anatomic locations

Tumor location	Ablation technique	Technical challenges	Special considerations	Clinical outcomes
Liver	RFA, MWA, CA, HIFU, histotripsy	Proximity to major blood vessels, risk of bile duct injury/fistula	Need for real-time imaging guidance (universal consideration), risk of incomplete ablation	High response rate for small tumors, varies with tumor size and location
Lung	RFA, MWA, CA, experimental (HIFU, histotripsy)	Air-filled lung tissue provides poor acoustic access, risk of pneumothorax/effusion/fistula	Requirement for minimizing patient motion with respiration, use of adjunctive therapies to enhance efficacy	High technical success rate, varies with tumor size and location, high innovation to overcome acoustic access limitations
Kidney	RFA, MWA, CA, experimental (HIFU, histotripsy)	Proximity to adrenal gland, renal pelvis, and major blood vessels, risk of urinary tract injury	Need for careful post-procedural monitoring of vitals and chemistries	High technical success rate, lower recurrence with longer follow-up
Soft tissue	RFA, MWA, CA, HIFU, histotripsy	Involvement with muscle tissue, difficulty in achieving complete ablation without damaging surrounding structures, locally invasive	High recurrence rate, need for combination with systemic therapies and long-term management	High response rate in small studies, varies with tumor location and previous treatments, high success rate with disease burden reduction and quality of life improvement

RFA: Radiofrequency ablation; MWA: Microwave ablation; CA: Cryoablation; HIFU: High-intensity focused ultrasound.