Medical Articles

Radio Frequency Ablation – An evidence based approach

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What is RFA?

Radio Frequency Ablation is a technique that uses high frequency alternating current to heat and thus destroy tumour.

An internally cooled needle is placed within the tumour and current is applied. Temperature, current and resistance are monitored in real time. An ablation takes 12 minutes and a spherical lesion of 3cm diameter is formed

• Image guided placement of RFA probe to achieve complete tumour ablattion with appropriate margin.
• Overlapping of ablations to achieve above

Cool-tip™ Radio Frequency Ablation

History of RFA in tumours

• 1990 McGahan-animal liver
• 1992 Rosenthal-osteoid osteoma
• 1992 Buscarini-Rossi- human liver tumours
• 1995 Goldberg-Gazelle-Solbiati-Livraghi – human liver tumours
• 1998 Dupuy-bone metastases
• 1998 Solbiati/Dupuy-recurrent thyroid CA
• 1998 Rossi/Wood-Renal tumours
• 1999 Dupuy-lung tumours

RFA – The Evidence

• Liver
  • HCC
  • Colorectal
• Lung
• Renal
• Bone

RFA - Liver

• Bulk of research done in liver
• Advantages
  • Short hospital stay (Discharge day 1)
  • Percutaneous, laparoscopic or at open surgery
  • Excellent safety profile
  • Good long term results
  • Low cost

Liver - HCC

Early HCC

• Sustained complete response in 97% of 218 patients with single lesion <2cm at a median of 31months
• Mortality: 0 Major morbidity: 1.8%
• 5 year survival: 68%
• Advantages over resection
  • Less invasive
  • Lower complication rate
  • Lower cott
  • As effecttive as surgery in tthe treatment of very early HCC
  • Can be repeated

Liver - HCC

Liver – Colorectal Metastasis

• The 5 year overall survival rate after hepatic resection ranges from 27% to 58%.
• Only 10– 20% of patients with CRC mets isolated to the liver are eligible for surgical resection.
• 30 % of the patients with CRM are suitable for RFA.

Long term results of RFA

• Long Term results in RFA for liver colorectal metastasis
• Improved outcome with increasing experience.
• 166 Patients with 378 metachronous liver metastasis
• Survival rates:
  • 1-Year: 96%
  • 2-Year: 64%
  • 3-Year: 46%
  • 4-Year: 37%
  • 5-Year: 22%

Liver – Colorectal metastasis

RFA of Colorectal Liver Metsastasis

• 3 year 5 years
• Solbiati: 46% 22% Radiology 2003
• Oshowo: 52% NA BJS 2003
• Abdalla: 57% 37% Ann. Surg.2004
• Lencioni: 47% 24% Radiology 2004
• Gillams: 58% 30% Eur. Rad. 2004
• Sorensen 64% 44% Acta Radiol.2007

An example of RFA

Survival - colorectal liver metastase

Summary - Liver

• Surgery remains the gold standard for metastases
• Current acceptted inclusion criteria
  • <5 lesions
  • >4 cm diameter
  • Primary disease under control
  • Only in tumours with a proven benefit
  • Debulking only in the setting of active neuroendocrine tumours for symptom control

Radiofrequency Ablation Liver - Conclusion

• The use off RFA tto treat unresectable liver tumours is unlikely to be curative for many patients; however, a subset of patients treated with RFA may achieve long-term disease-free survival.
• RFA of unresectable liver tumour provides a safe and highly effective method to achieve local disease control.

RFA - Lung

• Exciting modality
• 3 and 5 year trials now appearing
• Applied to NSCLC and metastasis
• Advantages
  • Ability to treat non surgical patients
  • Negligible decrease in lung function
  • Repeatable
  • Low cost (Discharge day 1)
  • Low morbidity and mortality
  • Encouraging long term results

Lung - NSCLC

Stage 1 NSCLC survival:

• RFA RFA + RadioTx
• 1 year 78% 83%
• 2 year 57% 62%
• 5 year 27% 39%

Lung - Metastasis

• Majority of the work has been done on colorectal metastasis
• Long term results:
  • Survival Progression free survival
  • <3cm >3cm metastasis
  • 1 year 87% 83% 45%
  • 2 years 78% 64% 25%
  • 5 years 57% 47% 25%

Lung RFA - Complications

Lung RFA - Summary

• Surgery remains the gold standard for both primary and secondary tumours
• Proven alternative if surgery is not possible
• Good safety profile
• Prognostic indicators for ablation
  • Size of lesion
  • Proximity to hilum
  • Proximity to vessels and bronchi
  • Number of lesions

RFA - Kidney

• Long term data awaited
• Predictors of complete ablation
  • Lesions <3cm
  • Exophitic lesions
• Advantages of RFA
  • Perinephric fat insulates kidney from surrounding organs
  • Nephron sparing (Contralateral nephrectomy, Renal impairment)
  • Minimally invasive, low cost
  • Good safety profile

RFA – Bone Metastasis

• Advantages
  • Promising palliation modality
  • Mean pain score 8.1 pre RFA to a mean of 3.1 at 4 weekspost RFA. Marked reduction of analgesia usage over the 6 month follow up.
  • Excellent safety profile
• Indications
  • Failed radioTx or chemoTx
  • Painful lesions
  • >1cm from spinal cord

RFA – The future

• New image guidance techniques

• Advanttages off synchronised CT//Sonar
  • Sonographically undetectable lesions
  • Large lesions partially visible on US
  • Complex lesions where multiple ablation spheres have tto be created
  • Lesion “disappears” on US during ablation
  • Lesion adjacent to at risk anatomical structures
  • Lesion only visible on contrasted scan
• Otther ablational technologies
  • Hiighly focused ultrasound
  • Steam injection
  • Laser
  • Cryo
  • Microwave
    • Most promising of the new technologies
    • Released in Europe 2 months ago (SA 8/2008)
    • Larger lesion size – 5cm