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Dear Editor,

We are pleased to see the level of interest aroused by our article ‘High-powered percutaneous microwave ablation of stage I medically inoperable non-small cell lung cancer: A preliminary study’.[1] Thank you for the opportunity to respond to the letter to the editor by the Liverpool team, entitled ‘Minimally invasive techniques for medically inoperable stage I non-small cell lung cancer: Radiotherapy is still the gold standard’.[2]

Allow us to provide detailed comments to the raised issues:

Lack of any mention of the well-established treatment option of external beam radiation

  1. Top of page
  2. Lack of any mention of the well-established treatment option of external beam radiation
  3. Radiotherapy as the standard of care for medically inoperable stage I NSCLC
  4. Complication rate and local recurrence
  5. Prospective randomised trials
  6. References

Wisnivesky et al.[3] assessed the outcome of 4357 stage I and II NSCLC patients, 88% of whom were stage I patients, who were not surgical candidates and received either conventional radiotherapy or observation only. In the two groups, the median survival time for patients with stage I disease differed by 7 months, and for stage II disease by 5 months with no survival difference at 5 years (11% vs. 10%).

Radiotherapy as the standard of care for medically inoperable stage I NSCLC

  1. Top of page
  2. Lack of any mention of the well-established treatment option of external beam radiation
  3. Radiotherapy as the standard of care for medically inoperable stage I NSCLC
  4. Complication rate and local recurrence
  5. Prospective randomised trials
  6. References

It is disappointing to have to use a 14-year-old reference (Saunders etal., “Continuous, hyperfractionated, accelerated radiotherapy (CHART) versus conventional radiotherapy in non-small cell lung cancer.”) as current level II evidence supporting radiotherapy as standard of care.

Stereotactic body radiotherapy (SBRT) is, at present, considered the gold standard for the non-surgical treatment of node-negative small NSCLC. Unfortunately, despite having the required equipment at our hospital, we are unable to offer SBRT to our lung cancer patients on a routine base. Hence, we cannot randomise and prospectively compare the two therapy options. Most importantly, all our patients are discussed at weekly lung cancer multidisciplinary team meetings, also attended by radiation oncologists, and joint decisions are made as to the best treatment option to be recommended to the patients.

Complication rate and local recurrence

  1. Top of page
  2. Lack of any mention of the well-established treatment option of external beam radiation
  3. Radiotherapy as the standard of care for medically inoperable stage I NSCLC
  4. Complication rate and local recurrence
  5. Prospective randomised trials
  6. References

A small, asymptomatic pneumothorax is not considered a significant complication – it resorbs spontaneously and does not leave sequelae. Patients requiring chest tube insertion are well and compassionately managed and come through the procedure undamaged. A 13% chest tube insertion rate in a patient population (as Yap and colleagues[2] correctly point out), with substantial co-morbidities and a respiratory reserve too poor to tolerate lobectomy, is considered a very acceptable figure. It is comparable with the pneumothorax and chest tube insertion rate after CT-guided core biopsy.[4]

We are now almost 1 year post-submission of our manuscript and we sustain a local control rate of 75% (one false positive case in the initial published data, based on positron emission tomography scan only).

Microwave ablation seems to be superior to radiofrequency ablation (RFA) in the treatment of early-stage NSCLC, achieving better local tumour control; discussion of this is, however, beyond the scope of this letter.

Furthermore, especially in the Australian setting with many patients coming from remote areas, having the option of treatment as an outpatient or as an overnight stay adds to quality of life – always an important consideration.

A recent article comparing SBRT with image-guided thermal ablation (IGTA) for early-stage NSCLC concludes that there is no difference in survival outcome between the two modalities.[5] This is partially owing to the fact that IGTA can be repeated in locally recurring tumours as often as necessary.[6] Given the fact that SBRT is not devoid of complications and is approximately four times the cost of IGTA,[5] thermal ablation seems like an avenue worth pursuing.

Prospective randomised trials

  1. Top of page
  2. Lack of any mention of the well-established treatment option of external beam radiation
  3. Radiotherapy as the standard of care for medically inoperable stage I NSCLC
  4. Complication rate and local recurrence
  5. Prospective randomised trials
  6. References

Realistically, multi-centre prospective randomised trials comparing SBRT with IGTA are unlikely to happen any time soon, not least because of – at least in Australia – too few centres offering both treatment modalities.

We are fortunate to have collegiate radiation oncologists in our institution with whom we are in constant constructive dialogue. In the absence of SBRT as part of our routine service for lung cancer treatment and a disappointingly high local recurrence rate post-conventional radiotherapy, with patients being increasingly referred to us for salvage thermal ablation (manuscript to be submitted), we for now offer thermal ablation as the treatment modality of choice in these node-negative small early-stage NSCLC patients, with our preliminary results published in the paper commented on.[1]

References

  1. Top of page
  2. Lack of any mention of the well-established treatment option of external beam radiation
  3. Radiotherapy as the standard of care for medically inoperable stage I NSCLC
  4. Complication rate and local recurrence
  5. Prospective randomised trials
  6. References
  • 1
    Liu H, Steinke K. High-powered percutaneous microwave ablation of stage I medically inoperable non-small cell lung cancer: a preliminary study. J Med Imaging Radiat Oncol 2013; 57: 466474.
  • 2
    Yap ML, Vinod SK, Delaney GP. Minimally invasive techniques for medically inoperable stage 1 non small cell lung cancer: radiotherapy is still the gold standard. J Med Imaging Radiat Oncol 2013 (in press).
  • 3
    Wisnivesky JP, Bonomi M, Henschke C, Iannuzzi M, McGinn T. Radiation therapy for the treatment of unresected stage I–II non-small cell lung cancer. Chest 2005; 128: 14611467.
  • 4
    Hiraki T, Mimura H, Gobara H et al. Incidence of and risk factors for pneumothorax and chest tube placement after CT fluoroscopy-guided percutaneous lung biopsy: retrospective analysis of the procedures conducted over a 9-year period. AJR Am J Roentgenol 2010; 194: 809814.
  • 5
    Dupuy DE. Treatment of medically inoperable non-small-cell lung cancer with stereotactic body radiation therapy versus image-guided tumor ablation: can interventional radiology compete? J Vasc Interv Radiol 2013; 24: 11391145.
  • 6
    Lanuti M, Sharma A, Willers H, Digumarthy SR, Mathisen DJ, Shepard JA. Radiofrequency ablation for stage I non-small cell lung cancer: management of locoregional recurrence. Ann Thorac Surg 2012; 93: 921927.