Cryotherapy for renal cancer (interventional procedure consultation document)
NATIONAL INSTITUTE FOR HEALTH AND CLINICAL EXCELLENCE
Interventional Procedure Consultation Document
Cryotherapy for renal cancers
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Renal cancers occur in the lining of the very small tubes (nephrons) in the kidney. Cryotherapy involves the use of cold temperature to destroy cancer cells through the insertion of a freezing probe into the tumour. |
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The National Institute for Health and Clinical Excellence is examining insertion of pleuro-amniotic shunt to drain fetal pleural effusion and will publish guidance on its safety and efficacy to the NHS in England, Wales and Scotland. The Institute's Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisors, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about cryotherapy for renal cancers.
Note that this document is not the Institute's formal guidance on this procedure. The recommendations are provisional and may change after consultation. The process that the Institute will follow after the consultation period ends is as follows.
For further details, see the Interventional Procedures Programme manual, which is available from the Institute's website (www.nice.org.uk/ipprogrammemanual). Closing date for comments: 27 June 2006 |
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Note that this document is not the Institute's guidance on this procedure. The recommendations are provisional and may change after consultation. |
| 1 | Provisional recommendations |
| 1.1 |
The evidence about cryotherapy for renal cancers is limited and is of poor quality. The available evidence suggests that this procedure reduces tumour bulk and that it is relatively safe. However, the evidence about its effect on local control and/or survival is not yet adequate to support the use of this procedure without special arrangements for consent and for audit or research. |
| 1.2 | Patient selection is important and the procedure should normally be limited to patients for whom partial or total nephrectomy is not recommended, or to those who choose the procedure. The procedure should only be offered after assessment by a specialist multidisciplinary team, which should include a urologist, an oncologist and an interventional radiologist. |
| 1.3 | Clinicians wishing to undertake cryotherapy for renal cancers should take the following actions.
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| 1.4 | Controlled studies into the long-term clinical outcomes will be useful. The Institute may review the procedure upon publication of further evidence. |
| 2 | The procedure |
| 2.1 | Indications |
| 2.1.1 | The most common type of renal cancer in adults is renal cell carcinoma. Most tumours are identified at a relatively late stage. Symptoms and signs may include pain, blood in the urine (haematuria), weight loss and a palpable abdominal mass. Some cases are linked to hereditary syndromes. |
| 2.1.2 | If operable, the standard treatment for renal cancer has been partial or total nephrectomy. The prognosis is better with small tumours (less than 4 cm) and some of these tumours can be treated with minimally invasive techniques such as laparoscopic partial nephrectomy. Other treatment options for small tumours include radiofrequency ablation, high-intensity focused ultrasound and cryotherapy. |
| 2.1.3 | Cryotherapy may be a treatment option for patients for whom surgery is not recommended because of tumour stage (making the tumour inoperable) or anaesthetic risk. Cryotherapy may also be a treatment option for patients in whom maximum preservation of renal function is desired, for example in patients with a solitary kidney or with compromised renal function. |
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| 2.2 | Outline of the procedure |
| 2.2.1 | Cryotherapy is most frequently performed percutaneously or laparoscopically under imaging guidance (although the advantages of performing this procedure laparoscopically are unclear). |
| 2.2.2 |
The procedure is performed under general anaesthesia. A probe is inserted into the tumour and delivers a coolant at subfreezing temperatures, with the tip of the probe acting as the site of freezing. An ice ball is created around the tip of the probe, destroying cells through a cyclical process of direct freezing, dehydration and hypoxia. Each freeze cycle is followed by a heat (thaw) cycle to allow removal of the probe. A double freeze-thaw cycle is usually performed to ablate the tumour, with the aim of extending the ice ball approximately 1 cm beyond the tumour margins. Additional freeze-thaw cycles may be repeated if necessary, and more than one probe can be used. |
| 2.2.3 |
The maximum renal tumour size recommended for cryotherapy is approximately 4 cm (that is, small stage I tumours). Lesions of this size or smaller can be treated with a single probe, which is associated with less morbidity than use of multiple probes. |
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| 2.3 | Efficacy |
| 2.3.1 |
The evidence base for this procedure was based on one non-randomised comparative study and eight case series. In some studies, tumour diagnosis was based solely on imaging and was not confirmed histologically. When histology was performed before the procedure, a number of tumours were found to be benign. Thus, the exact proportion of non-malignant tumours included in the reviewed studies is uncertain. Furthermore, in some studies, follow-up was based on imaging criteria alone, without histological confirmation of any possible recurrence. |
| 2.3.2 | The longest mean follow-up was reported in a case series of 56 patients undergoing laparoscopic cryotherapy; this study reported an overall 3-year survival rate of 89%. |
| 2.3.3 | In a study comparing laparoscopic cryotherapy with partial nephrectomy, tumours recurred in 2/78 patients (3%) in the cryotherapy group (mean follow-up 24.6 months) and 1/153 (<1%) in the surgery group (mean follow-up 5.8 months). In another case series, 2/59 patients (3%) developed local recurrence following laparoscopic cryoablation (mean follow-up 26.8 months).For more details, refer to the sources of evidence (see appendix). |
| 2.3.4 |
The Specialist Advisors commented that long-term efficacy has yet to be established because only a small number of patients have been treated with this procedure. They also noted that the lack of histological data makes it difficult to determine whether total ablation of tumours has been achieved. |
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| 2.4 | Safety |
| 2.4.1 | In one study of 271 patients undergoing either cryotherapy or radiofrequency ablation for renal cancer, cryotherapy (performed laparoscopically or percutaneously) was associated with a complication rate of 14% (19/139), including 10 instances of probe-site pain. In another study comparing laparoscopic cryotherapy (n = 78) with partial nephrectomy (n = 153), 6 complications were reported in the cryotherapy group, compared with 49 in the surgery group. Complications reported in the studies included haematoma, ileus and respiratory difficulty. For more details, refer to the sources of evidence (see appendix). |
| 2.4.2 | The Specialist Advisors listed the main adverse events as bleeding, injury to adjacent structures, urinary leakage and infection. |
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| 2.5 | Other comments |
| 2.5.1 | The lack of histology and limitations of tumour assessment using imaging techniques alone may make it difficult to determine whether total ablation of tumours has been achieved. In addition, little is known about the natural history of small renal tumours and the survival of patients with small tumours. The site (whether located centrally or peripherally on the kidney) and size of the tumour appear to be important, and results may be better for smaller and peripheral renal tumours. |
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3 | Further information |
| 3.1 | The Institute has issued interventional procedures guidance on percutaneous radiofrequency ablation of renal cancer (www.nice.org.uk/IPG091). |
Bruce Campbell
Chairman, Interventional Procedures Advisory Committee
June 2006
| Appendix: | Sources of evidence |
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The following document, which summarises the evidence, was considered by the Interventional Procedures Advisory Committee when making its provisional recommendations.
Available from: www.nice.org.uk/ip344overview | |