TARGIT

From Infogalactic: the planetary knowledge core
Jump to: navigation, search

<templatestyles src="Module:Hatnote/styles.css"></templatestyles>

This article is about the medical technique. For the business intelligence developer, see TARGIT Business Intelligence.

TARGIT (TARGeted Intra-operative radioTherapy) is a technique of giving radiotherapy to the tissues surrounding a cancer after its surgical removal. The technique was designed in 1998 at the University College London. In patients having lumpectomy for breast cancer, the TARGIT-A(lone) randomized controlled trial (recruitment from 2000-2012) tested whether TARGIT within a risk-adapted approach is non-inferior to conventional course of external beam postoperative radiotherapy given over several weeks. Over 10,000 patients have been treated with this technique in 250 centres around the world. The ongoing TARGIT-B(oost) randomized controlled trial is testing whether TARGIT tumour bed boost given after lumpectomy for breast cancer in younger patients or those with a high risk of recurrence, is superior to conventional external beam radiotherapy boost for breast cancer.

Definition

TARGIT is a method where the radiation is applied during an operation and targeted to the peri-tumoural tissues. TARGIT technique was designed at University College London[1] by Jayant S Vaidya (who coined the TARGIT acronym) and Michael Baum along with Jeffrey S Tobias in 1998. The term was first used when the technique was described,[2] and the protocol for a randomised trial was published by the Lancet.[3]

Rationale

When breast cancer is surgically excised, it can come back (local recurrence) in the remaining breast or on the chest wall in a small proportion of women. Adjuvant radiotherapy is necessary if breast cancer is treated by removing only the cancerous lump with a rim of surrounding normal tissue, as it reduces the chance of local recurrence significantly. When cancer does come back, it most commonly occurs in the tissues surrounding the original cancer (the tumour bed), even though there are multicentric cancers in remote areas of the breast. This suggests that it is most important to treat the tumour bed.[4] The rationale for TARGIT is to deliver a high dose of radiation precisely to the tumour bed. Conventional radiation techniques such as external beam radiotherapy (EBRT) following surgical removal of the tumor have been time tested and proven to be effective. EBRT is usually given as a course of whole breast radiotherapy and an additional tumour bed boost. However, it has a few drawbacks; for example, the tumour bed where the boost dose should be applied can be missed ("geographical miss") due to the difficulties in localization of the complex wound cavity even when modern radiotherapy planning is used. Additionally, the usual delay ("temporal miss") between the surgical removal of the tumour and EBRT may allow a repopulation of the tumour cells. These potentially harmful effects can be avoided by delivering the radiation more precisely to the targeted tissues leading to immediate sterilization of residual tumour cells. Furthermore, TARGIT inhibits the stimulating effects of wound fluid on cancer cells, suggesting for the first time, a beneficial effect of intraoperative radiotherapy (IORT) on tumour microenvironment.[5][6]

technique

File:The technique of targeted intraoperative radiotherapy for breast cancer.png
TARGeted Intraoperative radioTherapy (TARGIT) IORT for breast cancer

The machine used for TARGIT is Intrabeam (Carl Zeiss, Germany). It is a miniature and mobile X-ray source which emits low energy X-ray radiation (max. 50 kV) in isotropic distribution. Due to the higher ionization density caused by soft X-ray radiation in the tissue, the relative biological effectiveness (RBE) of low-energy X-rays on tumour cells is higher when compared to high-energy X-rays or gamma rays which are delivered by linear accelerators. The radiation which is produced by mobile radiation systems has a limited range. For this reason, conventional walls are regarded sufficient to stop the radiation scatter produced in the operating room and no extra measures for radiation protection are necessary. This makes IORT for breast cancer by the TARGIT technique available in most operating rooms. The surgical technique[7] is relatively simple but needs to be meticulously followed.[8]

Medical uses

Breast cancer

The largest experience with IORT using the TARGIT technique and the best evidence for its potentials exists in breast cancer where a substantial number of patients have already been treated.[9]

TARGIT-A (Alone)

The TARGIT-A Trial was an international multicenter prospective randomised phase 3 clinical trial designed to test whether a single dose of targeted intraoperative radiotherapy could replace the usual 3-6 week course of postoperative radiotherapy. The original trial original accrual goal of 2232 breast cancer patients was completed in 2010 and the results were announced at the American Society of Clinical Oncology meeting in Chicago (ASCO, June 4–8, 2010) and simultaneously published online on 5 June 2010 in the Lancet - Online First.[10] The local tumour control using single-dose targeted intraoperative radiotherapy was found to be equivalent to several weeks' of whole breast external beam radiotherapy. The difference in local recurrece rate between the two treatments at 4 years was 0.25% (95% CI -1.0% to +1.5%) which means that TARGIT could be at most 1.5% worse or 1% better than whole breast radiotherapy. TARGIT also caused less radiotherapy related toxicity than whole breast radiotherapy. A brief explanation of the results is at [7] and in a short interview on eCancerTV.

In an invited lecture at the Churchill Hospital in Oxford in 2010, quoted in the Sydney Morning Herald, Professor John Boyages, author of Breast Cancer:Taking Control l expressed concern about the early release of the TARGIT trial. He noted that the average follow-up for all patients in the trial was only 2 years and that this was far too short to determine its routine efficacy [8]. However, this criticism had already been addressed by the authors within the original paper PDF and subsequently.[11]

At the San Antonio Breast Cancer Symposium (3–8 December 2012), updated results of the IORT for breast cancer - TARGIT-A trial, which closed after recruiting 3451 patients, were presented and showed that giving TARGIT at the time of lumpectomy, gives results similar to whole breast radiotherapy in terms of breast cancer control (particularly in ER PR positive cases), with fewer non-breast cancer deaths[12] [9] and a trend for lower overall mortality compared with conventional external beam whole breast radiotherapy. 2012 SABCS, Thursday 6 December, General Session 4. The breast's normal tissue tolerance to radiation does not allow a second full-dose course of EBRT, even after several years. TARGIT and other forms of partial breast irradiation may be an option for selected patients with local recurrence of breast cancer after traditional radiation therapy.

Peer-reviewed publication of these main results in the Lancet from this updated analysis of mature data of TARGIT on 11 November 2013 showed

  • that with longer follow up, the results are stable,
  • local recurrence in the conserved breast with TARGIT concurrent with lumpectomy is similar to whole breast radiotherapy,
  • breast cancer mortality is similar with TARGIT and EBRT, and
  • deaths from causes other than breast cancer- cardiovascular and other cancers - are significantly reduced.

The authors concluded that TARGIT during lumpectomy should be offered as an alternative to whole breast radiotherapy in suitable patients.[13] The results of TARGIT TARGIT IORT for breast cancer are discussed in a podcast of the TARGIT-A and ELIOT trials on the Lancet website.. As the effect of radiotherapy on local recurrence of breast cancer is mostly in the first 2–3 years and almost none after the first 5 years, it is thought that sufficiently large number of patients in the TARGIT-A trial have an adequately long follow up [10]. A robust response to scientifically weak criticisms for use of TARGIT IORT during lumpectomy breast cancer, including a decision aid (figure 4) is given in the Red Journal.[14]

TARGIT-B (Boost)

TARGIT as a tumour bed boost: In conventional EBRT, the boost is delivered at the end of a complete course of EBRT. Clinical evidence suggests that boost radiation improves treatment outcome for breast cancer.[15] With TARGIT the boost can be delivered intraoperatively without any delay and more precisely as compared to conventional EBRT. A multicenter clinical trial has demonstrated that the boost administered with IORT resulted in a lower than expected rate of local recurrence (1.73%) as compared to an EORTC study which used external boost radiation.[16][17][18] As a tumour bed boost, TARGIT has been found to have a better than expected effectiveness[9][17][18] These results have prompted the inclusion of TARGIT boost as an option to EBRT boost in national clinical guidelines of many countries including Germany. Whether TARGIT is superior to an EBRT boost is being tested in a randomised trial IORT Boost TARGIT-B trial.

Worldwide adoption of TARGIT IORT

At the St Gallen Breast Cancer Conference (16–19 March 2011) the consensus amongst over 52 breast cancer expert panelists was that TARGIT alone could be used as the only radiation treatment in selected cases after breast conserving surgery, or as a tumour bed boost instead of external beam radiotherapy boost. At the Miami Breast Cancer conference (14–17 March 2012), 91% of the audience in the surgical oncology stream felt the same.

On 25 July 2014 the UK National Institute for Health and Care Excellence (NICE) gave provisional recommendation for the use of TARGIT IORT with Intrabeam in the UK National Health Service [11].[19] In September 2014, NICE requested further information from the clinical trial investigators, citing several comments and concerns.[20] Concerns cited included the immaturity of the data with a median follow up of the entire population being only 2 years and 5 months as well as the noninferiority criterion used in the study.[21] This extra information was supplied by the authors.

The 2015 update of guidelines of the Association of Gynecological Oncology (AGO), an autonomous community of the German Society of Gynecology and Obstetrics (DGGG) and the German Cancer Society includes TARGIT IORT during lumpectomy as a recommended option for women with a T1, Grade 1 or 2, ER positive breast cancer 2015E_Updated_guidelines-see-page-633.

On 21 May 2015, the Australian Government Medical Services Advisory Committee (MSAC) announced that "After considering the available evidence in relation to safety, clinical effectiveness and cost-effectiveness, MSAC supported public funding of a new Medicare Benefits Schedule (MBS) item for treatment of pathologically documented invasive ductal breast cancer in eligible patients with TARGIT-IORT when used concurrently with breast-conserving surgery.[22]" The Australian Government also approved budget item for the treatment of early stage breast cancer using targeted intraoperative radiotherapy[23] and patients can avail of this treatment from 1 September 2015 [24]

On 26 May 2015, in response to a query by the British Medical Journal (BMJ), NICE clarified that while their appraisal is going on, TARGIT IORT with Intrabeam can continue to be offered to patients who need it [25]

There are over 250 centres worldwide using TARGIT IORT for treating breast cancer in USA (about 60 centres), Europe (60 centres in Germany), Australia, Middle East, Far East, South America. More than 8,000 patients have been treated.[26]

Professional Society for Intraoperative Radiation Therapy

In 1998, the International Society of IORT (ISIORT) was formed to foster the scientific and clinical development of IORT. The ISIORT has more than 1000 members worldwide and meets every two years.[27]

See also

References

  1. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  2. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  3. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  5. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  6. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  7. ↑ Lua error in package.lua at line 80: module 'strict' not found.}
  8. ↑ The surgical technique of IORT for breast cancer
  9. ↑ 9.0 9.1 Lua error in package.lua at line 80: module 'strict' not found.
  10. ↑ Vaidya JS, Joseph DJ, Tobias JS, Bulsara M, Wenz F, Saunders C, Alvarado M, Flyger HL, Massarut S, Eiermann W, Keshtgar M, Dewar J, Kraus-Tiefenbacher U, Sutterlin M, Esserman L, Holtveg HM, Roncadin M, Pigorsch S, Metaxas M, Falzon M, Matthews A, Corica T, Williams NR, Baum M. Targeted intraoperative radiotherapy versus whole breast radiotherapy for breast cancer (TARGIT-A trial): an international, prospective, randomised, non-inferiority phase 3 trial. Lancet. 2010;376(9735):91-102.
  11. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  12. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  13. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  14. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  15. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  16. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  17. ↑ 17.0 17.1 Lua error in package.lua at line 80: module 'strict' not found.
  18. ↑ 18.0 18.1 Lua error in package.lua at line 80: module 'strict' not found.
  19. ↑ The Times, London, UK
  20. ↑ [1] NICE Intrabeam evaluation Status
  21. ↑ NICE concerns and requested actions for TARGIT Trialists
  22. ↑ [2]
  23. ↑ [3]
  24. ↑ [4]
  25. ↑ [5]
  26. ↑ [6]
  27. ↑ http://www.isiort.org/htm/index.shtm

External links

Retrieved from "https://infogalactic.com/w/index.php?title=TARGIT&oldid=3818458"