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| LETTER TO EDITOR |
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| Year : 2019 | Volume
: 2
| Issue : 2 | Page : 139-140 |
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Is there any difference in response to treatment between radiotherapy techniques in Cushing's disease?
Yasemin Benderli Cihan
Department of Radiation Oncology, Kayseri Education and Research Hospital, Kayseri, Turkey
| Date of Web Publication | 10-Jan-2020 |
Correspondence Address:
Dr. Yasemin Benderli Cihan
Department of Radiation Oncology, Kayseri Education and Research Hospital, 38010 Kayseri
Turkey
 Source of Support: None, Conflict of Interest: None
DOI: 10.4103/IJNO.IJNO_8_19
How to cite this article:
Cihan YB. Is there any difference in response to treatment between radiotherapy techniques in Cushing's disease?. Int J Neurooncol 2019;2:139-40 |
Sir,
Cushing's syndrome (CS) is a clinical picture of endogenous or exogenous chronic glucocorticoid. It is frequently seen in adult women between the ages of 25 and 45 years. The annual incidence is estimated at 2–3 million per million. CS is examined in two groups as spontaneous and iatrogenic. The most common cause of spontaneous CS in adults (70%) is Cushing's disease (CD) which develops as a result of pituitary adenoma secreting adrenocorticotropic hormone (ACTH). In CD, the secretion of ACTH from the pituitary adenoma leads to bilateral adrenal cortical hyperplasia, resulting in clinical manifestations of excessive secretion of adrenal cortical hormones. Many signs and symptoms of CD are nonspecific. To confirm the diagnosis, a very good history and physical examination as well as biochemically hypercortisolemia should be demonstrated. If CD is not treated, it has high mortality and morbidity rates.[1],[2],[3]
Surgical treatment is the first treatment option since approximately half of the patients diagnosed with Cushing's disease will be lost within 5 years if they are not treated. Surgery for the pituitary gland is applied to control systemic findings due to the elevation of cortisol and/or to eliminate pressure findings related to pituitary adenoma. These patients should be followed up for long-term follow-up due to high recurrence rates in CD. In cases where surgery is not possible in residual or recurrent tumors, radiotherapy or medical treatment is applied.[2],[3],[4],[5],[6],[7]
Radiotherapy is preferred as the second-line treatment in recurrent or recurrent CD cases in patients with invasive and surgical removal. Radiation therapy (RT) consists of conventional radiotherapy, stereotactic radiosurgery/radiotherapy, particle radiotherapy, and radioactive implants. The radiation effect occurs over months to years. After RT treatment, hypopituitarism, cerebrovascular events, cognitive impairment, cranial nerve neuropathies, and secondary malignancy can be observed in patients. Radiosurgery is a shorter treatment time than conventional RT, faster biochemical control, and less damage to environmental structures. In the literature, the rate of hormonal remission in the Gamma-knife, CyberKnife, and conventional RT was 10%–100%, 40%–100%, and 25%–84%, respectively.[5],[6],[7],[8],[9],[10],[11]
In conventional radiotherapy, the linear accelerator applies X-ray at a dose of 45 Gy or more (at least 6 weeks) with the fractionated photon bundle 3-field technique.[5],[6],[7] Höybye et al. reported that the occurrence of conventional RT effect was between 6 and 60 months and the remission rates with RT were reported as 83%.[5] Stereotactic RT is administered as a single dose of sterotactic radiosurgery (SRS) and multifractive SRC (2–5 fractions). Gamma-knife, linear accelerator, and proton beam treatments are implemented in this way. Different stereotactic methods have different advantages or disadvantages, and their optimal indications are still controversial.[11] Today, mostly, gamma knife method is used, and the biochemical remission rates which can be reached in 13–22 months vary between 42% and 76%.[6],[7],[10]
As a result, radiotherapy in Cushing's disease can be performed in non-operative and recurrent cases. Conventional or stereotactic methods are used in the treatment. Tumor control and biochemical remission rate were higher in stereotactic methods than in conventional RT. There is no direct comparison between stereotactic methods in terms of efficacy and safety in the literature. Studies on this subject are needed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | |  |
| 1. | Lacroix A, Feelders RA, Stratakis CA, Nieman LK. Cushing's syndrome. Lancet 2015;386:913-27.  |
| 2. | Broersen LHA, Jha M, Biermasz NR, Pereira AM, Dekkers OM. Effectiveness of medical treatment for cushing's syndrome: A systematic review and meta-analysis. Pituitary 2018;21:631-41. |
| 3. | Moore JM, Sala E, Amorin A, Martinez H Jr. Bhowmik AC, Chang SD, et al. CyberKnife radiosurgery in the multimodal management of patients with cushing disease. World Neurosurg 2018;112:e425-30. |
| 4. | Höybye C, Grenbäck E, Rähn T, Degerblad M, Thorén M, Hulting AL. Adrenocorticotropic hormone-producing pituitary tumors: 12- to 22-year follow-up after treatment with stereotactic radiosurgery. Neurosurgery 2001;49:284-91. |
| 5. | Mehta GU, Ding D, Patibandla MR, Kano H, Sisterson N, Su YH, et al. Stereotactic radiosurgery for cushing disease: Results of an international, multicenter study. J Clin Endocrinol Metab 2017;102:4284-91. |
| 6. | Marek J, Ježková J, Hána V, Kršek M, Liščák R, Vladyka V, et al. Gamma knife radiosurgery for cushing's disease and nelson's syndrome. Pituitary 2015;18:376-84. |
| 7. | Tritos NA, Biller BM. Update on radiation therapy in patients with cushing's disease. Pituitary 2015;18:263-8. |
| 8. | Wilson PJ, Williams JR, Smee RI. Cushing's disease: A single centre's experience using the linear accelerator (LINAC) for stereotactic radiosurgery and fractionated stereotactic radiotherapy. J Clin Neurosci 2014;21:100-6. |
| 9. | Wattson DA, Tanguturi SK, Spiegel DY, Niemierko A, Biller BM, Nachtigall LB, et al. Outcomes of proton therapy for patients with functional pituitary adenomas. Int J Radiat Oncol Biol Phys 2014;90:532-9. |
| 10. | Sheehan JP, Xu Z, Salvetti DJ, Schmitt PJ, Vance ML. Results of gamma knife surgery for cushing's disease. J Neurosurg 2013;119:1486-92. |
| 11. | Minniti G, Clarke E, Scaringi C, Enrici RM. Stereotactic radiotherapy and radiosurgery for non-functioning and secreting pituitary adenomas. Rep Pract Oncol Radiother 2016;21:370-8. |
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