Intensity Modulated Radiation Therapy for Three Dimensional Breast Cancer

PICHON RIVIERE, A.; AUGUSTOVSKI, F. A.; GARCIA MARTI, S.; GLUJOVSKY, D.; ALCARAZ, A.; LOPEZ, A.; BARDACH, A.; CIAPPONI, A; SPIRA, C

Documento de Evaluación de Tecnologías Sanitarias

IECS

Año: 2012 p. 1 - 30

1668-2793

Breast cancer is the most deadly cancer for women in developed and most developing countries. Standard treatment usually consists of conservative surgery followed by adjuvant radiotherapy to the breast. This strategy produces low rates of local recurrence and mortality, with good cosmetic results and provides an effective alternative to mastectomy.Radiation therapy is an important therapeutic tool in decreasing the risk of recurrence, improving disease-free survival and overall survival in patients with systemic treatment. In recent years, significant progress has been made in the development of radiotherapy treatments.TechnologyThe three-dimensional intensity-modulated radiotherapy (IMRT) is a high-precision radiotherapy that uses X-ray linear accelerators to deliver computer-controlled doses of radiation to conform to the dimensional shape of the tumor. This results in potential savings of radiation in normal tissues and, ultimately, to limit adverse effects.ObjectiveEvaluate the available evidence about the efficacy, safety and policy issues related to insuring the use of three-dimensional intensity-modulated radiotherapy (IMRT) in patients with breast cancer.MethodsA search was conducted in the major bibliographic databases DARE, NHS EED generic Internet search engine, rating agencies and health technology assessment agencies and health funders. Priority was given to the inclusion of systematic reviews, randomized controlled trials (RCTs), health and economic technology assessments, clinical practice guidelines and insurance policies of other health systems.ResultsA systematic review was included, published in 2010, with clinical evidence about the use of IMRT and a clinical trial published after the search date.The review included 6 comparative studies, two RCTs (664 patients) and 4 non-RCTs (875 patients), between conventional radiotherapy (C-RT) and IMRT in breast cancer patients. The evidence showed no differences between techniques in the results of disease-free survival, local recurrence, severe side effects or overall survival. Both types of studies concluded that IMRT decreased acute adverse effects, mainly cutaneous (acute dermatitis and desquamation), and did not produce major changes in the appearance of the breast. They also agree that there is no improvement in the quality of life. A randomized phase III clinical trial, subsequent to the review, compared C-RT vs. IMRT in 259 patients. It observed 22% of skin toxicity grade 1 and grade 2 19% in the group treated with C-RT compared with 5% and 0.8% respectively in the group treated with IMRT.There are potential risks with this technique. Increasing the dose of radiation may increase the frequency of late complications, reduce the ratio between the maximum tolerated dose and the minimum curative dose, and increase the exposure of normal tissues to the peripheral radiation dose thus increasing the carcinogenic risk. On the other hand, given that treatment planning is based on static images, there may be differences between the planned dose and the emitted dose.Different insurance policies agree that IMRT is not indicated in most cases of early breast cancer, and could be recommended only in cases where there is a radiosensitive tumor, which is adjacent to critical structures that cannot guarantee their protection with conventional radiotherapy.ConclusionsThere is no evidence about the superiority of IMRT in outcomes of clinical relevance such as local recurrence, serious side effects, disease-free survival or mortality. Studies also agree that this new technique reduces the acute toxic effects, mainly mild to moderate cutaneous and cosmetic, but does not alter the quality of life of patients.Based on the evidence analyzed, IMRT is not routinely indicated but may be considered in selected cases where the minimization of tissue surrounding the tumor is crucial and where refined accuracy is critical.No clinical practice guidelines were detected that conclude that IMRT could be routinely indicated in breast cancer.In conclusion, breast IMRT does not appear to provide clinical benefit in most patients with breast cancer.