Catálogo de publicaciones - libros

Local recurrences after conservative surgery and WBRT are most likely to occur in the immediate vicinity of the lumpectomy site. This fact has prompted the investigation of new approach of limited-field RT. Brachytherapy using either low or high dose rates delivering the total dose during a few days after surgery is advocated by several teams. While with interstitial brachytherapy the first results at 5 years are promising, the results with the MammoSite balloon device are still immature with a relatively short follow-up. The balloon catheter applicator has been developed in North America because of the theoretical disadvantages reported after the standard catheter-based interstitial brachytherapy. In the U.S. very few clinicians are familiar with the technique: many patients and health care find the placement, appearance, and the numerous puncture sites disturbing. If a simpler, safer, and quicker technique for the delivery of radiation could be offered to patients with early-stage breast cancer, such an approach could theoretically increase the breast-conserving therapy option to more women and improve their quality of life.

Accelerated PBI is logistically simpler and a more practical method for breast-conserving therapy, but it has to be demonstrated in randomized phase-III trials that it is at least equivalent to WBRT before its routine use.

Stereotactic radiation treatment of extracranial targets shows promising initial results. The techniques are getting increasingly more specialized, especially in the treatment of small lung tumors; however, many questions remain unanswered. More experimental work and clinical trials are underway which should answer these question and should strengthen this promising approach.

Target volume definition is an interactive process. Based on radiological (and biological) imaging, the radiation oncologist has to outline the GTV, CTV, ITV, and PTV and BTV. In this process, a lot of medical and technological aspects have to be considered. The criteria for GTV, CTV, etc. definition are often not exactly standardised, and this leads, in many cases to variability between clinicians; however, exactly defined imaging criteria, imaging with high sensitivity and specificity for tumour tissue and special training could lead to a higher consensus in target volume delineation and, consequently, to lower differences between clinicians. It must be emphasised, however, that further verification studies and cost-benefit analyses are needed before biological target definition can become a stably integrated part of target volume definition.

The ICRU report 50 from 1993 and the ICRU report 62 from 1999 defining the anatomically based terms CTV, GTV and PTV must still be considered as the gold standard in radiation treatment planning; however, further advances in technology concerning signal resolution and development of new tracers with higher sensitivity and specificity will induce a shift of paradigms away from the anatomically based target volume definition towards biologically based treatment strategies. New concept and treatment strategies should be defined based on these new investigation methods, and the standards in radiation treatment planning — in a continuous, evolutionary process — will have to integrate new imaging methods in an attempt to finally achieve the ultimate goal of cancer cure.