- Citado por SciELO
versión On-line ISSN 1678-7099
Radiol Bras v.41 n.2 São Paulo mar./abr. 2008
Causes of unplanned interruption of radiotherapy
PhD, Professor, Division of Radiotherapy, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, SP, Brazil. E-mail: firstname.lastname@example.org
The usual external beam radiotherapy fractionation schedule consists of daily sessions five days a week, over a period of five to eight weeks. The current medical conduct is based on this periodicity, resulting in foreseeable healing and toxicity rates(1,2). The overall treatment time in case of combined radiotherapy/brachytherapy, particularly for treating uterine cervix cancer, also affects the outcome of these treatments(3).
The significance of radiotherapy interruption, either for treatment toxicity, technical problems in equipment maintenance or breakdown, or for operational and socio-economic difficulties, is well documented in several scientific papers, reporting harmful effects on the treatments outcomes, especially in cases of highly prevalent tumors such as head & neck and uterine cervix cancers(13).
Preventive maintenance of radiotherapy equipment, taking at maximum two working days every three months, in association with an appropriate logistics for spare parts inventory, is essential for avoiding long-lasting treatment interruptions(4). This issue has effectively been resolved by the pressures from the market, considering that only equipment manufacturers providing high quality technical support and minimizing downtime for technical reasons, can remain active
Operational and socio-economic difficulties have been discussed in the press (newspaper Folha de S. Paulo, March 26, 2008), where delayed treatment initiation is reported, including in reference centers for cancer treatment. Although the delay in the treatment initiation cannot be considered as an unplanned interruption, its occurrence leads to the disease progression, resulting in the worsening of outcomes and increase in morbidity. Additionally, it is worthwhile to note that, generally, low socio-economic level patients live far away from radiotherapy centers, many times requiring financial support to attend treatment sessions on a regular basis, the lack of this financial support being determining factors for frequent non-attendance and treatment abandonment.
From the medical point of view, aggressive schemes of combined radiotherapy/chemotherapy may also lead to interruptions because of the treatment toxicity. A multidisciplinary approach of the oncological treatment, in compliance with appropriately structured standards and protocols, and a proactive clinical support is essential, considering the minimization of the risks from this type of event and the more severe complications which might affect the outcomes in terms of healing rates, as well as decreasing the quality of life of the patients(58). Another aspect to be taken into consideration is represented by the technological developments in radiotherapy, which may reduce the incidence of side effects, contributing for the treatment success with a higher tolerance by the patients and a lower rate of interruptions and consequential higher risk for sequelae(79).
1. Nakfoor BM, Spiro IJ, Wang CC, et al. Results of accelerated radiotherapy for supraglottic carcinoma: a Massachusetts General Hospital and Massachusetts Eye and Ear Infirmary experience. Head Neck. 1998;20:37984. [ Links ]
2. Semrau R, Mueller RP, Stuetzer H, et al. Efficacy of intensified hyperfractionated and accelerated radiotherapy and concurrent chemotherapy with carboplatin and 5fluorouracil: updated results of a randomized multicentric trial in advanced headandneck cancer. Int J Radiat Oncol Biol Phys. 2006;64:130816. [ Links ]
3. Perez CA, Grigsby PW, CastroVita H, et al. Carcinoma of the uterine cervix. I. Impact of prolongation of overall treatment time and timing of brachytherapy on outcome of radiation therapy. Int J Radiat Oncol Biol Phys. 1995;32:127588. [ Links ]
4. Colligan SJ, Mills JA. A philosophical approach to treatment machine maintenance and breakdown. Br J Radiol. 1997;70:12749. [ Links ]
5. Bull KS, Spoudeas HA, Yadegarfar G, et al. Reduction of health status 7 years after addition of chemotherapy to craniospinal irradiation for medulloblastoma: a followup study in PNET 3 trial survivors on behalf of the CCLG (formerly UKCCSG). J Clin Oncol. 2007;25:423945. [ Links ]
6. Merseburger AS, Kuczyk MA. The value of bladderconserving strategies in muscleinvasive bladder carcinoma compared with radical surgery. Curr Opin Urol. 2007;17:35862. [ Links ]
7. McMillan AS, Pow EH, Kwong DL, et al. Preservation of quality of life after intensitymodulated radiotherapy for earlystage nasopharyngeal carcinoma: results of a prospective longitudinal study. Head Neck. 2006;28:71222. [ Links ]
8. Zelefsky MJ, Levin EJ, Hunt M, et al. Incidence of late rectal and urinary toxicities after threedimensional conformal radiotherapy and intensitymodulated radiotherapy for localized prostate cancer. Int J Radiat Oncol Biol Phys. 2008;70:11249. [ Links ]
9. Vuong T, Kopek N, Ducruet T, et al. Conformal therapy improves the therapeutic index of patients with anal canal cancer treated with combined chemotherapy and external beam radiotherapy. Int J Radiat Oncol Biol Phys. 2007;67:1394400. [ Links ]