Familial Nasopharyngeal Carcinoma 6

144 R. Ove, R. R. Allison, and J. J. Luexcellent results for 67 nasopharynx patients treatedwith IMRT (Lee et al. 2002). At 4 years, local controlwas 97% and regional control 98%. Xerostomia wasremarkably mild, considering the need to cover thebilateral neck.For early stage disease, results with IMRT havebeen promising, as described in a series of 203nasopharyngeal patients from Taiwan treated witheither IMRT or conformal techniques (Fang et al.2008). Roughly half were treated with IMRT. Fortyfiveof the patients were AJCC 1997 stage I or II.Quality of life was superior for the IMRT group, withno significant difference in oncologic measures.Three year survival for the IMRT group was 94 and89% for stage I and II, respectively. The correspondingsurvival numbers for conformal radiotherapywere 100 and 80%. A series of 33 T1N0 patientstreated in Hong Kong established good results at 3year follow-up, with 100% overall survival and localcontrol, with one neck failure (Kwong et al. 2004).Mean parotid dose was high, at 38 Gy, but 85% ofpatients recovered 25% of their baseline parotidfunction at 2 years. The National Cancer Centre inSingapore published its nasopharyngeal experience,which included 72 stage I and II patients (Tham et al.2009). Disease-free survival was excellent, at approximately95% for T1 and 90% for stage II, but detailedmorbidity information was not reported. Somepatients also received an intracavitary boost.It has been argued that IMRT should not be usedfor head and neck cancer if the upper aspects of necklevel II require treatment bilaterally, as sparingparotid function will prevent adequate coverage ofthe upper portions of level II. In the case of nasopharyngealcancers, early stage or otherwise, it is certainlythe case that level II should be treated. Atpresent, it appears that using IMRT in this scenariohas important benefits, with a reduction in the risk ofCNS complications, improved parotid function, andno unusual incidence of neck failures. Although meanparotid doses tend to be higher than for other ipsilateralhead and neck cancers, there does appear to be aclinical reduction in xerostomia and improvement inquality of life (Hsiung et al. 2006; Fang et al. 2008).10.4.3BrachytherapyIntracavitary brachytherapy is often used to boost theprimary site. Owing to the limitation of the effectivetreatment range, brachytherapy is considered moreeffective in early T-classification disease. Technicaldetails and dosing are often omitted from publications,and the technique has been used selectively. Thetypical technique utilizes one or two pediatric endotrachealtubes, with sources placed between the posteriorwall of the maxillary sinus and the free edge ofthe soft palate. Dose is then prescribed to a point orsurface 0.5 cm deep to the vault mucosa, pending normaltissue tolerance of adjacent structures (Wanget al. 1975). Custom applicators are also commerciallyavailable. Both high-dose rate (HDR) and low-doserate brachytherapy have been used.Brachytherapy boosts have been associated withimproved local control, and allow a higher dose to bedelivered than could be safely delivered with conventionalexternal beam techniques (Wang 1991).Retrospective data suggest that early stage patientstreated with conventional radiotherapy techniquebenefit from a brachytherapy boost, with bothimprovement in local control and survival seen(Chang et al. 1996; Cao et al. 2007). The use ofbrachytherapy has declined in recent years as theuse of IMRT has become more widespread, but HDRhas been used with IMRT for nasopharyngeal cancer(Tham et al. 2009). HDR brachytherapy has beenstudied prospectively, with 100% local controlachieved for a series of stage I and II patients (Luet al. 2004). The regimen used was 5 Gy × 2 delivered1 week apart, after delivering 66 Gy to the primarysite with conventional external beam radiotherapy.Dose was prescribed 1 cm superior to the midpointof the sources.HDR brachytherapy is not without risk, particularlylate complications, and care must be taken iftarget tissue is adjacent to the optic apparatus. Forearly stage disease, normal anatomy will most likelylead to acceptable tolerances with standard technique.Complications have been reported, however.The largest published series employing routine HDRbrachytherapy for early stage nasopharyngeal carcinomatreated 133 patients, with 64.8–68.4 Gy externalbeam RT and 1–3 HDR boosts of 5–5.5 Gy each(Chang et al. 1996). The results were compared to asimilar cohort treated with external beam RT alone,dosed slightly higher at 68.4–72 Gy. Brachytherapyuse was associated with improved survival and localcontrol. It was also associated with perforation of thesphenoid sinus floor, necrosis of soft tissue, and othercomplications involving the palate. The authors recommendedlimiting the fraction size, but limitingthe number of fractions to two 5 Gy fractions is verylikely safe and effective.