2018-19 Section 7-Neoplastic and Inflammatory Diseases of the Head and Neck eBook

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Survival in Carcinoma of the Minor Salivary Gland

Numerous studies have found stage and tumor grade to be consistently associated with survival in MSG carcino- ma. 9,12,14,15 However, the data regarding the prognostic value of age, histologic subtype, and tumor subsite are equivocal. In a 1991 single-institution studybySpiroet al, 9 stage andhistologic gradewere found to be themost important independent prog- nostic factors for CSS in 378 patients withMSGmalignant neo- plasms. Histologic subtype, subsite, and agewere not found to be of prognostic value onmultivariable analysis. Similarly, An- derson et al 12 analyzed 95 patients and demonstrated that age andtumorsubsitewerenotsignificantprognosticfactors.Vander Poorten et al 14 described55 patients fromtheNetherlands Can- cer Institute from1973 to 1994 and found stage and subsite but not age tobe significant prognostic factors. Lohet al 16 also stud- ied 171 patients and foundonlyhistologic grade tobe associated with survival onmultivariable analysis, but not age, histologic subtype, or subsite.We observed that age and tumor subsite are independent prognostic survival factors. We did not anticipate the survival results generated based on LNE. On multivariable analysis, LNE was associated with worse CSS at 5 and 10 years. Lymph node examination was as- sociatedwithahigher likelihoodof regional anddistant disease thannoLNE. In fact, 477of 811patientswhounderwent LNEhad regional disease (58.8%) compared with 1452 of 4184 patients whodidnot undergoLNE (34.7%).Wehypothesized that this as- sociation could be owing to residual confounding by stage be- cause we were only able to include broad stage grouping. In terms of survival, a site in thenasal cavity and/or parana- salsinuscarriedaworseCSSacrossallhistologicsubtypes,which is consistent with findings in the existing literature. 16,27,28 Sur- vival data onMSGmalignant neoplasms of the larynx are sparse owing to their rarity. Ganly et al 29 reported 12 cases of laryngeal MSG carcinoma, with ACC being the most common histologic subtype and as many as 60% of all cases developing local, re- gional, or distant recurrent disease. Herein, we report 229 cases of laryngeal MSGmalignant neoplasms and found that tumors atthissubsitewereassociatedwithsignificantlyworse5-and10- year CSS comparedwithother subsites. Themost commonhis- tologic subtypesencountered inthe larynx inour study included 44.5%of other rare carcinomas (102of 229) and25.3%of adeno- carcinoma (58 of 229).We suspect such poor survival is associ- atedwithadvanceddiseaseat presentationowing to thepropen- sity for submucosal growthwithminimal symptoms, recurrent disease, and distant metastases. In this study, thepoint estimate for partial surgery (HR, 0.33; 95%CI,0.23-0.47)waslowerthanthatfortotalsurgery(HR,0.55; 95%CI, 0.41-0.74). However, because the 95%CIs overlap, this difference (partial vs total) isnot statisticallysignificant. Patients undergoingtotalandpartialsurgeryhadbettersurvivalcompared with thoseundergoingno surgery.We adjusted for receipt of ra- diotherapyinourmultivariablemodels;however,wedidnothave data related to the completionanddoseof radiotherapy. This re- sidual confounding couldaccount for point estimatedifferences between partial and total surgery. Several limitations to this study areworthy ofmention, in- cluding those inherent to theuseof anyadministrativedatabase, suchas errors incoding and sampling. Inaddition, noSEERdata werefoundregardingpatientcomorbiditiesandintentofsurgery.

The 5-year CSS for patients with other rare carcinomas stratified by site was worse for those with tumors located in the larynx (HR, 4.32; 95%CI, 2.53-7.39), followedby thosewith tumors located in the nasal cavity and/or paranasal sinus (HR, 2.14; 95% CI, 1.11-4.12). Patients 75 years or older also had de- creased CSS (HR, 2.15; 95% CI, 1.23-3.75). Compared with pa- tients with other rare carcinomas who did not undergo sur- gery, improved CSS was found in patients undergoing local tumor destruction (HR, 0.80; 95% CI, 0.52-1.22), partial sur- gery (HR, 0.56; 95%CI, 0.30-1.02), and total surgery (HR, 0.70; 95% CI, 0.40-1.21). When we performed multivariable CSS analysis without histologic stratification and included all histologic subtypes and subsites, additional interesting findings were generated. A significantly worse 5-year CSS was portended by malignant neoplasms of theMSG located in the larynx (HR, 2.42; 95%CI, 1.67-3.50) and nasal cavity and/or paranasal sinus (HR, 1.73; 95% CI, 1.29-2.32). Being older than 75 years was associated with significantly worse 5-year CSS (HR, 2.88; 95% CI, 2.05- 4.06). Patients aged 65 to 74 years had worse CSS of marginal significance (HR, 1.50; 95% CI, 1.08-2.08). Lymph node ex- aminationwas also found to be associatedwith poor CSS (HR, 1.30; 95% CI, 1.05-1.59). Similar to models stratified by histo- logic subtype, patients who underwent no surgery again had a significantlyworse prognosis comparedwith thosewho un- derwent local tumor destruction (HR, 0.44; 95% CI, 0.30- 0.64), partial surgery (HR, 0.33; 95% CI, 0.23-0.47), and total surgery (HR, 0.55; 95% CI, 0.41-0.74). We observed no differ- ences in the 5-year hazard of death for race/ethnicity, sex, di- agnosis year, or socioeconomic status using the model strati- fied by histologic subtype or the unstratified model. Patterns for adjusted 10-year hazard of death on multivariable analy- sis were similar to those observed for 5-year data. Discussion To our knowledge, the present study represents the largest re- ported survival analysis for MSG carcinoma in the United States. The existing literature on survival of patientswithMSG carcinoma includes smaller case-series and/or is restricted to 1 to 2 subsites or histologic subtypes. 2,4,14,15 Our study in- cluded 5334patientswithMSGmalignant neoplasms of all his- tologic subtypes collected for 2 decades. Malignant neo- plasms located in the larynx and nasal cavity and/or paranasal sinus were associated with worse survival. Being older than 75 years was associated with decreased CSS across all histo- logic subtypes. High grade was found to be associated with worse CSS for adenocarcinoma NOS. Lymph node examina- tionwas also identified as a poor prognostic factor, whichwill be discussed in further detail below. Surgical therapy was as- sociated with increased survival for all types of MSG carci- noma. Nevertheless, because comorbidity is not addressed in the SEER database, healthier patients may have been more likely to undergo surgery and therefore had improved out- comes. Race/ethnicity, sex, diagnosis year, and socioeco- nomic status were not found to be of prognostic significance when accounting for other factors.

JAMA Otolaryngology–Head & Neck Surgery January 2016 Volume 142, Number 1 (Reprinted)

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