In this study we evaluated 28 patients with sinonasal carcinomas. According to other studies this malignancy is more common among the male that is in line with our finding that men comprised 60% of patients(1).
Based on the large-scale investigations, the 5 and 10-year survival of malignant sinonasal tumors are 52% and 44%, respectively(2). Based on our results, the 3-year survival rate was56% that is comparable to other investigations with similar distribution of histological types(8).
Focusing on each histological type, in a study between 1998 to 2012 the 2 and 5-year local recurrence was 37.5%. The involvement of suprastructures decreased the rates of OS,PFS and local control (9).In a study by Michel et al. in 1995–2008 the authors evaluated 33 patients with sinonasal SCC.A quintile was female and the most common site was maxillary sinus. The proportion with invasion to orbital fossa and infra-temporal fossa, base of skull and sphenoid bone were 24%,18%,9% and 6%, respectively. The 1,5 and 10-year DFS rates were 58%,46% and 46%, respectively. The 1,5 and 10-year OS were 70%,40% and 40%, respectively. Eight patients had recurrence, that 5 of them were local and 3 of them were locoregional. Suprastructure involvement was a significant poor prognostic factor (10). In our study SCC was the most common histopathology with slightly more than half of patients. About two-thirds were male. According to TNM staging, half of them had T2 and most of patients were N0. In terms of suprastructureinvolvement13% had orbital invasion and 6.7% had pterygoid fossa invasion but cranial fossa invasion was not seen in our patients. None of our patients with SCC had regional recurrence but 13% of them had local recurrence and distant metastasis was seen in 26.7% of them. In follow up of patients with this pathology 3-year overall survival was 48% and median survival was 28 months. Our rates are comparable to other studies.
Frequency of AdCC is higher among irradiated sinonasal malignancies than overall population(11).Male and female are equally involved. Perineural, skull base, orbital and cavernous sinus involvements are common in this histopathology. Most of patients die from local recurrence rather than distant metastases. The 5-year OS and DSS in the literature were both 86.5%, and 10-year OS and DSS were both 66%. 5-year RFS was 71.8% and was related to the stage of disease. PNI affected the survival and 10-year survival with and without neural infiltration were 44.4% and 75%, respectively. Percentage of relapse was higher in maxillary sinus, sphenoid sinus and nasopharynx, probably due to relationship with major nerves. Lymph node metastases and distant metastases are rare in this pathology, usually somewhat around 0–5%and 1–3%, respectively(12).
In the present study 8 patients had AdCC and about 75% of them were female. According to TNM staging half of patients presented with T3 or 4 tumors. As we expected, AdCC lymph node involvement was low and 87% of our patients were neck negative and the remaining had N1 disease. Bone invasion was seen in 87% of patients that was similar to SCC but suprastructure involvement was higher than SCC that may be justified with the predilection to involve nerves. None of patients had regional recurrence but maximum local recurrence rate was seen in patients with AdCC which has been reported in previous studies using 3D conformal technique for radiation therapy as well(13). According to other studies distant metastases is more commonly seen in this pathology compared to the SCC, and in our analysis 37% of our patients had distant metastases(13). Three-year overall survival and median survival were 73% and 60 months, respectively. This rate is comparable to other series that reported histology-specific survival rates(11).This pathology had the highest survival rate despite relatively higher metastasis, perhaps due to the low fatality and indolent nature of the metastasis in this type.
Around 10–20% of primary neoplasms of sinonasal sinus are adenocarcinoma in the radiotherapy cohorts(11).The most common site is ethmoid sinus(40%). Risk factors include exposure to hardwood dust, nickel and who work with leather, thus, this histopathology is more common in males than females(2 to 6 folds). Due to the anatomical challenges in surgery, local recurrence is the main cause of failure(about 50%), lymph node metastases and distant metastases occur in about 10% and 13% of patients, respectively(14).A study was done in 1993–2009 that Bhayani et al evaluated 66 patients with sinonasal AC that half of them received post-operative radiation; 5-year survival, local recurrence and distant metastases were 66%, 29% and 7.6%, respectively. Sphenoid sinus involvement, T4 and higher-grade histology decreased survival significantly(15). In a study carried out between 1995 to 2010 on sinonasal AC, distribution of suprastructure involvement such as skull base and orbit, dura, brain and sphenoid bones were 29% and 21%,16%,8% and 8%, respectively. In this study,1,5 and 10-year DFS rates were 87%,44% and 39%,respectively. The 1,5 and 10-year OS rates were 86%,72% and 50%, respectively(16).
Five patients had AC in our study. The majority were male as was expected due to the relationship between of adenocarcinoma with occupational causative factors. All of patients had locally advanced disease (T3-T4) and 80% were N0.Due to the location of the lesions, advanced T staging and more suprastructure involvement that prohibited curative surgery, there was the highest rate of radical (definitive) irradiation with AC in our study. In patients with AC, despite limitations in surgery, we did not find local or regional recurrence but the highest rate of distant metastases. Three-year overall survival was 50% and median survival was 42 months. This rate is similar to the SCC type but lower than AdCC due to more aggressive distant metastasis in AC.
Our limitation in this study is the small number of patients and the use of the 3D conformal technique for all patients that limited the prescribed dose for tumors in the challenging locations.