Base of skull recurrences after treatment of salivary gland cancer with perineural invasion reduced by postoperative radiotherapy

Abstract

The use of postoperative radiation therapy significantly reduced the incidence of skull base recurrence among salivary gland carcinoma patients with perineural invasion.

Perineural invasion and spread in head and neck cancer

“…The probability of skull base recurrence was 15 and 5% (p = 0.03) with and without postoperative radiation therapy, respectively. Patients with skull base recurrence had a 5-year overall survival of only 19% compared with 91% for patients without skull base recurrence [47], consistent with the findings of other authors [46,48,49]. The retrospective nature of these trials, the heterogeneity of pathologies included in many of the series of salivary gland tumors and lack of routine use of pretreatment MRI, which could have identified the presence of macroscopic PNS, are limits to the interpretation of these studies.…”

“…Clinical target volume encompasses the GTV or site of resected tumor with an additional margin to account for subclinical spread of cancer [59][60][61]. In the report by Chen et al there was a trend for reduced recurrence for those patients in whom the skull base was included in the radiation portal, compared with those in whom it was not [47]. Other authors also concur about including the base of skull for ACC [45].…”

Perineural Invasion and Perineural Tumor Spread in Head and Neck Cancer

“…13,39 We consider electively covering the CN innervating the primary tumor site in highgrade salivary gland tumors, including ACC and SDC, and in cutaneous SCC of the face involving a named nerve. 49,52 In cases that warrant this elective neural coverage, one can consider covering additional CNs at risk secondary to anastomotic interconnections, such as those running between CNs V and VII. 53,54 These interconnections should be always covered in cases of PNTS or pathologically positive margins in immediately adjacent named nerve pathways.…”

Perineural Spread in Noncutaneous Head and Neck Cancer: New Insights into an Old Problem

“…70 Accordingly, inclusion of the skull base in the irradiated volumes resulted in a trend for lower recurrence compared with treatment in which it was not included. 71 Some authors suggested that in cases with ACC involvement of a named nerve, clinical target volume should include the course of the nerve back to the skull base. 16,62 Inclusion of the brainstem should possibly be required in the presence of macroscopic disease or positive surgical margins in the skull base and neural foramens.…”