Parotid gland carcinoma is a rare and complicated histopathological classification. Therefore, assembling a sufficient number of cases with long-term outcomes in a single institute can present a challenge.

The medical records of 108 parotid gland carcinoma patients who were treated at Kyushu University Hospital, Fukuoka, Japan, between 1983 and 2014 were reviewed. The survival outcomes were analysed according to clinicopathological findings.

Forty-six patients had low clinical stage tumours (I–II), and 62 patients had high clinical stage tumours (III–IV). Fifty-two, 10 and 46 patients had low-, intermediate- and high-grade tumours, respectively. Twenty-seven of 65 cases had positive surgical margins. In high clinical stage and intermediate- to high-grade tumours, adjuvant radiation therapy was correlated with local recurrence-free survival (p = 0.0244). Intermediate- to high-grade tumours and positive surgical margins were significantly associated with disease-specific survival in multivariate analysis (p = 0.0002 and p = 0.0058).

The results of this study show that adjuvant radiation therapy is useful for improved local control in patients with high clinical stage and intermediate- to high-grade tumours.

Traditionally, a 1-cm surgical resection margin is used for early oral tongue tumours.

All tumour stage one (n = 65) and stage two (n = 13) oral tongue cancers treated between January 1999 and January 2009 were followed for a median of 38 months (minimum 12 months). The sites of close and involved margins were histologically reviewed.

Involved and close margins occurred in 14 and 55 per cent of cases, respectively. The number of involved vs clear or close margins was equivalent in tumour stage one (90 vs 82 per cent), node-negative (100 vs 84 per cent) and perineural or lymphovascular invasion (20 vs 21 per cent) cases. Close or involved margins were similarly likely to be posterior (59 per cent) as anterior (41 per cent, p = 0.22), lateral (57 per cent) as medial (43 per cent, p = 0.34), and mucosal (59 per cent) as deep (41 per cent, p = 0.22). Local recurrence occurred in 28 per cent of cases at a median of 12 months, and was more likely in cases with involved (50 per cent) than clear or close margins (25 per cent, p = 0.10). Disease-free survival was worse in involved margins cases (p = 0.002).

Involved margins are common in early tongue tumours, and are associated with increased local recurrence and worse survival. Close or involved margins occur in all directions and all tumour types. A wider margin may be justified.