Surgery versus surgery and postoperative radiotherapy in squamous cell carcinoma of the buccal mucosa: a comparative study.

BACKGROUND

The efficacy of postoperative radiotherapy for squamous cell carcinoma of the buccal mucosa was evaluated.

METHODS

One hundred seventy-six patients treated between 1989 and 1993 were analyzed. One hundred fifteen patients were treated with surgery alone (Group 1), and 61 patients were treated with a combination of surgery and postoperative radiotherapy (Group 2).

RESULTS

Actuarial 3-year locoregional control in Groups 1 and 2 was 11% and 48% for patients with stage III + IV cancer (P = .001) and 71% and 75% for patients with stage I + II cancer (P = .74), respectively. On multivariate analysis for locoregional failure, surgical margin, bone invasion, high grade, and node involvement were significant factors in Group 1, whereas in Group 2 only tumor thickness was a significant factor. For local failure, margin, bone invasion, and stage in Group 1 and tumor thickness in Group 2 appeared as significant factors. For nodal failure, clinical nodal (cl N0 vs. N+) stage and grade in Group 1 and pathologic nodal stage (pN0 + 1 vs. pN2) in Group 2 were observed as significant factors. On subset analysis, postoperative radiotherapy was observed to have a significant advantage for surgical margins of 2 mm or less in both early pT (T1 + T2) (P = .019) and late pT (T3 + T4) (P = .016) stages. The local failure rate was higher if the time between surgery and radiotherapy was greater than 30 days.

CONCLUSIONS

Postoperative radiotherapy was effective in decreasing locoregional failure in patients with close surgical margins, tumor thicker than 10 mm, high-grade tumors, positive node, and bone invasion. The effect of interval between surgery and postoperative radiotherapy on local failure was margin-dependent.