Impact of target volumes and radiation technique on loco-regional control and survival for patients with unilateral cervical lymph node metastases from an unknown primary

Abstract 

Purpose

To compare the impact of an unilateral post-operative irradiation or a bilateral irradiation in terms of loco-regional control and survival in patients with cervical lymph node of squamous cell carcinoma from an unknown primary (CUP).

Methods and materials

Ninety five patients with epidermoid carcinoma involving unilateral cervical lymph nodes from an unknown primary were treated in two institutions from 1990 to 2007. Post-operative radiation therapy was delivered to one side of the neck in 59 cases, to both sides of the neck in 36 cases. There were 11 women and 84 men ranging in age from 38 to 80years (median 59years). Neck dissection was performed in 79 patients while 16 patients underwent single lymph node sampling only.

Results

After a median follow-up of 3.3years, the nodal relapse rate was 34% after unilateral neck irradiation and 25% after bilateral radiotherapy (p=0.21). Six contralateral lymph node relapses occurred after unilateral irradiation (10%). The 5-year overall survival rate of the entire group was 24%. The 5-year OS rates were 22% after unilateral irradiation and 23%, after bilateral radiotherapy (p=0.944). The occult primary occurred in 12% after unilateral irradiation and 6% after bilateral radiotherapy. The radiation technique (3D-CRT or IMRT vs. 2D: p=0.026) was prognostic on loco-regional control. Independent prognostic determinants on overall survival were the WHO status (p=0.013) and the radiation technique (2D vs.3D-CRT or IMRT; p=0.029). There was no difference in loco-regional control (p=0.639) and no difference in survival (p=0.493) when chemotherapy was associated.

Conclusions

Retrospective comparisons between bilateral and unilateral neck radiotherapies did not show differences in terms of loco-regional control and survival. However, patient’s local regional control and survival are significantly improved after 3D-CRT or IMRT.

Keywords: Squamous cell carcinoma, Unilateral radiotherapy, Bilateral radiotherapy, Unknown primary, Lymph node metastases