Postoperative irradiation for squamous cell carcinoma of head and neck: Retrospective comparison of accelerated radiochemotherapy and standard radiotherapy

Background: Comparison of accelerated radiochemotherapy (aRCT) and standard radiotherapy (sRT) in postoperative treatment after macroscopically comple te resection of squamous cell cancers of head and neck. Material and Method s: 229 patients treated within the same period had either (no randomization ) postoperative radiotherapy with conventional fractionation (60-70 Gy, 2.0 Gy per day) or received 2 fractions of 2.1 Gy per day, 8 times\week, up to a total dose of 56.7 Gy with a treatment split after 2 weeks and simultane ous low dose cisplatin or carboplatin on treatment clays (cumulative dose > 66 mg/m(2) or 550 mg/m(2) in 83% of patients). Results: 65 patients complet ed their course of twice-daily irradiations within a maximum of 35 days and therefore had aRCT; their 3-year locoregional tumor control (Kaplan-Meier estimate) was 86%, whereas that of 42 patients with prolonged twice-daily r adiochemotherapy was 65% (p=0.0509). After sRT, i.e. 1 fraction daily and t reatment time up to 45 days, locoregional tumor control was 67%, this resul t being significantly inferior to that after aRCT (p=0.0282). In multivaria te analysis, pN stage, tumor site oral cavity/floor of mouth, high/moderate differentiation of squamous cell carcinoma and conventional surgery (versu s CO2-laser surgery) were significantly predictive of locoregional failure. Whereas nodal status, the strongest prognostic factor, was evenly distribu ted among aRCT and sRT patients, there was a misbalance of 3 risk factors f avoring the aRCT collective. Superior tumor control after aRCT was confirme d unilaterally for nearly each subgroup (significant for recurrent tumors, close margins, pN1/2a-b). For pN2c/pN3 nodal stage, the results after aRCT were by tendency worse than after sRT, possibly due to a particularly long interval between surgery and start of radio(chemo)therapy for the patients with aRCT (mean 58.0 days vs. 43.8 days, p=0.037). Among the total of patie nts the 3-year hazard for late toxicity Ill-IV was 31% after twice-daily tr eatment and 17% after conventionally fractionated radiotherapy (p=0.083). C onclusions:This retrospective analysis provides some evidence that accelera ted radiotherapy with simultaneous chemotherapy is more potent than standar d radiotherapy. However, as multivariate analysis misses significance and t he influence of misbalance of some prognostic factors among aRCT and sRT pa tients remains unclear, only a randomized trial with stratification accordi ng to risk factors as well as a defined interval between surgery and initia tion of RT can provide more evidence.