Lack of a time-factor in alternating chemoradiotherapy for advanced head and neck squamous cell carcinoma

To assess wheiher a radiotherapy time factor exists also for patients affected by head and neck squamous cell carcinoma and receiving combined chemoradiotherapy.

From 1989 to 1997, of 121 patients affected by stage III or IV head and neck squamous cell carcinoma who underwent alternating chemotherapy and radiotherapy according to the Merlano regimen at our institution, 59 were selected for time factor analysis. Until 1995, if chemotherapy had to be delayed because of bone marrow toxicity, radiotherapy was also delayed accordingly. Since January 1996 in order to avoid treatment-free gaps, radiotherapy was delivered continuously until it was possible to resume chemotherapy. Potential predictive factors of local-regional control were included in univariate and multivariate models. The median follow-up is 26 months (5-121 months).

As a result of change in treatment policy, mean radiotherapy duration was shorter for 25 patients treated after 1995 (group A, 8.4 weeks) than for those treated during 1995 or before (group B, 9.4 weeks) (t test, P = 0.0012). In contrast, as expected, mean chemotherapy duration remained relatively unchanged through the years (10.9 vs 10.7 weeks for groups B and A, respectively, t test, P = 0.77). At 2 years, the actuarial local-regional control rate was 53 +/- 7% for the whole population. The estimated rates of local-regional control at 2 years were 49 +/- 10% and 56 +/- 9% for patients belonging to groups A and B, respectively. At univariate and multivariate analyses, treatment group was not predictive of local-regional control.

Our attempt to prospectively limit radiotherapy overall treatment time failed to improve outcome. The data, although obtained on a relatively limited number of patients, suggest that tumor cell repopulation during radiotherapy may not be clinically relevant when chemotherapy is part of the treatment for advanced head and neck squamous cell carcinoma.