title: In vivo cell kinetics in head and neck squamous cell carcinomas predicts local control and helps guide radiotherapy regimen.
abstract: OBJECTIVE
  To determine whether pretherapy cell kinetics can predict local control for patients affected by head and neck squamous cell carcinomas (HN-SCCs) to be treated by primary radiotherapy and, moreover, guide to a choice between conventional and accelerated radiotherapy.
  
  
  METHODS
  Between 1989 and 1993, 83 patients with stage II to IV HN-SCC entered the study. Multiple primary tumor biopsies were obtained 6 hours after in vivo infusion of bromodeoxyuridine (BrdUrd). In vivo S-phase fraction labeling index (LI), duration of S phase (Ts), and potential doubling time (Tpot) were obtained by analysis of multivariate flow-cytometric data. Between April 1989 and January 1991, 49 patients were treated by conventional radiotherapy (70 Gy in 35 fractions over 7 weeks), whereas, afterwards, 34 patients entered an accelerated radiotherapy regimen with the concomitant boost technique (75 Gy in 40 fractions over 6 weeks).
  
  
  RESULTS
  Univariate analysis showed that, among patients treated by conventional radiotherapy, local control probability was affected by tumor stage (P = .02), Tpot (P < .001), and LI (P = .04). Similarly, among patients treated with accelerated radiotherapy, we found that local control probability was related to tumor stage (P = .03) and primary tumor site (P = .05). For the subgroup of patients with tumors characterized by fast growth (Tpot < or = 5 days), accelerated radiotherapy gave a better local control rate than conventional radiotherapy (P = .02). Cox multivariate analysis of the total number of patients showed that the only significant independent prognostic factors related to local control were tumor stage (P = .002) and Tpot (P = .004). Moreover, when the Cox analysis was restricted to the subgroup of patients treated with conventional radiotherapy, Tpot was the most significant factor to predict local outcome (P < .01).
  
  
  CONCLUSIONS
  Pretreatment tumor Tpot appears to be an important independent prognostic factor for local control of HN-SCC treated by primary radiotherapy.
authors.affiliation: Divisiones di Oncologia Radioterapica e Oncologia Chirurgica, Laboratorio di Biofisica e Citometria, Istituto Nazionale per la Ricerca sul Cancro di Genova, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Corvò
authors.forename: W
authors.initials: W
authors.lastname: Giaretti
authors.forename: G
authors.initials: G
authors.lastname: Sanguineti
authors.forename: E
authors.initials: E
authors.lastname: Geido
authors.forename: R
authors.initials: R
authors.lastname: Orecchia
authors.forename: M
authors.initials: M
authors.lastname: Guenzi
authors.forename: G
authors.initials: G
authors.lastname: Margarino
authors.forename: A
authors.initials: A
authors.lastname: Bacigalupo
authors.forename: G
authors.initials: G
authors.lastname: Garaventa
authors.forename: M
authors.initials: M
authors.lastname: Barbieri
mesh_terms: D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000532:radiotherapy; D002453:Cell Cycle; D005260:Female; D005434:Flow Cytometry; D006258:Head and Neck Neoplasms / Q000473:pathology* / Q000532:radiotherapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D011879:Radiotherapy Dosage; D012074:Remission Induction