Long-term results of RTOG 91-11: a comparison of three nonsurgical treatment strategies to preserve the larynx in patients with locally advanced larynx cancer

Abstract

Purpose: To report the long-term results of the Intergroup Radiation Therapy Oncology Group 91-11 study evaluating the contribution of chemotherapy added to radiation therapy (RT) for larynx preservation.

Patients and methods: Patients with stage III or IV glottic or supraglottic squamous cell cancer were randomly assigned to induction cisplatin/fluorouracil (PF) followed by RT (control arm), concomitant cisplatin/RT, or RT alone. The composite end point of laryngectomy-free survival (LFS) was the primary end point.

Results: Five hundred twenty patients were analyzed. Median follow-up for surviving patients is 10.8 years. Both chemotherapy regimens significantly improved LFS compared with RT alone (induction chemotherapy v RT alone: hazard ratio [HR], 0.75; 95% CI, 0.59 to 0.95; P = .02; concomitant chemotherapy v RT alone: HR, 0.78; 95% CI, 0.78 to 0.98; P = .03). Overall survival did not differ significantly, although there was a possibility of worse outcome with concomitant relative to induction chemotherapy (HR, 1.25; 95% CI, 0.98 to 1.61; P = .08). Concomitant cisplatin/RT significantly improved the larynx preservation rate over induction PF followed by RT (HR, 0.58; 95% CI, 0.37 to 0.89; P = .0050) and over RT alone (P < .001), whereas induction PF followed by RT was not better than treatment with RT alone (HR, 1.26; 95% CI, 0.88 to 1.82; P = .35). No difference in late effects was detected, but deaths not attributed to larynx cancer or treatment were higher with concomitant chemotherapy (30.8% v 20.8% with induction chemotherapy and 16.9% with RT alone).

Conclusion: These 10-year results show that induction PF followed by RT and concomitant cisplatin/RT show similar efficacy for the composite end point of LFS. Locoregional control and larynx preservation were significantly improved with concomitant cisplatin/RT compared with the induction arm or RT alone. New strategies that improve organ preservation and function with less morbidity are needed.

Fig 1.

CONSORT diagram. RT, radiation therapy.

Fig 2.

(A) Laryngeal preservation, (B) laryngectomy-free survival, (C) overall survival, and (D) locoregional control according to treatment group. conc., concomitant; ind., induction; RT, radiation therapy.

Fig 3.

Survival according to whether or not a laryngectomy was performed in the first year: (A) all treatment arms combined (P = .21); (B) induction arm (P = .03); (C) concomitant arm (P = .01); and (D) radiation therapy–only arm (P = .20).

Fig 4.

Survival, limited to (A) deaths from study cancer and (B) deaths not caused by study cancer according to treatment group. conc., concomitant; ind., induction; RT, radiation therapy.