Long Term Results of the Concomitant Boost Fractionation Schedule for Treatment of Oropharyngeal Carcinoma
Presenter: Morrison WH
Affiliation: M.D. Anderson Cancer Center
A potential deterrent to obtaining local control with radiation therapy for head and neck cancer is the problem of accelerated repopulation of cancer cells. This becomes more problematic after several weeks of treatment. The rationale for this study of a concomitant boost to treat oropharyngeal cancer arises in response to this problem and attempts to overcome it by shortening the treatment time.
Two hundred patients with T1-T4 N0-3 squamous cell cancer of the oropharynx were treated with radiation therapy including the twice daily (concomitant boost) schedule for the last twelve fractions of the treatment. This reduces the overall treatment time to a median of 42 days.
- The median followup for the entire group was 50 months.
- Local control at 5 years was 92% for T1, 94% for T2, 73% for T3, and 50% for T4 tumors.
- The overall local control rate was 64%.
- The five year overall survival and disease free survival were 60% and 74%, respectively.
- Patients who received a neck dissection prior to RT had a local-regional control of 90% versus a local-regional control of 90% for those who underwent neck dissection post RT for residual disease on exam or CT.
- Seventy-five perecent of the patients developed acute confluent mucositis and 10% were hospitalized.
- The median weight loss on treatment was 15 pounds.
- Long term complications included 5 late G-tube dependent patients, 4 mandibular resections, 3 esophageal strictures, 2 episodes of trismus, and 2 cranial neuropathies.
- Local control with the concomitant boost technique appeared to be somewhat higher than historical controls when compared between similar stages.
- Late effects were somewhat increased and continue to increase over time.
- A neck dissection may be reserved for residual disease after definitive radiation as the local control is similar to pre-RT neck dissection.
- This fractionation scheme appears to be convenient and has been shown in a recently reported randomized trial (RTOG 90-03) to be superior to standard fractionation and other methods of altered fractionation. It should be considered as an option for organ preservation for patients with squamous cell cancer of the oropharynx.
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