Post-operative Concurrent Chemo-radiotherapy Versus Post-operative Radiotherapy for Cancer of the Head and Neck

Two in every 3 Australians will be affected by skin cancer over their lifetime. The prevalence of skin cancer will continue to increase due to the ageing population and represents a significant problem in our community. Cure of early (T1-2) de novo cutaneous squamous cell carcinoma (CSCC) treated with either curative intent surgery or radiotherapy is 85-100%. However, the cure rate for locally advanced, recurrent, or metastatic disease to regional nodes following surgery alone are much lower, in the order of 20-70%. Metastatic CSCC is the most common malignancy of the parotid region in Australia. The 5 year loco-regional control with surgery alone is in the order of 40%-45%. The addition of post-operative radiotherapy improves loco-regional control by 15-20%, and is therefore considered the standard of care in this group of patients.

Recent data have shown that synchronous post-operative chemo-radiotherapy is superior to post-operative radiotherapy alone in "high-risk" mucosal head and neck squamous cell carcinoma (HNSCC). However, to date, there is no evidence from randomised trials that such a benefit exists in CSCC of the head and neck. At present there is little consensus amongst clinicians in Australia as to who should receive post-operative chemo-radiotherapy in CSCC. Although tumour control rates may be improved, the addition of chemotherapy may also significantly increase treatment related toxicity. Nonetheless, some centres have adopted the use of post-operative chemo-radiotherapy in selected patients with CSCC based on extrapolation from mucosal sites. This has resulted in a wide variability in practice for this disease.

Australia is uniquely placed to perform such a trial comparing post-operative chemo-radiotherapy to post-operative radiotherapy alone in high-risk CSCC due to the high rate of skin cancer. Currently there are limited data to guide management of patients with resected CSCC who are at high risk for recurrence. While it is reasonable to hypothesize that concurrent chemotherapy in this setting will confer a similar benefit to that seen in mucosal HNSCC, this can only be established by a randomized trial as proposed. If the addition of chemotherapy is shown to be beneficial and safe, then these results are likely to be translated into standard practice both nationally and internationally quite rapidly. On the other hand, if the treatment is found to be ineffective then patients will be spared the unnecessary toxicity and inconvenience associated with the addition of chemotherapy. A further important aspect of this trial will be the assessment of patient-related outcomes using a validated quality of life questionnaire. It will be important to ascertain whether any improvement in locoregional control due to the addition of chemotherapy, is also associated with improvement in quality of life compared to the control arm.