Background:
Though risk factors for SCC recurrence have been reported, those specific to SCC of the scalp have been poorly studied. Previously published studies have cohort sizes of only 8 and 54. Kadakia et al have reported improved survival outcomes (63% to 80% in 3 years) from adjuvant operative radiotherapy in immunocompromised patients receiving radiotherapy for scalp SCC.
Aim:
To determine the most important risk factors for locoregional recurrence of SCC of the scalp
Methods:
Retrospective case controlled study of consecutive patients during a 2 year period, examining patient factors (age, gender, immunocompromise, previous SCC scalp), tumour factors (width, depth, perineural and lymphovascular invasion, histological differentiation), surgical factors (circumferential and deep margins, burring of skull), and adjuvant treatment factors (radiotherapy and reoperation).
Results:
125 lesions in 99 patients were included (mean age: 79.6 years, female: 28%). 28% had had previous SCC of the scalp, with an average of 41 months before recurrence. 15 patients had recurrence (6 local and regional, 5 local only, 4 regional only). Case control analysis found two statistically significant factors for local recurrence; perineural invasion (36.4% vs 11.4%, RR: 3.2, p=0.04) and immunocompromise (63.6% vs 10.5%, RR: 6.1, p=0.000). Immunocompromise was the only significant predictor for regional recurrence (70% vs 10.4%, RR: 6.7, p=0.000), though deep margins less than 1mm were close to significance (36.4% vs 24.6%, RR: 1.5, p=0.07). Ominously, 47.4% of immunocompromised patients had recurrence.
Conclusion:
The impact of immunocompromise on scalp SCC outcomes is not always fully appreciated, but our study show it is the most important factor in predicting recurrence. Where appropriate, we recommend dual modality treatment (surgery and radiotherapy) for immunocompromised patients with scalp SCC.