Page 149 - Clinical relevance of current materials for cranial implants

Virtual surgical planning for skincancer with cranial bone invasion
Based on best level of evidence, various national and international multidisciplinary guidelines provide treatment recommendations to aid clinicians to obtain best possible loco-regional control in case of high risk lesions25–29. Although first line treatment is complete surgical excision with histopathological control of excision margins, the optimal surgical margins are unknown. For high risk tumors, a margin of at least 6 mm is considered necessary, although experts may consider an extended margin of 10 mm to be safer25–29. If a R0 resection is not feasible, the patient refuses surgery or in the adjuvant setting, radiotherapy can be considered25–27,29. Data on elective lymph node dissection or sentinel lymph node biopsy are not conclusive21,25–27,29. Therefore, strict lymph node examination during follow-up is recommended until more clinical data become available.
When compared with cSCC in general, scalp lesions may have some complicating characteristics unique to this anatomic site. First, the presence of hair follicles at this
location are known to potentially delay accurate diagnosis. Secondly, the microscopic
extent of the tumor can be difficult to delineate and exceed clinical apparent margins,
as the subgaleal plane offers little resistance to tumor and facilitates radial spread6,16.
Also, extensive actinic damage with field cancerization and multiple foci of invasive 7 growth, could impede defining clinical margins. Thirdly, accurate diagnosis of minimal
invasion into the cranium may be difficult. This accurate diagnosis is of importance, because bone involvement requires resection of the affected bone. In these cases, the surgeon should consider a CT scan or obtain bone chips for microscopic examination, as pitting of bone has not always proven to be reliable16. And fourthly, when bone resection is needed, many open questions remain with respect to the optimal reconstructive approach regarding the need for cranioplasty and ideal soft tissue coverage.
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