What is the prognosis for squamous cell carcinoma (SCC) that originated in the scalp and has metastasized to the skull?

From the Guidelines

The prognosis for squamous cell carcinoma (SCC) that has spread from the scalp to the skull is generally poor, with a five-year survival rate that varies significantly based on the extent of invasion, tumor size, and whether it has spread to lymph nodes or other organs. This represents a locally advanced stage of skin cancer with bone invasion, which typically has a less favorable outlook than early-stage disease confined to the skin. Treatment usually involves a multidisciplinary approach including surgical resection of the tumor and affected bone, followed by radiation therapy 1. In some cases, systemic therapy such as chemotherapy (cisplatin-based regimens) or immunotherapy (pembrolizumab or cemiplimab) may be necessary, particularly if there's evidence of further spread.

Key Factors Influencing Prognosis

• Depth of skull invasion
• Tumor differentiation
• Perineural invasion
• Patient's overall health status Regular follow-up imaging and examinations are essential after treatment to monitor for recurrence, as these advanced cases have a higher risk of coming back. Patients should also be vigilant about sun protection and regular skin checks to prevent new skin cancers from developing. According to recent guidelines, careful consideration must be given to immunosuppressed individuals with high-risk localized or metastatic cSCC, given its more aggressive clinical behavior and poor prognosis 1.

Treatment Approach

• Surgical resection of the tumor and affected bone
• Radiation therapy
• Systemic therapy, such as chemotherapy or immunotherapy, in cases of further spread The available literature on management of in-transit and lymph node metastases is largely limited to retrospective reviews and case series of patients with head and neck cSCC, and therapeutic recommendations are based on the extent of disease 1. Given the rarity and complexity of metastatic cSCC, multidisciplinary consultation is recommended. For inoperable lymph node metastases, combination chemoradiation therapy should be considered, and for patients with advanced disease, it is also appropriate to provide or refer to best supportive and palliative care to optimize symptom management and maximize quality of life 1.

From the Research

Prognosis for Squamous Cell Carcinoma (SCC) of the Scalp with Metastasis to the Skull

• The prognosis for SCC that originated in the scalp and has metastasized to the skull is generally poor, with a high risk of recurrence and limited treatment options 2, 3.
• Studies have shown that the disease-free survival rate for patients with invasive SCC of the scalp is around 62.5% to 66.7% 4.
• The local control rate for patients with SCC of the scalp can be achieved in up to 75% of cases, depending on the extent of the disease and the treatment approach 4.
• Multidisciplinary treatment, including surgery, radiation, and reconstruction, is often necessary to manage SCC of the scalp with skull involvement 2, 3.
• The use of checkpoint inhibitors, such as pembrolizumab, has improved treatment options for patients with advanced HNSCC, but the response rate is still relatively low, around 30% 5.

Factors Affecting Prognosis

• The human papillomavirus (HPV) status is a significant prognostic factor for patients with oropharyngeal cancer, but its role in SCC of the scalp is less clear 5, 6.
• Other factors, such as the tumor mutational burden and the immune microenvironment, have been studied as potential prognostic markers, but more research is needed to validate their use 5.
• The extent of the disease, including the presence of skull invasion or brain involvement, can significantly impact the prognosis and treatment approach 2, 4, 3.

Treatment Approaches

• Surgery, including skull base resection and reconstruction, is often necessary to manage SCC of the scalp with skull involvement 2, 4, 3.
• Radiation therapy, including photon or proton radiation, may be used as an adjuvant or neoadjuvant treatment to improve local control and survival 3.
• Multidisciplinary care, including a team of surgeons, radiation oncologists, and medical oncologists, is essential to provide optimal treatment and improve outcomes for patients with SCC of the scalp and skull involvement 2, 3.