Manual of Clinical Oncology by Casciato Dennis A. & Territo Mary C

Author:Casciato, Dennis A. & Territo, Mary C. [Casciato, Dennis A.]
Language: eng
Format: epub
ISBN: 9781451171471
Publisher: Lippincot (Wolters Kluwer Health)
Published: 2012-08-28T00:00:00+00:00

Physical examination, concentrating especially on regional lymph nodes and computerized tomography scan of the chest, abdomen and pelvis, should be used as a part of staging investigations.

IV. MANAGEMENT. Merkel cell carcinoma is a rare disease, and no randomized trials have been performed to establish standard care.

A. Surgery. Patients who have no evidence of metastatic disease should be considered for primary RT or wide excision of the primary tumor with 2- to 3-cm margins. In some centers, primary RT is the treatment of choice because the malignancy is extremely radiosensitive. Some evidence from nonrandomized trials indicates that Mohs’ micrographic surgery improves local tumor control when compared with standard surgical resection.

B. Assessment of the regional lymph nodes. Individuals who had negative lymph nodes on surgical assessment of their status by SNLB, elective lymph node dissection, or therapeutic nodal staging had a 97% 5-year disease-free survival (DFS) compared with a 75% 5-year DFS for individuals whose lymph nodes were assessed only clinically. Most of the centers recommend SNLB as the most appropriate method of lymph node status assessment. Patients who have a positive SNLB or have clinically or radiographically demonstrable nodal involvement are treated with total lymphadenectomy.

C. Radiation therapy. Adjuvant RT to the primary site improves local tumor control. Patients treated with surgery alone are 3.7 times more likely to develop a local recurrence and 2.7 times more likely to develop a regional recurrence than patients who received combination surgery and RT. The rate of distant metastasis is similar between the groups. Adjuvant RT to nodes is recommended when SNLB has not been performed or when clinically or pathologically evident nodal disease is present. Delays before commencement of RT should be minimized because they may result in disease progression.

D. Chemotherapy. The role of adjuvant chemotherapy is controversial and most studies suggest that, although it may improve the locoregional control, it does not prolong survival. In a study performed by Trans-Tasman Radiation Oncology Group, patients with high-risk features (size of the primary tumor >1 cm, lymph node involvement, recurrence after primary therapy, or gross residual disease after resection) received synchronous RT and chemotherapy with carboplatin and etoposide; this approach resulted in an excellent overall survival at 3 years of 76%. In a subsequent follow-up study, a greater number of patients were compared with historical controls, and this comparison revealed no benefit in overall survival for individuals receiving chemotherapy.

Currently, chemotherapy is not recommended for patients with node-negative disease, but can be considered for high-risk patients. Individuals with metastatic disease should be treated with chemotherapy.

No standard chemotherapy regimen has been established, but regimens commonly used for the treatment of small cell lung cancer, such as CAV (cyclophosphamide, doxorubicin, vincristine), CEV (cyclophosphamide, etoposide, vincristine) with or without prednisone, and EP (etoposide, cisplatin), have been prescribed most frequently. Use of CAV or CEV resulted in 75% response rate, including 35% complete responses; EP resulted in 60% response rate and 35% complete responses. Median overall survival for patients treated with any type of chemotherapy is 22 months (ranging from 1 to 118 months), and at 2 years, 36% individuals remain alive.

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