OBJECTIVES
To review the known histopathologic findings and clinical behavior of mammary analogue secretory carcinoma (MASC).
DATA SOURCES
PubMed
REVIEW METHODS
Literature search using the terms “Mammary analogue secretory carcinoma,” “Mammary analog secretory carcinoma,” and “MASC” to identify all relevant publications.
RESULTS
MASC is an unusual and rare malignant salivary gland tumor first described in 2010. It shares histologic, immunohistochemical, and genetic features with secretory carcinoma of the breast. The clinical behavior of MASC ranges from slowly growing tumors that infrequently recur after surgical resection to aggressive tumors that cause widespread metastasis and death. Many cases of MASC were discovered in archived cases previously classified as acinic cell carcinoma, mucoepidermoid carcinoma, and adenocarcinoma not otherwise specified.
CONCLUSION
MASC is a newly recognized variant of salivary gland malignancy. Further research is needed to better delineate its overall prevalence and to define an appropriate treatment algorithm for this new clinical entity.
BACKGROUND
The leading cause of death for patients with hereditary retinoblastoma is second malignancy. Radiotherapy (RT), despite its high rate of efficacy, is often avoided due to fear of inducing a secondary tumor. Proton RT allows for significant sparing of non-target tissue. We compared the risk of second malignancy in retinoblastoma patients treated with photon and proton RT.
METHODS
We performed a retrospective review of patients with retinoblastoma treated with proton RT at the Massachusetts General Hospital or photon RT at Children’s Hospital Boston between 1986 and 2011.
RESULTS
Eighty-six patients were identified. Fifty-five patients received proton RT, and 31 patients received photon RT. Patients were followed for a median of 6.9 years (range, 1.0 to 24.4) in the proton cohort and 13.1 years (range, 1.4 to 23.9) in the photon cohort. The 10-year cumulative incidence of RT-induced or in-field second malignancies was significantly different between radiation modalities (Proton vs. Photon; 0% vs. 14%; p=0.015). The 10-year cumulative incidence of all second malignancies was also different, though with borderline significance (5% vs. 14%; p=0.120).
CONCLUSION
Retinoblastoma is highly responsive to radiation. The central objection to the use of radiation--the risk of second malignancy--is founded on studies of patients treated with antiquated, relatively non-conformal techniques. We present the first series of patients treated with the most conformal of currently available external beam therapy modalities. While longer follow up is necessary, our preliminary data suggest that proton RT significantly lowers the risk of RT-induced malignancy.
Outcomes for children treated with PRT compare favorably with the literature. STR correlated with inferior outcome. The young age at diagnosis and the proximity of critical structures in patients with ependymoma make PRT an ideal radiation modality.
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