13-year survival oligometastatic Merkel cell carcinoma: a case report.

BACKGROUND: Merkel cell carcinomas are rare, aggressive skin tumors with high metastatic potential and poor prognosis. Their treatment is classically based on surgery with adjuvant external radiotherapy for localized tumors or on immunotherapy or chemotherapy, sometimes associated with radiotherapy, for metastatic stages. Those tumors are highly radiosensitive due to their neuroendocrine and undifferentiated nature, but they usually fail to rapidly respond to treatment. CASE PRESENTATION: We report the case of a 65-year-old retired female patient of Caucasian (German) origin with locally advanced Merkel cell carcinoma of the buttock, with pancreatic metastases synchronous at diagnosis, treated with local radiotherapy of the right buttock without regional lymph node irradiation followed by a sequential chemotherapy; 1 year later, the patient developed an isolated pancreatic recurrence treated with exclusive radiotherapy. The patient was still alive at 13 years with complete remission. CONCLUSION: External radiotherapy can be an effective alternative to surgery for locally advanced or even oligometastatic Merkel cell carcinomas.

Can we predict the cardiac benefit of deep inspiration breath hold for left breast and regional nodal irradiation?

PURPOSE: Deep inspiration breath hold (DIBH) is used to decrease the dose of radiotherapy delivered to the heart. There is a need to define criteria to select patients with the potential to derive a real clinical benefit from DIBH treatment. Our study's main goal was to investigate whether two CT-scan cardiac anatomical parameters, cardiac contact distance in the parasagittal plane (CCDps) and lateral heart-to-chest distance (HCD), were predictive of unmet dosimetric cardiac constraints for left breast and regional nodal irradiation (RNI). MATERIALS AND METHODS: This retrospective single-institution dosimetric study included 62 planning CT scans of women with left-sided breast cancer (BC) from 2016 to 2021. Two independent radiation oncologists measured HCD and CCDps twice to assess inter- and intra-observer reproducibility. Dosimetric constraints to be respected were defined, and dosimetric parameters of interest were collected for each patient. RESULTS: Mean heart dose was 7.9Gy. Inter-rater reproducibility between the two readers was considered excellent. The mean heart dose constraint<8Gy was not achieved in 25 patients (40%) and was achieved in 37 patients (60%). There was a significant correlation between mean heart dose and HCD (rs=-0.25, P=0.050) and between mean heart dose and CCDps (rs=0.25, P=0.047). The correlation between HCD and CCDps and unmet cardiac dosimetric constraints was not statistically significant. CONCLUSION: Our dosimetric analysis did not find that the cardiac anatomical parameters HCD and CCDps were predictive of unmet dosimetric cardiac constraints, nor that they were good predictors for cardiac exposure in left-sided BC radiotherapy comprising RNI.