Radiation-Induced Second Malignancies

Cardiac radiation-induced sarcomas: A SEER population-based study and a literature review

PURPOSE

The aim of this study was to better understand the incidence and the clinical characteristics of cardiac radiation-induced sarcomas (RIS).

MATERIAL AND METHODS

We used the surveillance, epidemiology, and end results (SEER) program cancer registry data, the largest cancer database in the United States in order to identify all cardiac RIS between 1973 and 2015. We relied on the Memorial Sloan-Kettering Cancer Center (MSKCC)-modified 1948 Cahan criterions for RIS identification.

RESULTS

Out of 8,136,951 cancer patients from the SEER database, we identified 448 patients diagnosed with cardiac sarcomas. Of these 448 cardiac sarcoma patients, two were considered to have developed a cardiac RIS: a metastatic rhabdomyosarcoma occurring after one to two years following lung carcinoma irradiation, and a soft tissue sarcoma (of unspecified type) developed six years after radiation therapy for an aggressive left-sided breast carcinoma. Based on this observation, we estimated that cardiac RIS represented about 0.4% (95% CI 0.1%-1.6%) of all cardiac sarcomas. A literature review has been conducted and yielded three additional cases of cardiac RIS.

CONCLUSION

Cardiac RIS are extremely rare malignancies, associated with a very pejorative prognosis. The two reported histologies are angiosarcomas and rhabdomyosarcomas, which might be over-represented among cardiac RIS. A metastatic evolution is possible for cardiac radiation-induced rhabdomyosarcomas. Surgical excision, when feasible, is a therapeutic option and is the only specific treatment reported to this date.

Clinical characteristics and prognostic analysis of multiple primary malignant neoplasms in patients with lung cancer

Retrospective analysis of data from 14,528 lung cancer patients with multiple primary malignant neoplasm (MPMN) revealed that 2.5% (364/14,528) were MPMN cases and 96.2% (350/364) were diagnosed with two primary malignancies, 3.6% (13/364) with three primary malignancies, and 0.3% (1/364) with four primary malignancies. Among 350 lung cancer patients diagnosed with two primary malignancies, 26.6% (93/350) had lung cancer diagnosed first (LCF) and 73.4% (257/350) had other cancers diagnosed initially (OCF), whereas synchronous MPMN (SMPMN) accounted for 21.1% (74/350) and metachronous MPMN (MMPMN) accounted for 78.9% (276/350) of the cases. Detection of first primary neoplasms were at an early stage for LCF patients and the age of the first lung cancer diagnosis was 59.3 years vs. 55.4 years in the OCF group (P = 0.008), whereas the onset age of second primary neoplasm diagnosis was similar in both groups (62.5 and 61.6 years, P = 0.544). Median survival times of MMPMN and SMPMN patients in the LCF group were 6.83 and 2.42 years and in the OCF group 8.67 years and 2.25 years, respectively. Multivariate analysis showed that SMPMN, LCF and the age of the primary cancer diagnosed first ( ≥ 60 years) and NSCL staging  > II were significant independent factors for inferior prognosis of patients.

Radiation-Induced Intraspinal Chondrosarcoma: A Case Report

Study Design Case report and review of the literature. Objective To report a unique case of an intraspinal chondrosarcoma that was diagnosed 18 years after radiotherapy for a cervical carcinoma and its remarkably unusual clinical presentation. Methods A retrospective case description of an intraspinal mass lesion that occurred 6 weeks after previous spinal surgery. Results Within ∼9 weeks, the tumor had infiltrated the peritoneal cavity and reached the lumbar subcutaneous tissue. Conclusion Radiation-induced sarcomas are rare, are highly aggressive, and may be difficult to diagnose. Furthermore, the only means of achieving long-term survival is through early and extensive surgery.

Dermoscopy of multiple radiation-induced basal cell carcinomas in a patient treated previously for pinealoma

BACKGROUND

Malignancies secondary to radiation, such as radiation-induced skin cancer, are possible consequences of radiation therapy. The most frequent post-radiation skin neoplasm is basal cell carcinoma.

MAIN OBSERVATION

We report a case of a 49-year-old woman who underwent multiple radiotherapy sessions for pinealoma and developed post-radiation alopecia. After 26 years the patient noticed the emergence of eighteen superficial scalp lesions in the previously irradiated areas. Dermoscopy showed predominance of ovoid nests and presence of arborizing vessels on pink background, consistent with basal cells carcinoma. The diagnosis was confirmed by histopathology.

CONCLUSIONS

There is an absolute need to guide patients through the possible late adverse events of radiotherapy. Regular dermoscopy examinations should be performed, especially in areas previously exposed to radiation.

Radiation dose at cardiac computed tomography: facts and fiction

Cardiac computed tomography (CT) dosimetry makes use of two radiation parameters: a volume CT dose index (CTDI) and a dose length product (DLP). The volume CTDI quantifies the intensity of the radiation used to perform CT examinations, whereas DLP quantifies the amount of radiation used. CTDI metrics can be converted into patient dose metrics by using dose/CTDI conversion factors. In cardiac CT imaging, these need to take into account the x-ray tube voltage, scan length, and scan region, as well as patient size. Organ doses to patients in cardiac CT can be converted into cancer risks when patient demographic factors are taken into account. A risk analysis of patients undergoing cardiac CT angiography at our institution showed that a majority (62%) were males, with a median age of approximately 60 years and a median weight of approximately 90 kg. The median DLP was approximately 1100 mGy cm, corresponding to an effective dose of approximately 29 mSv in normal-sized patients. The average patient lifetime risk for a radiation-induced cancer was estimated to be 0.12%, with 85% of it attributed to lung cancer. Patients with an age and weight at the 10th percentile, who also received a DLP at the 90th percentile, would have cancer risk estimates approximately double the average value. Radiation risks are required to determine whether examinations are indicated, defined as examinations in which individual patient benefit exceeds corresponding patient risk. Understanding radiation risks in cardiac CT encourages operators to use the least amount of radiation to achieve satisfactory diagnostic performance.

A prediction study on radiation-induced second malignancies for IMRT treatment delivery

Low-level peripheral organ dose and its effect on second malignancies for patients undergoing radiation therapy have been reported in the literature. However, a comprehensive database outlining the treatment modalities, the tumor location, and a quantification of the overall relative risk of second malignancies is rather limited. In this work, we quantify the relative risks or percent likelihood of second malignancies for patients undergoing IMRT and conventional radiotherapy for four different tumor sites: breast, head and neck, lung, and prostate. We utilize Monte Carlo methods based on actual patient plans to compute the whole body effective dose equivalent for each plan and then deduce the percent likelihood of the occurrence of second malignancy. Based on an evaluation of over 30 actual patient plans and Monte Carlo simulations using 6, 10, and 18MV photon beam energies, we observed that the IMRT patients treated for head and neck cancer showed a 40% increase in risk for developing a second malignancy compared to those treated with conventional radiotherapy. The increase in risk for prostrate patients was 30% while the IMRT lung patients gave the highest relative risk almost tripling that observed in their conventionally treated counterparts. There was negligible difference in risk between breast patients undergoing IMRT treatment versus conventional therapy. The overall relative risk of radiation induced malignancy observed was below 6% in all treatment plans considered.