Feasibility of Radiotherapy in Pregnancy - A Case of a 41-Year-Old Pregnant Patient Diagnosed with Primary Cutaneous Anaplastic Large Cell Lymphoma (ALCL) Planned for Radiotherapy
The estimated incidence of pregnancy-associated cancer is approximately 1 in 1000, of which 25% are diagnosed during pregnancy.
In this case report, we present a 41-year-old patient referred to our institution for consideration of radiotherapy for angiocentric CD30-positive anaplastic large cell lymphoma (ALCL). This diagnosis was histologically proven with a left ankle punch biopsy of the skin in January 2025. On initial consultation, she was in the 26th week of her second pregnancy.
Management strategies of cutaneous ALCL are guided by disease extent with international guidelines from the National Comprehensive Cancer Network and European Organization for Research and Treatment of Cancer recommending excision and/or radiotherapy to localized ALCL cutaneous lesions. An international multi-institution retrospective study found complete clinical response in 95% of included patients with primary cutaneous ALCL who underwent treatment with a median dose of 35Gy. [1]
Materials and Methods/Case Presentation/Objective:
Radiotherapy simulation was conducted for dose measurements and setup, and the optimal treatment plan was determined to be anterior-posterior posterior-anterior fields (AP-PA). Fetal dose estimation was performed with a plastic water phantom and cylindrical ionization chamber.
Results/Description/Main Outcome Measure(s):
Potential fetal risks of radiotherapy in pregnancy include deterministic effects such as congenital malformations and mental retardation, and stochastic effects of childhood cancer induction.
In our study, the radiotherapy plan was simulated for a prescription of 30Gy over 15 fractions to her cutaneous lesions. Out of field dose at midplane of 6cm gave 0.183%, 0.089% and 0.054% dose to isocenter dose at fetal distances from field edge dedge = 30cm, 40cm and 50cm respectively. At the actual fetal dedge of 50cm, 9 different depths (1cm, 3cm, 4cm, 5cm, 6cm - mid plane, 7cm, 9cm, 11cm) were measured. The maximal fetal dose was then determined to be 16.5mGy with an average depth dose of 15.8mGy.
The International Commission on Radiological protection Publication 84 recommends a minimum threshold fetal dose of 10mGy below which termination of pregnancy due to radiation risk is not justified as risk of malformations and mental retardation are unlikely, with very low individual risk of radiogenic cancer. [2] Above fetal doses of 50-100mGy, the American Association of Physicists in Medicine advocates lead shielding. This may be accomplished with various techniques including bridge over patient, table over treatment couch and mobile shields.
Conclusion(s).:
Radiotherapy is a key element in the management of many cancers. However, pregnancy introduces safety implications which can affect the timing, method, and efficacy of dose delivery. In this case report, we show that radiotherapy for distal extremity primary cutaneous ALCL in our patient can be carried out with estimated fetal doses below the recommended minimum threshold dose.
Trademarked Items:
References: [1] Million L, Yi EJ, Wu F, Von Eyben R, Campbell BA, Dabaja B, Tsang RW, Ng A, Wilson LD, Ricardi U, Kirova Y, Hoppe RT. Radiation Therapy for Primary Cutaneous Anaplastic Large Cell Lymphoma: An International Lymphoma Radiation Oncology Group Multi-institutional Experience. Int J Radiat Oncol Biol Phys. 2016 Aug 1;95(5):1454-1459. doi: 10.1016/j.ijrobp.2016.03.023.
[2] International Commission on Radiological Protection. (2000). Pregnancy and medical radiation (ICRP Publication 84). Annals of the ICRP, 30(1). https://www.icrp.org/publication.asp?id=icrp+publication+84
