Comment
Local radiotherapy is considered a first-line treatment of pcALCL; however, there is limited evidence on its clinical efficacy as well as the optimal dose and technique. Although no standard dose exists for pcALCL, the National Comprehensive Cancer Network guidelines8 recommend doses of 12 to 36 Gy in mycosis fungoides/Sézary syndrome subtypes of cutaneous T-cell lymphoma, which are consistent with guidelines published by the European Society for Medical Oncology.9 High complete response rates have been demonstrated in pcALCL at doses of 34 to 44 Gy6; however, lesions tend to recur elsewhere on the skin in 36% to 41% of patients despite treatment.2,10 Lower doses of radiation therapy would provide several advantages over higher-dose therapy if a complete response could be achieved without greatly increasing the local recurrence rate. In cases of local recurrence, low-dose radiation would more easily permit retreatment of lesions compared to higher doses of radiation. Similarly, in patients with multifocal pcALCL, lower doses of radiotherapy may allow for treatment of larger skin areas while limiting potential treatment risks. Furthermore, low-dose therapy would allow for treatments to be delivered more quickly and with less inconvenience to the patient who is likely to need multiple future treatments to other areas. Low-dose radiation has been described with a favorable efficacy profile for mycosis fungoides7,11 but has not been studied in patients with CD30+ pcLPDs.
Our case is notable because the patient remained on MTX during radiation therapy. Because MTX can act as a radiosensitizer, current standard practice is to stop MTX while administering radiation therapy. High oncologic doses of MTX can occasionally produce severe skin reactions at the irradiated site12-14; however, reports of the use of lower weekly doses in combination with radiation are sparse. Our patient had refractory disfiguring facial lesions that would immediately recur once MTX was stopped. Low-dose radiation therapy was administered while she remained on her weekly MTX doses. With this treatment, she achieved a complete response, developed no radiation dermatitis, and had no further new skin lesions appear.
Conclusion
We reported the use of low-dose radiation therapy for the treatment of localized pcALCL in a patient who remained on low-dose oral MTX. Additional studies will be necessary to more fully evaluate the efficacy of using low-dose radiation both as monotherapy and in combination with MTX for pcALCL.
