This retrospective study, which included mostly patients with dark phototype, confirmed the efficacy and safety of phototherapy in the treatment of MF. Recurrence rates and recurrence-free survival were not significantly different in patients who received maintenance phase and those who underwent follow-up.
The treatment of MF with PUVA therapy was first described by Gilschrest et al in 1976 (10). UVA penetrates the entire dermis and possibly the subcutaneous tissue. Therefore, PUVA represents a good therapeutic option for plaque stage disease (up to 85% of patients with stage IA experienced complete response) (4,11,12). Complete response rates were slightly lower in patients treated with NB-UVB (54% to 90%) (4). Therefore, NB-UVB is considered a convenient therapeutic option for patch stage disease. The efficacy of NB-UVB is however partial in folliculotropic and plaque-type MF. This could be explained by its limited dermal and adnexal penetration.
Treatment strategy depends also on skin phototype. Pavlosky et al found that patients with skin phototypes I-III reached higher complete remission rates and required a lower dose to achieve complete remission compared to patients with dark phototype (13). In the largest series to date of MF patients treated with phototherapy, only 6 patients with dark phototype received NB-UVB (8). In our study, nineteen patients received NB-UVB therapy. Response rates were comparable with previous reports and thus despite including an important proportion of patients with dark phototype (14,15).
The benefits of maintenance PUVA therapy is still contested. To date, only rare single-center studies evaluated recurrence rates and recurrence-free survival in patients who received maintenance therapy (5–7). None of these studies has shown a significant difference in both recurrence rates and recurrence-free survival (5–7).
Maintenance NB-UVB is also still debated. Encouraging results were reported in a few studies (16,17). These results should, however, be interpreted with caution due to distinct maintenance regimens.
There are several concerns regarding maintenance phototherapy. As discussed earlier, evidence of its efficacy is lacking. In the other, phototherapy is associated with an increased incidence of carcinomas. Non-melanoma skin cancers are related to phototherapy in a dose-dependent manner (18). Therefore, maintenance therapy could increase the risk of the development of skin cancers without gaining substantial therapeutic outcomes.
Limitations of this study are the relatively small number of enrolled patients, its retrospective and monocentric nature which may lead to missing data and selection bias. Maintenance treatment was proposed to patients at the end of the consolidation phase. We found no significant association between the recurrence rates in patients who received maintenance therapy and those who underwent follow-up. These results may be confounded by an indication as maintenance therapy could be encouraged for patients with more extensive or severe disease.