Melanoma regression associated with improved prognosis

Key takeaways:

• Patients with regressive melanoma had favorable relapse-free rates (HR = 0.52).
• Regression was associated with favorable progression-free survival during checkpoint inhibitor therapy (HR = 0.43).

Histopathologic regression of melanoma may be associated with favorable outcomes in patients eligible for sentinel lymph node biopsy and those with irresectable melanoma receiving immune checkpoint inhibitor therapy, according to a study.

“There has been a long-lasting controversy on the origin and the prognostic impact of histologic regression of primary melanoma,” Nikolaus B. Wagner, MD, of the department of dermatology at Kantonsspital St.Gallen in Switzerland and Eberhard Karls University of Tübingen in Germany, and colleagues wrote. “Histologic evidence of regression has long been considered as an indicator for host immune reaction against the tumor processed by infiltrating immune cells.”

To investigate the prognostic importance of regression in primary cutaneous melanoma, the researchers conducted a retrospective study of 1,179 patients diagnosed with melanoma that underwent sentinel lymph node biopsy (SLNB).

Results showed that patients with regressive melanoma experienced favorable relapse-free rates (HR = 0.52; 95% CI, 0.38-0.73). They also experienced positive distant metastasis-free survival (HR = 0.56; 95% CI, 0.39-0.81) and melanoma-specific survival outcomes (HR = 0.35; 95% CI, 0.2-0.64).

Histopathologic regression was significantly less frequent among patients with a positive SLN vs. a negative SLN (10.7% vs. 20.0%; P = .0077), indicating that regression is associated with a negative SLN (OR = 0.48; P = .0077).

The authors also found that regression was associated with favorable progression-free survival under immune checkpoint inhibition among patients who progressed to an unresectable stage (HR = 0.43; P = .031). However, the same did not apply to patients who progressed to an unresectable stage that underwent targeted therapy (HR = 1.14; 95% CI, 0.54-2.4) or chemotherapy (HR = 3.65; 95% CI, 1.37-9.68).

“Overall, our data suggest that presence of histopathologic regression is significantly associated with favorable [relapse-free survival, distant metastasis-free survival and melanoma-specific survival] in patients with cutaneous melanoma eligible for SLNB,” the authors concluded. “In our opinion, presence or absence of regression could be utilized to improve prognostic risk stratification in patients who are candidates for SLNB.”