Graftversuslymphoma Effect

Evidence for a graft-versus-malignancy or GvL effect in NHL is mixed (Table 65.2). In a review, Mollee and colleagues13 noted the conflicting results in a number of studies, as the GvL effect was not uniform in the

Table 65.1 Allo SCT compared to auto SCT for NHL:

advantages and disadvantages

Advantages

Disadvantages

Normality of infused stem cells

Increased non-relapse mortality

Grafts-versus-lymphoma effect

Increased "allogeneic-radated" morbidity

Avoidance of secondary AML/MDS

Age and donor restrictions

No graft contamination by lymphoma

Increased costs

Lack of randomized trials

AML, acute myeloid leukemia; MDS, myelodys plastic syndrome.

AML, acute myeloid leukemia; MDS, myelodys plastic syndrome.

Table 65.2 Evidence of graft-versus-malignancy effect in humans

■ Abrupt immunosuppression withdrawal or GvHD or flare reestablishes complete remissions

■ Relapse higher in syngeneic than in allogeneic graft recipients

■ GvHD protective against relapse in some patient subgroups

■ T-cell depletion increases relapse rates in CML patients

■ Donor lymphocyte infusions can induce complete remissions

■ Allo SCT relapse rates are lower than those for auto SCT

GvHD, graft-versus-host disease; CML, chronic myeloid leukemia intermediate- and high-grade histologic subtypes. The data for follicular NHL, a slower growing neoplasm, are more convincing. Tse and colleagues14 recently reported the benefit of GvL across many studies in which low-grade NHL patients underwent allo SCT using either a myeloablative or reduced-conditioning regimen.

NHL, 52 intermediate- and high-grade, and 8 had other types such as composite, mantle-cell, and peripheral T-cell NHL. A variety of graft sources were used (61% sibling-matched; 14% haploidentical sib; 25% unrelated). Treatment-related mortality was 22% at 1 year and 25% at 5 years. Overall survival at 3 years was 33% and decreased to 24% by 5 years after allo SCT. Similarly, progression-free survival (PFS) was 25% and 5% at 3 and 5 years, respectively. Complete remission at time of transplant and use of total body irradiation (TBI) in the preparative regimen were associated with lower rates of tumor progression and higher overall survival. These results are quite disappointing, but reflect both a poor-risk patient group, as well as an emerging approach. Specifically, van Besien and col-leagues16 noted dramatic improvement in overall survival after myeloablative HLA sibling-matched allo SCT from 39% during the 1990-1993 period to 72% over 1997-1999. Readers of the literature must take into account such improvements when comparing studies, especially when not conducted during concurrent periods of time.

0 0

Post a comment