 Aside from bone marrow suppression, frequent side effects included nerve injury caused by vincristine and allergic reactions to procarbazine.Long-term effects were also a concern, as patients were often cured and could expect long survival after chemotherapy.Infertility was a major long-term side effect, and even more seriously, the risk of developing treatment-related myelodysplasia or acute leukemia was increased up to 14-fold in patients who received MOPP.