Clinical Research: Supportive CareCervical Papanicolaou Smears in Hematopoietic Stem Cell Transplant Recipients: High Prevalence of Therapy-Related Atypia during the Acute Phase

- Eleven percent of Pap smears in allogeneic recipients have atypical cells mimicking cancer
- Therapy-related atypia is common before day +100 but uncommon after day +100
- All therapy-related atypia cases received busulfan-containing conditioning therapy

Hematopoietic stem cell transplant (HSCT) recipients have a higher risk of cervical cancer. Papanicolaou (Pap) smear is the standard tool for screening cervical cancer, but there is limited research about the cervical cytology in HSCT recipients. Here, we retrospectively included adult female patients who underwent allogeneic or autologous HSCT at National Taiwan University Hospital during 2009 to 2015 and reviewed their Pap smears before and after HSCT. There were 248 allogeneic and 131 autologous HSCT recipients in our study. In allogeneic HSCT recipients, 38.7% (96 of 248) had pre-HSCT Pap smears and 17.1% (44 of 248) had post-HSCT Pap smears. In the autologous HSCT recipients, 35.1% (46 of 131) had pre-HSCT Pap smears and 13.7% (18 of 131) had post-HSCT Pap smears. Compared with allogeneic HSCT recipients without post-HSCT Pap smears, more recipients with post-HSCT Pap smears received bone marrow-derived stem cells (18.2% versus 4.9% respectively; P = .0077) and had longer overall survival (median overall survival, not reached versus 22.1 months; P < .0001). The abnormal rates of post-HSCT Pap smear were 13% (6 of 44) and 11% (2 of 18) in allogeneic and autologous recipients respectively, higher than in the general Taiwanese population (1.22%). Infections were rare in post-HSCT Pap smears. Of note, 11% (5 of 44) of post-HSCT Pap smears from allogeneic recipients showed therapy-related atypia, manifesting as enlarged hyperchromatic nuclei, vacuolated cytoplasm, and occasional tadpole-like cells. These atypical cytological features mimic precancerous lesions, but cervical biopsies and human papilloma virus tests were negative. The atypical cytological features resolved spontaneously in the subsequent follow-up Pap smears. On average, Pap smears with therapy-related atypia were sampled at day +77, significantly earlier than those without therapy-related atypia (P = .016). Therapy-related atypia was more frequent in post-HSCT Pap smears sampled within 100 days after HSCT (before day +100, 4 of 5, 80%, versus after day +100, 1 of 39, 2.56%; P = .0002). The strong temporal relationship suggests these atypical cytological changes resulted from conditioning regimen, most likely busulfan-containing chemotherapy. No therapy-related atypia were observed after total body irradiation or nonbusulfan-containing chemotherapy. In conclusion, therapy-related atypia was common in post-HSCT Pap smears sampled within 100 days after HSCT. Clinical information is critical for correct cytological diagnosis.