97 patients with anal cancer were identified, of which 44 were PLWH. Complete CBC counts were available for 90 patients. Radiation therapy was commonly prescribed to 50.4-54 Gy using IMRT; 3 patients underwent RT alone (all PLWH); Chemotherapy was 5-FU+Mitomycin-c (34 HIV-/27 PLWH), Capecitabine+Mitomycin-c (16 HIV-/11 PLWH), or other (3 HIV-/3 PLWH).
Median follow-up was 55 months in HIV- patients (rg: 10-150) vs. 59 months in PLWH (rg: 5-164). Among HIV- patients there were 45% stage I/II and 55% stage III, in PLWH there were 40% stage I/II and 60% stage III. There were 10/53 vs. 7/44 loco-regional recurrences in the HIV- vs. PLWH group, 9 vs. 2 distant metastases, and 9 deaths in both. Outcomes (HIV- vs. PLWH) were comparable with 2‑year PFS at 76.9% vs. 83.8% (p=.40) and OS at 92.3% vs. 92.8% (p=0.93). Substitution of 5-FU with capecitabine had no effect on outcomes in either group (p>0.73).
G3+ Lymphopenia occurred in 83% (n=44) vs. 89% (n=32) (p=.35), G3+ neutropenia occurred in 21% (n=11) vs. 56% (n=20) (p<.01), and G3+ thrombocytopenia occurred in 8% (n=4) vs. 33% (n=12) (p<.01) of patients in the HIV- and PLWH groups, respectively. Absolute ABM V5Gy to V40Gy was associated with delayed recovery in platelet counts for HIV- (0.40‑0.56; p≤.04) and PLWH (0.41; p=.04) patients (Fig.1), with a sharp increase at volumes above 275cm3 (HIV-) and 350cm3 (PLWH), while rel. V5Gy (-0.29; p<.04) for HIV- and abs. V5Gy to V40Gy (-0.43; p≤.02) for PLWH were associated with a more rapid drop in lymphocytes showing no threshold (Fig.2).
![](https://www.estro.org:443/ESTRO/media/Abstracts/169/5aa9a5ec-e60d-4eab-acc1-da3fcfb6d44e.png)
Figure 1. Time to recovery association with ABM V5Gy and V15Gy.
![](https://www.estro.org:443/ESTRO/media/Abstracts/907/4af896cb-47f5-492e-a833-279082575884.png)
Figure 2. Time to nadir association with volumetric ABM dose metrics.