Impact of Hypoxia on Radiation-Based Therapies for Liver Cancer.

Background: Hypoxia, a state of low oxygen level within a tissue, is often present in primary and secondary liver tumors. At the molecular level, the tumor cells' response to hypoxic stress induces proteomic and genomic changes which are largely regulated by proteins called hypoxia-induced factors (HIF). These proteins have been found to drive tumor progression and cause resistance to drug- and radiation-based therapies, ultimately contributing to a tumor's poor prognosis. Several imaging modalities have been developed to visualize tissue hypoxia, providing insight into a tumor's microbiology. Methods: A systematic literature search was conducted in PubMed, EMBASE, Cochrane, and Google Scholar for all reports related to hypoxia on liver tumors. All relevant studies were summarized. Results: This review will focus on the impact of hypoxia on liver tumors and review PET-, MRI-, and SPECT-based imaging modalities that have been developed to predict and assess a tumor's response to radiation therapy, with a focus on liver cancers. Conclusion: While there are numerous studies that have evaluated the impact of hypoxia on tumor outcomes, there remains a relative paucity of data evaluating and quantifying hypoxia within the liver. Novel and developing non-invasive imaging techniques able to provide functional and physiological information on tumor hypoxia within the liver may be able to assist in the treatment planning of primary and metastatic liver lesions.

Engagement and outcomes of cancer patients referred to a tobacco cessation program at a National Cancer Institute-designated cancer center.

INTRODUCTION: Tobacco cessation is a critical but challenging intervention for cancer patients. Our National Cancer Institute-designated Comprehensive Cancer Center instituted a tobacco cessation program in 2019. This manuscript reports on the first 2 years of our experience. METHODS: Patients were referred to the program by their care team, and a certified tobacco treatment specialist contacted patients remotely and provided behavioral therapy and coordinated pharmacotherapy. We retrospectively captured data from patients with a cancer diagnosis referred to the tobacco cessation program. Univariate and multivariable logistic regression analyses with the backward elimination approach were performed to determine factors associated with patient acceptance of referral to the tobacco cessation program. Tobacco cessation rates after referral to the program were also captured. RESULTS: Between July 2019 and August 2021, 194 patients were referred to the tobacco cessation program. Of the 194 patients referred, 93 agreed to enroll in the tobacco cessation program (47.9%), of which 84 requested pharmacotherapy (90.3%). Twenty-four were able to cease tobacco use (25.8%). Only 7 patients out of the 101 patients (6.9%) who declined cessation services were successful (p < 0.001). On univariate logistic regression, race (p = 0.027) and marital status (p = 0.020) were associated with referral acceptance. On multivariable analysis, single patients (odds ratio [OR] = 0.33) and Caucasian patients (OR = 0.43) were less likely to accept a referral. CONCLUSIONS: Access to tobacco cessation services is a critical component of comprehensive cancer care. Our experience highlights the need to understand patient-specific factors associated with engagement with a tobacco cessation program during cancer treatment. The use of pharmacotherapy is also a critical component of successful tobacco cessation.

Patterns-of-failure guided biological target volume definition for head and neck cancer patients: FDG-PET and dosimetric analysis of dose escalation candidate subregions.

BACKGROUND: To identify the radio-resistant subvolumes in pretreatment FDG-PET by mapping the spatial location of the origin of tumor recurrence after IMRT for head-and-neck squamous cell cancer to the pretreatment FDG-PET/CT. METHODS: Patients with local/regional recurrence after IMRT with available FDG-PET/CT and post-failure CT were included. For each patient, both pre-therapy PET/CT and recurrence CT were co-registered with the planning CT (pCT). A 4-mm radius was added to the centroid of mapped recurrence growth target volumes (rGTV's) to create recurrence nidus-volumes (NVs). The overlap between boost-tumor-volumes (BTV) representing different SUV thresholds/margins combinations and NVs was measured. RESULTS: Forty-seven patients were eligible. Forty-two (89.4%) had type A central high dose failure. Twenty-six (48%) of type A rGTVs were at the primary site and 28 (52%) were at the nodal site. The mean dose of type A rGTVs was 71Gy. BTV consisting of 50% of the maximum SUV plus 10mm margin was the best subvolume for dose boosting due to high coverage of primary site NVs (92.3%), low average relative volume to CTV1 (41%), and least average percent voxels outside CTV1 (19%). CONCLUSIONS: The majority of loco-regional recurrences originate in the regions of central-high-dose. When correlated with pretreatment FDG-PET, the majority of recurrences originated in an area that would be covered by additional 10mm margin on the volume of 50% of the maximum FDG uptake.