Five-year outcomes of sparing level IB in node-positive, human papillomavirus-associated oropharyngeal carcinoma: A safety and efficacy analysis.

INTRODUCTION: The conformality of modern intensity modulated radiation therapy (IMRT) allows avoidance of the submandibular glands (SMG) in select patients, potentially improving late xerostomia. This study explores the safety and efficacy of this approach in select oropharyngeal carcinoma (OPC) patients. METHODS: Patients with T1-2N+ human papillomavirus (HPV)-associated OPC treated with definitive IMRT at one institution from 2009 to 2014 were identified. Patients were divided into 3 groups: bilateral level IB targeted (A, n = 16), a single level IB targeted (B, n = 61), and bilateral IB spared (C, n = 9). Outcomes were reviewed to identify the rate of level IB regional recurrence. Odds ratios were calculated for xerostomia between groups. RESULTS: Level Ib was targeted in 93 instances (54.1%) and avoided in 79 instances (45.9%). Mean SMG doses were significantly lower when level IB was spared compared to when targeted (37.5 Gy vs 67.5 Gy; P < 0.0001). Median doses to oral cavity decreased with increasing level Ib sparing (40.7 Gy [A] vs 35.4 Gy [B] vs 30.7 [C]; P = 0.002). The rate of late grade ≥2 xerostomia was significantly lower in patients with bilateral 1b sparing (53% in A vs 0% in C; P = 0.007). Sparing 1b unilaterally resulted in a non-significant decrease in late grade ≥2 xerostomia (P = 0.181). No regional failures were identified in levels IB (median follow up = 59.3 months). CONCLUSION: Sparing level IB is safe in T1-2N+ HPV+ OPC. Avoiding level Ib translates into significantly lower SMG and oral cavity doses. Larger studies are needed to validate these findings and the impact of this technique.

It is not just IMRT: Human papillomavirus related oropharynx squamous cell carcinoma is associated with better swallowing outcomes after definitive chemoradiotherapy.

OBJECTIVES: Long term swallowing dysfunction in patients with oropharynx squamous cell carcinoma (OPSCC) treated with concurrent chemoradiation (CRT) is declining. While the use of intensity modulated radiotherapy (IMRT) is commonly believed to be a potential cause, we hypothesize that the increasing incidence of human papillomavirus (HPV) related disease may also favorably impact this outcome. MATERIALS AND METHODS: We reviewed 130 HPV+ and 17 HPV- patients with stage III-IV OPSCC treated exclusively with conventional 3-field radiotherapy with chemotherapy between 2002 and 2010. The rates of normal diet, limited diet (significant restrictions in the types of foods eaten, and/or requiring nutritional supplementation for weight maintenance) and feeding tube dependence (FTD) were compared between HPV+ and HPV- patients. Cox proportional hazards modeling were used to perform univariate analysis (UVA) to examine predictors of a combined endpoint of dietary limitation, which included limited diet and/or FTD. These outcomes were also compared to our previously reported cohort of OPSCC patients treated between 1989 and 2002 to assess changes in toxicity over time given the changing disease epidemiology, in the setting of identical treatment regimens. RESULTS: With a median follow-up of 55 months, HPV+ patients more frequently had resumed a normal diet (87% vs. 65%) at last follow up and had lower rates of limited diet (9% vs. 18%) and FTD (4% vs. 18%) compared to HPV- patients (p=0.02). HPV status was the only significant predictor of reduced swallowing dysfunction on UVA (HR 0.19; p=0.008). When compared to our 1989-2002 cohort, patients treated between 2002 and 2010 had less FTD (7.5% vs. 34%, p<0.001) and dietary limitations (26% vs.46%, p<0.001) at 6 months post treatment. CONCLUSIONS: HPV+ patients with OPSCC have reduced late swallowing dysfunction after chemoradiation compared to HPV- patients. The changing epidemiology of OPSCC may play a role in toxicity reduction in these patients, independent of the increasing use of IMRT.

Radiation therapy in pregnancy: risk calculation and risk minimization.

The benefits of radiation therapy (RT) as part of a treatment regimen for cancer must be weighed against the potential risk of harm to the patient and in the pregnant patient, the risk to the developing fetus. Information necessary for determining the potential effects of RT on the developing fetus include the gestational age, absorbed fetal dose-equivalent, and dose-rate. The risk periods in humans for RT-induced prenatal or neonatal death, congenital anomalies, severe mental retardation (SMR), temporary (TGR) or permanent growth retardation (PGR), carcinogenesis, sterility, and germ cell mutations have been elicited directly from the study of Japanese victims of the atomic bombs and unintentional medical exposures, and indirectly from animal experiments. The wide range of congenital anomalies elicited from animal studies have not occurred in the Japanese atomic bomb victims exposed in utero. The major congenital anomaly observed in the Japanese cohort has been microcephaly. The highest risk period for SMR correlates with the proliferation, differentiation, and, most importantly, migration of neurons from their proliferative zones. PGR was apparent 17 years after ionizing radiation (IR) exposure at Hiroshima in children who were within 1,500 meters of the hypocenter. Children were on average 2.25 cm shorter, 3 kg lighter, and had head diameters 1.1 cm smaller than age-matched children. The projected lifetime risk of cancer mortality in the Japanese cohort is 14% per gray. The risk of a radiation-induced hereditary disorder is reported to be approximately 1% per gray. RT plays a major role in the definitive treatment of cervical and breast carcinomas, Hodgkin's disease, and non-Hodgkin's lymphoma. With appropriate abdominal shielding in place, the estimated fetal dose can be reduced by 50% or greater in most cases. In certain clinical situations, RT may be administered during pregnancy.

Treatment outcome for patients with primary nonsmall-cell lung cancer and synchronous brain metastasis.

The purpose of this study was to evaluate the outcome of treatment for patients with newly diagnosed nonsmall-cell lung cancer (NSCLC) with an isolated, single, synchronous brain metastasis. A retrospective review was performed evaluating any patient diagnosed between 1982 and 1996 at the Cleveland Clinic Foundation with NSCLC metastatic only to the brain. Patients with multiple brain metastases or with systemic metastases to any other organ were excluded. Survival was measured from the date of the first treatment for malignancy. All hospital records were thoroughly reviewed in a retrospective manner. Thirty-three patients were identified who met the study criteria. Twelve patients had primary disease limited to the lung and hilar nodes, and 21 had more advanced primary disease with involvement of the mediastinum. Treatment of the chest was considered aggressive in 13 patients and palliative in 15. The primary tumor was observed in 5 patients. The management of the brain metastasis was as follows: 21 patients underwent surgical resection and postoperative whole brain radiotherapy (WBRT), 5 underwent stereotactic radiosurgery (SRS) and WBRT, 3 had resection alone, 2 had SRS alone, and 2 underwent WBRT alone. The median overall and disease-free survival for all patients was 6.9 months and 3.3 months, respectively. Overall survival was markedly improved with the addition of WBRT (P = 0.002) and with the aggressive management of the primary tumor (P = 0.005). A total of 9 patients experienced CNS failure, including both patients receiving WBRT alone. CNS failures were divided as follows: 3 local, 5 distant, and 1 local and distant. Two of the 4 patients with a local failure were salvaged, and ultimate local control of the original brain metastasis was achieved in 93.6% of cases. Survival remains poor for patients with Stage IV NSCLC even when metastatic disease is limited to a single site within the brain; however, aggressive therapy of both the lung primary and the brain metastasis may provide a survival advantage. Excellent local control of single brain metastases was achieved with a combination of WBRT with either surgical resection or SRS.

An expression for the RBE of neutrons as a function of neutron energy.

The goal of this paper is to develop a relationship between a neutron RBE and neutron energy, En, which can be used to design neutron sources for BNCT. In an earlier calculation of a neutron RBE as a function of En, we approximated the contribution to a total neutron RBE, RBEt (En), arising from 14N(n,p)14C reactions. In this paper, we recalculate RBEt (En), accounting more exactly for the contribution to RBEt (En) from 14N(n,p)14C reactions.