ESTRO 2021 Abstract Book

S803

ESTRO 2021

This is a retrospective single institution study of consecutive patients treated for oropharyngeal cancer with radiotherapy alone or chemoradiotherapy Apr 2017-May 2020. Direct logistic regression was performed to assess the impact of variables on likelihood of requiring a feeding tube. Secondary outcomes included failure free survival and Overall Survival. Statistical analyses were carried out using IBM SPSS Statistics version 25. Results One hundred and nine patients were identified (24% HPV(-) and 76% HPV (+)). Median follow-up 15.7 months. Stage III/IV disease was more common for HPV(-) patients than HPV (+) patients (90% vs 26%). Overall 42% (46/109) required a feeding tube (NGT, 33% gastrostomy 9%). The percentage of patients requiring NGT, gastrostomy tube and no feeding tube was 13%, 23% and 65% for HPV(-) disease and 41%, 4% and 55% for HPV(+) disease respectively. Most common timing of tube insertion: pre-RT HPV(-) patients and 5 th week of RT HPV(+) patients (<0.0005). The most common reason for tube insertion was a combination of weight loss and pain. Mean % weight loss (pre-RT to tube insertion) was HPV(-) 3.4%; HPV(+) 11.4%. Baseline BMI and chemotherapy were not predictive of tube insertion. Median baseline FOIS score: HPV(-) 7; HPV(+) 7. The median FOIS score was 4 at time of tube insertion but improved to baseline during follow-up. Only 9% HPV(-) pts and 1.3% of HPV(+) patients had a feeding tube at last follow up. Logistic regression found four variables predictive for NGT insertion including HPV status, PTV, GTV primary and nodes, and psychology input. The strongest predictor was HPV status (OR 4.3) 1-year OS: 82%(95% CI:67% -96%) and 94%(95% CI:89%-100%) and 1-year local failure free survival: 73.5%(95% CI:58-89%) and 86%(95% CI:79%- 94%) and for HPV-/+ disease respectively. Conclusion HPV(-) pts are more likely to need a prophylactic gastrostomy and to need it longer term. HPV+ pts have greater weight loss at time of tube insertion. Despite good baseline swallow scores and more than double the median weight loss during the first 3 weeks, HPV+ pts are 4 times more likely to require a feeding tube during RT but < 2 % required tube feeding longer term. Patients requiring psychology support were 3 times more likely to require a tube. Further studies of optimal timing and focus of psycho oncology intervention are required. PO-0968 ongoing head and neck contour peer review improves quality of radiotherapy targets L. McGee 1 , J. Rwigema 1 , M. Halyard 1 , T. DeWees 1 , J. Gagneur 1 , S. Patel 1 1 Mayo Clinic Arizona, Radiation Oncology, Phoenix, USA Purpose or Objective Head and neck (HN) radiotherapy contour peer review (PR) was trialed in our department in 2018. During the first 8 month pilot period, the number of major revisions decreased for the HN team as a whole (p<0.0001) as well as for each individual radiation oncologist (RO). This update reports outcomes of continued PR during a maintenance phase from the 4th quarter of 2018 through the end of 2020. Materials and Methods A formal HN contour PR process was implemented within our department in 2018. Contours were reviewed by (RO) who specialize in HN cancer treatment and revised prior to initiation of radiotherapy planning (RP). A PR task item was built into the care path of the electronic medical record (EMR) to track the PR process. Dosimetry was not allowed to initiate RP until the PR task in the care path had been completed by the RO HN team. RO participated in a weekly meeting to review contours. Together, the RO evaluated factors pertinent to individual patient contours including pretreatment imaging, physical examination photographs, recorded flexible scope examination, operative notes and surgical pathology. Contours were assessed by the RO HN team, and feedback was provided to the treating physician if contour revision was recommended. Contour revisions were graded by the RO present as follows: R0 (no change), R1 (minor revision, not deemed high risk) or R2 (major revision, deemed to have potential to negatively impact patient outcomes). The PR task was completed and contour grade was recorded in the EMR. Results From September 2018-December 2020, 374 HN cancer patients had the contour PR task completed in the EMR; 100% had contour revision grade recorded. Of these, contour grade was assigned to an attending RO completing contours (N=229) or resident (N=145). This analysis reports the outcomes for the attending RO; resident physician data was excluded. On evaluation of data by quarter (3 months) the median R2 revision rate was 5%, range 0-17.6%. The R2 revision rate by quarter from 4 th quarter 2018 through 4 th quarter 2020 were as follows: 10%, 17.6%, 11.1%, 4%, 7.7%, 0%, 5.9%, 8.1% and 0%. All but two quarters had an R2 revision rate of less than 10%. Two quarters (1 st and 4 th quarter of 2020) had an R2 revision rate of 0%. Upon evaluation of each individual RO, all 3 RO had steady, small rates of R2 revision over time and there was not a difference by RO. Conclusion Ongoing routine HN contour PR continually identifies small rates of R2 revisions. This data supports the ongoing process of peer review to improve quality of radiotherapy targets and RP. PO-0969 Evaluation of the use of reirradiation in head and neck recurrent cancer or second primary tumor. L. Gutiérrez Bayard 1 , M.C. Salas Buzón 1 , R. Rodriguez Sanchez 2 1 Hospital Universitario Puerta del Mar, Oncology Radiotherapy, Cádiz, Spain; 2 Hospital Universitario Puerta del Mar, Oncology Radiotherapy, Cadiz, Spain Purpose or Objective Patients with recurrent head and neck cancer in a previously irradiated anatomical area represent a new therapeutic challenge, due to the great heterogeneity in the literature that makes it difficult to have clearly defined criteria to perform reirradiation. The treatment of choice for recurrences or second tumors of head