Hallemeier, Christopher Leigh

4595 Background: For stage I-II testicular seminoma, RT is highly effective at eradicating disease in the abdominopelvic lymph nodes, but results in unnecessary exposure to normal tissues including the GI tract. The purpose of this study was to define the incidence and risk factors for late GI complications in this patient population. Methods: A retrospective review was performed of 251 patients with stage I-II testicular seminoma treated with curative intent RT at our institution from 1974-2009. All patients underwent orchiectomy and postoperative external beam RT to the involved and/or at-risk nodal basins. Potential late GI complications that were assessed included endoscopically-confirmed gastric or duodenal ulceration, small bowel obstruction (SBO), and biopsy-confirmed malignancy of the GI tract. Risks were estimated using the Kaplan-Meier (KM) technique and univariate/multivariate analyses were performed using the Cox proportional hazards model. Results: Median age at diagnosis was 36 years (range 18 – 80). Clinical stage was I (n=199) or II (n=52). Median abdominopelvic RT dose was 26 Gy (interquartile range 25 – 30). Median follow-up was 15 years (range 0.1 – 38). KM estimates for any GI complication (ulcer, SBO, or GI malignancy) at 10, 20, and 30 years were 7, 10 and 24%, respectively. Four patients died as result of a GI complication. KM estimates for ulcer at 10, 20, and 30 years were 4, 7, and 9%, respectively. Age at RT (Hazard Ratio [HR] 1.05, 95% Confidence Interval [CI] 1.00 – 1.10, p=0.03) and RT total dose (per Gy, HR 1.20, 95% CI 1.09 – 1.31, p<0.01) were associated with risk of ulcer. KM estimates for SBO at 10, 20, and 30 years were 2%, 2%, and 3%, respectively. History of inflammatory bowel disease was associated with risk of SBO (HR 43, 95% CI 7-325, p<0.01). KM estimates for GI malignancy at 10, 20, and 30 years were 0.5, 3 and 16%, respectively. Age at RT was associated with risk of GI malignancy (HR 1.07, 95% CI 1.02-1.14, p=0.01). Conclusions: In patients with stage I-II testicular seminoma treated with RT, late GI complications were a relatively uncommon, but clinically significant source of late morbidity. Use of low dose, limited field, and/or proton RT may reduce these risks.

239 Background: Pancreatic adenocarcinoma is a rapidly fatal cancer with 5-year overall survival <5%. 5-10% of pancreatic cancers occur in patients with family history of disease, and 5-27% of these familial cancers are BRCA associated, with defects in Homologous Recombination Repair (HRR). In breast and ovarian cancer, BRCA mutations may be associated with increased risk for brain metastasis (BM). BM is rare in pancreatic cancer, but it is suggested HRR deficient pancreatic cancer patients may have an increased risk for BM/LC. Methods: We analyzed 3030 prospectively identified patients with pancreatic cancer and HHR mutation germline sequencing data (BRCA1/2, ATM, PALB2) from the Mayo Clinic Pancreatic Cancer SPORE Registry. We used clinical databases (2000-2018) to assess the presence of BM or leptomeningeal carcinomatosis (LC). Unconditional logistic regression analysis, with Odds Ratio (OR) and 95% Confidence Interval (CI), assessed the association between HRR gene germline mutation carrier status and any BM. Results: Of 3030 total pancreatic cancer patients, 8 were diagnosed with clinically evident BM/LC (0.26%), confirming the very low incidence of this metastasis site (Table). Of these, all had BM, and 4 also had LC present. No patients had LC diagnosed without BM present. 175/3030 (5.8%) patients had a germline HHR gene mutation. Of these, 1 patient was a BRCA2 carrier (0.57% of HRR deficient patients). 7 /2763 (0.25%) patients without germline HRR mutations had BM or LC (p = 0.44, OR 2.26; 95% CI: 0.27, 18.49). Conclusions: To our knowledge, this is the largest review of BRCA-associated pancreatic cancer patients with BM or LC. The incidence of BM is rare at 0.27%, with LC at 0.14%. Limitations include likely underdiagnosis given short clinical course and lack of availability of somatic HRR gene status. Our study suggests HRR germline carrier patients may have an increased risk of BM/LC development compared to non-carriers. Given rarity, larger studies should be explored. [Table: see text]

147 Background: Lymphopenia during radiation therapy (RT) has been associated with worse oncologic outcomes in a number of malignancies, including esophageal cancer (EC). No studies to date have investigated specific dosimetric parameters associated with this lymphopenia in EC. We performed an analysis of RT dose to multiple organs at risk (OARs) to investigate associations with grade 4 lymphopenia (G4L). Methods: Consecutive EC patients receiving curative intent chemoradiotherapy +/- surgery between July of 2015 and December of 2017 were included. Lymphocyte nadir was defined as the lowest lymphocyte count during RT. G4L was defined as absolute lymphocyte count <200/mm3. Dose to OARs including aorta, body, bone marrow, heart, liver, lung, and spleen were calculated. Univariate logistic regression analyses were performed for each OAR at the 1, 5, 10, 15, 20, 30, 35, 40, and 50 Gy levels with volume receiving dose ‘x’(VxGy) analyzed as a continuous variable per 10% increase. Clinical tumor volume (CTV) and RT modality (photon vs. proton) as well clinical factors including sex, stage (I/II vs. III/IV), age (per 10 year increase), and BMI (per 5 unit increase) were also analyzed. Results: One hundred forty-four pts were identified for inclusion. Seventy-nine pts received photon RT and 65 proton RT. Chemotherapy was weekly carbotaxol (99%). G4L at nadir was 40% overall (56% photon, 22% proton). By organ, body V1-V30Gy (OR 1.45-8.18, p<0.01), heart V1-V30Gy (OR 1.24-1.49, p<0.01), liver V1-V35Gy (OR 1.23-2.75, p<0.01), lung V1-V30Gy (OR 1.26-5.73 p<0.01), and spleen V1-V40Gy (OR 1.26-1.49 p<0.01) were highly associated with G4L whereas dose to aorta and bone marrow were not. Advanced stage (OR, 3.92 p<0.01), photon vs. proton (OR 4.58 p<0.01), and CTV (per 100 cc’s (OR=1.21, p<0.01)) were also associated with G4L. Sex, age, and BMI were not associated with G4L. Conclusions: Low to intermediate dose volumes to OARs including body, spleen, liver, lungs, and heart were associated with G4L. These findings provide rational for the differences seen in rates of G4L for photon versus proton RT.

131 Background: Trimodality therapy is the standard of care for patients with resectable cancer of the esophagus. However, patients ≥75 years have been underrepresented or excluded from landmark clinical trials to date. We investigated the feasibility and safety of treatment of esophageal cancer with trimodality therapy in patients’ ≥ 75 years. Methods: We performed a retrospective review of all patients ≥75 years who received trimodality therapy for esophageal cancer in 3 high volume tertiary cancer institutions from June 2007 to June 2013. All patients received neoadjuvant radiation with concomitant chemotherapy followed by esophagectomy. Toxicities and clinical outcomes were abstracted from the electronic medical record and partially from a prospectively maintained database. Overall and disease-free survival were estimated using the Kaplan-Meier method. Results: Five hundred seventy patients were treated with trimodality therapy for esophageal cancer from 2007-2013. Of these, 38 patients (7%) were 75 or older at the time of diagnosis. At diagnosis, comorbidities included coronary artery disease (32%), atrial fibrillation (11%) and COPD (13%). The majority of patients (87%) received 50.4Gy/28 fractions. 5-fluorouracil (5-FU)/cisplatin was the most common chemotherapy regimen (37%), followed by 5-FU/docetaxel (24%). A total of 13 patients (34%) developed acute grade ≥3 toxicity associated with neoadjuvant therapy. The most common acute grade 3 toxicities were haematological (10%), nausea (8%), esophagitis (5%) and fatigue (5%). Significant postoperative complications included respiratory (empyema, ARDS, pleural effusion) (39%), arrhythmia (32%), anastomotic leak (5%), and ileus (5%). There were 2 deaths (5%) within 90 days of surgery: one was secondary to empyema, the other developed DIC and sepsis. Median overall survival and disease free survival were 4.4 and 2.3 years respectively. Conclusions: Trimodality treatment is a reasonable approach for management of carefully selected elderly patients with esophageal cancer, with similar rates of cancer outcomes, and treatment related morbidity and mortality as compared to younger patients.

121 Background: We evaluated the role of pre-treatment pulmonary function testing (PFT) in predicting the likelihood of cardiac and/or pulmonary toxicity for esophagus cancer patients receiving trimodality therapy. Methods: From 2007 to 2013, 64 patients with esophageal cancer received trimodality therapy at a single tertiary center with pre-treatment PFTs. The odds ratio of pre-treatment PFT as a predictor of cardiopulmonary toxicity was assess with univariate analysis (UVA). FEV1 (forced expiratory volume in 1 second) and DLCO (diffusion capacity for carbon monoxide) were assessed per 0.5-unit decrease. Percent FEV1 and DLCO predicted were assessed per 10% decrease. Results: The median age was 62 years (range, 41-79) with 88% male patients. A total of 70% of patients had adenocarcinoma with 66% having stage 3 disease. Most patients were former (43%) or current smokers (32%) and 18% had COPD. One or more cardiac comorbidities were observed in 54% of patients. The median RT dose was 50 Gy and the most frequent concurrent chemotherapy was cisplatin/5FU (53%). The median pre-treatment FEV1 and DLCO was 2.8 liters (range, 1-4.9) and 22.5 mL/min/mmHg (range, 17.2-25.5), respectively. This correlated to a median percent predicted value for FEV1 and DLCO of 85% (range, 30-124%) and 81.5% (range, 49-119%), respectively. The overall rate of any cardiac and pulmonary toxicity was 35% and 50%, respectively. Percent predicted value of both FEV1 and DLCO was statistically associated with pulmonary but not cardiac toxicity (Table). Conclusions: Patients with compromised pre-treatment pulmonary function are at higher risk of developing post-treatment pulmonary toxicities. Pulmonary function testing should be routinely performed prior to initiation of trimodality therapy for patient risk stratification. [Table: see text]

BACKGROUND Few reports describe squamous cell carcinoma (SCC) arising in hidradenitis suppurativa (HS). OBJECTIVE The 2 objectives were (1) to describe the clinical characteristics, pathologic findings, and postoperative outcomes of SCC in HS and (2) to assess whether human papillomavirus (HPV) is involved in the pathogenesis. MATERIALS AND METHODS Cases of SCC in HS were identified through institutional medical records (1976–2013) and the Rochester Epidemiology Project. Tumor specimens were assessed for HPV DNA/RNA with in situ hybridization. RESULTS Twelve patients were identified (11 Caucasians and 9 men). All SCCs involved gluteal, perianal, or perineal skin; 1 patient had, in addition, involvement of the vagina. Surgical excision was performed on all 12 patients, 4 of whom had a colostomy. Mean duration of HS before SCC development was 28.5 years (range, 15–53 years). Mean follow-up was 4.3 years after surgical excision. Seven of 12 patients followed had postoperative SCC recurrence. Squamous cell carcinoma caused death despite wide surgical excision in these 7 patients. Of the remaining 5 patients, 4 are unknown and 1 who did not recur had an in situ SCC (Bowen disease carcinoma). Squamous cell carcinoma was not associated with high-risk or low-risk HPV. CONCLUSION Invasive SCC arising in HS carries a high risk of death.

864 Background: Definitive chemoradiotherapy (CRT) is the standard of care for localized or locally advanced ACSCC, while surgery is typically reserved for salvage therapy. Outcome of treatment with local excision alone is unknown and is currently not recommended by NCCN. We retrospectively analyzed outcome of the patients with small (T1 lesion) incidentally found ACSCC who were treated with local excision alone. Methods: On retrospective analysis, a cohort of 12 patients with pathologically confirmed stage I ACSCC treated at Mayo Clinic between 1994 and 2014 was identified who were managed with local excision alone. Baseline as well as followup data were obtained by electronic chart review. Results: Median age of the patients at diagnosis was 68 years (range: 36-81 years) and majority were females (76.9%). Median follow-up duration was 7.5 years. Of the 12 patients, 2 patients did not receive standard CRT due to co-morbid conditions and other 10 patients chose surveillance over CRT. There was only one patient with disease recurrence at 3 years which was salvaged by abdominoperineal resection (APR). This subject remains alive and disease free at the time of data collection (4 years out from APR). There were 4 deaths, all unrelated to ACSCC. Of 12 patients, 10 patients (83%) remained disease free at 5 years and beyond, 1 patient had recurrence and 1 patient was lost to follow up at 5 months from diagnosis. Conclusions: Local excision as a single modality of treatment may be safe and effective for highly selected small stage I ACSCC. Further clinical study is warranted to accurately define the patient population who can be treated with local excision alone, potentially sparing them long term toxicities.

AbstractAimShort‐term morbidity and long‐term functional outcome of patients with an ileal pouch‐anal anastomosis (IPAA) exposed to pelvic external beam radiation therapy (EBRT) remains unknown. We report the largest series to date regarding the effects of pelvic EBRT on: (i) 30‐day postoperative outcomes; and (ii) long‐term functional outcome following IPAA.MethodA retrospective chart review was conducted of patients who received EBRT before or after IPAA between 1980 and 2017 across three international inflammatory bowel disease referral centres.ResultsNineteen patients were included. Indications for EBRT were rectal adenocarcinoma (n = 13), prostate adenocarcinoma (n = 4) or anal squamous cell carcinoma (ASCC) (n = 2). EBRT was given prior to IPAA in 12 (63%) patients and after IPAA in seven (37%). In EBRT before IPAA, patients had a median of 5 (range: 4–8) daytime bowel movements, 1 (range: 0–5) night‐time bowel movement, no daytime incontinence, and only one patient used pads at a median follow up of 25 (range: 11–163) months; one patient underwent pouch excision 15 months after IPAA. In EBRT after IPAA, patients reported a median of 8 (range: 5–10) daytime and 2 (range: 0–5) night‐time bowel movements, 80% had either daytime or night‐time incontinence and 80% used pads at a median follow up of 90 (range: 25–315) months.ConclusionPelvic EBRT administered prior to IPAA is associated with acceptable long‐term function outcome. However, when pelvic EBRT is given to an IPAA in situ, most patients experience poor long‐term pouch function without pouch failure.

3556 Background: To define and update survival rates and relapse patterns in patients (pts) with isolated advanced abdominal nodal metastasis secondary to colorectal cancer (CRC), treated with curative intent using aggressive trimodality therapy. Methods: Fifty-seven pts with isolated advanced abdominal lymph node metastasis (retroperitoneal and mesenteric) secondary to colorectal cancer received trimodality therapy defined as chemotherapy delivered in conjunction with external beam radiotherapy (EBRT) followed by lymphadenectomy and intraoperative radiotherapy (IORT). Infusional 5-FU was the most common radiosensitizer used (66%, 38 pts). The median dose of EBRT was 50 Gy & the median dose of intraoperative radiotherapy was 12.5 Gy. End points included distant metastasis, toxicities, local failure within EBRT field, recurrence within the intraoperative radiotherapy field, and survival. Results: 49% of pts were male, median age 50.5 yrs. All patients had ECOG ≤ 1. 27 pts had primary right sided colon cancer, 16 left sided colon cancer and 14 rectal primaries. Median time from initial CRC diagnosis to development of abdominal lymph node metastatic disease was 24 months (95% CI, 23.5-45.1 months). 84% (48 pts) had paraaortic nodal metastases, 12% (7 pts) had mesenteric nodal metastases, and 3% (2 pts) had both. With a median follow up of 89.4 months, the median overall survival and 5-year estimated survival rate were 53.2 months (95% CI, 46.4-78.8 months) and 42%, respectively. Median progression free survival was 19.3 months (95% CI, 15.6-32.8 months). 21 (37%) pts never developed distant disease. Outcome was not affected by disease sidedness, rectal primary, or mutational profile. Treatment was well tolerated without any grade 3/4 toxicities. Conclusions: The use of trimodality therapy including EBRT with radiosensitizing chemotherapy, lymphadenectomy and IORT produces sustainable long-term survival in selected metastatic CRC pts presenting with isolated retroperitoneal/mesenteric nodal relapse.