Adjuvant Radiation Therapy Improves Local Control in the Treatment of Adnexal Carcinoma

PURPOSE/OBJECTIVE(S)

Adnexal carcinoma (AC) is a rare subset of cutaneous malignancies derived from skin adnexa. There are limited data on the role of adjuvant radiation therapy (RT). This study investigates outcomes associated with adjuvant RT at our high-volume referral center.

MATERIALS/METHODS

Using an institutional pathology database we identified 45 patients with locoregionally-confined AC treated between 2001-2020 with curative intent surgery and RT at initial diagnosis or at the time of locoregionally-confined recurrence. Clinicopathologic variables were described and time to relapse events were assessed by the Kaplan-Meier method.

RESULTS

Median age was 64 yrs (IQR 57-71). Primary tumors were in the head and neck (H&N, n = 36, 80%), trunk/extremities (n = 8, 18%) or unknown (n = 1). The most common histologic subtypes were: sebaceous-14 (31%), microcystic adnexal carcinoma-9 (20%), eccrine-6 (13%), and trichilemmal-5 (11%). Twenty-two (50% of known primaries) had PNI. All patients had primary tumor excision. Six had clinically evident lymphadenopathy (13%), all of whom had lymph node dissection (LND). Five patients without evidence of nodal disease (13%) had sentinel lymph node biopsy (SLNB) with one having SLN+ disease. Thirty patients (67%) received adjuvant locoregional RT at initial diagnosis with the following targets: 21 (30%) primary only, 4 (13%) nodal only, and 5 (17%) both. Of those receiving nodal RT, 7 (78%) had LN+ LND with 2 of those receiving concurrent platinum-based chemoradiation. Sixteen were treated at recurrence with the following targets: 4 (25%) primary only (1 having had prior adjuvant nodal RT), 4 (25%) nodal only, and 8 (50%) both. Across the full cohort, median RT dose was 60 Gy in 30 fractions. Median follow-up from initial surgical resection was 60 months (IQR 30-160). 5-year LC, NC, DFS and DSS were 71%, 86%, 66%, and 91% respectively. The only evaluated factor associated with better outcome was adjuvant primary site RT (5-yr LC 83% vs. 56%, p = 0.01 and 5-yr DFS 83% vs. 46%, p = 0.0003). All 15 patients with local recurrence (LR) had salvage surgery with median subsequent follow-up of 75 months (IQR 2-94). Overall, 5 patients receiving adjuvant primary site RT at any time (initial or salvage) developed subsequent local recurrence (13%). Of the 8 patients who developed nodal recurrence (NR) during follow-up, 1 received adjuvant nodal RT at initial diagnosis. Six of 7 who did not receive prior RT then received adjuvant nodal RT after LND and only 1 developed subsequent NR.

CONCLUSION

AC is a rare skin cancer with a primarily locoregional recurrence pattern. In our experience, adjuvant RT was associated with improved LC which, depending on the tumor location, may help prevent morbid or cosmetically-impactful salvage surgery. Patients with AC would benefit from radiation oncology referral to discuss adjuvant treatment.

Evaluating the Utility of Traditional Bowel Dose Constraints when Treating Abdominal and Pelvic Sarcomas with Preoperative Radiation Therapy

PURPOSE/OBJECTIVE(S)

Abdominopelvic soft tissue sarcomas (AP-STS) are selectively treated with preoperative radiation therapy (RT) followed by surgery. Due to their rarity, most bowel dose constraints are extrapolated from dosimetric studies for other abdominal or pelvic malignancies where concurrent chemotherapy is often given in addition to RT. We sought to investigate associations between dosimetric bowel constraints and the risk for developing acute and long-term toxicities in patients who received preoperative RT for AP-STS.

MATERIALS/METHODS

We performed a retrospective review of patients treated at a tertiary cancer center for non-metastatic AP-STS between 2005 and 2020. Dosimetric parameters for the "bowel bag" organ at risk structure were extracted for each patient. Chi-Square or Fisher's Exact Test, where appropriate, was utilized to compare the proportion of patients who exceeded constraints to the bowel bag contour as per the consensus RT retroperitoneal sarcoma guidelines, and the development of acute and long-term toxicities.

RESULTS

We identified 39 patients with available dosimetric data. The median follow-up was 34 months (IQR 20-47). Approximately half of the tumors were located in the pelvis (n = 20, 51%), and the majority were treated with IMRT/VMAT (n = 35, 90%). 31 patients (80%) presented with de novo disease, and 20% (n = 8) were recurrent presentations but had not received prior RT. The most common histology was leiomyosarcoma (n = 15, 38%), followed by de-differentiated liposarcoma (n = 8, 21%). The median bowel max dose (defined as D0.1cc) was 5309cGy [IQR 5262-5830]. Thirteen patients (33%) exceeded the volumetric V15 Gy <830cm3 bowel bag constraint, and 18 (46%) exceeded the V45 Gy ≤ 195cm3 bowel bag constraint. Overall, 17 patients (44%) had acute grade 1 diarrhea, and 11 (28%) had grade 1-2 nausea. Five patients (13%) had long-term radiation-related toxicities, including 1 patient who developed an enterocutaneous fistula. There was no association between exceeding V15 Gy>830 cm3 (p = 0.31) or V45 Gy≥195cm3 (p = 0.65) bowel bag constraints and developing a long-term RT toxicity. Similarly, exceeding V15 Gy>830 cm3 or V45 Gy≥195cm3 did not lead to increased risks of developing acute diarrhea, nausea, or any other acute RT toxicity (all p>0.05).

CONCLUSION

Traditional volumetric bowel bag dose constraints are frequently exceeded given the large size of AP-STS at presentation and thus the large RT target volumes. Despite a significant proportion of patients exceeding these constraints, these data suggest that RT is overall well-tolerated, and the risk of developing toxicities does not correlate with traditional bowel bag volumetric constraints. There are ongoing efforts to substantially expand this cohort for further investigation into the relationship between dosimetric data and bowel toxicities in order to identify more predictive bowel constraints that can be used during treatment planning of AP-STS.

Outcomes for Patients with Head and Neck Sarcoma Treated Curatively with Radiation Therapy and Surgery

PURPOSE/OBJECTIVE(S)

Soft tissue sarcomas (STS) of the head and neck are rare and diverse entities that are challenging to manage. Definitive treatment requires surgery, often with radiation therapy (RT). We sought to describe the outcomes of patients treated curatively with surgery and RT for head and neck STS.

MATERIALS/METHODS

We performed a retrospective review of patients treated at a tertiary cancer center for non-metastatic STS of the head and neck between 1968 and 2020; over half were treated in the modern era defined as 2005 or after. Patients with rhabdomyosarcomas or cutaneous angiosarcoma were excluded. The Kaplan-Meier method was used to estimate actuarial overall survival (OS), disease-specific survival (DSS) and local control (LC). Multivariable analyses (MVA) were conducted using Cox proportional hazards model.

RESULTS

Median follow-up was 82 months. Of the 192 patients, the majority were male (n = 111, 58%), White (n = 158, 82%), and median age was 49.5 [IQR 32.5-64]. The highest proportion of tumors were in the neck (n = 50, 26%), paranasal sinuses (n = 36, 19%), or face (n = 23, 12%). The most common histology was sarcoma, not otherwise specified (n = 44, 23%), followed by undifferentiated pleomorphic sarcoma (n = 32, 17%), and neurogenic sarcoma (n = 15, 8%). Most patients were treated with postoperative RT (n = 134, 70%). Patients treated with preoperative RT were older (median 56.5 yrs vs post-op 44 yrs, p = 0.009). Post-op RT doses were higher (median 60 Gy, pre-op 50 Gy, p<0.001), and margins were more likely to be negative in those treated with pre-op RT (n = 39, 67%, post-op 69, 51%, p = 0.02). 5-year LC, DSS, and OS for the entire cohort was 76% (95% CI 69-82), 74% (67-80), and 71% (64-77), respectively. LC was not affected by treatment sequence (pre-op RT 78% (63-88), post-op RT 75% (66-82), p = 0.48). Patients with negative margins had improved 5-yr LC (86% (77-92), positive/uncertain 65% (53-74), p = 0.003). On MVA, positive/uncertain margin was the only variable associated with LC (HR 2.54 (1.34-4.82), p = 0.004). Poorer 5-yr DSS was associated with higher grade (grade 3 75% (63-84), grade 1-2 89% (75-94), p = 0.02), and treatment era (pre-2005 68% (57-76), on/after 2005 80% (70-87), p = 0.04). These both remained significant on MVA (grade 3 HR 2.39 (1.07-5.36), p = 0.034; pre-2005 HR 2.31 (1.03-5.21), p = 0.043). Sixteen patients (8%) developed a late RT toxicity, including fibrosis (n = 4, 2%), necrosis (osteoradionecrosis n = 2, brain necrosis n = 1, soft tissue necrosis n = 1), and eye dryness (n = 2, 1%). Neither the timing of RT nor dose was found to be associated with developing a late RT toxicity.

CONCLUSION

Head and neck STS continues to have relatively poorer local control than STS of the trunk or extremities. Timing of RT did not impact oncologic or long-term RT-related toxicity outcomes. However, more data are needed to ascertain whether preoperative RT may impact acute surgical toxicities. These data contribute to multidisciplinary care planning for patients with STS in these challenging anatomic locations.

Outcomes after definitive treatment for cutaneous angiosarcomas of the face and scalp: Reevaluating the role of surgery and radiation therapy

INTRODUCTION

We investigated outcomes and prognostic factors for patients treated for cutaneous angiosarcoma (CA).

METHODS

We conducted a retrospective review of patients treated for CA of the face and scalp from 1962 to 2019. All received definitive treatment with surgery, radiation (RT), or a combination (S-XRT). The Kaplan-Meier method was used to estimate outcomes. Multivariable analyses were conducted using the Cox proportional hazards model.

RESULTS

For the 143 patients evaluated median follow-up was 33 months. Five-year LC was 51% and worse in patients with tumors >5 cm, multifocal tumors, those treated pre-2000, and with single modality therapy (SMT). These remained associated with worse LC on multivariable analysis. The 5-year disease-specific survival (DSS) for the cohort was 56%. Tumor size >5 cm, non-scalp primary site, treatment pre-2000, and SMT were associated with worse DSS.

CONCLUSION

Large or multifocal tumors are negative prognostic factors in patients with head and neck CA. S-XRT improved outcomes.

MRI may be used as a prognostic indicator in patients with extra-abdominal desmoid tumours

OBJECTIVE

To determine the association of MRI features of extra-abdominal desmoid tumours (DTs) with prognosis.

METHODS

MRIs for 90 patients with DT were retrospectively reviewed for imaging features associated with biological behaviour. The primary end point was progression (for lesions managed with chemotherapy, radiation therapy and observation) or recurrence (following surgery). Time to event was studied using univariate and multivariable Cox proportional hazards regression models when accounting for demographic, clinicopathological and imaging variables. Kaplan-Meier plots were used to estimate event-free rate (EFR).

RESULTS

Univariate analysis revealed a significant relationship between EFR and treatment, location and compartment of origin [subcutaneous (SC), superficial fascial, intramuscular (IM) and deep fascial/intermuscular]. None of the imaging features commonly associated with biological behaviour of DTs (e.g., shape, enhancement, T2 signal etc.) or surgical margins (in surgical cases) was associated with EFR. Multivariate analysis showed that treatment modality and compartment of origin were independent predictors of EFR. Superficial and deep fascial lesions had a significantly worse EFR as a group [hazard ratio: 3.9; 95% confidence interval (CI): 1.83-8.32; p = 0.0004] than did the SC and IM lesions as a group. 5-year EFR for the fascial lesions was 18% (95% CI: 6-36%), compared with 57% (95% CI: 25-79%) for the SC and IM groups.

CONCLUSION

Intramuscular or SC DTs may be associated with improved prognosis. If validated on multireader and prospective studies, these results can provide for rapid risk stratification at the time of initial MRI.

ADVANCES IN KNOWLEDGE

This work has shown that imaging features commonly associated with biological activity of desmoid tumours (e.g. shape, T2 signal and enhancement) do not appear to be associated with prognosis in patients undergoing a variety of treatment modalities. The compartment of origin of the lesion, which can be determined on pre-operative MRI, was shown to be associated with prognosis and can allow for risk stratification in patients with DTs.