Double diagnostic deviance: Case report of chest wall liposarcoma mimicking inflammatory myofibroblastic tumor mimicking costochondritis.

Inflammatory myofibroblastic tumor and liposarcoma very rarely present as tumors of the chest wall. Never have both been reported together in the same lesion. We present a case wherein a 72-year-old man with a rapidly progressing lesion initially mistaken for a local infection underwent resection with diagnosis of inflammatory myofibroblastic tumor. He experienced recurrence less than 6 months before radical resection revealed well to dedifferentiated liposarcoma with areas of inflammatory myofibroblastic tumor. He is now doing well with over 4 years of follow-up.

Three-dimensional printed titanium chest wall reconstruction for tumor removal in the sternal region.

Resection of thoracic wall tumors results in significant defects in the chest wall, leading to various complications. In recent years, the use of three-dimensional (3D) printed titanium alloy prostheses in clinical practice has demonstrated enhanced outcomes in chest wall reconstruction surgery. A cohort of seven patients with sternal tumors was identified for this study. Following a helical CT scan, a digital model was generated for the design of the prosthesis. Subsequently, the tumors were then removed together with the affected sternum and ribs. The chest wall was then reconstructed using 3D-printed titanium alloy prosthesis for bone reconstruction, mesh for pleural reconstruction, and flap for soft tissue reconstruction. Patients were monitored for a period of one year post-surgery. In the seven cases examined, the tumors were found in various locations with varying degrees of invasion. Based on the scope of surgical resection and the size of the defect, 3D-printed titanium alloy prosthesis was custom-designed for chest wall reconstruction. Prior to bone reconstruction, pleural reconstruction was achieved with Bard Composix E/X Mesh, while soft tissue repair involved muscle flap and musculocutaneous flap procedures. A one-year follow-up assessment revealed that the utilization of the 3D-printed titanium alloy prosthesis led to secure fixation, favorable histocompatibility, and enhanced lung function. The findings demonstrate that the utilization of 3D printed titanium alloy prostheses represents a significant advancement in the field of chest wall reconstruction and thoracic surgical procedures.

Innovative Approach to Chest Wall Reconstruction Using Autologous Tissue - The Fascia Lata in Pediatric Patients.

Chest wall reconstruction poses significant challenges. One of those challenges is choosing the correct material for reconstruction. There is debate on using prosthetic materials versus autologous tissues and rigid versus nonrigid materials. This article showcases the novel use of fascia lata for chest wall reconstruction in children.

Chest wall resections for non-small cell lung cancer: a literature review.

Background and Objective: The development of early screening for lung cancer has led to improved overall survival in patients with non-small cell lung cancer (NSCLC). However, the management of NSCLC patients with resectable and potentially resectable chest wall invasion (CWI) requires attention. The purpose of this review is to summarize the role of surgery (chest wall resections) in NSCLC patients with CWI. Methods: A literature search and review from three databases (PubMed, Embase, and ScienceDirect) comprised the last 39 years. This review was focused on the treatment of NSCLC patients with CWI, mainly including the preoperative evaluation, principles of treatment and strategic decision-making, surgical complications, and prognostic factors. Key Content and Findings: Through the collection of relevant literature on NSCLC that invades the chest wall, this narrative review describes the actual role in clinical practice and future developments of chest wall resections. Preoperative treatment requires the multidisciplinary team (MDT) team to conduct accurate clinical staging of the patient and pay attention to the patient's lymph node status and rib invasion status. The successful implementation of chest wall resection and possible chest wall reconstruction requires refined individualized treatment based on the patient's clinical characteristics, supplemented by possible postoperative systemic treatment. Conclusions: Surgery plays an important role in treating NSCLC patients with CWI, and a collaborative, experienced MDT is an essential component of the successful treatment of CWI with lung cancer. In the future, more high-quality clinical research is needed to focus on CWI patients so that patients can receive more effective treatment options and better clinical prognosis.

Complex chest wall reconstruction after failure: a literature review.

Background and Objective: Primary and secondary chest wall tumors (bone, breast, and soft tissue), congenital defects, and chest wall osteoradionecrosis often require extensive full-thickness local excisions to guarantee safe oncological margins (in cases of tumors) and complex reconstruction to provide stabilization and good biomechanical results avoiding postoperative respiratory failure. Thus, a personalized approach is required when dealing with chest wall defects, and reconstruction is planned. This review summarizes failed chest wall reconstruction procedures, identifies causes of failure, and highlights principles for complex chest wall reconstruction post-failure. Methods: We performed a narrative review of the literature on PubMed, Scopus, ScienceDirect, and Google Scholar, including all the relevant studies published from 1970. Key Content and Findings: The available experiences in literature are only anecdotic and no current guidelines or rules exist on this topic, also given to its rarity. Proper pre-surgical planning and a multidisciplinary team (MDT) discussion are crucial for complex cases such as infections and radiation-induced chest ulcers after previous surgical treatment. Procedures should eventually include thoracic wall debridement, necrotic tissue excision, pulse-jet lavage, prosthesis removal, and vacuum assisted closure (VAC) therapy as a bridge for chest wall re-reconstruction. Sternotomy wounds require wire and prosthesis removal, and the use of meshes or bone allografts. This review aims to summarize experiences and highlight surgical and oncologic principles for complex chest wall reconstruction after failure. Conclusions: This review summarizes literature experiences to identify common key points for chest wall reconstruction after failure and to give some advice to surgeons managing this rare, challenging surgery.

Thoracic cavity remodeling and pulmonary function change after chest wall resection.

Background: Chest wall resection (CWR) is an essential procedure for treating malignancies and infectious conditions of the chest wall. However, there are few studies on the pulmonary function and changes in thoracic cavity volume (TCV) related to CWR. This study aims to investigate the effects of CWR on long-term changes in TCV and pulmonary function. Methods: Data of patients who underwent CWR between 2001 and 2021 were retrospectively reviewed. Patients who underwent single rib or lung resection rather than wedge resection were excluded. TCV (liter) was defined as the sum of the right and left TCVs (RCV and LCV) and was measured using computed tomography image reconstruction software. Changes in pulmonary function and TCV 1 year postoperatively were analyzed. Results: A total of 45 patients were included. The number of resected ribs was 2 in 16 (35.6%) and ≥3 in 29 (64.4%) patients. Thirty patients underwent reconstruction. Long-term post-CWR decreased in forced vital capacity (FVC) (-7.9%, P=0.004) and forced expiratory volume in 1 second (FEV1) (-7.0%, P=0.002) were significant. There was no significant decrease in FEV1/FVC ratio (-3.0%, P=0.06), diffusing capacity of the lung for carbon monoxide (DLCO) (-5.9%, P=0.18) and TCV (-3.1%, P=0.10). There was no correlation between changes in TCV and decreases in FVC (r=0.12, P=0.56) or FEV1 (r=0.15, P=0.45). After right-side CWR (n=27), RCV (-7.8%, P=0.01) decreased significantly, whereas LCV (+2.1%, P=0.58) did not. The left-side CWR exhibited an identical pattern. (LCV: -8.5%, P=0.004; RCV: +1.3%, P=0.85). In the ≥3 rib-resection group, FVC (-9.5%, P=0.02), FEV1 (-7.9%, P=0.02) and TCV (-6.4%, P=0.04) decreased significantly. No significant changes were noted in the 2 rib-resection group. There were no significant differences in the changes in pulmonary function nor TCV between the reconstruction and no-reconstruction groups. Conclusions: The long-term decrease in pulmonary function after CWR was significant, especially after ≥3-rib resection.

Surgical Outcomes after Full Thickness Chest Wall Resection Followed by Immediate Reconstruction: A 7-Year Observational Study of 42 Cases.

Introduction: Reconstruction of full thickness chest wall defects is challenging and is associated with a considerable risk of complications. Therefore, the aim of this study was to investigate the surgical outcomes and their associations with patient and treatment characteristics following full thickness chest wall reconstruction. Patients and methods: A retrospective observational study was performed by including patients who underwent reconstruction of full thickness chest wall defect at the Erasmus MC between January 2014 and December 2020. The type of reconstruction was categorized into skeletal and soft tissue reconstructions. For skeletal reconstruction, only non-rigid prosthetic materials were used. Patient and surgical characteristics were retrieved and analyzed for associations with postoperative complications. Results: Thirty-two women and 10 men with a mean age of 60 years were included. In 26 patients (61.9%), the reconstruction was performed using prosthetic material and a soft tissue flap, in nine cases (21.4%) only a soft tissue flap was used, and in seven other patients (16.7%) only the prosthetic material was used. Pedicled musculocutaneous latissimus dorsi flaps were used most often (n=17), followed by pectoralis major flaps (n=8) and free flaps (n=8). Twenty-two patients (52.4%) developed at least one postoperative complication. Wounds (21.4%) and pulmonary (19.0%) complications occurred most frequently. Five (11.9%) patients required reoperation. There were no associations between patient and treatment characteristics and the occurrence of major complications. There was no mortality. Conclusions: Reconstruction of full thickness chest wall defects using only non-rigid prosthetic material for skeletal reconstruction appears safe with an acceptable reoperation rate and low mortality, questioning the need for rigid fixation techniques.

Primary Chest Wall Ewing Sarcoma: Treatment and Long-Term Results.

OBJECTIVE: The aim of the study is to evaluate early and long-term results of chest wall primary Ewing's sarcoma patients treated in the time period February 2000-February 2023 by a multidisciplinary approach. METHODS: We retrospectively reviewed the medical records of patients who underwent chest wall resection for a primary tumor. Treatment approach, extent of resection, 30-day mortality, overall survival (OS), local recurrence-free survival (LRFS), and metastasis-free survival (MFS) were analyzed. RESULTS: Overall, n = 15 consecutive patients were treated for chest wall primary Ewing's sarcoma. A median of n = 3 ribs was resected with a median of n = 2 ribs adjacent to the lesion. Resections were extended to the adjacent structures in n = 5 patients (33.3%). In all cases, we performed a prosthetic reconstruction, associated with muscle flap (n = 10, 66.6%) or with rigid titanium bars and muscle flap (n = 6, 40%). A radical resection was accomplished in n = 13 patients (84.6%). The median surgical time was 310 ± 120 min; median hospitalization was 7.8 ± 1.9 days. Post-operative mortality was zero. We recorded n = 4 (30.7%) post-operative complication. The median follow-up (FU) was 26 months. Moreover, 5-year overall and event-free survival were 52% and 48%, respectively. CONCLUSIONS: This case series confirms the benefit of the multidisciplinary approach for Ewing sarcomas in early and long-term results.

Enhanced recovery after chest wall resection and reconstruction: a clinical practice review.

Since the late 1990s, and Henrik Kehlet's hypothesis that a reduction of the body's stress response to major surgeries could decrease postoperative morbidity, "Enhanced Recovery After Surgery" (ERAS) care pathways have been streamlined. They are now well accepted and considered standard in many surgical disciplines. Yet, to this day, there is no specific ERAS protocol for chest wall resections (CWRs), the removal of a full-thickness portion of the chest wall, including muscle, bone and possibly skin. This is most unfortunate because these are high-risk surgeries, which carry high morbidity rates. In this review, we propose an overview of the current key elements of the ERAS guidelines for thoracic surgery that might apply to CWRs. A successful ERAS pathway for CWR patients would entail, as is the standard approach, three parts: pre-, peri- and postoperative elements. Preoperative items would include specific information, targeted patient education, involvement of all members of the team, including the plastic surgeons, smoking cessation, dedicated nutrition and carbohydrate loading. Perioperative items would likely be standard for thoracotomy patients, namely carefully selective pre-anesthesia sedative medication only in some rare instances, low-molecular-weight heparin throughout, antibiotic prophylaxis, minimization of postoperative nausea and vomiting, avoidance of fluid overload and of urinary drainage. Postoperative elements would include early mobilization and feeding, swift discontinuation of intravenous fluid supply and chest tube removal as soon as safe. Optimal pain management throughout also appears to be critical to minimize the risk of respiratory complications. Together, all these items are achievable and may hold the key to successful introduction of ERAS pathways to the benefit of CWR patients.

Large Penetrating Wounds to the Chest Managed With Immediate Chest Wall Reconstruction Using Biologic Mesh, Titanium Plates, and Rotational Tissue Flaps.

Large open chest wall wounds can be difficult to manage due to full-thickness tissue loss with underlying rib fractures and exposed lung parenchyma. Historically, the use of synthetic material has been discouraged in the traumatic setting with the concern that it may be associated with an increased risk of infection. We present 4 patients with large open injuries to the thorax-one from blunt and three from penetrating trauma. We describe our initial management followed by prompt surgical repair using biologic mesh, titanium rib spanning plates, and rotational tissue flaps with Z-plasty of the skin for definite closure. All patients did well post-operatively without complications or wound infections. With the appropriate management, we suspect there may be an advantage in performing immediate reconstruction and closure in large open thoracic injuries utilizing biologic mesh and titanium rib spanning plates with a lower risk of infection than previously believed.

Three-dimensional printed pure-titanium implantation for chest wall reconstruction involving the sternum and ribs: a novel approach.

Chest wall reconstruction is challenging due to the complex shape and large defect size. The three-dimensional printing technology enables the fabrication of customized implants, and 3D-printed pure-titanium could provide superior mechanical properties to conventional materials. The aim of this study was to evaluate long-term outcomes of patients undergoing chest wall reconstruction with a 3D-printed pure-titanium implant. Between August 2018 and May 2021, 5 patients underwent surgery due to sternal metastasis (n = 3), postoperative sternal wound infection (n = 1) and deformity (n = 1). The customized implant was designed and constructed based on the size and shape of the chest wall defect measured on computed tomography. All patients demonstrated uneventful recovery without complications during the hospital course. During the median follow-up of 20 months, 1 patient underwent revision surgery due to implant breakage, and 1 removed the implant due to trauma-related chest wall infection. One patient died from cancer progression, while 3 patients are alive without any implant-related complications. Chest wall reconstruction using a 3D-printed pure-titanium implant could be a novel alternative for patients with various conditions affecting the sternum and ribs.

Mind the gap! Interdisciplinary approach to anterior chest wall reconstruction after total sternectomy.

BACKGROUND: There are various reconstructive methods after total sternectomy. Reproducibility is scarce due to overall small patient numbers. Therefore we present a standardized, interdisciplinary approach for thoracic and plastic surgery. METHODS: Four patients underwent interdisciplinary chest wall reconstruction with STRATOS® titanium bars and myocutaneous vastus lateralis muscle free flap in our center. RESULTS: All patients reported chest wall stability after reconstruction. They reported good quality of life, no dyspnea, prolonged pain or impairment in lung function from rigid reconstruction. FEV1/FVC was overall better after surgery. Secondary wound healing was not impaired and there was no implant defect in follow up. CONCLUSIONS: We recommend an interdisciplinary surgical approach in chest wall reconstruction after total sternectomy. The combination of rigid reconstruction with titanium bars and a myocutaneous vastus lateralis muscle free flap renders excellent results in patient satisfaction and is objectifiable via spirometry.

The use of flaps for management of deep sternal wound complications: A systematic review and meta-analysis.

BACKGROUND: Many options are available for reconstruction after deep sternal wound infections. However, these options have not been critically appraised. The aim of this systematic review and meta-analysis was to assess the existing evidence on sternal rewiring versus flap reconstruction and pectoralis major muscle flaps (PMFs) versus greater omental flaps (GOFs). METHODS: A systematic review and meta-analysis was performed. CENTRAL, MEDLINE and EMBASE were searched. Outcomes of interest included mortality, treatment failure and length of hospital stay (LOS). RESULTS: Fourteen studies were included. Nine studies compared flaps to rewiring, reporting on 618 patients. Patients treated with flaps had significantly lower mortality compared with patient treated with rewiring (Risk ratio [RR] 0.42, 95% confidence interval [CI]: 0.23-0.77, P < 0.01). Flap patients had significantly lower treatment failure compared with those who were treated with rewiring (RR 0.22, 95% CI: 0.14-0.37, P < 0.01). No statistically significant differences were observed in LOS between patients treated with flaps compared those treated with rewiring (standard mean difference -0.84, 95% CI: -1.91 to 0.24, P = 0.13). Five studies compared PMF with GOF, reporting on 599 patients. No statistically significant differences were found in mortality (RR 0.63, 95% CI: 0.24-1.68, P = 0.36), LOS (standard mean difference -14.52, 95% CI: -42.00 to 12.96, P = 0.30) or treatment failure (RR 1.37, 95% CI: 0.31-6.07, P = 0.68) in patients treated with PMF compared with patients treated with GOF. CONCLUSIONS: Flap-based reconstruction demonstrated improved mortality and treatment outcomes compared to sternal rewiring. However, no significant differences were observed in outcomes between the PMF- and GOF-based reconstructions.

Extended radical resection and chest wall reconstruction for a pulmonary sarcomatoid carcinoma: a case report.

BACKGROUND: Pulmonary sarcomatoid carcinoma (PSC) is a rare and highly malignant type of non-small cell lung cancer (NSCLC), for which the treatment of choice is surgery. For peripheral PSC growing outward and invading the chest wall, a complete resection of the affected lung lobes and the invaded chest wall can improve long-term prognosis. However, when the extent of the resected chest wall is large, reconstruction is often required to reduce the risk of postoperative complications. Here, we present a case of PSC invading the chest wall treated with successful extended radical resection for lung cancer and chest wall reconstruction. CASE PRESENTATION: A 58-year-old male patient with a nodule in the right upper lobe that had been identified on physical examination 2 years before presentation presented to our hospital with a recent cough, expectoration, and chest pain. Imaging revealed a mass in the right upper lobe that had invaded the chest wall. Preoperative puncture pathology revealed poorly differentiated NSCLC. We performed extended radical resection for lung cancer under open surgery and reconstructed the chest wall using stainless steel wire and polypropylene meshes. The procedure was uneventful, and the patient was discharged 7 days postoperatively. Furthermore, the final pathology revealed PSC. CONCLUSIONS: This case underscores the feasibility of surgical R0 resection in patients with PSC with chest wall invasion and no lymph node metastasis, potentially enhancing long-term outcomes. The novel aspect of this case lies in the individualized chest wall reconstruction for a large defect, using cost-effective materials that offered satisfactory structural support and postoperative recovery, thereby providing a valuable reference for similar future surgical interventions.

Reconstruction of massive chest wall defect after malignant chest wall mass excision in resource limited setting, a case report.

INTRODUCTION AND IMPORTANCE: Chest wall tumors, rare but impactful, constitute less than 2 % of the population and 5 % of thoracic neoplasms. Wide-margin resection is vital, often causing substantial defects necessitating reconstruction. However, in resource-limited settings like sub-Saharan Africa, access to reconstruction materials is limited. We present a successful case of managing a massive chest wall defect using flexible wire and polypropylene mesh in such a context. CASE PRESENTATION: A 40-year-old male presented with a gradually enlarging anterolateral chest wall mass, diagnosed as low-grade synovial sarcoma. Imaging revealed involvement of the 6th to 11th ribs with compression of the diaphragm and liver. A multidisciplinary team planned wide-margin excision, chest wall reconstruction, and adjuvant chemoradiation. Using a sternal wire bridge and polypropylene mesh, the 25 cm by 15 cm defect was reconstructed, covered with a latissimus dorsi flap. The patient recovered well postoperatively, highlighting the feasibility of innovative approaches in resource-limited settings. CLINICAL DISCUSSION: Defects larger than 5 cm or involving over 4 ribs require reconstruction to prevent lung herniation and respiratory issues, especially for anteriorolateral defects. Our case featured a 25 by 15 cm anteriorolateral chest wall defect, necessitating rigid reconstruction. Due to resource constraints, we utilized flexible wires and polypropylene mesh, offering a cost-effective solution for managing massive chest wall defects. CONCLUSION: This case underscores the challenges faced in managing chest wall tumors in resource-constrained regions and emphasizes the importance of innovative solutions for achieving successful outcomes in chest wall reconstruction.

The application of three-dimensional custom-made prostheses in chest wall reconstruction after oncologic sternal resection.

BACKGROUND AND OBJECTIVES: As one of the cutting-edge advances in the field of reconstruction, three-dimensional (3D) printing technology has been constantly being attempted to assist in the reconstruction of complicated large chest wall defects. However, there is little literature assessing the treatment outcomes of 3D printed prostheses for chest wall reconstruction. This study aimed to analyze the surgical outcomes of 3D custom-made prostheses for the reconstruction of oncologic sternal defects and to share our experience in the surgical management of these rare and complex cases. METHODS: We summarized the clinical features of the sternal tumor in our center, described the surgical techniques of the application of 3D customized prosthesis for chest wall reconstruction, and analyzed the perioperative characteristics, complications, overall survival (OS), and recurrence-free survival of patients. RESULTS: Thirty-two patients with the sternal tumor who underwent chest wall resection were identified, among which 13 patients used 3D custom-made titanium implants and 13 patients used titanium mesh for sternal reconstruction. 22 cases were malignant, and chondrosarcoma is the most common type. The mean age was 46.9 years, and 53% (17/32) of the patients were male. The average size of tumor was 6.4 cm, and the mean defect area was 76.4 cm2. 97% (31/32) patients received R0 resection. Complications were observed in 29% (9/32) of patients, of which wound infection (22%, 7/32) was the most common. The OS of the patients was 72% at 5 years. CONCLUSION: We demonstrated that with careful preoperative assessment, 3D customized prostheses could be a viable alternative for complex sternal reconstruction.

Vacuum-assisted closure for chest wall reconstruction infection caused by Streptococcus mitis after surgery of lung cancer: a case report.

BACKGROUND: Among a cohort of patients who underwent chest wall resection and reconstruction by rigid prosthesis, 6% required removal of the prosthesis, and in 80% of these cases the indication for prosthesis removal was infection. Although artificial prosthesis removal is the primary approach in such cases of infection, the usefulness of vacuum-assisted closure (VAC) has also been reported. CASE PRESENTATION: A 64-year-old man with diabetes mellitus underwent right middle and lower lobectomy with chest wall (3rd to 5th rib) resection and lymph node dissection because of lung squamous cell carcinoma. The chest wall defect was reconstructed by an expanded polytetrafluoroethylene (PTFE) sheet. Three months after surgery, the patient developed an abscess in the chest wall around the PTFE sheet. We performed debridement and switched to VAC therapy 2 weeks after starting continuous drainage of the abscess in the chest wall. The space around the PTFE sheet gradually decreased, and formation of wound granulation progressed. We performed wound closure 6 weeks after starting VAC therapy, and the patient was discharged 67 days after hospitalization. CONCLUSIONS: We experienced a case of chest wall reconstruction infection after surgery for non-small cell lung cancer that was successfully treated by VAC therapy without removal of the prosthesis. Although removal of an infectious artificial prosthesis can be avoided by application of VAC therapy, perioperative management to prevent surgical site infection is considered essential.

Outcome Analysis of Treatment Modalities for Thoracic Sarcomas.

BACKGROUND: Primary chest wall sarcomas are a rare and heterogeneous group of chest wall tumors that require multimodal oncologic and surgical therapy. The aim of this study was to review our experience regarding the surgical treatment of chest wall sarcomas, evaluating the short- and long-term results. METHODS: In this retrospective single-center study, patients who underwent surgery for soft tissue and bone sarcoma of the chest wall between 1999 and 2018 were included. We analyzed the oncologic and surgical outcomes of chest wall resections and reconstructions, assessing overall and recurrence-free survival and the associated clinical factors. RESULTS: In total, 44 patients underwent chest wall resection for primary chest wall sarcoma, of which 18 (41%) received surgery only, 10 (23%) received additional chemoradiotherapy, 7% (3) received surgery with chemotherapy, and 30% (13) received radiotherapy in addition to surgery. No perioperative mortality occurred. Five-year overall survival was 51.5% (CI 95%: 36.1-73.4%), and median overall survival was 1973 days (CI 95% 1461; -). As determined in the univariate analysis, the presence of metastasis upon admission and tumor grade were significantly associated with shorter survival (p = 0.037 and p < 0.01, respectively). Five-year recurrence-free survival was 71.5% (95% CI 57.6%; 88.7%). Tumor resection margins and metastatic disease upon diagnosis were significantly associated with recurrence-free survival (p < 0.01 and p < 0.01, respectively). CONCLUSION: Surgical therapy is the cornerstone of the treatment of chest wall sarcomas and can be performed safely. Metastasis and high tumor grade have a negative influence on overall survival, while tumor margins and metastasis have a negative influence on local recurrence.

Advanced lung cancer patient benefits from minimally invasive costal resection and reconstruction: an effective palliative approach for costal metastasis.

We hereby describe the resection and reconstruction of a rib infiltrated by a lung cancer metastasis. Despite prior radiation therapy aimed at mitigating pain from rib infiltration in a stage IV non-small cell lung cancer patient, results were unsatisfactory. Employing a minimally invasive palliative strategy, we executed a successful operation to address this issue. This technique presents a viable alternative for patients experiencing recurrent pain post radiation therapy.