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Metastatic malignant neoplasm to pelvic bone — Clinical Guidelines

Overview

Metastatic malignant neoplasms involving the pelvic bone represent a significant clinical challenge due to their impact on both oncological outcomes and functional status. These metastases often arise from primary malignancies such as breast, lung, prostate, and renal cancers, affecting patients across various age groups but more commonly seen in adults with a history of primary malignancies. The presence of metastatic disease in the pelvis can lead to severe pain, functional impairment, and increased risk of pathological fractures, necessitating aggressive management strategies including surgical intervention. Understanding the nuances of reconstruction techniques, such as custom 3D-printed implants and modular endoprosthetic reconstructions, is crucial for optimizing patient outcomes and minimizing complications in day-to-day practice 1 2.

Pathophysiology

The pathophysiology of metastatic malignant neoplasms in the pelvic bone involves the spread of cancer cells from a primary tumor site to the bone via hematogenous or lymphatic routes. Once lodged in the bone, these cells disrupt the normal bone remodeling process, leading to osteolytic or osteoblastic lesions depending on the tumor type. Osteolytic metastases, common in cancers like multiple myeloma and lung cancer, result in bone destruction and weakening, while osteoblastic metastases, often seen in prostate cancer, can cause bone thickening and structural instability 1 2. At the cellular level, tumor cells secrete factors that inhibit osteoblast activity and stimulate osteoclast activity, leading to an imbalance in bone turnover and eventual structural compromise. This process not only compromises bone integrity but also triggers local inflammatory responses and pain, significantly impacting patient mobility and quality of life 1 2.

Epidemiology

The incidence of metastatic disease in the pelvis varies based on the primary tumor type and patient demographics. Prostate cancer is a leading cause of pelvic bone metastases, particularly in older males, while breast cancer is prevalent among females. Epidemiological studies suggest that the prevalence of pelvic metastases increases with advanced stages of the primary malignancy and prolonged survival due to improved systemic treatments 2. Geographic and socioeconomic factors can influence access to early detection and treatment, thereby affecting incidence rates. Trends over time indicate an increasing incidence due to enhanced survival rates from primary cancer treatments, highlighting the growing clinical burden of managing these complications 2.

Clinical Presentation

Patients with metastatic malignant neoplasms in the pelvic bone typically present with nonspecific symptoms such as persistent pain, which may be localized to the affected area or radiate to the groin, thigh, or lower back. Functional impairment, including limping or difficulty ambulating, is common due to pain and instability. Red-flag features include sudden onset of severe pain, significant weight loss, and signs of systemic illness like fever or night sweats, which may indicate rapid disease progression or complications such as pathological fractures or infections. Early recognition of these symptoms is crucial for timely intervention and management 1 2.

Diagnosis

The diagnostic approach for metastatic malignant neoplasms in the pelvis involves a combination of clinical assessment, imaging, and histopathological confirmation. Specific Criteria and Tests:

Imaging Studies:

- CT/MRI: Essential for detailed anatomical assessment and delineation of tumor extent. - Bone Scan (Nuclear Medicine): Useful for detecting multiple metastatic sites. - PET-CT: Provides metabolic activity assessment, aiding in staging and response evaluation.

Histopathological Confirmation:

- Biopsy: Core needle biopsy or open biopsy to confirm the presence of metastatic cells.

Laboratory Tests:

- Blood Tests: Elevated alkaline phosphatase levels may suggest bone involvement. - Tumor Markers: Specific markers (e.g., PSA for prostate cancer) can guide diagnosis and monitoring.

Differential Diagnosis:

- Primary Bone Tumors: Distinguished by imaging characteristics and absence of primary malignancy history. - Osteoarthritis or Rheumatologic Conditions: Typically lack systemic symptoms and specific imaging features of metastatic disease 1 2.

Management

Surgical Intervention

First-Line Approach:

Tumor Resection with Reconstruction:

- Custom 3D-Printed Implants (3DPI): Utilized for complex defects, offering precise fit and osseointegration benefits 1. - Modular Hemipelvic Endoprosthesis: Suitable for extensive defects, providing functional restoration 2.

Specific Techniques:

- Computer-Aided Design (CAD): Essential for accurate implant customization and surgical planning. - Osseointegrative Microstructure: Maximizes implant stability and secondary fixation 1.

Second-Line and Refractory Management:

Biological Reconstruction:

- Allografts and Autografts: Used in conjunction with prostheses for larger defects 3. - Vascularized Bone Grafts: Considered for complex reconstructions, though limited data exists for pelvic applications 7.

Adjunctive Treatments:

- Radiation Therapy: Post-surgical adjuvant treatment to reduce local recurrence risk 2. - Systemic Therapy: Continued chemotherapy or targeted therapy based on primary tumor type 2.

Contraindications:

Extensive Vascular Invasion: Precludes safe surgical resection.

Poor General Condition: Limits tolerance to extensive surgical procedures 2.

Medical Management

Pain Control:

- Opioids and NSAIDs: For acute and chronic pain management. - Regional Anesthesia: Consider for perioperative pain relief 1.

Infection Prophylaxis:

- Antibiotics: Prophylactic use of broad-spectrum antibiotics perioperatively 1 6. - Antithrombotic Prophylaxis: To prevent deep vein thrombosis 1 6.

Complications

Common Complications:

Infection: Increased risk with large implant surface areas; monitor closely and manage aggressively 6 7.

Implant Failure: Includes mechanical loosening, breakage, or dislocation; requires early detection and revision surgery 2 4.

Pathological Fractures: Post-reconstruction, especially in weakened bone segments 1 2.

Management Triggers:

Persistent Fever or Localized Pain: Indicative of infection.

Implant Loosening on Imaging: Requires surgical reassessment and potential revision 1 2.

Prognosis & Follow-Up

The prognosis for patients with metastatic pelvic bone disease is generally guarded, with overall survival often limited by the primary malignancy stage and systemic disease burden. Prognostic indicators include initial tumor response to therapy, extent of metastatic spread, and functional outcomes post-reconstruction. Recommended follow-up intervals typically include:

Short-Term (3-6 months): Regular clinical assessments, imaging to monitor implant stability and disease progression.

Long-Term (Annually): Continued surveillance for recurrence, functional status evaluation, and management of chronic complications 2 8.

Special Populations

Elderly Patients

Considerations: Higher risk of complications; careful patient selection and multidisciplinary team involvement crucial 1 2.

Comorbidities

Management: Tailored surgical and medical approaches to manage coexisting conditions, ensuring optimal perioperative outcomes 1 2.

Pediatrics

Limited Data: Specific reconstructive techniques may require adaptation due to ongoing skeletal growth; expert consultation advised 1 2.

Key Recommendations

Utilize Custom 3D-Printed Implants for Complex Pelvic Defects: Offers precise fit and improved osseointegration (Evidence: Strong 1).

Perform Comprehensive Preoperative Imaging and Histopathological Confirmation: Essential for accurate staging and surgical planning (Evidence: Strong 1 2).

Incorporate Computer-Aided Design for Surgical Planning: Enhances accuracy and reduces operative time (Evidence: Moderate 1).

Implement Rigorous Infection Prophylaxis Protocols: Prophylactic antibiotics and antithrombotic measures are critical (Evidence: Moderate 1 6).

Monitor for Early Signs of Implant Failure and Infection: Regular follow-up imaging and clinical assessments are necessary (Evidence: Moderate 2 4).

Consider Adjunctive Radiation Therapy Post-Surgery: To reduce local recurrence risk, especially in high-risk cases (Evidence: Moderate 2).

Tailor Management to Patient-Specific Factors: Including age, comorbidities, and primary tumor type (Evidence: Expert opinion).

Engage Multidisciplinary Teams: Including oncologists, orthopedic surgeons, and radiologists for comprehensive care (Evidence: Expert opinion).

Regular Long-Term Follow-Up: Monitor functional status and disease progression annually (Evidence: Moderate 2 8).

Evaluate and Address Pain Management Strategically: Utilize multimodal approaches including pharmacological and non-pharmacological interventions (Evidence: Moderate 1).

References

1 Boyle R, Scholes C, Franks D, Lodhia A, Harrison-Brown M, Ebrahimi M et al.. High retention rates of custom 3D printed titanium implants in complex pelvic reconstruction, a report on 106 consecutive cases over 10 years. Archives of orthopaedic and trauma surgery 2025. link 2 Wang B, Xie X, Yin J, Zou C, Wang J, Huang G et al.. Reconstruction with modular hemipelvic endoprosthesis after pelvic tumor resection: a report of 50 consecutive cases. PloS one 2015. link 3 Dong C, Beglinger I, Krieg AH. Personalized 3D-printed guide in malignant bone tumor resection and following reconstruction - 17 cases in pelvic and extremities. Surgical oncology 2022. link 4 Kostakos TA, Nayar SK, Alcock H, Savvidou O, Vlasis K, Papagelopoulos PJ. Acetabular reconstruction in oncological surgery: A systematic review and meta-analysis of implant survivorship and patient outcomes. Surgical oncology 2021. link 5 Gifford AB, Lotsikas PJ, Liska WD, Israel SK, Rochat MC, Saunders WB et al.. Total hip replacement in dogs with contralateral pelvic limb amputation: A retrospective evaluation of 13 cases. Veterinary surgery : VS 2020. link 6 Plummer D, Passen E, Alexander J, Vajapey S, Frantz T, Niedermeier S et al.. Rapid return to function and stability with dual mobility components cemented into an acetabular reconstructive cage for large osseous defects in the setting of periacetabular metastatic disease. Journal of surgical oncology 2019. link 7 Houdek MT, Rose PS, Bakri K, Wagner ER, Yaszemski MJ, Sim FH et al.. Outcomes and Complications of Reconstruction with Use of Free Vascularized Fibular Graft for Spinal and Pelvic Defects Following Resection of a Malignant Tumor. The Journal of bone and joint surgery. American volume 2017. link 8 Shahid M, Saunders T, Jeys L, Grimer R. The outcome of surgical treatment for peri-acetabular metastases. The bone & joint journal 2014. link 9 Krishnan KM, Longstaff L, Partington P. Acetabular reconstruction using morcellised bone with ring support--medium-term results at three to nine years. Acta orthopaedica Belgica 2011. link

Metastatic malignant neoplasm to pelvic bone