Oncology Self-Study: Genitourinary Cancers and Malignant Melanoma

Feb 26, 2018

Test your knowledge of genitourinary cancers and malignant melanoma with questions from one of ASCO’s self-assessment resources, ASCO University Essentials.

ASCO University Essentials and the Personalized Learning Dashboard (PLD) is a trusted source for ABIM MOC Points. In particular, the PLD is an enhanced self-assessment tool designed to test your knowledge and provide you with customized content recommendations based on your learning style and individual learning gaps. 

Correct answers, rationales, and suggested reading are listed at the bottom of the page.

1. A 62-year-old man was diagnosed with high-risk prostate cancer. Due to confirmed elevation in prostate specific antigen (PSA) levels (8.7 ng/ml), he received urological consultation. Digital rectal examination showed a firm nodule in the right lobe involving less than half of the lobe. He was thus scheduled to undergo prostate biopsy which showed Gleason 4+4 in 2 out of 14 cores (maximum percentage of cancer involvement: 20%) and 3+4 in additional 2 cores (maximum percentage of cancer involvement: 30%). No multi-parametric prostate MRI was performed. An abdominopelvic CT scan done for staging purposes showed a suspicious enlarged lymph node (short axis diameter of 12 mm) in the left external iliac area without any other distant abnormalities. Staging bone scan was negative. After extensive counseling about possible different treatment options, the patient decided to undergo radical prostatectomy.

In this case:

  1. A limited pelvic lymph node dissection including obturator and external iliac lymph nodes (including suspicious lymph nodes) should be performed at the time of radical prostatectomy for staging purposes.
  2. Frozen section of the affected lymph node should be performed in order to tailor the extent of pelvic lymph node dissection at radical prostatectomy.
  3. A PET/CT is recommended to confirm lymph node invasion prior to surgery.
  4. If surgery is planned, an anatomically defined extended pelvic lymph node dissection should be performed at the time of radical prostatectomy.

2. A 34-year-old woman was recently diagnosed with a 0.53-mm–thick melanoma of her right posterior calf. Her tumor had no ulceration, was a Clark level III, and the mitotic count was zero. The patient had blood work performed that E1 included a CBC, chemistry panel, and lactate dehydrogenase, all of which were normal.  

Which of the following is appropriate for this patient?

  1. No imaging studies.                  
  2. Computed tomography (CT) scan of the chest/abdomen/pelvis and magnetic resonance imaging (MRI) of the brain.
  3. Positron emission tomography (PET)/CT scan and MRI of the brain.
  4. Bone scan, CT scan of the chest/abdomen/pelvis, and brain MRI.

Rationales

1: D

Despite advances in imaging techniques including functional approaches, extended pelvic lymph node dissection (ePLND) remains the most accurate staging procedure for the detection of lymph node invasion (LNI) in prostate cancer. Conventional imaging is not indeed sensitive or specific enough to reliably assess lymph node metastases. Higher sensitivity has been reported with PET/CT using choline or PSMA as radiotracers. However, all of them have significant lower performance diagnostics characteristics as compared to ePLND since they may miss micro-metastatic disease, especially in case of untreated prostate. Finally, extended PLND (ePLND; i.e., removal of obturator, external iliac, hypogastric with or without presacral and common iliac nodes) significantly improves the detection of lymph node metastases compared with limited PLND (lPLND; i.e., removal of obturator with or without external iliac nodes), which is associated with poor staging accuracy. Therefore, if surgery is planned for high-risk prostate cancer, this should include ePLND at least for staging purposes in the absence however of strong evidence supporting its role with regards to oncological outcomes.

Suggested Readings

Briganti A, et al. Performance characteristics of computed tomography in detecting lymph node metastases in contemporary patients with prostate cancer treated with extended pelvic lymph node dissection. Eur Urol 2012 Jun;61(6):1132-8.

Budäus L et al. Initial Experience of 68Ga-PSMA PET/CT Imaging in High-risk Prostate Cancer Patients Prior to Radical Prostatectomy. Eur Urol. 2015 Jun 24. pii: S0302-2838(15)00513-8. doi: 10.1016/j.eururo.2015.06.01

Heidenreich A, et al. EAU guidelines on prostate cancer. part 1: screening, diagnosis, and local treatment with curative intent-update 2013. Eur Urol 2014 Jan;65(1):124-37.

Vag T, et al. Preoperative lymph node staging in patients with primary prostate cancer: comparison and correlation of quantitative imaging parameters in diffusion-weighted imaging and 11C-choline PET/CT. Eur Radiol 2014 Aug;24(8):1821-6.

2: A

The staging evaluation of a patient with a low-risk melanoma should include a physical examination with a full-body including a skin exam. Routine blood work and imaging is not routinely recommended. The majority of patients who present with melanoma do not have distant metastatic disease at presentation; therefore, extensive evaluations with CT scans to search for distant metastases have an extremely low yield and, consequently, are not indicated in asymptomatic patients. More extensive staging evaluation with CT scans of the chest/abdomen/pelvis can be considered in patients with high-risk disease (Breslow depth greater than 4mm or node-positive disease) in whom the risk of distant metastatic disease is higher.

Suggested Readings

Coit DG, Thompson JA, Andtbacka R, et al. Melanoma, version 4.2014. J Natl Compr Cancer Netw. 2014;12:621-629. PMID: 24812131. http://www.jnccn.org/content/12/5/621.abstract

National Comprehensive Cancer Network. 2018. Melanoma Guidelines.

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