Soft Tissue Sarcoma Flashcards
All of the following are true about soft tissue sarcoma EXCEPT:
A. Most common site is trunk and retroperitoneum.
B. There are more than 11,000 new diagnoses of soft
tissue sarcoma annually in the United States.
C. Most soft tissue sarcoma-specific deaths are due to
uncontrolled pulmonary metastases.
D. The overall 5-year survival rate for all stages of soft
tissue sarcoma approximates 50 to 60%.
Answer: A
Incidence rates are declining for most cancer sites, but they are increasing among both men and women for melanoma of the skin, cancers of the liver and thyroid.
Incidence rates are decreasing for all four major cancer sites except for breast cancer in women.
Which of the following is NOT associated with the development of sarcoma?
A. Radiation exposure
B. Herbicide exposure
C. Chronic lymphedema
D. History of trauma
Answer: D
External radiation therapy is a rare but well-established risk factor for soft tissue sarcoma that may be associated with radiation-induced mutations of the p53 gene.
Exposure to herbicides, such as phenoxyacetic acids and to wood preservatives containing chlorophenols, has been linked to an increased risk of soft tissue sarcoma.
In 1948, Stewart and Treves first described the association between chronic lymphedema after axillary dissection and subsequent lymphangiosarcoma.
Although patients with sarcoma often report a history of trauma, no causal relationship has been established.
More often, a minor injury calls attention to a pre-existing tumor.
Internationale Contre le Cancer (AJCC/UICC) sarcoma staging system?
A. Tumor size
B. Number of mitoses per high-powered microscopic
field
C. Lymph node metastatic status
D. Retroperitoneal sarcoma nomograms
Answer: D
The seventh edition of the American Joint Committee on Cancer (AJCC) staging system for soft tissue sarcomas is based on histologic grade of aggressiveness, tumor size and depth, and the presence of nodal or distant metastases.
Histologic grade is the most important prognostic factor for patients with soft tissue sarcoma.
The features that define grade are cellularity, differentiation (good, moderate, or poor/anaplastic), pleo- morphism, necrosis (absent, <50%, or ≥50%), and number of mitoses per high-power field (<10, 10–19, or ≥20).
(See Schwartz 10th ed., p. 1470.)
All of the following are known molecular pathogenic events in sarcoma EXCEPT
A. Chromosomal translocations
B. Oncogene amplification
C. Complex genomic rearrangements
D. Epigenetic suppression
Answer: D
In general, sarcomas resulting rom identifiable molecular events tend to occur in younger patients with histology suggesting a clear line of differentiation.
The identifiable molecular events include point mutations, translocations causing overexpression of an autocrine grow factor, and oncogenic
fusion transcription actor producing a cellular environment prone to malignant transformation.
In contrast, sarcomas without identifiable genetic changes or expression profile signatures tend to occur in older patients and exhibit pleomorphic cytology and p53 dysfunction.
(See Schwartz 10th ed., pp. 1466–1467.)
For a T2G3N0M0 sarcoma (stage II), treatment typically consists of
A. Surgery alone
B. Surgery and radiotherapy
C. Surgery, radiotherapy, pre-surgical chemotherapy
D. Surgery, radiotherapy, pre-and post surgical chemotherapy
Answer: B
Recommendations for the management of soft tissue masses:
- Soft tissue tumors that are enlarging or greater than 3 cm should be evaluated with radiologic imaging (ultrasonography or computed tomography [CT]), and a tissue diagnosis should be made using core needle biopsy.
- Once a sarcoma diagnosis is established, obtain imaging (magnetic resonance imaging for extremity lesions and CT for other anatomic locations) and evaluate for metastatic disease with chest CT or intermediate- or high-grade (grade 2 or 3) or large (T2) tumors.
- A wide local excision with 1- to 2-cm margins is adequate therapy for low-grade lesions and T1 tumors.
- Radiation therapy plays a critical role in the management of large (T2), intermediate- or high-grade tumors.
- Patients with locally advanced high-grade sarcomas or distant metastases should be evaluated for chemotherapy.
- An aggressive surgical approach should be taken in the treatment of patients with an isolated local recurrence or resectable distant metastases.
(See Schwartz 10th ed., p. 1472.)
Which of the following is true about desmoid tumors?
A. Local recurrence is observed in up to one-third of patients regardless of microscopic margin of resection status.
B. A policy of watchful waiting for desmoids has been validated in prospective clinical trials.
C. Analogous to other nonmetastasizing tumors, chemotherapy has no role in the treatment of desmoid tumors.
D. Due to their propensity or local invasion, radiotherapy, when used, must be given at a dose of 75Gy.
Answer: A
The primary therapy for desmoid tumors has long been considered surgical resection with wide local excision to achieve negative margins.
However, local recurrence occurs in up to one-third of patients independently of the quality of surgical margins.
Moreover, some authors advocate the possibility to observe patients at presentation, limiting surgery to those who progress or fail medical therapies.
Radiation therapy may be effective in patients with unresectable tumors or as adjuvant therapy following surgery for recurrent disease although long-term side effects and the risk of radiation-induced sarcoma should always be considered.
When used, a dose of 50 to 54 Gy is usually recommended.
Systemic treatment is another option, when surgery is not indicated, although usually reserved or patients with tumor-associated symptoms who have not responded to other interventions.
Combinations of methotrexate and vinblastine have been shown to have activity, as have single-agent pegylated liposomal doxorubicin and sorafenib.
(See Schwartz 10th ed., p. 1485.)
