Salvage of the Unplanned Sarcoma Excision

Peter J. Buecker, MD

Louisville Oncology (Norton Healthcare)

Chief of Musculoskeletal Oncology

Introduction

Sarcomas are rare cancers that arise within connective tissues such as bone, muscle, cartilage, nerves and fat. Annually, they represent about 1% of newly diagnosed cancers. Because these tumors are exceedingly rare when compared with visceral cancers (carcinomas), awareness among health care providers and the population at large is limited. This leads to many unfortunate problems for patients with sarcoma. Among the most worrisome of these is the unplanned excision. This occurs when a lesion is felt to be “probably benign” and is removed with inadequate preoperative diagnostic evaluation (i.e. MRI, staging studies and biopsy) and without a well-planned attempt at securing clean margins. Only after removal of the mass is the diagnosis of sarcoma made, and inevitably the resection is incomplete. Care of the sarcoma is ultimately compromised and the risk of tumor recurrence and metastatic spread is potentially increased. Such an error may obviate the possibility of limb-sparing surgery and may even endanger the life of the patient.

Until Proven Otherwise

As a rule, any enlarging mass that is deep to fascia or is of uncertain etiology should be treated as a malignant tumor until proven otherwise. Appropriate management includes obtaining plain X-Rays and gadolinium-enhanced MRI. If malignancy is suspected, then staging with Chest +/- Abd/Pelvis CT, laboratory studies and a biopsy should be obtained. Ideally, the patient should be referred to a musculoskeletal oncologic surgeon before any procedure such as biopsy or excision is performed.

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The main culprit leading to an unplanned excision of a malignant tumor is lack of awareness. Surgeons who do not have experience with sarcomas may simply not consider it in their differential diagnosis for a given lesion. Fortunately, sarcomas are quite rare, and in the grand scheme, this error is made infrequently. However, when a subtotal sarcoma excision does occur accidentally, it is devastating for the patient and may significantly compromise his/her subsequent oncologic care. Physicians, nurses and practice extenders (nurse practitioners and physician’s assistants) must be better educated in an effort to diminish the number of unplanned excisions performed.

Clinical Evaluation and Staging

After an unplanned excision of sarcoma has occurred, the patient is typically referred to a center specializing in the care of sarcoma (occasionally, the patient may need to seek out such a center to prevent any undue delay in appropriate care). At that time, a thorough history and physical examination is performed. It is critical for the clinician to obtain information regarding the mass (i.e. how long it was present, if it was growing), any symptoms it may have caused, and any other symptoms the patient may be experiencing.

A complete physical examination should be performed. Evaluation of the primary site is, of course, critical. Of particular interest is the incision site and notation of any bruising or swelling. These can be clues as to where residual tumor cells may exist. The principle is that anywhere a red blood cell can track, so too can a tumor cell. Any area of ecchymosis (bruising) should be addressed in the treatment plan if cure is to be achieved. Also of great importance is the status of the individual’s lungs and lymph nodes. The vast majority of sarcomas spread to the lungs primarily. Rarely, nodal metastasis may occur. This is more common in epithelioid sarcoma, synovial sarcoma, clear cell sarcoma and rhabdomyosarcoma.

Staging studies are also critical in the evaluation of any person with a diagnosis of sarcoma. MRI with gadolinium contrast is the imaging modality of choice for the primary site (Figure 1). Interpretation of MRI after incomplete excision can be difficult due to post-surgical changes in the surrounding tissues and the fact that often what tumor remains is microscopic and undetectable by currently available imaging techniques. Review of any imaging showing the tumor prior to excision is of tremendous value, but is usually unavailable due to the lack of suspicion of malignancy initially.

Figure 1: A gadolinium contrast-enhanced MRI of a foot showing the surgical bed after unplanned excision of a soft tissue sarcoma. It is often difficult to determine the presence of tumor unless a large portion remains after the initial excision. In this case, preoperative radiation was given prior to re-excision.

The Utility of MRI

Studies on the utility of MRI after incomplete sarcoma resection have been reported [Davies 2004, Kaste 2002]. In these series, the sensitivity of MRI in detecting residual tumor in this setting was found to be 64% and 78% and the specificity 93% and 86% respectively. These authors support the use of MRI as a useful tool for evaluation of these patients, but indicate that MRI should not be used as the sole indication for re-operation.

Another key piece of the staging process is computed tomography (CT or CAT scan) of the lungs (and sometimes of the abdomen and pelvis). The presence of detectable metastasis on these studies may have profound prognostic and treatment implications. Occasionally, special tests such as a PET scan (Positron Emission Tomography) may be ordered. This is used most frequently for sarcomas with unusual patterns of spread (e.g., lymph nodes or visceral organs), particularly epithelioid sarcoma, synovial sarcoma, rhabdomyosarcoma and clear cell sarcoma, for instance.

Normally, biopsy is the final piece of the staging puzzle. In the case of unplanned excision, a tissue diagnosis has been already rendered. The incomplete resection, though crude and suboptimal for the reasons previously discussed, serves, in essence, as an excisional biopsy (normally not done for diagnostic purposes in cases of suspected sarcoma). Since most of these “biopsies” are done in non-tertiary centers (i.e., centers not specializing in sarcoma care), a review of the material by an experienced bone and soft tissue pathologist is necessary. Randall et al (2004) reported that upon re-review of material sent from non-specialty centers, 37% of the histological diagnoses actually changed, and 82% of the reviewed cases had positive margins (incomplete resection). These data reinforce the point that sarcoma care is best rendered in sarcoma specialty centers by professionals with training specific to the management of these rare tumors.

Treatment

Once the staging process is complete, a treatment plan is formulated. Typically this follows detailed discussion by a multidisciplinary team involving a radiation oncologist (radiation therapy), a medical oncologist (chemotherapy), a radiologist (image interpretation), a pathologist (review of diagnostic material) and a musculoskeletal oncologic surgeon.

Local treatment for incomplete sarcoma excision involves re-excision with or without radiation therapy (RT) (Figure 2). Radiation, when given, is used to kill microscopic tumor cells left behind by the initial procedure in order to aid with local control, since surgery in this instance may often be less than exact. The decision whether or not to include systemic chemotherapy depends on many factors, including the tumor type, the initial tumor size, presence of metastatic disease on staging studies, and the histologic grade of the lesion, as well as the overall health of the patient.

Figure 2 A

Figure 2 B

Figure 2 C

Figures 2 A, B, C: This sequence of photographs demonstrates a re-excision procedure: A) All tissue potentially exposed to viable tumor cells at the initial procedure should be removed at the time of re-excision, including the surgical scar; B) Careful preoperative planning is critical to successful tumor bed excision. Obtaining clean surgical margins is essential. In this case, fascia was kept with the specimen as the deep margin, leaving the deeper structures intact: C) The specimen after excision. The orientation has been marked for review by the pathologist.

Another factor that comes into consideration when planning the operative care of any sarcoma patient, particularly after radiation, is management of the surgical wound. Incisions in irradiated beds may have significantly impaired healing potential compared with other types of surgical incisions. Sometimes a transfer of healthy tissue into the area (a flap) with or without a skin graft is necessary for appropriate healing to occur. This may be done at the time of re-excision or after a period of attempted primary wound healing. Dialogue regarding soft tissue management and the potential need for tissue transfer is an important aspect of the preoperative discussion between the patient and his/her surgeon.

Additional Considerations

The rationale for surgical re-excision has been, in part, provided by the finding that 31-59% of re-resection specimens contain viable tumor [Davies 2004, Peiper 2004, Chui 2002, Kaste 2002, Gibbs 1997, Goodlad 1996, Noria 1996, Zornig 1995, Hays 1989, Giuliano 1985]. Since there is no reliable way to know which patients will and which will not have viable tumor at any given time, re-excision has been recommended for virtually everyone presenting with an incompletely excised sarcoma [Noria 1996]. Lower recurrence rates [Wong 2004, Chui 2002, Lin 2002, Gerrand 2001, Gibbs 1997, Zornig 1995, Hays 1989] and even improved overall survival [Lin 2002, Gibbs 1997, Giuliano 1985] have been associated with re-excising incompletely removed sarcomas.

While some authors have shown statistically significant improvements in local control with RT [Alektiar 2000], others have failed to show any difference when revision surgery is performed [Lin 2002, Gibbs 1997]. However, it has been demonstrated that the risk of local recurrence is higher in patients with viable tumor at re-excision [Peiper 2004, Davis 1997] and that a significant tumor burden may remain even after resection [Willeke 2001]. This combined with the fact that tumor cells may exist up to several centimeters from the main mass [White 2005] and the relative unreliability of MRI to determine the presence of viable cells [Davies 2004, Kaste 2002], has led most centers to include RT as an important part of the local control of these tumors. Brachytherapy may be considered in cases considered to be high-risk for local recurrence [Alekhteyar 1996].

Willeke and Sturm (2001) have reported on a novel technology that may help quantify residual tumor burden in these patients in the future, aiding physicians in determining who does and who does not require the previously described interventions. Utilizing the reverse transcriptase polymerase chain reaction (RT-PCR), they were able to perform “minimal residual disease tumor cell detection”. Such molecular approaches may impact significantly the way these patients are managed in the future.

Follow-Up

Once the course of treatment has been completed, a necessary schedule of follow-up begins. Usually, this means visits with various members of the sarcoma care team. Physical examination, imaging (local MRI, chest CT, x-rays) and sometimes other ancillary testing (cardiac testing, laboratory exams, etc.) are performed every 3 months for 2-3 years, every 4-6 months until 5 years after treatment, then annually for at least 5 years after this. Many permutations of the follow up schedule exist, and may be varied for particular individuals. This may predicated on many potential factors, most frequently the type and grade of tumor, and the presence of metastasis. As opposed to certain other types of cancer, there is really no time when “cure” is felt to have been definitively achieved. Sarcoma is a lifelong diagnosis, and should be treated as such.

Sarcoma is a lifelong diagnosis, and should be treated as such.

Having said this, most recurrences or metastases will be discovered within the first two to five years of the diagnosis and treatment. The longer a given person can go without evidence of systemic disease, the less likely it is that such disease will be detected. Still, late recurrences and metastases do occur, and therefore some type of follow-up is usually recommended for the rest of the patient’s life.

As with many entities in medicine, prevention of unplanned excision is the best method of intervention. Unfortunately, they continue to occur on a regular basis. The problem usually is a lack of consideration of sarcoma in the initial differential diagnosis of a given mass. Only through improved awareness of these rare tumors among health care providers and the population-at-large, will the frequency of unplanned sarcoma resections diminish.

References

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