Evaluating Bacterial Response in Sarcoma Management Using Fluorescence Imaging

The investigators have recently developed an innovative optical molecular imaging platform (called PRODIGI) based on high-resolution fluorescence and white-light technologies in a hand-held, real-time, high-resolution, non-invasive format. PRODIGI offers a non-contact means of obtaining instantaneous image-based measurements of diagnostically-relevant biological and molecular information of a wound and surrounding skin tissues for the first time and could have significant impact on improving conventional wound care, management, and guidance of intervention. In preliminary preclinical testing, the investigators have discovered that when wounds are illuminated by violet/blue light, endogenous collagen in the connective tissue matrix emit a characteristic green fluorescent signal, while most pathogenic bacterial species emit a unique red fluorescence signal due to the production of endogenous porphyrins. Therefore, with autofluorescence imaging, no exogenous contrast agents are needed during imaging, making this approach particularly appealing as a diagnostic imaging method for clinical use. In the context of this study, PRODIGI is used to assess wound complications in patients diagnosed with soft tissue sarcoma and treated with pre-operative radiotherapy. Both pre- and postoperative external beam radiotherapy combined with limb salvage surgery have similarly high rates of local control in the management of extremity soft tissue sarcoma. The main acute side effect associated with preoperative radiotherapy is wound healing complications. Wound care overall is a major clinical challenge and presents an enormous burden to health care worldwide. The objective of this clinical study is to determine if PRODIGI coupled with an optical tracking platform has clinical utility in identifying, quantitatively measuring and longitudinally tracking bacterial imbalance on the patient's intact skin surface at the location of the surgical resection site for adult patients with lower limb soft tissue sarcoma treated with preoperative intensity-modulated radiation therapy and limb salvage surgery and, further, to investigate whether this bacterial imbalance is related to radiotherapy dose and wound complications.

Sex

All

Minimum age

18 Years

Inclusion Criteria:

* Histologically-proven soft tissue sarcoma following review by local reference pathologist.
* Deemed appropriate for preoperative radiotherapy and limb salvage surgery following patient assessment by a radiation oncologist and surgical oncologist and after discussion between both specialists.
* Lesion lies distal to the iliac crest and proximal to the ankle.
* Lesion is primary or locally recurrent. Patient may have undergone excisional biopsy with positive margins at a referring hospital and are eligible following discussion among the surgical oncologists and radiation oncologists that IMRT is an acceptable treatment for that case.
* Patient is aged 18 years or older.
* Patient must be available for treatment and follow-up at Mount Sinai Hospital/Princess Margaret Hospital.
* Protocol treatment is to begin within 4 weeks of entry.
* Patients must be capable of giving informed consent, and informed consent must be obtained according to local Research Ethics Board (REB) requirements.

Exclusion Criteria:

* Benign histology.
* Histology generally treated with adjuvant chemotherapy, such as rhabdomyosarcoma, primitive neurectodermal tumor (PNET), soft tissue Ewing's sarcoma or soft tissue osteosarcoma.
* Prior or concurrent malignancy, with the exception of adequately treated basal cell carcinoma of the skin or carcinoma in-situ of the cervix.
* Limb conservation is not appropriate.
* Prior radiotherapy to the local site or chemotherapy.
* Pathological review of total specimen required before the need for irradiation can be assessed.
* Chemotherapy is required as an adjuvant treatment.
* Presence of regional nodal disease or unequivocal distant metastases.
* Other major medical illness deemed to preclude safe administration of protocol treatment or required follow-up.
* Treatment with an investigational drug within 1 month before study enrolment.
* Any contra-indication to routine wound care and/or monitoring.
* Patients with pre-existing skin issues (e.g. melanomas, psoriasis) in areas close to the potential wound(s) that will be studied