Around 50 years back, sarcoma was synonymous with amputation (cutting the limb), but with the improvements in chemotherapeutic regimes, surgical techniques and imaging modalities, limb salvage surgeries have become the standard of care for patients of sarcoma. Limb salvage surgery (LSS) technically means removing the tumour enbloc (in one piece) with a cuff of normal tissue while preserving the limb along with its function. Although there are more than 60 subtypes of sarcomas, they can broadly be grouped into two categories- Sarcoma of the bone and sarcoma of soft tissues (muscle, nerve, fat, blood vessels etc).
In LSS for bone sarcomas, part of the bone involved with sarcoma is removed surgically (rather than cutting the whole limb) and the defect is reconstructed with artificial implant (megaprosthesis), thereby saving the limb. Since, most of bone sarcomas occur in children who have yet not achieved their full height, removal of cancerous bone also removes (in majority of cases) the growth plate (part of bone which grows with age to give length to the bone). Reconstructing such bone defects in growing children with conventional megaprosthesis gives additional problem of unequal limb lengths at skeletal maturity. To circumvent this problem, nowadays it is possible to reconstruct the defect with an expandable implant which can be made to grow as the child grows.
Not only that, in some cases we can even avoid putting artificial metal prosthesis. In those cases, the cancerous bone so removed is given very high dose of radiation so as to kill all the cancer cells and the sterilised bone so formed is fixed back to the parent bone with the help of plates and screws, a technique commonly called as Extra Corporeal Radiation Therapy (ECRT).
LSS for soft tissue sarcoma involves removing the tumour with healthy tissue all around. This is possible since the sarcomas usually push the important neurovascular structures rather than invading them. LSS for soft tissue sarcomas usually require radiation in addition to surgery. Radiation can be given before surgery (Pre Op RT) or after surgery (Post Op RT), each having it’s own advantages and disadvantages. Nowadays, radiation therapy can also be administered by a technique called as Brachytherapy in which catheters are placed in tumour bed after tumour excision and radiation is given through these catheters. Brachytherapy not only has the advantage of lesser dose being given to surrounding normal tissues and hence lesser side effects but also this process is finished in 7 days compared to 5 weeks for pre op RT and 6-7 weeks for post op RT.
Limb salvage surgery has its own challenges. Sometimes, the sarcoma tends to involve the major blood vessel in which blood vessel needs to be removed along with tumour and is reconstructed. A previous unplanned biopsy or inappropriate surgery can increase the complexity of LSS, it may lead to change in reconstruction plan along with the need for microvascular surgery in form of flaps for wound cover and so on thereby increasing the costs and complications and may even compromise final functional outcome.
This article is written by:
Dr Rajat Gupta
Bone Cancer Clinic
# 5, Sector 19