Surgical oncology
Surgical oncology refers to the use of surgery in cancer therapy. Surgery is a major modality in cancer, as it can be used for multiple purposes:
- Surgical resection of the entire tumour with curative intent
- Debulking (removing as much as possible of) a tumour with curative or palliative intent
- Easing symptoms caused by the cancer with palliative intent
- Diagnosing cancer by allowing for histology
- Staging cancers
- Prevention, in cases where the risk of cancer is unacceptably high (precancerous polyps, family history of breast or ovarian cancer, BRCA mutation)
- Cosmetic reconstruction after a drastic surgery
Generally, these three are true:
- If a tumour is confined to the mucosal or submucosal layers (T1, T2), curative surgery is an option
- If the tumour is locoregionally advanced (has spread to nearby organs), neoadjuvant treatment may be used to shrink it, hopefully to a point where curative surgery becomes possible
- If distant metastases are detected, there is no chance for cure, so palliative treatment is initiated
There are of course many exceptions to this. For example, in some cases surgery of metastases may be performed, like in liver or lung metastases from colorectal cancer.
Surgery can also be used palliatively as well, called palliative surgery.
Principles of surgical oncology
Debulking or cytoreduction refers to surgically removing as much of a tumour as possible, in cases where the whole tumour cannot be removed. Debulking can be performed palliatively, to increase survival, or with curative intent, by increasing the penetration of adjuvant radiation and/or chemo into the tumour. It is performed in ovarian cc, endometrial cc, etc.
En-bloc resection refers to removing the entire tumour and a continous layer of healthy tissue around together.
Surgical margin is the rim of the tissue removed during surgery. During surgery, the margin of the removed tissue is marked with ink. While the surgeons wait the pathologist will make frozen slides of the removed tissue and examine it histologically. By using the ink as a reference, the pathologist can determine whether the surgery removed all of the tumour or not. If the surgical margin is clear/negative/clean, there are no tumour cells at the margin, so further treatment is usually not needed. If the surgical margin is positive, more surgery or other adjuvant treatment is needed to ensure that no tumour cells remain
Here, the terms R0 – R2 resection are important:
- R0 resection – complete resection of the tumour
- No macroscopic evidence of tumour, with negative margins
- R1 resection – microscopic remnants of tumour remain
- No macroscopic evidence of tumour, but positive margins
- R2 resection – macroscopic remnants of tumour remain