Can classifying your cancer help predict whether it will spread to the lymph nodes?

This study looked at whether classifying a person’s cancer based on how it has started to grow into the local tissue can predict spread to lymph nodes (metastases). 

A common treatment option for patients with T1 colorectal cancer (cancer is beginning to spread into the muscle layer) which has not spread to local lymph nodes is endoscopic resection. This is where a tube is guided up through the anus to remove cancerous lesions. People who have a higher risk of their cancer spreading to their lymph nodes often need surgery to fully remove their cancer.

Without a way of accurately determining which patients are likely to have their cancer spread, unnecessary surgery may be performed.

 This study looked at whether accurately classifying a patients' cancer helped to prevent unnecessary treatments.

This study looked back at surgeries which took place in six different hospitals in Japan. Over 806 patients were included in this study.
The type of tumor found in each patient was examined. Tumors could be Type A (where the tumor is polyp-like in shape and growing out from the body tissue) or Type B (where the tumor grows into the tissue).

14% of patients with type B tumors had their cancer spread to their lymph nodes. In comparison, 4% of type A tumors had spread to the lymph nodes.

15% of patients with tumors that had grown deeper into the tissue had cancer spread to the lymph nodes, compared to 2% of those whose cancer had not grown deeper. Tumors that had grown deeper into the tissue were 5.56 times more likely to have spread to the lymph nodes.

25% of patients with increased budding (where small cancer cells break off into deeper tissue) saw cancer spread to the lymph nodes, comapred to 7% of those with low levels of budding. Patients with budding  were 3.14 times more likely to have cancer spread to the lymph nodes. 

Several factors had no bearing on whether the tumors spread, including age, sex, the location of a tumor and its size.

This study concluded that the depth of cancer invasion into the muscle tissue and budding were powerful predictors of spread to lymph nodes. This may be useful for helping doctors decide whether surgery is required or not.

Further trials are needed to fully understand the usefulness of this classification system.