Non-metastatic rectal cancer: Special considerations

With rectal cancer rates rising especially in young people, here are some things to consider if you are newly diagnosed with non-metastatic rectal cancer (cancer that hasn’t metastasized to distant organs).

MMR (MisMatch Repair) status of your cancer

If your tumor is MSI-H, immunotherapy is an option and can lead to a cure. This way you may be able to avoid chemotherapy, radiation and surgery. It is critical to find out if your tumor is among the 5-10% that is MSI-H. 

It is important to remember that treatment of early-stage MSI-H rectal cancer with immunotherapy is only an option now as part of clinical trials. So this is one situation where you need this information, as it is actionable — and once you start standard of care treatment for rectal cancer, you will be ineligible for these trials.

The trial from Memorial Sloan Kettering Cancer Center was in the news recently after the almost miraculous results were presented at the annual ASCO meeting in Chicago. The second part of the video below talks about this trial.

Here’s a great video to watch:


Option for non-operative management

About 30% of early-stage rectal cancer patients may show a complete clinical response (cCR) to chemo-RT and chemotherapy, which allows them to opt for non-operative management NOM also called Watch and Wait (W & W), where surgery is deferred to a later time in case there is regrowth.

This means that they will be able to keep their rectum, but would need to undergo intensive surveillance, which includes a sigmoidoscopy, a digital rectal exam and pelvic MRIs every 3 months in the 1st 2 years following treatment. If the tumor regrows, they will be able to have surgery then.

A whole set of informative videos on Rectal Cancer is available in the Lecture Hall in COLONTOWN University and a few of them talk about non-operative management or Watch & Wait (W & W) as well. Here are 2 videos on the subject to watch:

If non-operative management is of interest to you, you would need to be knowledgeable about it, so you can ask your care team about its applicability in your situation. Your sequence of treatment may need to change a bit to increase your chances of a cCR. So knowing what all is involved is important, so you are empowered with information to have meaningful discussions with your care team.

Choice between short course and long course chemo-radiation

Recent studies have shown that short-course radiation therapy (SCRT) is comparable in efficacy and side effect profile with long course chemo-radiation (LCRT). However, SCRT is only 5 days, while LCRT is for 28 days, so patients may find SCRT convenient as it involves fewer days off work. In some cases, SCRT may also be less expensive than LCRT. That said, there may be other factors that indicate that LCRT may be better for you. It is important that you discuss pros & cons of SCRT and LCRT and have your care team explain to you why they have chosen the specific type for you.

Location of the tumor in your rectum

If your tumor is in the upper rectum in certain locations, it may be treated like colon cancer. What this means is that you may have Low Anterior Resection (LAR) surgery first and then may get 3 months of chemotherapy. This way you would be able to avoid chemo-radiation and associated side effects. So it is important to find out if this applies to you.

Extent of lymph node involvement

The most accurate way to identify lymph node involvement is a pathologic examination of the surgically removed tissue. In rectal cancer, a CT scan and pelvic MRI together may help estimate lymph node involvement prior to surgery, but the accuracy of this procedure depends on the experience of the care team. Suspected lymph node involvement may result in slightly different treatment decisions, so it is important that you ask your care team about lymph node involvement, how they estimated it and what that might mean for you. With lymph node involvement, the rectal cancer is called LARC or locally advanced rectal cancer.

Discussion about sexual health and fertility

All early-stage patients getting treated for rectal cancer need to talk to their care team about sexual health and fertility (if they are of childbearing age). Please don’t assume that your care team will bring this up. If these topics are important to you, please initiate a discussion with your team. There are a couple of videos that discuss sexual health in CTU. If you are a woman and getting radiation therapy, make sure to discuss the use of a vaginal dilator to prevent or reduce the chance of vaginal stenosis, which can cause scarring and shortening of the vagina and result in pain during sex. Here’s a video on sexual health after treatment:

Education about quality of life following an ostomy and/or LAR surgery

If due to the location of your tumor, your chances of an ostomy are high, it is important that you ask about resources regarding life with an ostomy. On the other hand, if your chances of an ostomy are low, it’s a good idea to ask about LARS (low anterior resection syndrome) and what can be expected in your specific case. Pelvic floor physical therapy within the 1st year following LAR surgery may help manage changes in bowel habits as a result of surgery, so this is something to ask the care team as well.

TNT and sequence of treatments

TNT or Total Neoadjuvant Therapy is a treatment protocol that is gaining popularity in the US. In TNT, rectal cancer patients get chemo then chemo-radiation or SCRT (the sequence may be reversed where patients get chemo-radiation or SCRT, then chemo) followed by a clinical assessment of treatment response and then surgery to remove the part of the rectum with the tumor. It seems that having chemo-radiation (or SCRT) 1st followed by chemotherapy (also called consolidation chemotherapy) is better if the patient is interested in non-operative management, where the patient may be able to keep the rectum and avoid surgery. This is because more time elapsed from the end of chemo-RT to surgery allows for better treatment responses to RT which continues to work for days/weeks following the end of RT. So it is important that you discuss the sequence of treatment modalities with your care team.

Transanal surgical options

If you have stage I rectal cancer, it may be important to learn about less invasive surgical options to remove your tumor. For example, smaller tumors that fit certain criteria may be safely removed using a transanal approach without having to reach the tumor through the abdominal wall. This allows the rectum to be preserved. Transanal surgery may also be an option in some patients after TNT, where the tumor has shrunk sufficiently that it can be removed using this approach.

ctDNA testing for Minimal Residual Disease (MRD) status

Though a lot of data on MRD testing in rectal cancer isn’t available yet, this is an area that is likely to become important in the coming years. If you are interested in ctDNA testing for surveillance, there is a lot of information available in CTU.

These 2 talks are a must-watch:

Information from these videos can help you be part of shared-decision making about the use of ctDNA testing for surveillance for you after the end of treatment. If you need to use a tumor-informed ctDNA test, you may need to ask about tissue availability before the start of your treatment.

I hope this list is useful to you.