Does local control even matter at the end of the day?

[LightHouse123]

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I am an MS3 who is gearing up for Radiation Oncology. Lately I have been reflecting on what my role will be min the battle against cancer.

My limited understanding is that radiation therapy is primarily for local control of tumor. However, there is the general understanding that even localized, non-metastatic tumor may already have seeding of tumor in distant sites that is too minuscule to be detected via imaging. This makes me feel that the future of cancer management might be more of a systemic approach. Aside from breast cancer, where local tumor control appears to provide good prognosis wrt overall survival, is there a SIGNIFICANT benefit for overall survival with local control of tumors? (There might be the occasional extra year of survival here or there, but is there anything more impressive?)

I am very interested in a good response. My question is an earnest desire to understand my future role as a rad onc. Obviously, I don't have enough understanding of cancer therapy...hence my question above.

Thanks.

 

[Cancerdancer]

Chemotherapy rarely "cures" a cancer patient, with a few notable exceptions. You might notice that we oncologists tend to advocate for surgical removal of a lot of tumors as well...local control. While it is attractive to think we can just give chemo and that will prevent mets and hold local tumor burden at bay, it's not the reality. Learn a bit more about cancer, read some textbooks, see some patients, you have a long way to go.

 

[medgator]

Considering half of what we do is curative, yes.

And the other half is full of situations where the patient has immense clinical benefits from "local" control of their tumor

 

[radonc22]

I am an MS3 who is gearing up for Radiation Oncology. Lately I have been reflecting on what my role will be min the battle against cancer.

My limited understanding is that radiation therapy is primarily for local control of tumor. However, there is the general understanding that even localized, non-metastatic tumor may already have seeding of tumor in distant sites that is too minuscule to be detected via imaging. This makes me feel that the future of cancer management might be more of a systemic approach. Aside from breast cancer, where local tumor control appears to provide good prognosis wrt overall survival, is there a SIGNIFICANT benefit for overall survival with local control of tumors? (There might be the occasional extra year of survival here or there, but is there anything more impressive?)

I am very interested in a good response. My question is an earnest desire to understand my future role as a rad onc. Obviously, I don't have enough understanding of cancer therapy...hence my question above.

Thanks.

Considering that you can only cure patients in 95% of cancers when it's localized, yes local control is paramount. Remember both surgery and radiation are for local control. Chemotherapy for distant metastases is only curable for a handful of rare cancers & lymphomas.

 

[LightHouse123]

Thanks for all the great responses.

So, the theory that there is seeding of tumors at distant sites even if a tumor appears localized is more of a hypothesis than a reality? I was thinking that having chemoradiation in most cases would be a great idea, but I guess the data doesn't support it in most cases.

 

[medgator]

Thanks for all the great responses.

So, the theory that there is seeding of tumors at distant sites even if a tumor appears localized is more of a hypothesis than a reality? I was thinking that having chemoradiation in most cases would be a great idea, but I guess the data doesn't support it in most cases.

It does though. Chemo isn't for distant mets in that situation, it's for sensitization and potentiation of the radiation.

H&N ca has plenty examples of this where distant met rates aren't improved but local control and survival are. This is the whole rationale behind the concepts of induction vs adjuvant chemotherapy after concurrent chemoradiation

 

[dpmd]

I am an MS3 who is gearing up for Radiation Oncology. Lately I have been reflecting on what my role will be min the battle against cancer.

My limited understanding is that radiation therapy is primarily for local control of tumor. However, there is the general understanding that even localized, non-metastatic tumor may already have seeding of tumor in distant sites that is too minuscule to be detected via imaging. This makes me feel that the future of cancer management might be more of a systemic approach. Aside from breast cancer, where local tumor control appears to provide good prognosis wrt overall survival, is there a SIGNIFICANT benefit for overall survival with local control of tumors? (There might be the occasional extra year of survival here or there, but is there anything more impressive?)

I am very interested in a good response. My question is an earnest desire to understand my future role as a rad onc. Obviously, I don't have enough understanding of cancer therapy...hence my question above.

Thanks.

Are you asking if local control attempts will go away and it will all be systemic? I'm going to go with no on this. As far at the SIGNIFICANT benefit, I suppose you will have to ask the family and the patient if that extra year is worth it (or maybe ask the patient how he likes getting to keep his butthole because the neoadjuvant chemo and rads worked so well he got to have a local resection instead of an APR).

 

[bubbachuck]

I think you are asking great questions that are appropriate for your level of training. I don't think anyone knows exactly whether a tumor has undetected distant spread or not, but if you go by survival data, many cancers fair decently well if detected and treated early. So yes, local control definitely matters. The concept of radiation as a mostly palliative treatment is widespread unfortunately, but you will regularly see patients survive many, many years on out in clinics. Every cancer type is its own entity though, and what works for one may not work for another.

 

[Lamount]

I am an MS3 who is gearing up for Radiation Oncology. Lately I have been reflecting on what my role will be min the battle against cancer.

My limited understanding is that radiation therapy is primarily for local control of tumor. However, there is the general understanding that even localized, non-metastatic tumor may already have seeding of tumor in distant sites that is too minuscule to be detected via imaging. This makes me feel that the future of cancer management might be more of a systemic approach. Aside from breast cancer, where local tumor control appears to provide good prognosis wrt overall survival, is there a SIGNIFICANT benefit for overall survival with local control of tumors? (There might be the occasional extra year of survival here or there, but is there anything more impressive?)

I am very interested in a good response. My question is an earnest desire to understand my future role as a rad onc. Obviously, I don't have enough understanding of cancer therapy...hence my question above.

Thanks.

As many of the above posters have alluded to, it is difficult for systemic therapies to achieve enough log kills (kill a enough the the tumor cells) in metastases to completely eradicate them. But as systemic therapies improve, it might be easier to keep metastatic disease from progressing. In this instance, there could be a role for radiation providing "local control" of metastases in the hopes of pursuing a cure. There is ongoing work in the use of stereotactic body irradiation in the treatment of oligometastatic disease (this is referring to patients with a few small-volume metastases). I believe that this field will become more expansive as targeted systemic therapies improve.

 

[ramsesthenice]

I am very interested in a good response. My question is an earnest desire to understand my future role as a rad onc. Obviously, I don't have enough understanding of cancer therapy...hence my question above.

Thanks.

As many people said above, local therapy for localized disease = curative and no chemotherapy will replace what a surgeon or rad onc can do for local control in the near future, likely ever. But let me give you some specific examples where local control matters.

Muscle invasive bladder cancer: you can do surgery or radiation and almost everyone will get chemotherapy. Problem is, despite the chemo half the patients will met out in the next few years no matter what you do. But, 75% of the surviving chemoradiation patients will maintain a functioning bladder. That is huge for quality of life. Imagine either having a stoma which you continuously pee in, or having a "neobladder" of which you have no sensation or control over. Even for the patients that do end up dying in a few years local control (ie, their normal, functioning bladder) can help them maintain a normal quality of life.

Locally advanced rectal cancer: Same principle. With locally advanced rectal cancer a lot of patients will end up having metastatic disease and die of it, even if you give them great chemo. However, chemoradiation can reduce the local recurrence rates. What do you do when someone recurrs locally? A bigger surgery which frequently involves an APR and permanent stoma. It doesn't take much imagination to see how keeping a functioning anus helps a patient feel more like themselves and lead a normal life, even if they eventually die from their cancer. In this instance, improving the local management (ie, pathologic complete response rate at surgery) may also translate to improved overall survival.

Advanced breast cancer: Metastatic breast cancer patients can live a long time. So what happens if you don't do a good job controlling their breast disease? They can develop a painful hole in their chest. It can smell terrible and get infected. Their breast can literally rot off their chest. Radiation may not help these patients live longer but it can certainly make them live better.

So many examples. Hope this helps.

 

[MegaVoltagePhoton]

I am an MS3 who is gearing up for Radiation Oncology. Lately I have been reflecting on what my role will be min the battle against cancer.

My limited understanding is that radiation therapy is primarily for local control of tumor. However, there is the general understanding that even localized, non-metastatic tumor may already have seeding of tumor in distant sites that is too minuscule to be detected via imaging. This makes me feel that the future of cancer management might be more of a systemic approach. Aside from breast cancer, where local tumor control appears to provide good prognosis wrt overall survival, is there a SIGNIFICANT benefit for overall survival with local control of tumors? (There might be the occasional extra year of survival here or there, but is there anything more impressive?)

I am very interested in a good response. My question is an earnest desire to understand my future role as a rad onc. Obviously, I don't have enough understanding of cancer therapy...hence my question above.

Thanks.

Your post highlights why radiation oncology should be addressed more in the preclinical years, and should definitely warrant at least a week rotation. What other specialty do med students get ZERO exposure to? The medicine shelf includes [rudimentary] ophthalmology and derm, and the boards include radiology and pathology.

I encourage you to spend some time in radiation oncology clinic, and hopefully you can glimpse what this specialty has to offer.

 

[thecarbonionangle]

I've seen attendings have absolutely no idea what radiation oncology does. I agree that this has to be started in the pre-clinical years. In my school the oncology portion was completely taught by med oncs. I remember maybe seeing like a line in a slide show mentioning radiation. They spent time in surgery and chemotherapy but never addressed the role of radiation in the treatment of cancer. Most students have no idea what rad onc does. And then comes the annoying perceptions that the field is some 8-2pm do nothing, non-patient treating lazy field which is so pervasive even at the level of medicine and surgery attendings. This can only be changed when people actually learn about the field in the pre-clinical years. I spent TWO mandatory MONTHS in psychiatry as a medical student and yet there isn't a single week of exposure in it during medical school for most?

 

[Palex80]

Both local and systemic control matter.

However it is important to understand that durable local control is crucial for systemic control. A local recurrence is often the seed for systemic progression and local recurrences after adjuvant systemic treatment tend to be quite aggressive (which is kind of logical, since we are talking about cells which outlived whatever adjuvant chemo was given).

 

[LightHouse123]

Thank you all for your enlightening comments.

I thoroughly appreciate the teaching.

Very very much appreciated!

 

[hot sauce]

Great answers and great question. When you consider the potential benefit of local control there are several things to consider. What is the salvage treatment if there is an isolated local recurrence and how effective is that salvage? As mentioned in posts above the consequences of a local failure may be the loss of important organs (think APR, laryngectomy, amputation) and other times the salvage treatment is much more benign. Of course survival matters and people can die of uncontrollable non-metastatic disease or distant disease that was seeded by a local recurrence. In some disease sites local control has been shown to improve survival and others that benefit has not been seen. Finally, what is the cost of improving local control? Radiation toxicity, the toxicity of more radical surgery, etc.

As chemotherapy improves, local control will likely become even more important. If chemotherapy can effectively eliminate the micrometastatic disease burden you mentioned in your original question, it is all the more important that the cancer not recur locally. Conversely, if a patient is doomed to fail distantly and soon die of metastatic disease, the importance of durable local control plummets.

As to what a significant overall survival benefit is, that is a subjective evaluation. Many exciting chemotherapy breakthroughs are approved based on data showing weeks to months of improvement in median survival. And median overall survival is not a great metric when evaluating cure. The fight against cancer is mostly incremental improvements in survival and incremental decreases in toxicity. While a magic bullet for cancer would be wonderful (even if it put me out of a job), we shouldn't dismiss more modest improvements in cancer care.

 

[Haybrant]

local control (radiation and surgical oncology) leads to far more cost savings than any chemotherapy ever will for distant disease (or local disease). Its a shame that students have these contorted views but it reflects the medical community (and insurance communities) at large. We need to take this concept of cost-saving from local control and shove it down the throats of every med onc, surgeon, insurance person, whoever is in the care of cancer.

If people have good analogies or annecdotes that go over well they can share (ie the cost of avastin alone outweighs the entire rad onc medicare budget) please do, would love to have more in the arsenal.