Unfortunately, this is a big problem in my area because of a shortage of radiologists. What he wrote would suggest that you are right to push to get the problem resolved quickly.
The citation is Dodwell and Crellin, Waiting for radiotherapy,
BMJ. 2006; 332: 107-109
I couldn't get into the article, since it first comes into the public domain in 2009, but somebody has quoted the relevant bit of it on his personal website:
http://www.thewelfarestatewerein.com...n_some_new.php
"The management of early breast cancer makes a colossal demand on radiotherapy services, and many studies have addressed the impact of delayed adjuvant radiotherapy in early breast cancer. A systematic review of 21 of these studies showed that local recurrence was increased by 60% if the interval between surgery and radiotherapy exceeded eight weeks. In a large epidemiological study involving 7800 patients treated with breast conserving surgery and postoperative radiotherapy, a surgery-radiotherapy delay of 20 weeks or more was associated with significantly increased mortality. These studies strongly suggest that delayed radiotherapy is harmful, and it would be specious to rely on the methodological shortcomings of these types of analyses to assert that delayed radiotherapy is safe. "
The 60% increase was mentioned other places as well, so I think that the quote is probably genuine.